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Interrupt List, part 4 of 14
This compilation is Copyright (c) 1989,1990,1991,1992,1993,1994,1995 Ralf Brown
--------P-17----DX0ABC-----------------------
INT 17 - PRINTER - LPTx v5.x INSTALLATION CHECK
DX = 0ABCh
Return: AX = AAAAh
DX = BAAAh
ES = code segment of resident portion
--------P-17----DX0B90-----------------------
INT 17 - PRINTER - LPTx v6.x INSTALLATION CHECK
DX = 0B90h
Return: DX = ABBBh
ES = code segment of resident portion
--------P-17----DX0B91-----------------------
INT 17 - PRINTER - LPTx v7.x INSTALLATION CHECK
DX = 0B91h
Return: DX = ABCBh
ES = code segment of resident portion
--------P-17----DX0F5F-----------------------
INT 17 - PRINTER - LPTx v4.x INSTALLATION CHECK
DX = 0F5Fh
Return: AX = AAAAh
DX = F555h
ES = code segment of resident portion
--------B-1700-------------------------------
INT 17 - PRINTER - WRITE CHARACTER
AH = 00h
AL = character to write
DX = printer number (00h-02h)
Return: AH = printer status (see #0512)
SeeAlso: AH=02h,AH=84h"AX",AX=6F02h,AH=F1h,INT 16/AX=FFE3h,INT 1A/AH=11h"NEC"

Bitfields for printer status:
Bit(s) Description (Table 0512)
7 not busy
6 acknowledge
5 out of paper
4 selected
3 I/O error
2-1 unused
0 timeout
--------B-1701-------------------------------
INT 17 - PRINTER - INITIALIZE PORT
AH = 01h
DX = printer number (00h-02h)
Return: AH = printer status (see #0512)
Note: some printers report that they are ready immediately after
initialization when they actually are not; a more reliable result may
be obtained by calling AH=02h after a brief delay
SeeAlso: AH=02h,AH=FFh"PC-MOS",INT 1A/AH=10h"NEC"
--------B-1702-------------------------------
INT 17 - PRINTER - GET STATUS
AH = 02h
DX = printer number (00h-02h)
Return: AH = printer status (see #0512)
Note: PRINTFIX from MS-DOS 5.0 hooks this function and always returns AH=90h
SeeAlso: AH=01h,AH=F2h,INT 1A/AH=12h"NEC"
--------P-1702--DX0000-----------------------
INT 17 - INSET - INSTALLATION CHECK
AH = 02h
DX = 0000h
CX = 07C3h (1987d)
Return: CX = 07C2h (1986d) if installed
Program: INSET is a text/graphics integration program
--------b-170200BX5050-----------------------
INT 17 - Advanced Parallel Port (EPP) BIOS - INSTALLATION CHECK
AX = 0200h
BX = 5050h ('PP')
CH = 45h ('E')
DX = printer port number (00h-02h)
Return: AH = status
00h if installed and port is an enhanced parallel port
CX:AL = installed BIOS type
5050h:45h ('PPE') if EPP v3.0+ BIOS installed
4550h:50h ('EPP') if EPP v1.0 BIOS installed
---EPP 1.0---
DX:BX -> far entry point to Advanced BIOS (see #0513)
---EPP Revision 7---
DX = EPP I/O base address
ES:BX -> far entry point to EPP BIOS (see #0513,#0514)
03h if installed but specified port not supported
CF set
Program: The Advanced Parallel Port BIOS provides support for parallel
port peripherals using the enhanced modes of the IEEE 1284.
SeeAlso: AH=E0h

(Table 0513)
Call EPP BIOS entry point with:
DL = port number (v1.0)
DX = EPP port I/O base address (Revision 7)
AH = function
00h Query Configuration
Return: AH = 00h if successful
AL = IRQ number used by port or FFh if no IRQ
BH = EPP BIOS revision (major in high nybble,
minor in low nybble)
BL = I/O capabilities (see #0516)
ES:DI -> ASCIZ driver information/version text
---v1.0,v3.0---
CX = I/O port base address for parallel port
---Revision 7---
CL = EPP chipset code (see #0517)
CH = hardware manufacturer's product code
01h Set Mode
AL = mode bits (see #0518)
Return: AX,BX destroyed
02h Get Mode
Return: AL = mode bits (see also #0518)
bit 7: EPP port interrupts enabled
AH = 00h
CF clear
BX destroyed
03h Interrupt Control
AL = subfunction
00h enable parallel port interrupts
01h disable parallel port interrupts
Return: AH = status (00h,05h,06h) (see also #0515)
04h EPP Reset
Return: AH = 00h if successful
AL destroyed
05h perform Address-Write/Device-Select I/O cycle
AL = device address
Return: AH = status
AL destroyed
06h perform Address-Read I/O cycle
Return: AL = returned address/device data
AH = status
07h write byte
AL = data byte to write
Return: AH = status
08h output block of data
DS:SI -> block of data to be sent to parallel port
CX = number of bytes to output
Return: AH = status (see #0515)
CX = number of unsent bytes
09h read byte of data
Return: AH = status (see #0515)
AL = byte read from parallel port
0Ah read block of data
ES:DI -> buffer for received data
CX = number of bytes to read from paralle port
Return: AH = status (see #0515)
ES:DI buffer filled if successful
CX = number of bytes not transferred
0Bh Address/Byte-Read
AL = device address
Return: AH = status (see #0515)
AL = byte read if successful
0Ch Address/Byte-Write
AL = device address
DH = data byte (v1.0,v3.0)
CL = data byte (Revision 7)
Return: AH = status (see #0515)
0Dh Address/Block-Read
AL = device address
ES:DI -> buffer for received data
CX = number of bytes to read
Return: AH = status (see #0515)
CX = number of bytes NOT transferred
0Eh Address/Block-Write
AL = device address
ES:DI -> data to be sent (v1.0,v3.0)
DS:SI -> data to be send (Revision 7)
CX = number of bytes to write
Return: AH = status (see #0515)
CX = number of bytes NOT transferred
0Fh Lock Port
AL = multiplexor port number
bits 7-4: daisy chain port number (1-8)
bits 3-0: mux device port number (1-8)
Return: AH = status (00h,03h,05h) (see #0515)
10h Unlock Port
AL = multiplexor port number
bits 7-4: daisy chain port number (1-8)
bits 3-0: mux device port number (1-8)
Return: AH = status (00h,03h,05h) (see #0515)
11h Device Interrupt
AL = multiplexor port number
00h if no multiplexor, else mux device port (01h-08h)
CH = subfunction
00h disable device interrupts
01h enable device interrupt
ES:DI -> interrupt event handler
Return: AH = status (00h,03h,05h,06h) (see #0515)
12h Real-Time Mode
AL = subfunction
00h check whether any real-time devices present
01h add (advertise) real-time device
02h remove real-time device
Return: AH = status (00h,05h,06h,07h) (see #0515)
AL = real-time devices present? (00h no, 01h yes)
Note: unlike all other functions, this one does not use DL/DX
Return: AH = status (see #0515)
CF clear if successful
CF set on error
BX destroyed
SeeAlso: #0514

(Table 0514)
Call EPP BIOS (Revision 7) entry point multiplexor functions with:
DX = EPP port base I/O address
AH = function
40h Query Mux
Return: AH = status (see #0515)
AL = currently-selected port
CH = status flags
bit 0: channel locked
bit 1: interrupt pending
BX destroyed
41h Query Device Port
AL = EPP multiplex device port (1-8)
Return: AH = status (see #0515)
CH = status flags (see #0519)
BX = EPP product/device ID (0000h if undefined)
42h Set Product ID
AL = EPP multiplex device port (1-8)
CX = EPP product ID
Return: AH = status (see #0515)
BX destroyed
50h Query Daisy Chain
AL = EPP multiplexor device port (1-8)
Return: AH = status (see #0515)
CH = status flags
bit 0: channel locked
bit 1: interrupt pending
BL = currently-selected device
BH = EPP daisy chain revision (high nybble = major)
CL = daisy-chain depth (00h if no daisy chain)
ES:DI -> ASCIZ driver vendor identification string
51h Rescan Daisy Chain (dynamically reassign port numbers)
AL = EPP multiplexor device port (1-8)
Return: AH = status (see #0515)
BX destroyed
Note: these functions are only valid if a port multiplexor or daisy chain
is present
SeeAlso: #0513,INT 2D/AL=DCh

(Table 0515)
Values for EPP BIOS function status:
00h successful
02h unsupported command/feature
03h unsupported parallel port
05h unsupported in current mode
06h invalid subfunction
07h already ???
40h multiplexor not present
41h multiplexor currently locked
80h I/O timeout
FFh invalid/unsupported function
SeeAlso: #0513,#0514

Bitfields for EPP (Revision 7) I/O capabilities:
Bit(s) Description (Table 0516)
0 multiplexor present
1 PS/2 bi-directional capable
2 daisy chain present
3 ECP capable
4 EPP software emulation supported
5 EPP capable
6 fast Centronics supported
7 standard EPP I/O map
SeeAlso: #0513

(Table 0517)
Values for EPP (Revision 7) chipset code:
00h Intel SL
01h FarPoint Communications
02h SMC
03h Chips&Technologies
04h Western Digital
05h National Semiconductor
SeeAlso: #0513

Bitfields for EPP BIOS mode bits:
Bit(s) Description (Table 0518)
0 set compatibility mode
1 set bi-directional mode
2 set EPP mode
---Revision 7---
3 set ECP mode
4 set EPP software emulation
5 set fast Centronics mode
6-7 reserved (0)
SeeAlso: #0513

Bitfields for EPP BIOS multiplex status flags:
Bit(s) Description (Table 0519)
0 port is selected
1 port is locked
2 interrupts are enabled
3 interrupt pending
SeeAlso: #0514
--------P-1703-------------------------------
INT 17 U - Emulaser ELTSR - INSTALL INTERRUPT HANDLERS
AH = 03h
Return: BX = ???
CX = ???
Program: ELTSR is the resident portion of the Emulaser PostScript emulator by
Vertisoft Systems, Inc.
SeeAlso: AH=04h"Emulaser",AH=0Eh,INT 1A/AH=E5h
--------c-1703-------------------------------
INT 17 - PC-MOS/386 v5.01 - PRINT SPOOLER - PRINT STRING
AH = 03h
DX = printer port number
CX = number of characters to print
DS:SI -> string
Return: AH = printer status (see #0512)
CX = number of characters actually printed
Desc: send an entire string of chars to the print spooler with a single call
Program: PC-MOS/386 v5.01 is a multitasking, multiuser MS-DOS 5.0-compatible
operating system by The Software Link, Inc.
SeeAlso: AH=00h,AH=01h,AH=02h,AH=FFh"PC-MOS"
--------c-1703--BX5A00-----------------------
INT 17 - DMP Print Spooler v2.03 - INSTALLATION CHECK
AH = 03h
BX = 5A00h
Return: AX = 5ACBh
DI = 0000h
ES = DMP code segment (also data segment)
Program: DMP is a Printer driver/spooler, by DMP (USA), available on the
PCTODAY disk, volume 10, March 1991
--------N-170300-----------------------------
INT 17 - DOSISODE to WATTCP TSR Interface - "socket"
AX = 0300h
CX = type of socket from socket( domain, type, protocol )
DX = local identifier of socket (0 - 31)
Return: AX = 0000h success
CX = segment of 4500 byte transfer buffer
DX = offset of 4500 byte transfer buffer
= FFFFH failure
CX = error code
ENFILE 23
Program: DOSISODE is the ISO developers environment which has been ported to
DOS and will run with the Waterloo TCP turned into a resident TSR.
Currently it allows a maximum of 6 open sockets.
Note: this function will initialize the interface the first time it is
called
SeeAlso: AX=0400h"DOSISODE",AX=0600h"DOSISODE",AX=0800h"DOSISODE"
SeeAlso: AX=0A00h"DOSISODE",AX=0C00h"DOSISODE",AX=0E00h"DOSISODE"
--------P-1704-------------------------------
INT 17 U - Emulaser ELTSR - BEGIN CAPTURING OUTPUT
AH = 04h
Note: has no effect unless ELTSR is deactivated (see AX=0503h)
SeeAlso: AH=03h"Emulaser",AX=0503h,INT 1A/AH=E5h
--------N-170400-----------------------------
INT 17 - DOSISODE to WATTCP TSR Interface - "bind"
AX = 0400h
Note: this function just returns
SeeAlso: AX=0300h"DOSISODE",AX=0500h"DOSISODE",AX=0C00h"DOSISODE"
--------P-170500-----------------------------
INT 17 U - Emulaser ELTSR - ???
AX = 0500h
???
Return: AX = unload status (0001h safe to unload, 0002h not safe)
BX = ???
CX = PSP segment of ELTSR
DX = activity flag (0000h disabled, 0001h capturing, 0002h ???printing)
SI = ???
DI = ???
SeeAlso: AH=04h,INT 1A/AH=E5h
--------N-170500-----------------------------
INT 17 - DOSISODE to WATTCP TSR Interface - "connect"
AX = 0500h
SeeAlso: AX=0400h"DOSISODE",AX=0700h"DOSISODE",AX=0C00h"DOSISODE"
--------P-170501-----------------------------
INT 17 U - Emulaser ELTSR - UNHOOK INTERRUPTS
AX = 0501h
Return: (see AX=0500h)
Note: restores interrupt vectors without checking whether they have been
hooked by later programs; should only be called if ELTSR reports
that it is safe to unload
SeeAlso: AH=04h,AX=0500h,AX=0503h,INT 1A/AH=E5h
Index: uninstall;Emulaser ELTSR
--------P-170502-----------------------------
INT 17 U - Emulaser ELTSR - SET ???
AX = 0502h
BL = Emulaser port (31h = LPT1, 32h = LPT2, 33h = LPT3)
CL = ???
DL = ???
Return: (see AX=0500h)
SeeAlso: AH=04h,AX=0500h,INT 1A/AH=E5h
--------P-170503-----------------------------
INT 17 U - Emulaser ELTSR - DEACTIVATE???
AX = 0503h
Return: (see AX=0500h)
SeeAlso: AH=04h,AX=0500h,AX=0501h,INT 1A/AH=E5h
--------P-1706-------------------------------
INT 17 U - Emulaser ELTSR - ???
AH = 06h
???
Return: ???
SeeAlso: AH=05h,INT 1A/AH=E5h
--------N-170600-----------------------------
INT 17 - DOSISODE to WATTCP TSR Interface - "listen"
AX = 0600h
Note: this function just returns
SeeAlso: AX=0300h"DOSISODE",AX=0700h"DOSISODE",AX=0C00h"DOSISODE"
SeeAlso: AX=0E00h"DOSISODE"
--------P-1707-------------------------------
INT 17 U - Emulaser ELTSR - OPEN CAPTURE FILE
AH = 07h
ES:DX -> ASCIZ filename to be opened
Return: ???
Note: new output will be appended to the specified file
SeeAlso: AH=08h,INT 1A/AH=E5h
--------N-170700-----------------------------
INT 17 - DOSISODE to WATTCP TSR Interface - "accept"
AX = 0700h
Note: this function just returns
SeeAlso: AX=0600h"DOSISODE",AX=0800h"DOSISODE",AX=0C00h"DOSISODE"
--------P-1708-------------------------------
INT 17 U - Emulaser ELTSR - CLOSE CAPTURE FILE
AH = 08h
???
Return: ???
Desc: close the file previously opened by function 07h
SeeAlso: AH=07h,INT 1A/AH=E5h
--------N-170800-----------------------------
INT 17 - DOSISODE to WATTCP TSR Interface - "recvfrom"
AX = 0800h
SeeAlso: AX=0500h"DOSISODE",AX=0900h"DOSISODE",AX=0A00h"DOSISODE"
--------P-1709-------------------------------
INT 17 U - Emulaser ELTSR - PRINT CAPTURE FILE???
AH = 09h
BX = ???
CX = ???
DX = printer port (01h COM1, 02h COM2, 05h LPT1, 06h LPT2)
Return: AX = status
00h successful
FFh failed
Program: ELTSR is the resident portion of the Emulaser PostScript emulator by
Vertisoft Systems, Inc.
Note: this function calls through to INT 1A/AX=E401h, and thus requires
that either ELSPL or Disk Spool II be installed
SeeAlso: AH=0Ah,INT 1A/AX=E401h,INT 1A/AH=E5h
--------N-170900-----------------------------
INT 17 - DOSISODE to WATTCP TSR Interface - "sendto"
AX = 0900h
SeeAlso: AX=0700h"DOSISODE",AX=0800h"DOSISODE",AX=0A00h"DOSISODE"
--------P-170A-------------------------------
INT 17 U - Emulaser ELTSR - SET ??? FILENAME
AH = 0Ah
ES:BX -> ??? buffer
CX = length of ??? buffer
Return: ???
Note: copies the specified name into the buffer passed to ELSPL as the
filename by AH=09h
SeeAlso: AH=09h,INT 1A/AH=E5h
--------N-170A00-----------------------------
INT 17 - DOSISODE to WATTCP TSR Interface - "select"
AX = 0A00h
SeeAlso: AX=0800h"DOSISODE",AX=0B00h"DOSISODE",AX=0E00h"DOSISODE"
--------P-170B-------------------------------
INT 17 U - Emulaser ELTSR - GET ???
AH = 0Bh
Return: AX:BX -> ???
SeeAlso: AH=0Ah,INT 1A/AH=E5h
--------N-170B00-----------------------------
INT 17 - DOSISODE to WATTCP TSR Interface - "ioctl"
AX = 0B00h
DX = local identifier of socket (0 - 31)
Note: this function sets the socket into non_block mode
SeeAlso: AX=0A00h"DOSISODE",AX=0C00h"DOSISODE",AX=0E00h"DOSISODE"
--------P-170C-------------------------------
INT 17 U - Emulaser ELTSR - SET ??? FLAG
AH = 0Ch
???
Return: ???
SeeAlso: AH=0Bh,INT 1A/AH=E5h
--------N-170C00-----------------------------
INT 17 - DOSISODE to WATTCP TSR Interface - "close"
AX = 0C00h
SeeAlso: AX=0300h"DOSISODE",AX=0500h"DOSISODE",AX=0D00h"DOSISODE"
--------P-170D-------------------------------
INT 17 U - Emulaser ELTSR - GET TRUE ScrlLk STATE
AH = 0Dh
Return: AX = state (0000h off, 0010h on)
Desc: determine the actual state of ScrlLk even when Emulaser is controlling
the ScrlLk light as its activity indicator
SeeAlso: AH=0Ch,INT 16/AH=02h,INT 1A/AH=E5h
--------N-170D00-----------------------------
INT 17 - DOSISODE to WATTCP TSR Interface - "shutdown" - SHUTDOWN INTERFACE
AX = 0D00h
Note: this function is used to shutdown the interface
SeeAlso: AX=0C00h"DOSISODE",AX=0E00h"DOSISODE"
--------P-170E-------------------------------
INT 17 U - Emulaser ELTSR - BACKGROUND PROCESSING
AH = 0Eh
Program: ELTSR is the resident portion of the Emulaser PostScript emulator by
Vertisoft Systems, Inc.
Note: this function is called by ELTSR on every INT 08 to allow data to be
processed in the background, but may also be called by applications
to give Emulaser additional CPU time
SeeAlso: AH=0Dh,INT 1A/AH=E5h
--------N-170E00-----------------------------
INT 17 - DOSISODE to WATTCP TSR Interface - INSTALLATION CHECK
AX = 0E00h
Return: CX = 1234h if installed
Program: DOSISODE is the ISO developers environment which has been ported to
DOS and will run with the Waterloo TCP turned into a resident TSR.
Currently it allows a maximum of 6 open sockets.
Note: this function is used to check if the interface is loaded
SeeAlso: AX=0300h"DOSISODE",AX=0A00h"DOSISODE"
--------P-172000-----------------------------
INT 17 - PC Paint Plus 2.0 - PRINTER DRIVER - INSTALLATION CHECK
AX = 2000h
BL = printer number???
Return: AX = status (see #0520)
BX = driver version number (BH=major,BL=minor)
CH = ??? (00h)
CL = ???
DX = ??? (0100h)
Note: also enables the remaining printer driver functions (2001h-2007h)
SeeAlso: AX=2001h,AX=2002h,AX=2003h,AX=2004h,AX=2005h,AX=2006h,AX=2007h

(Table 0520)
Values for PC Paint function status:
0000h successful
0001h invalid printer???
0002h ???
0003h invalid subfunction
0005h driver disabled, must call function 00h first
0009h unknown printer error
000Bh printer not selected
000Ch printer out of paper
000Eh error while writing to serial printer
000Fh ???
0010h invalid function number
0011h value out of range
--------P-172001-----------------------------
INT 17 - PC Paint Plus 2.0 - PRINTER DRIVER - SET ??? FLAG
AX = 2001h
BL = printer number???
Return: AX = status (see #0520)
--------P-172002-----------------------------
INT 17 - PC Paint Plus 2.0 - PRINTER DRIVER - GET INFORMATION
AX = 2002h
BL = printer number???
CL = desired information
00h printer type
Return: ES:DI -> ASCIZ printer name
01h paper size
DX = size index
Return: ES:DI -> ASCIZ paper size description
02h ???
Return: BX = ???
03h printer information???
DX = ???
ES:BX -> buffer for ??? (min 134 bytes)
Return: AX = status (see #0520)
SeeAlso: AX=2000h,AX=2004h
--------P-172003-----------------------------
INT 17 - PC Paint Plus 2.0 - PRINTER DRIVER - ???
AX = 2003h
ES:BX -> ???
Return: AX = status (see #0520)
SeeAlso: AX=2000h,AX=2004h
--------P-172004-----------------------------
INT 17 - PC Paint Plus 2.0 - PRINTER DRIVER - GET ???
AX = 2004h
BL = printer number???
Return: AX = status (see #0520)
ES:DI -> ???
SeeAlso: AX=2000h,AX=2003h
--------P-172005-----------------------------
INT 17 - PC Paint Plus 2.0 - PRINTER DRIVER - ADVANCE PRINTER TO NEXT PAGE
AX = 2005h
BL = printer number???
Return: AX = status (see #0520)
Note: this function also clears the flag set by AX=2001h
SeeAlso: AX=2000h,AX=2001h,AX=2006h
--------P-172006-----------------------------
INT 17 - PC Paint Plus 2.0 - PRINTER DRIVER - ADVANCE TO NEXT PAGE & SHUT DOWN
AX = 2006h
BL = printer number???
Return: AX = status (see #0520)
Note: this function also clears the flag set by AX=2001h and disables
functions other than AX=2000h
SeeAlso: AX=2000h,AX=2001h,AX=2005h
--------P-172007-----------------------------
INT 17 - PC Paint Plus 2.0 - PRINTER DRIVER - UNIMPLEMENTED
AX = 2007h
Return: AX unchanged
SeeAlso: AX=2000h
--------N-172400-----------------------------
INT 17 - Shamrock Software NET.24 v3.11+ - ENABLE/DISABLE API FUNCTIONS
AX = 2400h
DL = new state
00h disabled
01h enabled
Return: DL = 24h if installed
DH = minor version number
CX = network address of this machine
AL = status (see #0521)
SeeAlso: AX=2403h,INT 16/AX=4500h

(Table 0521)
Values for NET.24 function status:
00h successful
01h timeout
02h header error
03h data error
04h busy
05h invalid parameters
--------N-172401-----------------------------
INT 17 - Shamrock Software NET.24 v3.11+ - RECEIVE BLOCK, NO HANDSHAKE
AX = 2401h
BL = timeout in clock ticks
Return: AL = status (see #0521)
DX:BX -> receive buffer
SeeAlso: AX=2402h,AX=2404h,AX=2408h
--------N-172402-----------------------------
INT 17 - Shamrock Software NET.24 v3.11+ - TRANSMIT BLOCK, NO HANDSHAKE
AX = 2402h
transmit buffer filled (see AX=2403h)
Return: AL = status (see #0521)
SeeAlso: AX=2401h,AX=2403h,AX=2404h,AX=2409h
--------N-172403-----------------------------
INT 17 - Shamrock Software NET.24 v3.11+ - GET STATUS AND TRANSMISSION BUFFER
AX = 2403h
Return: AL = status (see #0521)
CX = number of characters in receive ring buffer
DX:BX -> transmit buffer
SeeAlso: AX=2400h,AX=2402h
--------N-172404-----------------------------
INT 17 - Shamrock Software NET.24 v3.11+ - SEND ACK BLOCK
AX = 2404h
BX = target address
Return: AL = status (see #0521)
SeeAlso: AX=2402h,AX=2405h
--------N-172405-----------------------------
INT 17 - Shamrock Software NET.24 v3.11+ - SEND NAK BLOCK
AX = 2405h
BX = target address
Return: AL = status (see #0521)
SeeAlso: AX=2402h,AX=2404h
--------N-172406-----------------------------
INT 17 - Shamrock Software NET.24 v3.11+ - PREPARE CHARACTER-ORIENTED RECEIVE
AX = 2406h
Return: AL = status (see #0521)
SeeAlso: AX=2407h,AX=240Ah
--------N-172407-----------------------------
INT 17 - Shamrock Software NET.24 v3.11+ - RECEIVE CHARACTER FROM REMOTE
AX = 2407h
Return: AL = status (see also #0521)
06h end of data
DL = received character
SeeAlso: AX=2406h
--------N-172408-----------------------------
INT 17 - Shamrock Software NET.24 v3.11+ - RECEIVE BLOCK, WITH HANDSHAKE
AX = 2408h
Return: AL = status (see also #0521)
06h end of data
CX = number of bytes in receive buffer
DX:SI -> receive buffer
SeeAlso: AX=2401h,AX=2405h,AX=2409h
--------N-172409-----------------------------
INT 17 - Shamrock Software NET.24 v3.11+ - TRANSMIT COMMAND, WITH HANDSHAKE
AX = 2409h
BX = target address
CX = number of data bytes
DL = command code to send
DS:SI -> data bytes for command
Return: AL = status (see also #0521)
03h no response
06h remote currently unable to perform command
SeeAlso: AX=2405h,AX=2408h
--------N-17240A-----------------------------
INT 17 - Shamrock Software NET.24 v3.11+ - PREPARE CHARACTER-ORIENTED TRANSMIT
AX = 240Ah
Return: AL = status (see #0521)
SeeAlso: AX=2406h,AX=240Bh,AX=240Ch
--------N-17240B-----------------------------
INT 17 - Shamrock Software NET.24 v3.11+ - TRANSMIT SINGLE CHARACTER TO REMOTE
AX = 240Bh
DL = character to send
Return: AL = status (see also AX=2400h)
03h transmission error
06h write error
SeeAlso: AX=2407h,AX=240Ah,AX=240Ch
--------N-17240C-----------------------------
INT 17 - Shamrock Software NET.24 v3.11+ - END CHARACTER-ORIENTED TRANSMIT
AX = 240Ch
Return: AL = status (see also AX=2400h)
03h transmission error
06h remote breaks connection
SeeAlso: AX=240Ah,AX=240Bh
--------J-175000-----------------------------
INT 17 - AX (Japanese AT) PRINTER - SET PRINTER COUNTRY CODE
AX = 5000h
BX = country code
0001h USA (English), 0051h Japan
Return: AL = status
00h successful
01h bad country code
02h other error
SeeAlso: AX=5001h,AH=51h,INT 10/AX=5000h,INT 16/AX=5000h
--------J-175001-----------------------------
INT 17 - AX (Japanese AT) PRINTER - GET PRINTER COUNTRY CODE
AX = 5001h
Return: AL = status
00h successful
BX = country code
02h error
SeeAlso: AX=5000h,AH=51h,INT 10/AX=5001h,INT 16/AX=5001h
--------J-1751-------------------------------
INT 17 - AX (Japanese AT) PRINTER - JIS to Shift-JIS CONVERSION
AH = 51h
DX = 2-byte JIS code
Return: DX = shift-JIS value or 0000h on error
Note: one of AH=51h and AH=52h converts from JIS (Japanese Industry Standard)
characters to Shift-JIS characters, and the other performs the
opposite conversion
SeeAlso: AX=5000h,AH=52h
--------J-1752-------------------------------
INT 17 - AX (Japanese AT) PRINTER - Shift-JIS to JIS CONVERSION
AH = 52h
DX = 2-byte shift-JIS code
Return: DX = JIS code or 0000h on error
Note: one of AH=51h and AH=52h converts from JIS (Japanese Industry Standard)
characters to Shift-JIS characters, and the other performs the
opposite conversion
SeeAlso: AH=51h
--------V-1760-------------------------------
INT 17 - FLASHUP.COM - INSTALLATION CHECK
AH = 60h
Return: AL = 60h
DX = CS of resident code
Notes: FLASHUP.COM is part of Flash-Up Windows by The Software Bottling Co.
FLASHUP also hooks INT 10 and receives commands via INT 10/AH=09h,0Ah
consisting of an 80h followed by the actual command
SeeAlso: INT 10/AH=09h,INT 10/AH=0Ah
--------V-1761-------------------------------
INT 17 - SPEEDSCR.COM - INSTALLATION CHECK
AH = 61h
Return: AL = 61h
DX = CS of resident code
Note: SPEEDSCR.COM is by The Software Bottling Co.
--------P-1762-------------------------------
INT 17 U - T2PS v1.0 - UNINSTALL
AH = 62h
Return: nothing
SeeAlso: AH=63h,AH=64h,INT 05/AX=554Eh
--------P-1763-------------------------------
INT 17 U - T2PS v1.0 - SET PARAMETERS
AH = 63h
ES:SI -> settings (see #0522)
Program: T2PS is a shareware ASCII-to-PostScript converter by A.N.D.
Technologies
SeeAlso: AH=62h,AH=64h,INT 05/AX=4E57h

Format of T2PS settings:
Offset Size Description (Table 0522)
00h WORD LPT port number (0=LPT1, etc.)
02h WORD page heigh in points
04h WORD page width in points
06h WORD top margin in points
08h WORD bottom margin in points
0Ah WORD left margin in points
0Ch WORD right margin in points
0Eh WORD font size in points
10h WORD tab size
12h WORD timeout in clock ticks
--------P-1764-------------------------------
INT 17 U - T2PS v1.0 - GET PARAMETERS
AH = 64h
ES:SI -> buffer for settings (see #0522)
Return: ES:SI buffer filled
SeeAlso: AH=62h,AH=63h,INT 05/AX=5053h
--------b-176F00BX0000-----------------------
INT 17 - HP Vectra - EXTENDED BIOS - "F17_INQUIRE" - INSTALLATION CHECK
AX = 6F00h
BX = 0000h
Return: BX = 4850h ("HP") if HP Extended BIOS printer extensions available
SeeAlso: AX=6F02h,INT 14/AX=6F00h,INT 10/AX=6F00h,INT 14/AX=6F00h
SeeAlso: INT 33/AX=6F00h,INT 6F/AH=00h"HP Vectra"
--------b-176F02-----------------------------
INT 17 - HP Vectra - EXTENDED BIOS - "F17_PUT_BUFFER" - PRINT BUFFER
AX = 6F02h
CX = size of buffer in bytes
DX = port number (0-3)
ES:DI -> buffer containing characters to be printed
Return: AH = printer status (see #0512)
CX = number of bytes successfully printed
---on error (AH bit 0 set)---
ES:DI -> next byte to be sent
---if successful---
ES:DI unchanged
SeeAlso: AH=00h,AX=6F00h,INT 14/AX=6F02h
--------N-1781-------------------------------
INT 17 - Alloy NTNX, MW386 - CANCEL JOBS FOR CURRENT USER
AH = 81h
AL = 00h (NTNX compatibility mode)
CL = number of jobs to cancel
Return: AL = status (see #0523)
Note: this function cancels the last CL printouts for the current task
SeeAlso: AH=82h

(Table 0523)
Values for Alloy status:
00h success
01h-7Fh warning
80h general failure
81h host overloaded (NTNX only)
82h module busy (NTNX only)
83h host busy (NTNX only)
84h re-entry flag set
85h invalid request
86h invalid printer
87h invalid process ID
89h access denied
8Ah option not available for given port type
8Bh option not available for given task type
91h printer busy
C2h file not found
C3h path not found
C4h file access failure
--------N-1782-------------------------------
INT 17 - Alloy NTNX, MW386 - CANCEL ALL JOBS FOR CURRENT USER
AH = 82h
AL = 00h (NTNX compatibility mode)
Return: AL = status (see #0523)
SeeAlso: AH=81h
--------N-1783-------------------------------
INT 17 - Alloy NTNX, MW386 - SET NUMBER OF COPIES
AH = 83h
AL = mode
00h NTNX compatibility
CL = number of copies (max 99, default 1)
02h MW386 v2+
BX = logical device number
00h-03h = LPT1-LPT4
04h-07h = COM1-COM4
CX = number of copies
Return: AL = status (see #0523)
Note: in NTNX compatibility mode, this function only affects LPT1
--------N-1784-------------------------------
INT 17 - Alloy NTNX, MW386 - GENERATE PRINT BREAK
AH = 84h
AL = mode
00h NTNX compatibility
02h MW386 v2+
BX = logical device number
00h-03h = LPT1-LPT4
04h-07h = COM1-COM4
Note: closes spool file and tells spooler to queue the print job (LPT1 only
under MW386 in NTNX compatibility mode)
--------J-1784-------------------------------
INT 17 - AX (Japanese AT) PRINTER - OUTPUT CHARACTER WITHOUT CONVERSION
AH = 84h
AL = character
DX = printer number
Return: AH = printer status (see #0512)
SeeAlso: AH=00h,AH=85h
--------J-1785-------------------------------
INT 17 - AX (Japanese AT) PRINTER - ENABLE/DISABLE CHARACTER CONVERSION
AH = 85h
AL = new state (00h enabled, 01h disabled)
SeeAlso: AH=84h"AX"
--------N-1787-------------------------------
INT 17 - Alloy NTNX - SET INDOS POINTER
AH = 87h
AL = 00h
CX:BX -> buffer for user-written printer drivers
Return: BX,CX destroyed
Note: must be executed before the printer is enabled
SeeAlso: AH=8Ah
--------N-1788-------------------------------
INT 17 - Alloy NTNX, MW386 - REMOVE PRINTER FROM SPOOLER
AH = 88h
AL = mode
00h NTNX compatibility
DX = NTNX printer number (see #0524)
01h MW386
DX = MW386 printer number
Return: AH = status (see #0523)
Note: removes specified printer from the spooler's list of printers
SeeAlso: AH=89h,AH=8Bh

(Table 0524)
Values for Alloy NTNX printer number:
00h host LPT1
01h host LPT2
02h host LPT3
03h host LPT4
04h host COM1
05h host COM2
06h user's logical COM2
07h user's terminal AUX port
08h user's logical COM1 (MW386 only)
--------N-1789-------------------------------
INT 17 - Alloy NTNX, MW386 - ADD PRINTER TO SPOOLER
AH = 89h
AL = mode
00h NTNX compatibility
DX = NTNX printer number (see #0524)
01h MW386
DX = MW386 printer number
Return: AL = status (see #0523)
Note: the specified printer is added to the spooler's list of available
printers
SeeAlso: AH=88h,AH=8Bh
--------N-178A-------------------------------
INT 17 - Alloy NTNX - ACTIVATE USER-WRITTEN PRINTER DRIVER
AH = 8Ah
???
SeeAlso: AH=92h
--------N-178B-------------------------------
INT 17 - Alloy MW386 - GET PHYSICAL DEVICE NUMBER FROM NAME
AH = 8Bh
DS:DX -> ASCIZ printer name
Return: AL = status (see also AH=81h)
00h successful
DX = physical device number
SeeAlso: AH=89h,AH=8Ch,INT 14/AH=20h"Alloy"
--------N-178C-------------------------------
INT 17 - Alloy MW386 - GET DEVICE NAME FROM PHYSICAL DEVICE NUMBER
AH = 8Ch
DX = physical device number
ES:DI -> 17-byte buffer for ASCIZ device name
Return: AL = status (see also AH=81h)
00h successful
ES:DI buffer filled
SeeAlso: AH=88h,AH=8Bh
--------N-178D-------------------------------
INT 17 - Alloy NTNX,MW386 - RESET SPOOLER
AH = 8Dh
AL = 00h
Return: AL = status (see #0523)
Notes: clears all buffers and resets spooler to boot-up values
MW386 supports this function for compatibility only; it is a NOP
--------N-178E-------------------------------
INT 17 - Alloy NTNX - GET INT 28 ENTRY POINT
AH = 8Eh
AL = 00h
Return: CX:BX -> INT 28 entry point
SeeAlso: AH=8Fh
--------N-178F-------------------------------
INT 17 - Alloy NTNX - GET DOS INTERCEPT ENTRY POINT
AH = 8Fh
AL = 00h
Return: CX:BX -> DOS intercept routine
SeeAlso: AH=8Eh
--------N-1790-------------------------------
INT 17 - Alloy NTNX, MW386 - SPOOL FILE BY NAME
AH = 90h
AL = mode
00h NTNX compatibility
DL = printer code (FFh=current) (NTNX, MW386 v1.x only)
DH = number of copies (FFh=current) (NTNX, MW386 v1.x only)
02h MW386 v2+
BX = logical device number
00h-03h = LPT1-LPT4
04h-07h = COM1-COM4
CX:SI -> ASCIZ pathname
Return: AL = status (see #0523)
Note: in mode 00h, the file is always sent to logical LPT1
SeeAlso: AH=A0h
--------N-1791-------------------------------
INT 17 - Alloy NTNX, MW386 - GET USER NUMBER AND CURRENT PRINTER
AH = 91h
AL = mode
00h NTNX compatibility
Return: CX = user number (00h = host)
DX = currently selected printer number (00h-08h)
01h MW386
Return: CX = user number
DX = physical dev number of currently selected printer
02h MW386 v2+
BX = logical device number
00h-03h = LPT1-LPT4
04h-07h = COM1-COM4
Return: CX = user number
DX = physical device number
Return: AL = status (see #0523)
SeeAlso: AH=8Ch
--------N-1792-------------------------------
INT 17 - Alloy NTNX - CHECK PRINTER DRIVER
AH = 92h
AL = 00h
CL = 00h
Return: CL = driver state
01h initialized
80h not initialized
AX = status (see #0523)
SeeAlso: AH=8Ah
--------N-1794-------------------------------
INT 17 - Alloy NTNX, MW386 - SELECT PRINTER
AH = 94h
AL = mode
00h NTNX compatibility
DX = NTNX printer number (see #0524)
01h MW386
DX = MW386 printer number
02h MW386 v2+
BX = logical printer number
DX = MW386 printer number
Return: AL = status (see #0523)
Note: modes 00h and 01h affect only logical LPT1
SeeAlso: AH=8Bh,AH=95h
--------N-1795-------------------------------
INT 17 - Alloy NTNX, MW386 - GET CURRENT PRINTER
AH = 95h
AL = mode
00h NTNX compatibility
Return: DX = NTNX printer number (see #0524)
(FFFFh if current printer not compatible with NTNX)
01h MW386
Return: DX = MW386 printer number
02h MW386 v2+
BX = logical device number
00h-03h = LPT1-LPT4
04h-07h = COM1-COM4
Return: DX = MW386 printer number (FFFFh = none)
Return: AL = status (see #0523)
Note: modes 00h and 01h return the printer number of logical LPT1 only
SeeAlso: AH=94h
--------N-1796-------------------------------
INT 17 - Alloy NTNX - SET SERIAL PORT PARAMETERS
AH = 96h
AL = 00h
Note: documentation states that this is a NOP, doing only XOR AX,AX before
returning
SeeAlso: INT 14/AH=24h
--------N-1797-------------------------------
INT 17 - Alloy NTNX, MW386 - SET DATA DRIVEN PRINT BREAK
AH = 97h
AL = mode
00h NTNX compatibility
02h MW386 v2+
BX = logical device number
00h-03h = LPT1-LPT4
04h-07h = COM1-COM4
CH,CL,DH = three character break sequence
DL = subfunction
00h set break string
else reset break
Return: AL = status (see #0523)
Notes: mode 00h affects only logical LPT1
when the break string is encountered, the spool file will be closed and
queued for printing automatically
the break string is not permanently saved, and will be reset each time
MW386 or the user is rebooted
SeeAlso: AH=9Bh
--------N-1798-------------------------------
INT 17 - Alloy NTNX,MW386 - RESTART PRINTER
AH = 98h
AL = 00h
DL = printer number (FFh=current)
Return: AL = status
00h successful
01h incorrect printer
02h task not found
Note: MW386 supports this function for compatibility only; it is a NOP
--------N-1799-------------------------------
INT 17 - Alloy NTNX, MW386 - GET/SET PRINTER MODE
AH = 99h
AL = mode
00h NTNX compatibility
DL = NTNX printer number (see #0524)
(FFh = task's current logical LPT1)
DH = mode (see #0525)
01h MW386
DX = MW386 printer number
CL = mode (as for DH above)
Return: AL = status (see #0523)
DH = mode (bits 1 and 2 set as above)
DL = printer owner's user number if not spooled

Bitfields for Alloy printer mode:
0 get mode if 1, set mode if 0 (Table 0525)
1 private ("attached")
2 direct instead of spooled
3-7 reserved (0)
--------N-179A-------------------------------
INT 17 - Alloy NTNX,MW386 - SET TAB EXPANSION
AH = 9Ah
AL = mode
00h NTNX compatibility
DX = NTNX printer number (see #0524)
(FFFFh = current logical LPT1)
01h MW386
DX = MW386 printer number
CL = tab length (00h = no expansion, 01h-63h = spaces per tab)
Return: AL = status (see #0523)
Note: beginning with MW386 v2.0, tab expansion is set on a per-printer basis
rather than a per-user basis; NTNX and MW386 v1.x ignore DX
SeeAlso: AH=A4h
--------N-179B-------------------------------
INT 17 - Alloy NTNX,MW386 - SET PRINT BREAK TIMEOUT
AH = 9Bh
AL = mode
00h NTNX compatibility
CX = timeout value in clock ticks (1/18 sec) (00h = never)
01h MW386
CX = timeout value in seconds (00h = never)
02h MW386 v2+
BX = logical device number
00h-03h = LPT1-LPT4
04h-07h = COM1-COM4
CX = timeout value in seconds (00h = never)
Return: AL = status (see #0523)
Notes: modes 00h and 01h affect only the current logical LPT1
if no data is sent to a printer for the specified amount of time, the
spool file will be closed and queued for printing automatically
SeeAlso: AH=97h
--------N-17A0-------------------------------
INT 17 - Alloy MW386 - SPOOL COPY OF FILE
AH = A0h
AL = mode
00h NTNX compatibility
DX = ??? (NTNX, MW386 v1.x only)
02h MW386 v2+
BX = logical device number
00h-03h = LPT1-LPT4
04h-07h = COM1-COM4
CX:SI -> ASCIZ pathname
Return: AL = status (see #0523)
Notes: makes a copy of the specified file in the spooler's directory, allowing
the original file to be modified or deleted while the copy is printed
in mode 00h, the file is printed on logical LPT1
SeeAlso: AH=90h
--------N-17A4-------------------------------
INT 17 - Alloy MW386 - ENABLE/DISABLE FORM FEED
AH = A4h
AL = new state
00h form feed after end of print job disabled
01h form feed enabled
Return: AL = status (see #0523)
Note: only affects the current logical LPT1
SeeAlso: AH=9Ah,AH=A6h,INT 7F/AH=05h"NTNX (Host)"
--------N-17A6-------------------------------
INT 17 - Alloy MW386 - ENABLE/DISABLE BANNER PAGE
AH = A6h
AL = new state
00h banner page before print job disabled
01h banner page enabled
Return: AL = status (see #0523)
Note: only affects the current logical LPT1
SeeAlso: AH=A4h
--------N-17A7-------------------------------
INT 17 - Alloy MW386 v2+ - GET/SET SPOOL FLAGS
AH = A7h
AL = spool flags (see #0526)
BX = logical device number
00h-03h = LPT1-LPT4
04h-07h = COM1-COM4
Return: AL = status (see #0523)
Note: the documentation does not state which register contains the result of
a GET
SeeAlso: AH=A4h,AH=A6h

Bitfields for Alloy spool flags:
Bit(s) Description (Table 0526)
0 banner page enabled (see AH=A6h)
1 form feed enabled (see AH=A4h)
2-6 reserved (0)
7 set flags if 1, get flags if 0
--------N-17A8-------------------------------
INT 17 - Alloy MW386 - DEFINE TEMPORARY FILENAME
AH = A8h
CX:SI -> ASCIZ filename without extension (max 8 chars)
Return: AL = status (see #0523)
Note: allows application to specify banner page filename for spool files
collected from the application's printer output
SeeAlso: AH=A9h
--------N-17A9-------------------------------
INT 17 - Alloy MW386 - CHANGE TEMPORARY SPOOL DRIVE
AH = A9h
AL = new spool drive (2=C:,3=D:,etc)
Return: AL = status (see #0523)
Note: does not remove previous spooling directory since jobs may be pending
SeeAlso: AH=A8h
--------N-17AA-------------------------------
INT 17 - Alloy MW386 v2+ - GET REAL-TIME PRINTER STATUS
AH = AAh
AL = mode
00h NTNX
DX = NTNX printer number (see #0524)
01h MW386
DX = MW386 printer number
Return: AH = instantaneous printer status
00h printer ready
01h not ready
12h off line
13h out of paper
14h general device failure
15h device timeout
16h bad device number
--------N-17AF-------------------------------
INT 17 - Alloy MW386 - CHECK SPOOLER
AH = AFh
Return: AX = 55AAh if spooler available
--------c-17C0-------------------------------
INT 17 - PC Magazine PCSpool - GET CONTROL BLOCK ADDRESS
AH = C0h
DX = printer port (0-3)
Return: ES:BX -> control block (see #0527)
SeeAlso: AH=C1h

Format of PCSpool control block:
Offset Size Description (Table 0527)
00h WORD printer number
02h WORD address of printer status port
04h WORD number of first record in queue
06h WORD number of last record in queue
08h DWORD characters already printed
0Ch DWORD number of characters remaining
10h DWORD pointer to dequeue buffer
14h DWORD previous count of characters printed
18h DWORD number of clock ticks taken to print them
1Ch WORD offset of next character to output
1Eh WORD offset of next character to print
20h WORD pointer to spooling queue record
22h BYTE current spooling status
23h BYTE current printer status:
00h OK
01h not ready
02h paused with message
03h paused
04h initializing
FEh non-existent port
FFh not spooled
24h BYTE current control record type
25h WORD observed printer speed
27h WORD characters to print per service
29h BYTE 01h if disk write needed
2Ah BYTE 01h if queued data should be flushed
2Bh BYTE 01h to update cps status
--------c-17C1--------------------------------
INT 17 - PC Magazine PCSpool - BUILD PAUSE CONTROL RECORD
AH = C1h
DX = printer port (0-3)
DS:SI -> ASCIZ string to save for display
Note: flushes pending writes
SeeAlso: AH=C0h,AH=C2h
--------c-17C2-------------------------------
INT 17 - PC Magazine PCSpool - FLUSH PENDING WRITES
AH = C2h
DX = printer port (0-3)
SeeAlso: AH=C3h
--------c-17C3-------------------------------
INT 17 - PC Magazine PCSpool - CANCEL PRINTER QUEUE (FLUSH ALL QUEUED OUTPUT)
AH = C3h
DX = printer port (0-3)
SeeAlso: AH=C2h,AH=C7h
--------c-17C4-------------------------------
INT 17 - PC Magazine PCSpool - QUERY SPOOLER ACTIVE
AH = C4h
Return: DI = B0BFh
SI = segment
--------c-17C5-------------------------------
INT 17 - PC Magazine PCSpool - JOB SKIP PRINTER QUEUE
AH = C5h
DX = printer port (0-3)
Note: cancels up to the pause record
--------c-17C6-------------------------------
INT 17 - PC Magazine PCSpool - CHECK PRINTER QUEUE STATUS
AH = C6h
DX = printer port (0-3)
Return: AX = queue status
0000h printer not active or at pause
0001h printer busy
--------c-17C7-------------------------------
INT 17 - PC Magazine PCSpool - CLOSE QUEUE
AH = C7h
DX = printer port (0-3)
SeeAlso: AH=C3h
--------P-17CD00-----------------------------
INT 17 - INSET - EXECUTE COMMAND STRING
AX = CD00h
DS:DX -> ASCIZ command string (max 80 bytes)
Return: CX = 07C2h (1986d)
Note: user interface menus pop up after last command, unless that command
exits INSET
--------P-17CD01-----------------------------
INT 17 - INSET - GET IMAGE SIZE
AX = CD01h
DS:DX -> ASCIZ name of image file
Return: AX = height in 1/720th inch
BX = width in 1/720th inch
CX = 07C2h (1986d)
--------P-17CD02-----------------------------
INT 17 - INSET - INITIALIZE
AX = CD02h
Return: CX = 07C2h (1986d)
Note: all open files are closed and the printer is reset
SeeAlso: AX=CD04h
--------P-17CD03-----------------------------
INT 17 - INSET - EXECUTE INSET MENU WITHIN OVERRIDE MODE
AX = CD03h
Return: CX = 07C2h (1986d)
--------P-17CD04-----------------------------
INT 17 - INSET - INITIALIZE LINKED MODE
AX = CD04h
ES:SI -> FAR routine for linked mode (see #0528)
Return: CX = 07C2h
SeeAlso: AX=CD02h,AX=CD08h

(Table 0528)
Values INSET linked-mode routine is called with:
AL = function
00h send character to printer
BL = character to send
01h send string to printer
CX = number of bytes to send
DS:DX -> buffer containing data
02h move print head to horizontal starting position of image
Return: AX = status
0000h success
0001h failure
--------P-17CD05-----------------------------
INT 17 - INSET - START MERGING IMAGE INTO TEXT
AX = CD05h
DS:DX -> ASCIZ name of PIX file
CX = left margin of text in 1/720th inch
Return: AH = printer type
00h page-oriented (multiple images may be placed side-by-side)
01h line-oriented (use AX=CD06h for vertical paper movement)
CX = 07C2h (1986d)
SeeAlso: AX=CD07h
--------P-17CD06-----------------------------
INT 17 - INSET - GRAPHICS LINE FEED
AX = CD06h
Return: AH = completion status
00h image complete
01h image incomplete
CX = 07C2h (1986d)
SeeAlso: AX=CD09h
--------P-17CD07-----------------------------
INT 17 - INSET - FLUSH GRAPHICS FROM MERGE BUFFER
AX = CD07h
Return: CX = 07C2h
SeeAlso: AX=CD05h
--------P-17CD08-----------------------------
INT 17 - INSET - CANCEL LINK MODE
AX = CD08h
Return: CX = 07C2h
SeeAlso: AX=CD04h
--------P-17CD09-----------------------------
INT 17 - INSET - ALTER TEXT LINE SPACING
AX = CD09h
CX = line spacing in 1/720th inch
Return: CX = 07C2h
Note: not yet implemented, line spacing is currently fixed at 1/6 inch
SeeAlso: AX=CD06h
--------P-17CD0A-----------------------------
INT 17 - INSET - GET SETUP
AX = CD0Ah
DS:DX -> buffer for IN.SET data
Return: CX = 07C2h
--------P-17CD0B-----------------------------
INT 17 - INSET - START GETTING SCALED IMAGE
AX = CD0Bh
DS:SI -> ASCIZ pathname of .PIX file
BX = number of bitplanes
CX = number of rows in output bitmap
DX = number of columns in output bitmap
Return: AX = status
0000h OK
FFFFh error
Note: image is returned in strips by repeated calls to AX=CD0Ch
--------P-17CD0C-----------------------------
INT 17 - INSET - GET NEXT IMAGE STRIP
AX = CD0Ch
Return: AX = status
0000h OK but not complete
0001h OK and image complete
FFFFh error
DS:SI -> buffer (max 4K) for bit map strip
CX = start row
DX = number of rows
BX = offset in bytes between bit planes
Note: buffer may be overwritten by subsequent calls
SeeAlso: AX=CD0Bh
--------P-17E0-------------------------------
INT 17 - EPP BIOS - INSTALLATION CHECK
AH = E0h
Return: ??? (AH <> E0h if installed ???)
SeeAlso: AX=0200h"EPP",AH=E1h,AH=E2h
--------P-17E1-------------------------------
INT 17 - EPP BIOS - DISABLE EPP
AH = E1h
???
Return: ???
SeeAlso: AX=0200h"EPP",AH=E0h,AH=E2h
--------P-17E2-------------------------------
INT 17 - EPP BIOS - ENABLE EPP
AH = E2h
???
Return: ???
SeeAlso: AX=0200h"EPP",AH=E0h,AH=E1h
--------P-17F0-------------------------------
INT 17 - NorthNet Jetstream API - INSTALLATION CHECK
AH = F0h
DX = printer port (0-3)
Return: AX = 0001h Jetstream present
else non-Jetstream port
Note: NorthNet Jetstream is a high-performance DMA-driven parallel card able
to drive printers at up to 80000 characters per second
--------P-17F1-------------------------------
INT 17 - NorthNet Jetstream API - PRINT DATA BUFFER
AH = F1h
CX = data buffer length
DX = printer port (0-3)
DS:SI -> data buffer
Return: AX = status
0000h printer not ready (see also AH=02h)
other printing started
SeeAlso: AH=00h,AH=F2h,AH=F3h,AH=F5h
--------P-17F2-------------------------------
INT 17 - NorthNet Jetstream API - GET PRINT PROGRESS STATUS
AH = F2h
DX = printer port (0-3)
Return: AX = status
0000h prior print request finished
other number of characters left to print
SeeAlso: AH=02h,AH=F1h,AH=F3h
--------P-17F3-------------------------------
INT 17 - NorthNet Jetstream API - ABORT PRINT OPERATION
AH = F3h
DX = printer port (0-3)
Return: AX = number of unprinted characters due to abort
SeeAlso: AH=F1h,AH=F4h
--------P-17F4-------------------------------
INT 17 - NorthNet Jetstream API - SET COMPLETION (POST) ADDRESS
AH = F4h
DX = printer port (0-3)
DS:DS -> FAR post address (called with interrupts on)
SeeAlso: AH=F1h,AH=F3h
--------P-17F5-------------------------------
INT 17 - NorthNet Jetstream API - PRINT DATA BUFFER FROM EXTENDED MEMORY
AH = F5h
CX = data buffer length
DX = printer port (0-3)
DS:SI -> data buffer (32-bit physical address)
Return: AX = status
0000h printer not ready (see also AH=02h)
other printing started
SeeAlso: AH=F1h
--------c-17FF--BX0000-----------------------
INT 17 U - PC-MOS/386 v5.01 - PRINT SPOOLER - CLOSE SPOOL FILE
AH = FFh
BX = 0000h
CX = 0000h
DX = printer port number
Return: AH = printer status (see #0512 at AH=00h)
Program: PC-MOS/386 v5.01 is a multitasking, multiuser MS-DOS 5.0-compatible
operating system by The Software Link, Inc.
Desc: close the spool file immediately instead of waiting for the close time
to elapse
SeeAlso: AH=01h,AH=03h"PC-MOS"
--------B-18---------------------------------
INT 18 - DISKLESS BOOT HOOK (START CASSETTE BASIC)
Desc: called when there is no bootable disk available to the system
Notes: only PCs produced by IBM contain BASIC in ROM, so the action is
unpredictable on compatibles; this interrupt often reboots the
system, and often has no effect at all
network cards with their own BIOS can hook this interrupt to allow
a diskless boot off the network (even when a hard disk is present
if none of the partitions is marked as the boot partition)
SeeAlso: INT 2F/AX=4A06h,INT 86"NetBIOS"
--------J-1800-------------------------------
INT 18 - NEC PC-9800 series - KEYBOARD - GET KEYSTROKE
AH = 00h
Return: AX = keystroke
SeeAlso: AH=01h,AH=02h,INT 16/AH=00h
--------J-1801-------------------------------
INT 18 - NEC PC-9800 series - KEYBOARD - CHECK FOR KEYSTROKE
AH = 01h
Return: BH = status
00h no keystrokes available
01h keystroke available
AX = keystroke
SeeAlso: AH=00h,AH=02h,INT 16/AH=01h
--------J-1802-------------------------------
INT 18 - NEC PC-9800 series - KEYBOARD - GET SHIFT STATUS
AH = 02h
Return: AL = shift flags
SeeAlso: AH=00h,AH=02h,AH=03h,AH=04h,INT 16/AH=02h
--------J-1803-------------------------------
INT 18 - NEC PC-9800 series - KEYBOARD - INITIALIZE
AH = 03h
???
Return: ???
SeeAlso: AH=00h,AH=04h
--------J-1804-------------------------------
INT 18 - NEC PC-9800 series - KEYBOARD - KEY PRESSED
AH = 04h
???
Return: ???
Note: details are not available at this time
SeeAlso: AH=00h,AH=02h,INT 16/AH=00h,INT 16/AH=01h,INT 16/AH=02h
--------J-18---------------------------------
INT 18 - NEC PC-9800 series - VIDEO
AH = function
0Ah set video mode
0Bh get video mode
0Ch start text screen display
0Dh end text screen display
0Eh set single display area
0Fh set multiple display area
10h set cursor shape
11h display cursor
12h terminate cursor
13h set cursor position
14h read font patter
16h initialize text video RAM
1Ah define user character
others
???
Return: ???
Notes: details are not available at this time
text video RAM is located at segments A000h (characters) and A200h
(attributes), graphics video RAM at segment C000h

Bitfields for NEC PC-9800 series video attributes:
Bit(s) Description (Table 0529)
0 disable drawing character
1 blinking
2 reverse video
3 underline
4 vertical line
7-5 color
(0=black, 1=blue, 2=red, 3=purple, 4=green, 5=cyan, 6=yellow, 7=white)
--------J-180E-------------------------------
INT 18 - NEC PC-9800 series - SET SINGLE DISPLAY AREA
AH = 0Eh
DX = offset of first byte to display???
Return: ???
SeeAlso: AH=1Bh,MEM 0050h:0001h
--------J-181B-------------------------------
INT 18 - NEC PC-9800 series - SET DISPLAY MODE
AH = 1Bh
AL = ??? (00h for text mode)
Return: ???
--------r-185350BX4849-----------------------
INT 18 - SPHINX C-- - WB.COM - API
AX = 5350h ('SP')
BX = 4849h ('HI')
CX = 4E58h ('NX')
DH = function
01h set ???
DL = ???
02h get ???
Return: DL = ???
03h get ???
Return: ES:DI -> ??? data buffer
06h ???
Return: AX = 7370h ('sp') if installed
BX = 6869h ('hi') if installed
CX = 6E78h ('nx') if installed
Program: SPHINX C-- is a shareware compiler by Peter Cellik for a language
which is a cross between C and assembler; WB.COM is the driver which
launches the WorkBench
--------s-186900-----------------------------
INT 18 - Gravis Ultra Sound YEA_GUS.EXE - GET STATUS
AX = 6900h
Return: AX = amount of DRAM on card or 0000h if GUS not available
Program: YEA_GUS is a driver for the Graphics Ultra Sound which hooks INT 18h
and then shells out the the program requiring its services
SeeAlso: AX=6901h,AX=690Ah,AX=690Bh
--------s-186901-----------------------------
INT 18 - Gravis Ultra Sound YEA_GUS.EXE - RESET
AX = 6901h
BX = number of active voices (14-32)
Return: nothing
SeeAlso: AX=6900h
--------s-186902-----------------------------
INT 18 - Gravis Ultra Sound YEA_GUS.EXE - SET VOLUME FOR SPECIFIC VOICE
AX = 6902h
BX = voice number (00h-1Fh)
CX = linear volume (0000h-01FFh)
Return: nothing
SeeAlso: AX=6900h,AX=6903h,AX=6904h,AX=6909h,AX=690Ah
--------s-186903-----------------------------
INT 18 - Gravis Ultra Sound YEA_GUS.EXE - SET FREQUENCY FOR VOICE
AX = 6903h
BX = voice number (00h-1Fh)
CX = frequency in Hz (0-44100)
Return: nothing
SeeAlso: AX=6902h,AX=6904h
--------s-186904-----------------------------
INT 18 - Gravis Ultra Sound YEA_GUS.EXE - SET LEFT/RIGHT BALANCE
AX = 6904h
BX = voice number (00h-1Fh)
CX = balance (0 = left, 7 = even, 15 = right)
Return: nothing
SeeAlso: AX=6902h,AX=6903h
--------s-186905-----------------------------
INT 18 - Gravis Ultra Sound YEA_GUS.EXE - PLAY MUSIC
AX = 6905h
BL = voice number
BH = sample type (0 = 8-bit, 1 = 16-bit)
CL = looping type (0 = none, 1 = forward, 2 = back and forth)
CH:DI = 20-bit starting address for voice data
DL:SI = 20-bit address for loop start
DH:BP = 20-bit address for loop end
SeeAlso: AX=6903h,AX=6906h,AX=690Bh
--------s-186906-----------------------------
INT 18 - Gravis Ultra Sound YEA_GUS.EXE - LOAD SOUND DATA
AX = 6906h
BL = data format (1 = twos-complement, 0 = not)
BH = sample type (0 = 8-bit, 1 = 16-bit)
CX = number of bytes to send
ES:SI -> buffer containing data
DL:DI = 20-bit address of GUS DRAM at which to load sound data
SeeAlso: AX=6900h,AX=6905h,AX=690Ch
--------s-186907-----------------------------
INT 18 - Gravis Ultra Sound YEA_GUS.EXE - STOP VOICE
AX = 6907h
BX = voice number (00h-1Fh)
Return: nothing
SeeAlso: AX=6908h,AX=690Dh
--------s-186908-----------------------------
INT 18 - Gravis Ultra Sound YEA_GUS.EXE - SET VOICE END
AX = 6908h
BX = voice number (00h-1Fh)
CL:DX = 20-bit ending address
Return: nothing
SeeAlso: AX=690Bh
--------s-186909-----------------------------
INT 18 - Gravis Ultra Sound YEA_GUS.EXE - RAMP VOLUME
AX = 6909h
BL = voice number (00h-1Fh)
BH = looping type (0 = none, 1 = forward, 2 = back and forth)
CX = starting volume
DX = ending volume
DI:SI = time
Return: nothing
SeeAlso: AX=6902h,AX=690Ah
--------s-18690A-----------------------------
INT 18 - Gravis Ultra Sound YEA_GUS.EXE - GET VOLUME
AX = 690Ah
BX = voice number (00h-1Fh)
Return: AX = current non-linear volume for voice
SeeAlso: AX=6902h,AX=6909h
--------s-18690B-----------------------------
INT 18 - Gravis Ultra Sound YEA_GUS.EXE - GET POSITION
AX = 690Bh
BX = voice number
Return: BX:AX = 20-bit address at which voice is playing
SeeAlso: AX=6900h,AX=6905h,AX=6908h
--------s-18690C-----------------------------
INT 18 - Gravis Ultra Sound YEA_GUS.EXE - SAVE SOUND DATA
AX = 690Ch
BL = data format (1 = twos-complement, 0 = not)
BH = sample type (0 = 8-bit, 1 = 16-bit)
CX = number of bytes to get
ES:SI -> buffer for retrieved data
DL:DI = 20-bit address in GUS DRAM from which to read voice data
Return: nothing
SeeAlso: AX=6906h
--------s-18690D-----------------------------
INT 18 - Gravis Ultra Sound YEA_GUS.EXE - RESTART VOICE
AX = 690Dh
BX = voice
CX = sample type (0 = 8-bit, 1 = 16-bit)
DX = looping type (0 = none, 1 = forward, 2 = back and forth)
Return: CX = balance value
SeeAlso: AX=6907h,AX=6908h
--------s-188000-----------------------------
INT 18 - Gravis Ultra Sound EURO_MOD.EXE - INITIALIZE
AX = 8000h
Program: EURO_MOD is a .MOD file player for the Gravis Ultra Sound which hooks
INT 18h and then shells out to the program requiring its services
SeeAlso: AX=8001h,AX=8004h
--------s-188001-----------------------------
INT 18 - Gravis Ultra Sound EURO_MOD.EXE - LOAD .MOD FILE
AX = 8001h
BX:CX -> ASCIZ filename
SeeAlso: AX=8000h,AX=8002h
--------s-188002-----------------------------
INT 18 - Gravis Ultra Sound EURO_MOD.EXE - PLAY .MOD FILE
AX = 8002h
SeeAlso: AX=8002h,AX=8003h
--------s-188003-----------------------------
INT 18 - Gravis Ultra Sound EURO_MOD.EXE - STOP PLAYING
AX = 8003h
--------s-188004-----------------------------
INT 18 - Gravis Ultra Sound EURO_MOD.EXE - SHUTDOWN
AX = 8004h
SeeAlso: AX=8000h,AX=8003h
--------B-19---------------------------------
INT 19 - SYSTEM - BOOTSTRAP LOADER
Desc: This interrupt reboots the system without clearing memory or restoring
interrupt vectors. Because interrupt vectors are preserved, this
interrupt usually causes a system hang if any TSRs have hooked
vectors from 00h through 1Ch, particularly INT 08.
Notes: Usually, the BIOS will try to read sector 1, head 0, track 0 from drive
A: to 0000h:7C00h. If this fails, and a hard disk is installed, the
BIOS will read sector 1, head 0, track 0 of the first hard disk.
This sector should contain a master bootstrap loader and a partition
table (see #0531). After loading the master boot sector at
0000h:7C00h, the master bootstrap loader is given control. It will
scan the partition table for an active partition, and will then load
the operating system's bootstrap loader (contained in the first
sector of the active partition) and give it control.
true IBM PCs and most clones issue an INT 18 if neither floppy nor hard
disk have a valid boot sector
to accomplish a warm boot equivalent to Ctrl-Alt-Del, store 1234h in
0040h:0072h and jump to FFFFh:0000h. For a cold boot equivalent to
a reset, store 0000h at 0040h:0072h before jumping.
VDISK.SYS hooks this interrupt to allow applications to find out how
much extended memory has been used by VDISKs (see #0530). DOS 3.3+
PRINT hooks INT 19 but does not set up a correct VDISK header block
at the beginning of its INT 19 handler segment, thus causing some
programs to overwrite extended memory which is already in use.
the default handler is at F000h:E6F2h for 100% compatible BIOSes
MS-DOS 3.2+ hangs on booting (even from floppy) if the hard disk
contains extended partitions which point at each other in a loop,
since it will never find the end of the linked list of extended
partitions
under Windows Real and Enhanced modes, calling INT 19 will hang the
system in the same was as under bare DOS; under Windows Standard
mode, INT 19 will successfully perform a cold reboot as it appears
to have been redirected to a MOV AL,0FEh/OUT 64h,AL sequence
SeeAlso: INT 14/AH=17h,INT 18,INT 5B"PC Cluster"

Format of VDISK header block (at beginning of INT 19 handler's segment):
Offset Size Description (Table 0530)
00h 18 BYTEs n/a (for VDISK.SYS, the device driver header)
12h 11 BYTEs signature string "VDISK Vn.m" for VDISK.SYS version n.m
1Dh 15 BYTEs n/a
2Ch 3 BYTEs linear address of first byte of available extended memory

Format of hard disk master boot sector:
Offset Size Description (Table 0531)
00h 446 BYTEs Master bootstrap loader code
1BEh 16 BYTEs partition record for partition 1 (see #0532)
1CEh 16 BYTEs partition record for partition 2
1DEh 16 BYTEs partition record for partition 3
1EEh 16 BYTEs partition record for partition 4
1FEh WORD signature, AA55h indicates valid boot block

Format of partition record:
Offset Size Description (Table 0532)
00h BYTE boot indicator (80h = active partition)
01h BYTE partition start head
02h BYTE partition start sector (bits 0-5)
03h BYTE partition start track (bits 8,9 in bits 6,7 of sector)
04h BYTE operating system indicator (see #0533)
05h BYTE partition end head
06h BYTE partition end sector (bits 0-5)
07h BYTE partition end track (bits 8,9 in bits 6,7 of sector)
08h DWORD sectors preceding partition
0Ch DWORD length of partition in sectors
SeeAlso: #0531

(Table 0533)
Values for operating system indicator:
00h empty
01h DOS 12-bit FAT
02h XENIX root file system
03h XENIX /usr file system (obsolete)
04h DOS 16-bit FAT (up to 32M)
05h DOS 3.3+ extended partition
06h DOS 3.31+ Large File System (16-bit FAT, over 32M)
07h QNX
07h OS/2 HPFS
07h Windows NT NTFS
07h Advanced Unix
08h AIX bootable partition, SplitDrive
09h AIX data partition
09h Coherent filesystem
0Ah OS/2 Boot Manager
0Ah OPUS
0Ah Coherent swap partition
10h OPUS
11h OS/2 Boot Manager hidden 12-bit FAT partition
12h Compaq Diagnostics partition
14h (resulted from using Novell DOS 7.0 FDISK to delete Linux Native part)
14h OS/2 Boot Manager hidden sub-32M 16-bit FAT partition
16h OS/2 Boot Manager hidden over-32M 16-bit FAT partition
17h OS/2 Boot Manager hidden HPFS partition
18h AST special Windows swap file
24h NEC MS-DOS 3.x
3Ch PowerQuest PartitionMagic recovery partition
40h VENIX 80286
42h SFS (Secure File System) by Peter Gutmann
50h Disk Manager, read-only partition
51h Disk Manager, read/write partition
51h Novell???
52h CP/M
52h Microport System V/386
56h GoldenBow VFeature
61h SpeedStor
63h Unix SysV/386, 386/ix
63h Mach, MtXinu BSD 4.3 on Mach
63h GNU HURD
64h Novell NetWare
65h Novell NetWare (3.11)
70h DiskSecure Multi-Boot
75h PC/IX
80h Minix v1.1 - 1.4a
81h Minix v1.4b+
81h Linux
81h Mitac Advanced Disk Manager
82h Linux Swap partition
83h Linux native file system (ext2fs/xiafs)
84h OS/2-renumbered type 04h partition (related to hiding DOS C: drive)
93h Amoeba file system
94h Amoeba bad block table
A5h FreeBSD, BSD/386
B7h BSDI file system (secondarily swap)
B8h BSDI swap partition (secondarily file system)
C1h DR-DOS 6.0 LOGIN.EXE-secured 12-bit FAT partition
C4h DR-DOS 6.0 LOGIN.EXE-secured 16-bit FAT partition
C6h DR-DOS 6.0 LOGIN.EXE-secured Huge partition
C7h Syrinx Boot
DBh CP/M, Concurrent CP/M, Concurrent DOS
DBh CTOS (Convergent Technologies OS)
E1h SpeedStor 12-bit FAT extended partition
E3h DOS read-only
E4h SpeedStor 16-bit FAT extended partition
F2h DOS 3.3+ secondary
F4h SpeedStor
FEh LANstep
FFh Xenix bad block table
SeeAlso: #0532
--------B-1A00-------------------------------
INT 1A - TIME - GET SYSTEM TIME
AH = 00h
Return: CX:DX = number of clock ticks since midnight
AL = midnight flag, nonzero if midnight passed since time last read
Notes: there are approximately 18.2 clock ticks per second, 1800B0h per 24 hrs
IBM and many clone BIOSes set the flag for AL rather than incrementing
it, leading to loss of a day if two consecutive midnights pass
without a request for the time (e.g. if the system is on but idle)
since the midnight flag is cleared, if an application calls this
function after midnight before DOS does, DOS will not receive the
midnight flag and will fail to advance the date
SeeAlso: AH=01h,AH=02h,INT 21/AH=2Ch,INT 62/AX=0099h,MEM 0040h:006Ch
--------B-1A01-------------------------------
INT 1A - TIME - SET SYSTEM TIME
AH = 01h
CX:DX = number of clock ticks since midnight
SeeAlso: AH=00h,AH=03h,INT 21/AH=2Dh
--------B-1A02-------------------------------
INT 1A - TIME - GET REAL-TIME CLOCK TIME (AT,XT286,PS)
AH = 02h
Return: CF clear if successful
CH = hour (BCD)
CL = minutes (BCD)
DH = seconds (BCD)
DL = daylight savings flag (00h standard time, 01h daylight time)
CF set on error (i.e. clock not running or in middle of update)
Note: this function is also supported by the Sperry PC, which predates the
IBM AT; the data is returned in binary rather than BCD on the Sperry,
and DL is always 00h
SeeAlso: AH=00h,AH=03h,AH=04h,INT 21/AH=2Ch
--------B-1A03-------------------------------
INT 1A - TIME - SET REAL-TIME CLOCK TIME (AT,XT286,PS)
AH = 03h
CH = hour (BCD)
CL = minutes (BCD)
DH = seconds (BCD)
DL = daylight savings flag (00h standard time, 01h daylight time)
Note: this function is also supported by the Sperry PC, which predates the
IBM AT; the data is specified in binary rather than BCD on the
Sperry, and the value of DL is ignored
SeeAlso: AH=01h,AH=03h,AH=05h,INT 21/AH=2Dh
--------B-1A04-------------------------------
INT 1A - TIME - GET REAL-TIME CLOCK DATE (AT,XT286,PS)
AH = 04h
Return: CF clear if successful
CH = century (BCD)
CL = year (BCD)
DH = month (BCD)
DL = day (BCD)
CF set on error
SeeAlso: AH=02h,AH=04h"Sperry",AH=05h,INT 21/AH=2Ah
--------b-1A04-------------------------------
INT 1A - Sperry PC - GET REAL-TIME CLOCK DATE
AH = 04h
Return: CF clear if successful
CL = year-1980
DH = month (binary)
DL = day (binary)
CF set on error
SeeAlso: AH=02h,AH=04h,AH=05h"Sperry",INT 21/AH=2Ah
--------B-1A05-------------------------------
INT 1A - TIME - SET REAL-TIME CLOCK DATE (AT,XT286,PS)
AH = 05h
CH = century (BCD)
CL = year (BCD)
DH = month (BCD)
DL = day (BCD)
SeeAlso: AH=04h,INT 21/AH=2Bh
--------b-1A04-------------------------------
INT 1A - Sperry PC - SET REAL-TIME CLOCK DATE
AH = 04h
CL = year-1980
DH = month (binary)
DL = day (binary)
SeeAlso: AH=02h,AH=04h"Sperry",AH=05h,INT 21/AH=2Bh
--------B-1A06-------------------------------
INT 1A - TIME - SET ALARM (AT,XT286,PS)
AH = 06h
CH = hour (BCD)
CL = minutes (BCD)
DH = seconds (BCD)
Return: CF set on error (alarm already set or clock stopped for update)
CF clear if successful
Notes: the alarm occurs every 24 hours until turned off, invoking INT 4A each
time
the BIOS does not check for invalid values for the time, so the CMOS
clock chip's "don't care" setting (any values between C0h and FFh)
may be used for any or all three part. For example, to create an
alarm once a minute, every minute, call with CH=C0h, CL=C0h, and
DH=00h.
SeeAlso: AH=07h,INT 4A
--------B-1A07-------------------------------
INT 1A - TIME - CANCEL ALARM (AT,XT286,PS)
AH = 07h
Return: alarm disabled
Note: does not disable the real-time clock's IRQ
SeeAlso: AH=06h,INT 70
--------B-1A08-------------------------------
INT 1A - TIME - SET RTC ACTIVATED POWER ON MODE (CONVERTIBLE)
AH = 08h
CH = hours in BCD
CL = minutes in BCD
DH = seconds in BCD
SeeAlso: AH=09h
--------B-1A09-------------------------------
INT 1A - TIME - READ RTC ALARM TIME AND STATUS (CONV,PS30)
AH = 09h
Return: CH = hours in BCD
CL = minutes in BCD
DH = seconds in BCD
DL = alarm status
00h alarm not enabled
01h alarm enabled but will not power up system
02h alarm will power up system
SeeAlso: AH=08h
--------B-1A0A-------------------------------
INT 1A - TIME - READ SYSTEM-TIMER DAY COUNTER (XT2,PS)
AH = 0Ah
Return: CF set on error
CF clear if successful
CX = count of days since Jan 1,1980
SeeAlso: AH=04h,AH=0Bh
--------B-1A0B-------------------------------
INT 1A - TIME - SET SYSTEM-TIMER DAY COUNTER (XT2,PS)
AH = 0Bh
CX = count of days since Jan 1,1980
Return: CF set on error
CF clear if successful
SeeAlso: AH=05h,AH=0Ah
--------J-1A10-------------------------------
INT 1A - NEC PC-9800 series - PRINTER - INITIALIZE
AH = 10h
???
Return: ???
SeeAlso: AH=11h,AH=12h,INT 17/AH=01h
--------J-1A1000-----------------------------
INT 1A - NEC PC-9800 series - INSTALLATION CHECK
AX = 1000h
Return: AX <> 1000h if NEC
--------J-1A11-------------------------------
INT 1A - NEC PC-9800 series - PRINTER - OUTPUT CHARACTER
AH = 11h
???
Return: ???
SeeAlso: AH=10h,AH=12h,INT 17/AH=00h
--------J-1A12-------------------------------
INT 1A - NEC PC-9800 series - PRINTER - SENSE STATUS
AH = 12h
???
Return: ???
SeeAlso: AH=10h,AH=11h,INT 17/AH=02h
--------A-1A3601-----------------------------
INT 1A - WORD PERFECT v5.0 Third Party Interface - INSTALLATION CHECK
AX = 3601h
Return: DS:SI = routine to monitor keyboard input, immediately preceded by the
ASCIZ string "WPCORP\0"
Notes: WordPerfect 5.0 will call this interrupt at start up to determine if a
third party product wants to interface with it. The third party
product must intercept this interrupt and return the address of a
keyboard monitor routine.
Before checking for keyboard input, and after every key entered by the
user, Word Perfect will call the routine whose address was provided
in DS:SI with the following parameters:
Entry: AX = key code or 0
BX = WordPerfect state flag
Exit: AX = 0 or key code
BX = 0 or segment address of buffer with key codes
See the "WordPerfect 5.0 Developer's Toolkit" for further information.
SeeAlso: INT 16/AX=5500h
--------N-1A6108-----------------------------
INT 1A - SNAP.EXE 3.2+ - "SNAP_SENDWITHREPLY" - SEND MSG AND GET REPLY
AX = 6108h
STACK: WORD conversation ID (0000h-0009h)
DWORD pointer to message buffer
WORD length of message
DWORD pointer to reply buffer
WORD length of reply buffer
WORD 0000h (use default "Cparams" structure)
Return: AX = status (see #0534)
STACK unchanged
Program: SNAP.EXE is a TSR written by IBM and Carnegie Mellon University
which implements the Simple Network Application Protocol
SeeAlso: AX=6205h

(Table 0534)
Values for SNAP.EXE status:
0000h successful
F830h "SNAP_ABORTED"
FC04h "SNAP_SERVERDIED"
FC05h "SNAP_RESEND"
FC06h "SNAP_SELECTFAILED"
FC07h "SNAP_WRONGVERSION"
FC08h "SNAP_INVALIDACK"
FC09h "SNAP_TIMEOUT"
FC0Ah "SNAP_SERVERREJECT"
FC0Bh "SNAP_NOREPLYDUE"
FC0Ch "SNAP_NOAUTHENTICATE"/"SNAP_GUARDIAN_ERROR"
FC0Dh "SNAP_NOINIT"
FC0Eh "SNAP_SOCKETERROR"
FC0Fh "SNAP_BUFFERLIMIT"
FC10h "SNAP_INVALIDCID"
FC11h "SNAP_INVALIDOP"
FC12h "SNAP_XMITFAIL"
FC13h "SNAP_NOMORERETRIES"
FC14h "SNAP_BADPARMS"
FC15h "SNAP_NOMEMORY"
FC16h "SNAP_NOMORECONVS"
FFFFh failed (invalid function/parameter)
--------N-1A6205-----------------------------
INT 1A - SNAP.EXE 3.2+ - "SNAP_SENDNOREPLY" - SEND MSG, DON'T AWAIT REPLY
AX = 6205h
STACK: WORD conversation ID (0000h-0009h)
DWORD pointer to message
WORD length of message
WORD 0000h (use default "Cparms" structure)
Return: AX = status (see #0534)
STACK unchanged
SeeAlso: AX=6108h
--------N-1A6308-----------------------------
INT 1A - SNAP.EXE 3.2+ - "SNAP_BEGINCONV" - BEGIN CONVERSATION
AX = 6308h
STACK: WORD offset of ASCIZ "guardian"
WORD offset of ASCIZ hostname
WORD offset of ASCIZ server name
WORD offset of ASCIZ userid
WORD offset of ASCIZ password
WORD offset of password length
WORD offset of password type
WORD offset of "Cparms" structure (see #0535)
Return: ???
STACK unchanged
Note: all stacked offsets are within the SNAP data segment (use AX=6A01h
to allocate a buffer)
SeeAlso: AX=6405h,AX=7202h

Format of SNAP.EXE Cparms structure:
Offset Size Description (Table 0535)
00h WORD retry delay in seconds
02h WORD timeout delay in seconds
04h WORD maximum buffer size
06h WORD encryption level
--------N-1A6405-----------------------------
INT 1A - SNAP.EXE 3.2+ - "SNAP_ENDCONV" - END CONVERSATION
AX = 6405h
STACK: WORD conversation ID (0000h-0009h)
DWORD pointer to message buffer
WORD length of message
WORD 0000h (use default "Cparms" structure)
Return: AX = status (see #0534)
STACK unchanged
Program: SNAP.EXE is a TSR written by IBM and Carnegie Mellon University
which implements the Simple Network Application Protocol
SeeAlso: AX=6308h
--------N-1A6900-----------------------------
INT 1A - SNAP.EXE 3.2+ - "SNAP_DATASEG" - GET RESIDENT DATA SEGMENT
AX = 6900h
Return: AX = value used for DS by resident code
SeeAlso: AX=6A01h,AX=6F01h
--------N-1A6A01-----------------------------
INT 1A - SNAP.EXE 3.2+ - "SNAP_ALLOC" - ALLOCATE BUFFER IN SNAP DATA SEGMENT
AX = 6A01h
STACK: WORD number of bytes to allocate
Return: AX = offset of allocated buffer or 0000h if out of memory
STACK unchanged
Program: SNAP.EXE is a TSR written by IBM and Carnegie Mellon University
which implements the Simple Network Application Protocol
SeeAlso: AX=6B01h
--------N-1A6B01-----------------------------
INT 1A - SNAP.EXE 3.2+ - "SNAP_FREE" - DEALLOCATE BUFFER IN SNAP DATA SEGMENT
AX = 6B01h
STACK: WORD offset within SNAP data segment of previously allocated
buffer
Return: STACK unchanged
Note: this call is a NOP if the specified offset is 0000h
SeeAlso: AX=6A01h
--------N-1A6C04-----------------------------
INT 1A - SNAP.EXE 3.2+ - "SNAP_COPYTO" - COPY DATA TO RESIDENT SNAP PACKAGE
AX = 6C04h
STACK: WORD offset within SNAP data segment of dest (nonzero)
WORD segment of source buffer
WORD offset of source buffer
WORD number of bytes to copy
Return: AX = offset of byte after last one copied to destination
STACK unchanged
Program: SNAP.EXE is a TSR written by IBM and Carnegie Mellon University
which implements the Simple Network Application Protocol
SeeAlso: AX=6D04h
--------N-1A6D04-----------------------------
INT 1A - SNAP.EXE 3.2+ - "SNAP_COPYFROM" - COPY DATA FROM RESIDENT SNAP PACKAGE
AX = 6D04h
STACK: WORD offset within SNAP data segment of source buffer
WORD segment of destination buffer
WORD offset of destination buffer
WORD number of bytes to copy
Return: AX = offset of byte after last one copied from source
buffer filled
STACK unchanged
SeeAlso: AX=6C04h
--------N-1A6E01-----------------------------
INT 1A - SNAP.EXE 3.2+ - "SNAP_SETDEBUG" - SET ???
AX = 6E01h
STACK: WORD new value for ???
Return: AX = old value of ???
STACK unchanged
Program: SNAP.EXE is a TSR written by IBM and Carnegie Mellon University
which implements the Simple Network Application Protocol
--------N-1A6F01-----------------------------
INT 1A - SNAP.EXE 3.2+ - "SNAP_CHKINSTALL" - INSTALLATION CHECK
AX = 6F01h
STACK: WORD 0000h
Return: AX = status
0000h SNAP is resident
other SNAP not present
STACK unchanged
Program: SNAP.EXE is a TSR written by IBM and Carnegie Mellon University
which implements the Simple Network Application Protocol, and is
required by PCVENUS (a network shell). The combination of SNAP and
PCVENUS allows the use of the Andrew File System as one or more
networked drives.
SeeAlso: AX=6900h,AX=7400h
--------N-1A7002-----------------------------
INT 1A - SNAP.EXE 3.2+ - "SNAP_SETANCHOR"
AX = 7002h
STACK: WORD anchor number (0000h-0009h)
WORD new value for the anchor
Return: AX = status
0000h successful
FFFFh failed (top word on stack not in range 00h-09h)
STACK unchanged
SeeAlso: AX=7101h
--------N-1A7101-----------------------------
INT 1A - SNAP.EXE 3.2+ - "SNAP_GETANCHOR"
AX = 7101h
STACK: WORD anchor number (0000h-0009h)
Return: AX = anchor's value
STACK unchanged
Program: SNAP.EXE is a TSR written by IBM and Carnegie Mellon University
which implements the Simple Network Application Protocol
SeeAlso: AX=7002h
--------N-1A7202-----------------------------
INT 1A - SNAP.EXE 3.2+ - "SNAP_SETCONVPARMS" - SET CONVERSATION PARAMETERS
AX = 7202h
STACK: WORD conversation ID (0000h-0009h)
WORD offset within resident data segment of "Cparms"
structure (see #0535)
Return: AX = status???
STACK unchanged
SeeAlso: AX=6308h
--------N-1A7302-----------------------------
INT 1A - SNAP.EXE 3.2+ - "SNAP_CLIENTVERSION" - ???
AX = 7302h
STACK: WORD conversation ID (0000h-0009h)
WORD offset within resident data segment of ???
Return: AX = ???
???
STACK unchanged
SeeAlso: AX=7400h
--------N-1A7400-----------------------------
INT 1A - SNAP.EXE 3.2+ - "SNAP_VERSION" - GET VERSION
AX = 7400h
Return: AX = version (AH=major, AL=minor)
Note: this call is only valid if SNAP is installed
SeeAlso: AX=7302h,INT 1A/AX=6F01h
--------N-1A75-------------------------------
INT 1A - SNAP.EXE 3.2+ - "SNAP_NOP" - ???
AH = 75h
AL = ???
Return: AX = ??? (0000h)
Program: SNAP.EXE is a TSR written by IBM and Carnegie Mellon University
which implements the Simple Network Application Protocol
--------N-1A76-------------------------------
INT 1A - SNAP.EXE 3.2+ - "SNAP_802_5" - ???
AH = 76h
AL = ???
Return: AX = ???
--------N-1A77-------------------------------
INT 1A - SNAP.EXE 3.4 - ???
AH = 77h
AL = ??? (at least 01h)
STACK: WORD ???
???
Return: ???
STACK unchanged
--------N-1A7802-----------------------------
INT 1A - SNAP.EXE 3.4 - ???
AX = 7802h
STACK: WORD ???
WORD ???
Return: ???
STACK unchanged
Program: SNAP.EXE is a TSR written by IBM and Carnegie Mellon University
which implements the Simple Network Application Protocol
--------s-1A7F-------------------------------
INT 1A - Tandy 2500, Tandy 1000L series - DIGITAL SOUND???
AH = 7Fh
???
Return: ???
Note: this function is not supported by the Tandy 1000SL/TL BIOS
SeeAlso: AH=80h,AH=83h,AH=85h
--------s-1A80-------------------------------
INT 1A - PCjr, Tandy 2500???, Tandy 1000SL/TL - SET UP SOUND MULTIPLEXOR
AH = 80h
AL = 00h source is 8253 channel 2
01h source is cassette input
02h source is I/O channel "Audio IN"
03h source is sound generator chip
Note: although documented in the 1000TL Technical Reference, the 1000TL
BIOS has just an IRET for this call
SeeAlso: AH=7Fh,AH=83h
--------X-1A80-------------------------------
INT 1A - PCMCIA Socket Services v1.00 - GET NUMBER OF ADAPTERS
AH = 80h
Return: CF clear if successful
CX = 5353h ('SS') if Socket Services installed
AL = number of adapters present (0-16)
AH destroyed
CF set on error
AH = error code (see #0536)
SeeAlso: AH=83h"PCMCIA"

(Table 0536)
Values for PCMCIA error codes:
01h "BAD_ADAPTER" nonexistent adapter
02h "BAD_ATTRIBUTE" invalid attribute specified
03h "BAD_BASE" invalid system memory base address
04h "BAD_EDC" invalid EDC generator specified
05h "BAD_INDICATOR" invalid indicator specified
06h "BAD_IRQ" invalid IRQ channel specified
07h "BAD_OFFSET" invalid PCMCIA card offset specified
08h "BAD_PAGE" invalid page specified
09h "BAD_READ" unable to complete request
0Ah "BAD_SIZE" invalid window size specified
0Bh "BAD_SOCKET" nonexistent socket specified
0Ch "BAD_TECHNOLOGY" unsupported Card Technology for writes
0Dh "BAD_TYPE" unavailable window type specified
0Eh "BAD_VCC" invalid Vcc power level index specified
0Fh "BAD_VPP" invalid Vpp1 or Vpp2 power level index specified
10h "BAD_WAIT" invalid number of wait states specified
11h "BAD_WINDOW" nonexistent window specified
12h "BAD_WRITE" unable to complete request
13h "NO_ADAPTERS" no adapters installed, but Socket Services is present
14h "NO_CARD" no card in socket
15h function not supported
16h invalid mode
17h invalid speed
18h busy
--------X-1A81-------------------------------
INT 1A - PCMCIA Socket Services v1.00 - REGISTER STATUS CHANGE CALLBACK
AH = 81h
DS:DX -> callback routine (see #0537) or 0000h:0000h to disable
Return: CF clear if successful
AH destroyed
CF set on error
AH = error code (see #0536)
Note: the callback will be invoked on any socket changes whose notification
has not been disabled with the status change enable mask; it may be
invoked either while processing a hardware interrupt from the adapter
or while processing the following Socket Services request
SeeAlso: AH=80h"PCMCIA",AH=82h"PCMCIA"

(Table 0537)
Values PCMCIA callback routine is invoked with:
AL = adapter number
BH = status change interrupt enable mask (see #0538)
BL = socket number
DH = current socket status (see #0539)
DL = current card status (see #0540)
Return: all registers preserved
Notes: the callback may be invoked during a hardware interrupt, and may not
call on Socket Services
the callback will be invoked once for each socket with a status change

Bitfields for PCMCIA status change interrupt enable mask:
Bit(s) Description (Table 0538)
7 card detect change
6 ready change
5 battery warning change
4 battery dead change
3 insertion request
2 ejection request
1-0 reserved (0)

Bitfields for PCMCIA current socket status:
Bit(s) Description (Table 0539)
7 card changed
6 reserved (0)
5 card insertion complete
4 card ejection complete
3 card insertion request pending
2 card ejection request pending
1 card locked
0 reserved (0)


Bitfields for PCMCIA current card status:
Bit(s) Description (Table 0540)
7 card detect
6 ready
5 battery voltage detect 2 (battery warning)
4 battery voltage detect 1 (battery dead)
3-1 reserved (0)
0 write protected
--------s-1A8100-----------------------------
INT 1A - Tandy 2500, Tandy 1000L series - DIGITAL SOUND - INSTALLATION CHECK
AX = 8100h
Return: AL > 80h if supported
AX = 00C4h if supported (1000SL/TL)
CF set if sound chip is busy
CF clear if sound chip is free
Note: the value of CF is not definitive; call this function until CF is
clear on return, then call AH=84h"Tandy"
--------s-1A82-------------------------------
INT 1A - Tandy 2500???, Tandy 1000SL/TL - DIGITAL SOUND - RECORD SOUND
AH = 82h
ES:BX -> buffer for sound samples
CX = length of buffer
DX = transfer rate (1-4095, 1 is fastest)
Return: AH = 00h
CF set if sound busy
CF clear if sound chip free
Note: the value in DX should be 1/10 the corresponding value for
INT 1A/AH=83h on the 1000TL, 1/11.5 on the 1000SL. Call
INT 1A/AX=8100h and INT 1A/AH=84h before invoking this function.
The BIOS issues an INT 15/AX=91FBh when the input is complete
DMA across a 64K boundary is masked by the BIOS
--------X-1A82-------------------------------
INT 1A - PCMCIA Socket Services v1.00 - REGISTER CARD TECHNOLOGY CALLBACK
AH = 82h
DS:DX -> callback routine (see #0541) or 0000h:0000h
Return: CF clear if successful
AH destroyed
CF set on error
AH = error code (see #0536)
Note: the callback is invoked on a Write Multiple request with an unsupported
card technology type
SeeAlso: AH=81h"PCMCIA",AH=94h

(Table 0541)
Values PCMCIA callback routine is invoked with:
ES:AX -> Low-Level Socket Services Routines (see #0543)
BH = socket attributes (see #0542)
CX = number of bytes or words to write
DS:SI -> data buffer to be written
DX:DI -> 26-bit linear card address
BP = card technology type
Return: CF clear if successful
CF set on error
AH = error code (07h,0Ch,12h,14h) (see #0536)

Bitfields for PCMCIA socket attributes:
Bit(s) Description (Table 0542)
7-4 reserved (0)
3 packed buffer
2 even bytes only (only valid if 1 set)
1 data width (clear = byte, set = word)
0 memory type (clear = common, set = attribute)

Format of PCMCIA Low-Level Socket Services Routines:
Offset Size Description (Table 0543)
00h WORD offset of Write Many routine (see #0544)
02h WORD offset of Write One routine (see #0545)
04h WORD offset of Read One routine (see #0546)
06h WORD offset of Increment Offset routine (see #0547)
08h WORD offset of Set Offset routine (see #0548)
0Ah WORD offset of Get Status routine (see #0549)

(Table 0544)
Call Write Many routine with:
BH = socket attributes (see #0542)
CX = number of bytes or words to write
DS:SI -> data to be written
Return: CF clear if successful
CF set on error

(Table 0545)
Call Write One routine with:
AL/AX = data to be written
BH = socket attributes (see #0542)
Return: CF clear if successful
CF set on error

(Table 0546)
Call Read One routine with:
BH = socket attributes (see #0542)
Return: CF clear if successful
AL/AX = data read
CF set on error

(Table 0547)
Call Increment Offset routine with:
BH = socket attributes (see #0542)
Return: CF clear if successful
CF set on error

(Table 0548)
Call Set Offset routine with:
DX:DI = new offset address
Return: CF clear if successful
CF set on error

(Table 0549)
Call Get Status routine with:
nothing
Return: AL = current card status (see #0540)
--------s-1A83-------------------------------
INT 1A - Tandy 2500, Tandy 1000L series - START PLAYING DIGITAL SOUND
AH = 83h
AL = volume (0=silence, 7=highest)
CX = number of bytes to play
DX = time between sound samples (multiples of 273 nanoseconds)
only bits 11-0 used
ES:BX -> sound data (array of 8-bit unsigned PCM samples)
Return: AH = 00h
CF set if sound is busy
CF clear if sound chip is free
Notes: this call returns immediately while the sound plays in the
background; the sound chip is clocked at 3.57 MHz, with the low 12
bits of DX specifying the clock divisor
The BIOS appears to call INT 15/AX=91FBh when the sound device
underflows to allow another INT 1A/AH=83h for seamless playing of
long sounds.
SeeAlso: AH=84h"Tandy",INT 15/AH=91h
--------X-1A83-------------------------------
INT 1A - PCMCIA Socket Services v1.00 - GET SOCKET SERVICES VERSION NUMBER
AH = 83h
AL = adapter number
Return: CF clear if successful
AX = Socket Services version (BCD)
BX = implementation version (BCD)
CX = 5353h ("SS")
DS:SI -> ASCIZ implementor description
CF set on error
AH = error code (01h) (see #0536)
Note: the current version (from the Revision A.00 documentation) of Socket
Services is 1.00 (AX=0100h)
SeeAlso: AH=80h"PCMCIA"
--------s-1A84-------------------------------
INT 1A - Tandy 2500, Tandy 1000L series - STOP PLAYING DIGITAL SOUND
AH = 84h
Return: ???
Note: the BIOS will call INT 15/AX=91FBh when the sound has stopped playing
SeeAlso: AH=83h"Tandy",AH=85h"Tandy"
--------X-1A84-------------------------------
INT 1A - PCMCIA Socket Services v1.00 - INQUIRE ADAPTER
AH = 84h
AL = adapter number
Return: CF clear if successful
AH destroyed
BH = number of windows
BL = number of sockets (1-16)
CX = number of EDCs
DH = capabilities (see #0550)
DL = status change interrupt used (only if DH bit 3 set)(see #0551)
CF set on error
AH = error code (01h) (see #0536)
SeeAlso: AH=80h"PCMCIA",AH=85h"PCMCIA",AH=87h

Bitfields for PCMCIA capabilities:
Bit(s) Description (Table 0550)
7-6 reserved (0)
5 status change interrupt is hardware shareable
4 status change interrupt is software shareable
3 status change interrupt
2 data bus width is per-socket rather than per-window
1 power management is per-adapter rather than per-socket
0 indicators are per-adapter rather than per-socket

(Table 0551)
Values for PCMCIA status change interrupt usage:
00h-0Fh IRQ level
10h NMI
11h I/O check
12h bus error
13h vendor specific
14h-FFh reserved
--------s-1A85-------------------------------
INT 1A - Tandy 2500, Tandy 1000L series - DIGITAL SOUND???
AH = 85h
???
Return: ???
Note: this function is not supported by the Tandy 1000SL/TL BIOS
SeeAlso: AH=7Fh,AH=83h"Tandy"
--------X-1A85-------------------------------
INT 1A - PCMCIA Socket Services v1.00 - GET ADAPTER
AH = 85h
AL = adapter number
Return: CF clear if successful
AH destroyed
DH = adapter attributes (see #0552)
CF set on error
AH = error code (01h) (see #0536)
SeeAlso: AH=84h"PCMCIA",AH=86h

Bitfields for PCMCIA adapter attributes:
Bit(s) Description (Table 0552)
7-5 reserved (0)
4 hardware share status change
3 software share status change
2 enable status change interrupts
1 adapter preserves state information during reduced power consumption
0 attempting to reduce power consumption
--------X-1A86-------------------------------
INT 1A - PCMCIA Socket Services v1.00 - SET ADAPTER
AH = 86h
AL = adapter number
DH = new adapter attributes (see #0552)
Return: CF clear if successful
AH destroyed
CF set on error
AH = error code (01h) (see #0536)
SeeAlso: AH=84h"PCMCIA",AH=85h"PCMCIA"
--------X-1A87-------------------------------
INT 1A - PCMCIA Socket Services v1.00 - INQUIRE WINDOW
AH = 87h
AL = adapter number
BH = window number
Return: CF clear if successful
AH destroyed
BL = capabilities (see #0553)
CX = bitmap of assignable sockets
DH = EISA A15-A12 address lines (in bits 7-4, bits 3-0 = 0)
DL = supported access speeds (see #0554)
DS:SI -> Memory Window Characteristics table (see #0555)
DS:DI -> I/O Window Characteristics table (see #0556)
CF set on error
AH = error code (01h,11h) (see #0536)
SeeAlso: AH=84h"PCMCIA",AH=88h,AH=89h,AH=8Ch

Bitfields for PCMCIA window capabilities:
Bit(s) Description (Table 0553)
7-5 reserved (0)
4 separate enable for EISA comon space
3 EISA I/O mappable
2 I/O space
1 attribute memory
0 common memory

Bitfields for PCMCIA supported access speeds:
Bit(s) Description (Table 0554)
7 reserved (0)
6 600 ns
5 300 ns
4 250 ns
3 200 ns
2 150 ns
1 100 ns
0 WAIT line monitoring

Format of PCMCIA Memory Window Characteristics table:
Offset Size Description (Table 0555)
00h WORD window capabilities (see #0557)
02h WORD minimum base address in 4K pages
04h WORD maximum base address in 4K pages
06h WORD minimum window size in 4K pages
08h WORD maximum window size in 4K pages
0Ah WORD window size granularity (4K units)
0Ch WORD required base address alignment (4K units)
0Eh WORD required card offset alignment (4K units)

Format of PCMCIA I/O Window Characteristics table:
Offset Size Description (Table 0556)
00h WORD window capabilities (see #0557)
02h WORD minimum base address in bytes
04h WORD maximum base address in bytes
06h WORD minimum window size in bytes
08h WORD maximum window size in bytes
0Ah WORD window size granularity (bytes)

Bitfields for PCMCIA window capabilities:
Bit(s) Description (Table 0557)
0 programmable base address
1 programmable window size
2 window disable/enable supported
3 8-data bus
4 16-data bus
5 base address alignment on size boundary required
6 power-of-two size granularity
---memory windows---
7 card offset must be aligned on size boundary
8 paging hardware available
9 paging hardware shared
10 page disable/enable supported
11-15 reserved (0)
---I/O windows---
7-15 reserved (0)
--------X-1A88-------------------------------
INT 1A - PCMCIA Socket Services v1.00 - GET WINDOW
AH = 88h
AL = adapter number
BH = window number
Return: CF clear if successful
AH destroyed
BL = socket number (0-16) (0 = not assigned)
CX = window size (bytes for I/O window, 4K units for memory window)
DH = window attributes (see #0558)
DL = access speed (only one bit set) (see #0554)
SI = window base address (bytes if I/O, 4K units if memory)
DI = card offset address (memory only, 4K units)
CF set on error
AH = error code (01h,11h) (see #0536)
SeeAlso: AH=87h,AH=89h,AH=8Ah

Bitfields for PCMCIA window attributes:
Bit(s) Description (Table 0558)
0 memory-mapped rather than I/O-mapped
1 attribute memory rather than common (memory-mapped)
EISA mapped (I/O)
2 enabled
3 16-data path
4 subdivided into pages (memory-mapped only)
5 non-specific access slot enable (EISA-mapped only)
6-7 reserved (0)
--------X-1A89-------------------------------
INT 1A - PCMCIA Socket Services v1.00 - SET WINDOW
AH = 89h
AL = adapter number
BH = window number
BL = socket number
CX = window size (bytes if I/O window, 4K units if memory window)
DH = window attributes (see #0558)
DL = access speed (only one bit set) (see #0554)
SI = window base address (bytes if I/O, 4K units if memory window)
DI = card offset addrress (memory only, 4K units)
Return: CF clear if successful
AH destroyed
CF set on error
AH = error code (01h,03h,07h,08h,0Ah,0Bh,0Dh,10h,11h) (see #0536)
SeeAlso: AH=87h,AH=88h,AH=8Bh
--------X-1A8A-------------------------------
INT 1A - PCMCIA Socket Services v1.00 - GET PAGE
AH = 8Ah
AL = adapter number
BH = window number
BL = page number
Return: CF clear if successful
AH destroyed
DX = page attributes (see #0559)
DI = memory card offset (4K units)
CF set on error
AH = error code (01h,08h,11h) (see #0536)
Notes: this function is only valid for memory-mapped windows
the socket being operated on is implied by the previous AH=89h call
SeeAlso: AH=88h,AH=8Bh

Bitfields for PCMCIA page attributes:
Bit(s) Description (Table 0559)
0 page enabled
15-1 reserved (0)
--------X-1A8B-------------------------------
INT 1A - PCMCIA Socket Services v1.00 - SET PAGE
AH = 8Bh
AL = adapter number
BH = window number
BL = page number
DX = page attributes (see #0559)
DI = memory card offset (4K units)
Return: CF clear if successful
AH destroyed
CF set on error
AH = error code (01h,02h,07h,08h,11h) (see #0536)
Notes: this function is only valid for memory-mapped windows
the socket being operated on is implied by the previous AH=89h call
SeeAlso: AH=89h,AH=8Ah
--------X-1A8C-------------------------------
INT 1A - PCMCIA Socket Services v1.00 - INQUIRE SOCKET
AH = 8Ch
AL = adapter number
BL = socket number (01h to maximum supported by adapter)
Return: CF clear if successful
AH destroyed
DH = capabilities (see #0560)
DL = hardware indicators (see #0561)
DS:SI -> Socket Characteristics table (see #0562)
DS:DI -> Power Management table (see #0564)
CF set on error
AH = error code (01h,0Bh) (see #0536)
SeeAlso: AH=87h,AH=8Dh,AH=8Eh

Bitfields for PCMCIA socket capabilities:
Bit(s) Description (Table 0560)
0 card change
1 card lock
2 insert card (motor control)
3 eject card (motor control)
4-7 reserved (0)

Bitfields for PCMCIA socket hardware indicators:
Bit(s) Description (Table 0561)
0 busy status
1 write-protected
2 battery status
3 card lock status
4 XIP status (eXecute-In-Place)
5-7 reserved (0)

Format of PCMCIA Socket Characteristics table:
Offset Size Description (Table 0562)
00h WORD supported card types (see #0563)
02h WORD steerable IRQ levels (bit 0 = IRQ0 to bit 15 = IRQ15)
04h WORD additional steerable IRQ levels
bit 0: NMI
bit 1: I/O check
bit 2: bus error
bit 3: vendor-unique
bits 4-7 reserved (0)

Bitfields for supported card types:
Bit(s) Description (Table 0563)
0 memory card
1 I/O card
2-7 reserved (0)

Format of PCMCIA Power Management table:
Offset Size Description (Table 0564)
00h WORD number of entries in table (0 if power management not avail)
02h 2N BYTEs power levels
byte 0: voltage in 0.1V units
byte 1: power supply
bit 7: Vcc
bit 6: Vpp1
bit 5: Vpp2
--------X-1A8D-------------------------------
INT 1A - PCMCIA Socket Services v1.00 - GET SOCKET

AH = 8Dh
AL = adapter number
BL = socket number (01h to maximum supported by adapter)
Return: CF clear if successful
AH destroyed
BH = status change interrupt enable mask (see #0538)
CH = Vcc level (lower nybble) (see #0564)
CL = Vpp1 level (upper nybble) and Vpp2 level (lower nybble)
DH = current socket status (see #0539)
DL = indicators (see #0561)
SI = card type (see #0565)
DI = IRQ level steering (I/O only) (see #0566)
CF set on error
AH = error code (01h,0Bh) (see #0536)
SeeAlso: AH=8Ch,AH=8Eh

Bitfields for PCMCIA card type:
Bit(s) Description (Table 0565)
0 memory
1 I/O
2-15 reserved (0)

Bitfields for PCMCIA I/O level steering:
Bit(s) Description (Table 0566)
15 interrupt steering enabled
14-5 reserved (0)
4-0 IRQ level (0-15=IRQ,16=NMI,17=I/O check,18=bus error,19=vendor)
--------X-1A8E-------------------------------
INT 1A - PCMCIA Socket Services v1.00 - SET SOCKET
AH = 8Eh
AL = adapter number
BL = socket number (01h to maximum supported by adapter)
BH = status change interrupt enable mask (see #0538)
CL = Vpp1 level (upper nybble) and Vpp2 level (lower nybble)
DH = current socket status (see #0539)
DL = indicators (see #0561)
SI = card type (see #0565)
DI = IRQ level steering (I/O only) (see #0566)
Return: CF clear if successful
AH destroyed
CF set on error
AH = error code (01h,02h,05h,06h,0Bh,0Eh,0Fh) (see #0536)
SeeAlso: AH=8Ch,AH=8Dh
--------X-1A8F-------------------------------
INT 1A - PCMCIA Socket Services v1.00 - GET CARD
AH = 8Fh
AL = adapter number
BL = socket number (01h to maximum supported by adapter)
Return: CF clear if successful
AH destroyed
DL = current card status (see #0540)
CF set on error
AH = error code (01h,0Bh) (see #0536)
SeeAlso: AH=8Dh,AH=90h
--------X-1A90-------------------------------
INT 1A - PCMCIA Socket Services v1.00 - RESET CARD
AH = 90h
AL = adapter number
BL = socket number (01h to maximum supported by adapter)
Return: CF clear if successful
AH destroyed
CF set on error
AH = error code (01h,0Bh,14h) (see #0536)
Note: toggles RESET pin of the specified card, but does not wait after
toggling the pin; it is the caller's responsibility to avoid
accessing the card before it is ready again
--------X-1A91-------------------------------
INT 1A - PCMCIA Socket Services v1.00 - READ ONE
AH = 91h
AL = adapter number
BL = socket number (01h to maximum supported by adapter)
BH = attributes (see #0567)
DX:SI = card address
Return: CF clear if successful
AH destroyed
CL/CX = value read
CF set on error
AH = error code (01h,07h,09h,0Bh,14h) (see #0536)
CX may be destroyed
Note: this function is only valid for I/O-mapped sockets
SeeAlso: AH=92h,AH=93h,INT 21/AX=440Dh"IOCTL"

Bitfields for PCMCIA attributes:
Bit(s) Description (Table 0567)
2 even bytes only
1 word rather than byte
0 attribute memory instead of common memory
--------X-1A92-------------------------------
INT 1A - PCMCIA Socket Services v1.00 - WRITE ONE
AH = 92h
AL = adapter number
BL = socket number (01h to maximum supported by adapter)
BH = attributes (see #0567)
CL/CX = value to write
DX:SI = card address
Return: CF clear if successful
AH destroyed
CF set on error
AH = error code (01h,07h,0Bh,12h,14h) (see #0536)
Note: this function is only valid for I/O-mapped sockets; it also does not
implement Card Technology handling--use AH=94h when writing to
non-RAM technologies
SeeAlso: AH=91h,AH=94h,INT 21/AX=440Dh"IOCTL"
--------X-1A93-------------------------------
INT 1A - PCMCIA Socket Services v1.00 - READ MULTIPLE
AH = 93h
AL = adapter number
BL = socket number (01h to maximum supported by adapter)
BH = attributes (see #0567)
CX = number of bytes or words to read
DX:SI = card address
DS:DI -> data buffer to be filled
Return: CF clear if successful
AH destroyed
CF set on error
AH = error code (01h,07h,09h,0Bh,14h) (see #0536)
Note: this function is only available on I/O-mapped sockets
SeeAlso: AH=91h,AH=94h,INT 21/AX=440Dh"IOCTL"
--------X-1A94-------------------------------
INT 1A - PCMCIA Socket Services v1.00 - WRITE MULTIPLE
AH = 94h
AL = adapter number
BL = socket number (01h to maximum supported by adapter)
BH = attributes (see #0567)
CX = number of bytes or words to read
DX:DI = card address
DS:SI -> buffer containing data
BP = Card Technology type (0000h = RAM)
Return: CF clear if successful
AH destroyed
CF set on error
AH = error code (01h,07h,0Bh,0Ch,12h,14h) (see #0536)
Notes: this function is only available on I/O-mapped sockets
Socket Services calls the Card Technology callback (see #0541) for
any card technology it does not directly support
SeeAlso: AH=82h"PCMCIA",AH=92h,AH=93h,INT 21/AX=440Dh"IOCTL"
--------X-1A95-------------------------------
INT 1A - PCMCIA Socket Services v1.00 - INQUIRE ERROR DETECTION CODE
AH = 95h
AL = adapter number
BH = EDC generator number
Return: CF clear if successful
AH destroyed
CX = bitmap of assignable sockets
DH = EDC capabilities (see #0568)
DL = supported EDC types (see #0569)
CF set on error
AH = error code (01h,04h) (see #0536)
SeeAlso: AH=96h,AH=9Ch

Bitfields for EDC capabilities:
Bit(s) Description (Table 0568)
0 unidirectional only generation
1 bidirectional only generation
2 register-based (I/O-mapped) support
3 memory-mapped support
4 pausable
5-7 reserved (0)

Bitfields for supported EDC types:
Bit(s) Description (Table 0569)
0 8-checksum
1 16-CRC-SDLC
2-7 reserved (0)
--------X-1A96-------------------------------
INT 1A - PCMCIA Socket Services v1.00 - GET ERROR DETECTION CODE
AH = 96h
AL = adapter number
BH = EDC generator number
Return: CF clear if successful
AH destroyed
BL = socket number
DH = EDC attributes (see #0570)
DL = EDC type (see #0569) (only one bit set)
CF set on error
AH = error code (01h,04h) (see #0536)
SeeAlso: AH=95h,AH=97h,AH=9Ch

Bitfields for EDC attributes:
Bit(s) Description (Table 0570)
0 unidirectional only
1 (if 0 set) clear=read, set=write
2-7 reserved (0)
--------X-1A97-------------------------------
INT 1A - PCMCIA Socket Services v1.00 - SET ERROR DETECTION CODE
AH = 97h
AL = adapter number
BH = EDC generator
BL = socket number
DH = EDC attributes (see #0570)
DL = EDC type (see #0569) (only one bit may be set)
Return: CF clear if successful
AH destroyed
CF set on error
AH = error code (01h,02h,04h,0Bh) (see #0536)
SeeAlso: AH=96h,AH=9Ch
--------X-1A98-------------------------------
INT 1A - PCMCIA Socket Services v1.00 - START ERROR DETECTION CODE
AH = 98h
AL = adapter number
BH = EDC generator
Return: CF clear if successful
AH destroyed
CF set on error
AH = error code (01h,04h) (see #0536)
SeeAlso: AH=96h,AH=99h,AH=9Bh,AH=9Ch
--------X-1A99-------------------------------
INT 1A - PCMCIA Socket Services v1.00 - PAUSE ERROR DETECTION CODE
AH = 99h
AL = adapter number
BH = EDC generator
Return: CF clear if successful
AH destroyed
CF set on error
AH = error code (01h,04h) (see #0536)
SeeAlso: AH=9Ah
--------X-1A9A-------------------------------
INT 1A - PCMCIA Socket Services v1.00 - RESUME ERROR DETECTION CODE
AH = 9Ah
AL = adapter number
BH = EDC generator
Return: CF clear if successful
AH destroyed
CF set on error
AH = error code (01h,04h) (see #0536)
SeeAlso: AH=99h,AH=98h
--------X-1A9B-------------------------------
INT 1A - PCMCIA Socket Services v1.00 - STOP ERROR DETECTION CODE
AH = 9Bh
AL = adapter number
BH = EDC generator
Return: CF clear if successful
AH destroyed
CF set on error
AH = error code (see #0536)
SeeAlso: AH=98h,AH=99h,AH=9Ch
--------X-1A9C-------------------------------
INT 1A - PCMCIA Socket Services v1.00 - READ ERROR DETECTION CODE
AH = 9Ch
AL = adapter number
BH = EDC generator
Return: CF clear if successful
AH destroyed
DL/DX = computed checksum or CRC
CF set on error
AH = error code (01h,04h) (see #0536)
SeeAlso: AH=95h,AH=96h,AH=98h,AH=99h,AH=9Bh
--------X-1A9D-------------------------------
INT 1A - PCMCIA Socket Services v2.1??? - GET VENDOR INFO
AH = 9Dh
AL = adapter number
BH = EDC generator
ES:EDI -> vendor information structure (see #0571)
Return: CF clear if successful
AH destroyed
DX = vendor release number in BCD
ES:EDI unchanged
CF set on error
AH = error code (01h,15h) (see #0536)
Notes: this API is supported by recent versions of the AMI BIOS
the low-level API described here is hidden by the higher-level
ExCA API once Card Services has been installed
SeeAlso: AH=9Dh"ExCA"

Format of Vendor Information structure:
Offset Size Description (Table 0571)
00h WORD buffer length (set to size of buffer below)
04h WORD (ret) data length
08h x BYTEs implementor name (ASCIIZ string)
--------X-1A9D-------------------------------
INT 1A - Intel PCMCIA ExCA Card Services - API
AH = 9Dh
AL = subfunction (see #0572)
???
Return: ???
SeeAlso: AH=9Dh"ExCA"

(Table 0572)
Values for PCMCIA ExCA Card Services subfunction number:
00h Client Services: Get Number of Sockets
01h Advanced Client Utilities: Initialize
02h Client Services: Register Client
03h Client Services: Deregister Client
04h Advanced Client Utilities: Enumerate Clients
05h Client Services: Register SCB
06h Client Services: Deregister SCB
07h Advanced Client Utilities: Register MTD
08h Advanced Client Utilities: Deregister MTD
09h Advanced Client Utilities: Enumerate MTD
0Ah Client Services: Get Status
0Bh Client Services: Reset Card
0Ch Client Utilities: Get First Tuple
0Dh Client Utilities: Get Next Tuple
0Eh Client Utilities: Determine First Region
0Fh Client Utilities: Determine Next Region
10h Client Utilities: Get First Region
11h Client Utilities: Get Next Region
12h Client Utilities: Get First Partition
13h Client Utilities: Get Next Partition
14h Bulk Memory Services: Open Region
15h Bulk Memory Services: Read Memory
16h Bulk Memory Services: Write Memory
17h Bulk Memory Services: Copy Memory
18h Bulk Memory Services: Erase Memory
19h Resource Management: Request I/O
1Ah Resource Management: Release I/O
1Bh Resource Management: Request Memory
1Ch Client Services: Modify Window
1Dh Resource Management: Release Memory
1Eh Client Services: Map Mem Page
1Fh Advanced Client Utilities: Return SS Entry
20h Advanced Client Utilities: Map Log to Phy
21h Advanced Client Utilities: Map Log Phy to Log
22h Resource Management: Request IRQ
23h Resource Management: Release IRQ
24h Bulk Memory Services: Close Region
--------X-1A9E-------------------------------
INT 1A - PCMCIA Socket Services v2.1 - ACKNOWLEDGE INTERRUPT
AH = 9Eh
AL = adapter number
Return: CF clear if successful
AH destroyed
CX = bitmap representing sockets which have changed status
CF set on error
AH = error code (01h) (see #0536)
Note: this API is supported by recent versions of the AMI BIOS
--------X-1A9F-------------------------------
INT 1A - PCMCIA Socket Services v2.1 - GET/SET PRIOR INT 1A HANDLER
AH = 9Fh
AL = adapter number
BL = mode
00h get prior INT 1Ah handler
01h set prior INT 1Ah handler
CX:DX -> new prior handler
Return: CF clear if successful
AH destroyed
CX:DX -> old prior handler
CF set on error
AH = error code (01h,15h,18h) (see #0536)
Desc: allows hooking of INT 16h "behind" the Socket Services hook
Note: this API is supported by recent versions of the AMI BIOS
SeeAlso: AH=9Eh,AH=A0h"PCMCIA",AH=AEh"PCMCIA"
--------c-1AA0-------------------------------
INT 1A U - Disk Spool II v2.07+ - INSTALLATION CHECK
AH = A0h
Return: AH = B0h if installed
AL = pending INT 1A/AH=D0h subfunction if nonzero???
ES = code segment
ES:BX -> name of current spool file
ES:SI -> current despool file
CL = despooler state (00h disabled, 41h enabled)
CH = spooler state (00h disabled, 41h enabled)
DL = despooler activity
00h currently active printing a file
41h standing by
DH = 00h ???
= 41h ???
DI = 0000h ???
0001h ???
Program: Disk Spool II is a shareware disk-based print spooler by Budget
Software Company
Note: this function is also supported by Vertisoft's Emulaser utility ELSPL,
as that is a licensed version of Disk Spool II
SeeAlso: AH=ABh,AH=C0h,AH=D0h,AH=E1h
--------X-1AA0-------------------------------
INT 1A - PCMCIA Socket Services v2.1 - GET/SET SOCKET SERVICES ADDRESS
AH = A0h
AL = adapter number
BH = mode
00h real mode
01h 16:16 protected mode
02h 16:32 protected mode
03h 00:32 (Flat) protected mode
BL = subfunction
00h return number of additional data areas (see #0573)
01h return description of additional data areas (see #0574)
02h accept mode-specific pointers to data areas (see #0575)
ES:EDI -> buffer supplied by caller
Return: CF clear if successful
AH destroyed
CX = number of additional data areas
ES:EDI unchanged
CF set on error
AH = error code (01h,02h,15h,16h,18h) (see #0536)
SeeAlso: AH=9Fh,AH=AEh

Format of PCMCIA Subfunction 00h Buffer Table Entry structure:
Offset Size Description (Table 0573)
00h DWORD 32-bit linear base address of the code segment
04h DWORD segment limit of the code segment
08h DWORD entry point offset
0Ch DWORD 32-bit linear base address of the data segment
(ignored in 00:32 flat mode)
10h DWORD segment limit of the data segment
14h DWORD data area offset. Only used in 32-bit protected mode.
SeeAlso: #0574,#0575

Format of PCMCIA Additional Data Area Description structure [array]:
Offset Size Description (Table 0574)
00h DWORD 32-bit linear base address of the additional data segment
(ignored in 00:32 flat mode)
04h DWORD segment limit of the code segment
08h DWORD data area offset (only used in 32-bit protected mode)
SeeAlso: #0573,#0575

Format of PCMCIA Subfunction 02h Buffer Table Entry structure:
Offset Size Description (Table 0575)
00h DWORD 32-bit offset(ignored in 16:16 protected mode)
04h DWORD selector (only used in 00:32 flat mode)
08h DWORD reserved
SeeAlso: #0573,#0574
--------X-1AA1-------------------------------
INT 1A - PCMCIA Socket Services v2.1 - GET ACCESS OFFSETS
AH = A1h
AL = adapter number
BH = Mode
00h = Real Mode
01h = 16:16 Protected Mode
02h = 16:32 Protected Mode
03h = 00:32 Protected Mode
CX = Number of access offsets
ES:EDI -> buffer supplied by caller, CX words long (see #0576)
Return: CF clear if successful
AH destroyed
DX = number of access offsets supported
ES:EDI unchanged
CF set on error
AH = error code (01h,15h,16h) (see #0536)
Desc: Returns an array of low-level adapter-specific optimized
PC Card access routines for adapters that use registers
or I/O ports to access PC Card memory. Adapters that access
PC Card memory through windows mapped to host system memory
do not support this function.
Note: offsets returned are 16-bit offsets into the
Socket Services code segment. They must be called
appropriately for the processor mode selected.
(Real, 16:16 and 16:32 modes use FAR CALL,
Flat 00:32 mode uses a 32-bit NEAR CALL).
SeeAlso: AH=AEh

Format of Offset Table structure:
Offset Size Description (Table 0576)
00h WORD Set Address
02h WORD Set Auto Increment
04h WORD Read Byte
06h WORD Read Word
08h WORD Read Byte with Auto Increment
0Ah WORD Read Word with Auto Increment
0Ch WORD Read Words
0Eh WORD Read Words with Auto Increment
10h WORD Write Byte
12h WORD Write Word
14h WORD Write Byte with Auto Increment
16h WORD Write Word with Auto Increment
18h WORD Write Words
1Ah WORD Write Words with Auto Increment
1Ch WORD Compare Byte
1Eh WORD Compare Byte with Auto Increment
20h WORD Compare Words
22h WORD Compare Words with Auto Increment
--------c-1AAB-------------------------------
INT 1A U - Disk Spool II v1.83 - INSTALLATION CHECK
AH = ABh
Return: AH = BAh if installed
AL = pending INT 1A/AH=ADh subfunction if nonzero???
ES = code segment
ES:BX -> name of current spool file
ES:SI -> current despool file
CL = despooler state (00h disabled, 41h enabled)
CH = spooler state (00h disabled, 41h enabled)
DL = despooler activity
00h currently active printing a file
41h standing by
DH = 00h ???
= 41h ???
DI = 0000h ???
0001h ???
Program: Disk Spool II is a shareware disk-based print spooler by Budget
Software Company
SeeAlso: AH=A0h,AH=ACh,AH=ADh,AH=E1h
--------c-1AAC-------------------------------
INT 1A U - Disk Spool II v1.83 - INSTALLATION CHECK
AH = ACh
Return: (see AH=ABh)
Note: this function is identical to AH=ABh
SeeAlso: AH=A0h,AH=ABh,AH=ADh
--------c-1AAD-------------------------------
INT 1A U - Disk Spool II v1.83 - FUNCTION CALLS
AH = ADh
AL = function code (see #0577)
Return: AH = 00h if successful
SeeAlso: AH=ABh

(Table 0577)
Values for Disk Spool function code:
02h enable spooler only
03h enable the despooler
04h disable the despooler
08h inhibit popup menu
09h enable popup menu
0Ah ???
0Bh disable the spooler
0Ch start despooler after last successfully printed document???
0Dh start despooler at the exact point where it last left off???
0Eh pop up the menu
0Fh ???
11h ???
14h ???
15h ???
16h ???
17h ???
18h ???
19h ???
20h clear file pointed to by the despooler???
21h ???
22h ???
23h ???
30h ???
--------X-1AAE-------------------------------
INT 1A - PCMCIA Socket Services v2.1 - VENDOR SPECIFIC
AH = AEh
AL = adapter number
all other registers are vendor-specific
Return: vendor specific
SeeAlso: AH=A1h,AH=AFh
--------X-1AAE-------------------------------
INT 1A - PCMCIA Socket Services v2.1 - API
AH = AEh
SI = function
0002h ???
0100h ???
0101h ???
8000h ???
8001h ???
details not yet available
Return: CF clear if successful
CF set on error
AH = error code (02h,0Bh,11h,15h,17h) (see #0536)
SeeAlso: AH=9Eh
--------X-1AAF-------------------------------
INT 1A - PCMCIA v2 - API
AH = AFh
details not yet available
SeeAlso: AH=AEh
--------X-1AB000-----------------------------
INT 1A U - HP 100LX/200LX - PCMCIA - ???
AX = B000h
ES:BX -> parameter block ???
Return: CF clear if ???
CF set if ???
Note: called by HP 100LX/200LX PCMCIA client CIC100.EXE
--------d-1AB001CX4D52-----------------------
INT 1A - Microsoft Real-Time Compression Interface (MRCI) - ROM-BASED SERVER
AX = B001h
CX = 4D52h ("MR")
DX = 4349h ("CI")
Return: CX = 4943h ("IC") if installed
DX = 524Dh ("RM") if installed
ES:DI -> MRCINFO structure (see #0578)
Note: this call is functionally identical to INT 2F/AX=4A12h, which should
be called first, as this call is used for the first, ROM-based
MRCI server, while the other call is used for RAM-based servers
which may be partially or entirely replacing a prior server
SeeAlso: INT 2F/AX=4A12h

Format of MRCINFO structure:
Offset Size Description (Table 0578)
00h 4 BYTEs vendor signature
"MSFT" Microsoft
04h WORD server version (high=major)
06h WORD MRCI specification version
08h DWORD address of server entry point (see #0580)
0Ch WORD bit flags: server capabilities (see #0579)
0Eh WORD bit flags: hardware assisted capabilities (see #0579)
10h WORD maximum block size supported by server (at least 8192 bytes)

Bitfields for MRCI capabilities:
Bit(s) Description (Table 0579)
0 standard compress
1 standard decompress
2 update compress
3 MaxCompress (not present in initial public release)
4 reserved
5 incremental decompress
6 MRCI 2.0 standard compress
7 MRCI 2.0 standard decompress
8-14 reserved
15 this structure is in ROM and can't be modified
(server capabilities only)

(Table 0580)
Call MRCI entry point with:
DS:SI -> MRCREQUEST structure (see #0581)
CX = type of client (0000h application, 0001h file system)
AX = operation
0001h perform standard compression
0002h perform standard decompression
0004h perform update compression
0008h perform MaxCompress
0020h perform incremental decompression
0040h perform MRCI 2.0 standard compression
0080h perform MRCI 2.0 standard decompression
AX = FFFFh clear flags
BX = bitmask of flags to clear (set bits in BX are flags to clear)
Return: AX = status
0000h successful
0001h invalid function
0002h server busy, try again
0003h destination buffer too small
0004h incompressible data
0005h bad compressed data format
BP destroyed (MS-DOS 6.2)
Note: MRCI driver may chain to a previous driver

Format of MRCREQUEST structure:
Offset Size Description (Table 0581)
00h DWORD pointer to source buffer
04h WORD size of source buffer (0000h = 64K)
06h WORD (UpdateCompress only)
(call) offset in source buffer of beginning of changed data
(ret) offset in destination buffer of beginning of changed
compressed data
08h DWORD pointer to destination buffer
must contain original compressed data for UpdateCompress
0Ch WORD size of destination buffer (0000h = 64K)
any compression: size of buffer for compressed data
standard decompression: number of bytes to be decompressed
incremental decompression: number of byte to decompress now
(ret) actual size of resulting data
0Eh WORD client compressed data storage allocation size
10h DWORD incremental decompression state data
set to 00000000h before first incremental decompression call
Notes: the source and destination buffers may not overlap
the source and destination buffer sizes should normally be the same
application should not update the contents of the MRCREQUEST structure
between incremental decompression calls
--------X-1AB101-----------------------------
INT 1A - Intel PCI BIOS v2.0c - INSTALLATION CHECK
AX = B101h
Return: AH = 00h if installed
CF clear
EDX = 20494350h (' ICP')
EDI = physical address of protected-mode entry point (see #0584)
AL = PCI hardware characteristics (see #0583)
BH = PCI interface level major version (BCD)
BL = PCI interface level minor version (BCD)
CL = number of last PCI bus in system
EAX, EBX, ECX, and EDX may be modified
all other flags (except IF) may be modified
Note: this function may require up to 1024 byte of stack; it will not enable
interrupts if they were disabled before making the call
SeeAlso: AX=B181h

(Table 0582)
Values for PCI BIOS v2.0c status codes:
00h successful
81h unsupported function
83h bad vendor ID
86h device not found
87h bad PCI register number

Bitfields for PCI hardware characteristics:
Bit(s) Description (Table 0583)
0 configuration space access mechanism 1 supported
1 configuration space access mechanism 2 supported
2-3 reserved
4 Special Cycle generation mechanism 1 supported
5 Special Cycle generation mechanism 2 supported
6-7 reserved

(Table 0584)
Call protected-mode entry point with:
registers as for real/V86-mode INT call
CS = ring 0 descriptor with access to full address space
Return: as for real/V86-mode call
--------X-1AB102-----------------------------
INT 1A - Intel PCI BIOS v2.0c - FIND PCI DEVICE
AX = B102h
CX = device ID
DX = vendor ID
SI = device index (0-n)
Return: CF clear if successful
CF set on error
AH = status (00h,83h,86h) (see #0582)
00h successful
BH = bus number
BL = device/function number (bits 7-3 device, bits 2-0 func)
EAX, EBX, ECX, and EDX may be modified
all other flags (except IF) may be modified
Notes: this function may require up to 1024 byte of stack; it will not enable
interrupts if they were disabled before making the call
device ID FFFFh may be reserved as a wildcard in future implementations
the meanings of BL and BH on return were exchanged between the initial
drafts of the specification and final implementation
all devices sharing a single vendor ID and device ID may be enumerated
by incrementing SI from 0 until error 86h is returned
SeeAlso: AX=B182h
--------X-1AB103-----------------------------
INT 1A - Intel PCI BIOS v2.0c - FIND PCI CLASS CODE
AX = B103h
ECX = class code (see also #F056,#0585)
bits 31-24 unused
bits 23-16 class
bits 15-8 subclass
bits 7-0 programming interface
SI = device index (0-n)
Return: CF clear if successful
CF set on error
AH = status (00h,86h) (see #0582)
00h successful
BH = bus number
BL = device/function number (bits 7-3 device, bits 2-0 func)
86h device not found
EAX, EBX, ECX, and EDX may be modified
all other flags (except IF) may be modified
Notes: this function may require up to 1024 byte of stack; it will not enable
interrupts if they were disabled before making the call
the meanings of BL and BH on return were exchanged between the initial
drafts of the specification and final implementation
all devices sharing the same Class Code may be enumerated by
incrementing SI from 0 until error 86h is returned
SeeAlso: AX=B183h
--------X-1AB106-----------------------------
INT 1A - Intel PCI BIOS v2.0c - PCI BUS-SPECIFIC OPERATIONS
AX = B106h
BL = bus number
EDX = Special Cycle data
Return: CF clear if successful
CF set on error
AH = status (00h,81h) (see #0582)
EAX, EBX, ECX, and EDX may be modified
all other flags (except IF) may be modified
Note: this function may require up to 1024 byte of stack; it will not enable
interrupts if they were disabled before making the call
SeeAlso: AX=B186h
--------X-1AB108-----------------------------
INT 1A - Intel PCI BIOS v2.0c - READ CONFIGURATION BYTE
AX = B108h
BL = device/function number (bits 7-3 device, bits 2-0 function)
BH = bus number
DI = register number (0000h-00FFh) (see #0585)
Return: CF clear if successful
CL = byte read
CF set on error
AH = status (00h,87h) (see #0582)
EAX, EBX, ECX, and EDX may be modified
all other flags (except IF) may be modified
Notes: this function may require up to 1024 byte of stack; it will not enable
interrupts if they were disabled before making the call
the meanings of BL and BH on entry were exchanged between the initial
drafts of the specification and final implementation
SeeAlso: AX=B188h
--------X-1AB109-----------------------------
INT 1A - Intel PCI BIOS v2.0c - READ CONFIGURATION WORD
AX = B109h
BL = device/function number (bits 7-3 device, bits 2-0 function)
BH = bus number
DI = register number (0000h-00FFh) (see #0585)
Return: CF clear if successful
CX = word read
CF set on error
AH = status (00h,87h) (see #0582)
EAX, EBX, ECX, and EDX may be modified
all other flags (except IF) may be modified
Notes: this function may require up to 1024 byte of stack; it will not enable
interrupts if they were disabled before making the call
the meanings of BL and BH on entry were exchanged between the initial
drafts of the specification and final implementation
SeeAlso: AX=B189h
--------X-1AB10A-----------------------------

INT 1A - Intel PCI BIOS v2.0c - READ CONFIGURATION DWORD
AX = B10Ah
BH = bus number
BL = device/function number (bits 7-3 device, bits 2-0 function)
DI = register number (0000h-00FFh) (see #0585)
Return: CF clear if successful
ECX = dword read
CF set on error
AH = status (00h,87h) (see #0582)
EAX, EBX, ECX, and EDX may be modified
all other flags (except IF) may be modified
Notes: this function may require up to 1024 byte of stack; it will not enable
interrupts if they were disabled before making the call
the meanings of BL and BH on entry were exchanged between the initial
drafts of the specification and final implementation
SeeAlso: AX=B18Ah

Format of PCI Configuration Data:
Offset Size Description (Table 0585)
00h WORD vendor ID (read-only) (see #0586)
FFFFh returned if requested device non-existent
02h WORD device ID (read-only)
04h WORD command register (see #0587)
06h WORD status register (see #0588)
08h BYTE revision ID
09h 3 BYTEs class code
bits 7-0: programming interface
bits 15-8: sub-class
bits 23-16: class code (see also #F056)
0Ch BYTE cache line size
0Dh BYTE latency timer
0Eh BYTE header type
bits 6-0: header format
00h other
01h PCI-to-PCI bridge
bit 7: multi-function device
0Fh BYTE Built-In Self-Test result (see #0589)
10h DWORD base address 0 (see #0590)
14h DWORD base address 1
---header type 00h---
18h DWORD base address 2
1Ch DWORD base address 3
20h DWORD base address 4
24h DWORD base address 5
28h DWORD CardBus CIS pointer (read-only) (see #0592)
2Ch WORD subsystem vendor ID or 0000h
2Eh WORD subsystem ID or 0000h
30h DWORD expansion ROM base address (see #0591)
34h 2 DWORDs reserved
3Ch BYTE interrupt line
00h = none, 01h = IRQ1 to 0Fh = IRQ15
3Dh BYTE interrupt pin (read-only)
(00h = none, else indicates INTA# to INTD#)
3Eh BYTE minimum time bus master needs PCI bus ownership, in 250ns units
(read-only)
3Fh BYTE maximum latency, in 250ns units (bus masters only) (read-only)
---header type 01h---
18h BYTE primary bus number (for bus closer to host processor)
19h BYTE secondary bus number (for bus further from host processor)
1Ah BYTE subordinate bus number
1Bh BYTE secondary latency timer
1Ch BYTE I/O base (see #0593)
1Dh BYTE I/O limit (see #0593)
1Eh WORD secondary status
20h WORD memory base (see #0594)
22h WORD memory limit
24h WORD prefetchable memory base
26h WORD prefetchable memory limit
28h DWORD prefetchable base, upper 32 bits
2Ch DWORD prefetchable limit, upper 32 bits
30h WORD I/O base, upper 16 bits
32h WORD I/O limit, upper 16 bits
34h DWORD reserved
38h DWORD expansion ROM base address
3Ch BYTE interrupt line
3Dh BYTE interrupt pin (read-only)
3Eh WORD bridge control
------
40h 48 DWORDs varies by device (see #0595,#0596,#0597,#0598)

(Table 0586)
Values for PCI vendor ID:
1000h NCR
1002h ATI
1003h ULSI
1004h VLSI Technologies
1005h Avance Logics (ADL)
1006h Reply Group
1007h Netframe
1008h Epson
100Ah Phoenix
100Bh National Semiconductor
100Ch Tseng Labs
100Dh AST
100Eh Weitek
1010h Video Logic
1011h DEC
1012h Micronics
1013h Cirrus Logic (see also #0028)
1014h IBM
1016h ICL
1017h SPEA
1018h Unisys
1019h EliteGroup
101Ah NCR
101Bh Vitesse
101Ch Western Digital
101Eh AMI
101Fh Picturetel
1020h Hitachi
1021h Oki
1022h AMD
1023h Trident
1025h Acer
1028h Dell
1029h Siemens Nixdorf
102Ah LSI Logic
102Bh Matrox
102Ch Chips & Technologies
102Dh Wyse
102Eh Olivetti
102Fh Toshiba
1030h TMC
1031h Miro
1032h Compaq
1033h NEC
1034h Burndy
1035h Computers and Communications Research Lab
1036h Future Domain
1037h Hitachi
1038h AMP
1039h SIS
103Ah Seiko Epson
103Bh Tatung
103Ch Hewlett-Packard
103Eh Solliday
103Fh Logic Modeling
1040h Kubota Pacific
1041h Computrend
1042h PC Technology (see also PORT 03F0h"PCTech")
1043h Asustek
1044h Distributed Processing Technology (DPT)
1045h OPTi
1046h IPC
1047h Genoa
1048h Elsa
1049h Fountain
104Ah SGS Thomson
104Bh BusLogic
104Ch Texas Instruments
104Dh Sony
104Eh Oak
104Fh Co-Time
1050h Winbond
1051h Anigma
1052h Young
1054h Hitachi
1055h EFAR
1056h ICL
1057h Motorola
1058h Electronics and Telec. RSH
1059h Teknor
105Ah Promise
105Bh Foxconn
105Ch Wipro
105Dh Number9
105Eh VTech
105Fh Infotronic
1060h UMC
1061h X Tech
1062h Maspar
1063h Ocean
1064h Alcatel
1065h Texas Micro
1066h PicoPower
1067h Mitsubishi
1068h Diversified
1069h Mylex
106Ah Aten
106Bh Apple
106Ch Hyundai
106Dh Sequent
106Eh DFI
106Fh City Gate
1070h Daewoo
1071h Mitac
1072h GIT
1073h Yamaha
1074h NexGen
1075h Advanced Integration
1076h Chaintech
1077h Q Logic
1078h Cyrix
1079h I-Bus
107Ah Networth
107Bh Gateway 2000
107Ch Goldstar
107Dh Leadtek
107Eh Interphase
107Fh DTC
1080h Contaq
1081h Supermac
1082h EFA
1083h Forex
1084h Parador
1085h Tulip
1086h J. Bond
1087h Cache
1088h Microcomputer Systems
1089h Data General
108Ah Bit3
108Ch lonex
108Dh Olicom
108Fh Systemsoft
1090h Encore
1091h Intergraph
1092h Diamond
1093h National Instruments
1094h FIC
1095h CMD
1096h Alacron
1097h Appian
1098h Vision
1099h Samsung
109Ah Packard Bell
109Bh Gemlight
109Ch Megachips
109Dh Zida
109Eh Brooktree
109Fh Trigem
10A0h Meidensha
10A1h Juko
10A2h Quantum
10A3h Everex
10A4h Globe
10A5h Racal Interlan
10A6h Informtech
10A7h Benchmarq
10A8h Sierra
10A9h Silicon Graphics
10AAh ACC
10ABh Digicom
10ACh Honeywell
10ADh Symphony
10AEh Cornerstone
10AFh Microcomputer Systems
10B0h CardExpert
10B1h Cabletron
10B2h Raytheon
10B3h Databook
10B4h STB
10B5h PLX
10B7h 3com
10B8h Standard Microsystems Corporation (SMC)
10B9h Acer Labs
10BAh Mitsubishi
10BBh Dapha
10BCh ALR
10BDh Surecom
10BEh Tseng Labs
10BFh Most Inc.
10C0h Boca Research
10C1h ICM
10C2h Auspex
10C3h Samsung
10C4h Award
10C5h Xerox
10C6h Rambus
10C7h Media Vision
10C8h Neomagic
10C9h DataExpert
10CAh Fujitsu
10CBh Omron
10CCh Mentor
10CDh Advanced System Products
10CEh Radius
10CFh Citicorp
10D0h Fujitsu
10D1h Future+
10D2h Molex
10D3h Jabil
10D4h Hualon
10D5h Autologic
10D6h Cetia
10D7h BCM
10D8h Advanced Peripherals
10D9h Macronix
10DAh Thomas-Conrad
10DBh Rohm
10DCh CERN/ECP/EDU
10DDh Evans & Sutherland
10DEh NVidia
10DFh Emulex
10E0h IMS
10E1h TekRAM
10E2h Aptix
10E3h Newbridge
10E4h Tandem
10E5h Micro Industries
10E6h Gainbery
10E7h Vadem
10E8h Applied Micro
10E9h ALPS
10EAh Integraphics
10EBh Artists
10ECh Realtek
10EDh ASCII Corporation
10EEh Xilinx
10EFh Racore
10F0h Peritek
10F1h Tyan
10F2h Achme
10F3h Alaris
10F4h S-MOS Systems
10F5h NKK
10F6h Creative Electronic
10F7h Matsushita
10F8h Altos
10F9h PC Direct
10FAh Truevision
10FBh Thesys
10FCh I/O Data Device
10FDh Soyo
10FEh Fast
10FFh N-Cube
1100h Jazz
1101h Initio
1102h Creative Labs
1103h Triones
1104h Rasterops
1105h Sigma
1106h VIA
1107h Stratus
1108h Proteon
110Bh Xenon
110Ch Mini-Max
110Dh ZNyX
110Eh CPU Tech
110Fh Ross
1110h Powerhouse
1111h S.C.O.
1112h Rockwell
1113h Accton
1114h Atmel
1115h DuPont
1116h Data Translation
1117h Datacube
1118h Berg
1119h Vortex
111Ah Efficient Networks, Inc.
111Bh Teledyne
112Fh Imaging Technology
113Ch PLX
1159h MuTech
1193h Zeinet
120Eh Cyclades
1C1Ch Symphony
1DE1h TekRAM
5333h S3
8086h Intel
9004h Adaptec
907Fh Atronics
EDD8h "HER"
SeeAlso: #0585

Bitfields for PCI Configuration Command Register:
Bit(s) Description (Table 0587)
0 I/O access enabled
1 memory access enabled
2 master enable
3 special cycle recognition enabled
4 memory write and invalidate enabled
5 VGA palette snoop enabled
6 parity error response enabled
7 wait cycles enabled
8 system error (SERR# line) enabled
9 fast back-to-back transactions enabled
15-10 reserved
SeeAlso: #0585,#0588

Format of PCI Configuration Status Register:
Bit(s) Description (Table 0588)
4-0 reserved (0)
5 capable of running at 66 MHz
6 UDF supported
7 capable of fast back-to-back transactions
8 data parity error reported
10-9 device select timing
00 fast
01 medium
10 slow
11 reserved
11 signaled target abort
12 received target abort
13 received master abort
14 signaled system error (SERR# line)
15 detected parity error (set even if parity error reporting is disabled)
SeeAlso: #0585,#0587

Bitfields for PCI Configuration Built-In Self-Test register:
Bit(s) Description (Table 0589)
3-0 completion code (0000 = successful)
5-4 reserved
6 start BIST
7 BIST-capable
SeeAlso: #0585

Bitfields for PCI Configuration Base Address:
Bit(s) Description (Table 0590)
0 address type (0 = memory space, 1 = I/O space)
---memory address---
2-1 address type
00 anywhere in first 4GB
01 below 1MB
10 anywhere in 64-bit address space
11 reserved
3 prefetchable
31-4 bits 31-4 of base memory address if addressable in first 1MB or 4GB
63-4 bits 63-4 of base memory address if addressable in 64-bit memory
(bits 63-32 are stored in the following base address DWORD)
---I/O address---
1 reserved
31-2 bits 31-2 of base I/O port
SeeAlso: #0585

Bitfields for PCI Configuration Expansion ROM Address:
Bit(s) Description (Table 0591)
0 address decode enable (ROM address is valid)
10-1 reserved
31-11 bits 31-11 of ROM's starting physical address
SeeAlso: #0585

Bitfields for PCI Configuration CardBus CIS Pointer:
Bit(s) Description (Table 0592)
27-0 offset within address space defined by bits 30-28
30-28 address space
000 in device's device-specific configuration space
001 in memory pointed to by base address register 0
...
110 in memory pointed to by base address register 5
111 in device's expansion ROM
31 reserved (0)

Bitfields for PCI Configuration I/O base and limit:
Bit(s) Description (Table 0593)
3-0 (read-only) address decoding type
0000 16-bit
0001 32-bit
other reserved
7-4 bits 15-12 of I/O address range
SeeAlso: #0585,#0594

Bitfields for PCI Configuration memory base and limit:
Bit(s) Description (Table 0594)
3-0 address decode type
0000 32-bit address decoder
0001 64-bit address decoder
other reserved
15-4 bits 31-20 of memory address range
SeeAlso: #0585,#0593

Format of PCI Configuration Data for VLSI VL82C591 Host/PCI bridge:
Offset Size Description (Table 0595)
00h 64 BYTEs header (see #0585)
(device ID 0005h)
40h BYTE bus number
41h BYTE subordinate bus number
42h WORD reserved
44h 4 DWORDs reserved
54h 2 BYTEs device-specific configuration registers
56h WORD reserved
58h 2 BYTEs device-specific configuration registers
5Ah WORD reserved
5Ch 5 BYTEs device-specific configuration registers
...
FFh BYTE device-specific configuration register
SeeAlso: #0585,#0586,#0596

Format of PCI Configuration data for VLSI VL82C593 PCI/ISA bridge:
Offset Size Description (Table 0596)
00h 64 BYTEs header (see #0585)
(device ID 0006h)
40h 4 DWORDs reserved
50h 11 BYTEs device-specific configuration registers
5Bh BYTE reserved
5Ch 25 BYTEs device-specific configuration registers
75h 138 BYTEs reserved
FFh BYTE device-specific configuration register
SeeAlso: #0585,#0595

Format of PCI Configuration data for Intel 82434 Cache/DRAM Controller:
Offset Size Description (Table 0597)
00h 64 BYTEs header (see #0585)
(vendor ID 8086h, device ID 0484h)
40h 16 BYTEs unused (hard-wired to 00h)
50h BYTE secondary (L2) cache control???
bit 0: ???
bit 1: ???
bit 2: enable L2 cache
51h BYTE deturbo frequency control register
when deturbo mode is selected (see PORT 0CF9h), the chipset
places a hold on the memory bus for a fraction of the
time inversely proportional to the value in this register
(i.e. C0h = 1/4, 80h = 1/2, 40h = 3/4, 20h = 7/8, etc.)
(only bits 7-6 writable, bits 5-0 hardwired to 0)
52h BYTE ???
bits 6-7: ???
bit 1: ???
bit 0: ???
53h BYTE ???
54h BYTE ???
bit 2: ???
55h 2 BYTEs ???
57h BYTE ???
58h BYTE ???
bit 0:
59h BYTE ???
bits 3-0: ???
bit 4:
bit 5:
bit 6:
5Ah 2 BYTEs ???
5Ch 4 BYTEs ???
60h 6 BYTEs DRAM row boundary registers???
(on a system with four 4M SIMMs, contains 08h 08h 10h 10h 10h)
65h BYTE memory size in megabytes
66h 2 BYTEs ??? (set to same value as 65h)
68h 4 BYTEs ???
6Ch DWORD unused??? (apparently hardwired to 00000000h)
70h BYTE ???
bits 1-0: ???
71h BYTE ???
bit 3: ???
72h 6 BYTEs ???
78h WORD ???
7Ah 2 BYTEs ???
7Ch DWORD ???
80h 128 BYTEs unused???
Note: the 82434 is part of the Intel Neptune chipset
SeeAlso: #0598

Format of PCI Configuration data for Intel 82425EX PSC:
Offset Size Description (Table 0598)
00h 64 BYTEs header (see #0585)
(vendor ID 8086h, device ID 0486h)
40h BYTE PCI control register (see #0599)
41h 3 BYTEs ???
44h BYTE host device control register (see #0600)
45h 3 BYTEs ???
48h WORD PCI local-bus IDE control register (see #0601)
4Ah 2 BYTEs ???
4Ch BYTE ISA I/O recovery timer register (see #0602)
4Dh BYTE part revision register (see #0603)
4Eh BYTE X-bus Chip Select A register (see #0604)
4Fh BYTE ???
50h BYTE host select register
51h BYTE deturbo frequency control register
when deturbo mode is selected (see PORT 0CF9h), the chipset
places a hold on the memory bus for a fraction of the
time inversely proportional to the value in this register
(i.e. C0h = 1/4, 80h = 1/2, 40h = 3/4, 20h = 7/8, etc.)
52h WORD secondary (L2) cache control register
54h 2 BYTEs ???
56h WORD DRAM control register
58h BYTE ???
59h BYTE programmable attribute map (PAM) register 0
5Ah 6 BYTEs programmable attribute map (PAM) registers 1-6
60h 5 BYTEs DRAM row boundary registers 0-4
65h BYTE ???
66h BYTE PIRQ route control register 0
67h BYTE PIRQ route control register 1
68h BYTE DRAM memory hole register
69h BYTE top of memory
6Ah 6 BYTEs ???
70h BYTE SMRAM control register
71h 47 BYTEs unused???
A0h BYTE SMI control register
A1h BYTE ???
A2h WORD SMI enable register
A4h DWORD system event enable
A8h BYTE fast off timer register
A9h BYTE ???
AAh WORD SMI request register
ACh BYTE clock throttle STPCLK# low timer
ADh BYTE unused???
AEh BYTE clock throttle STPCLK# high timer
AFh BYTE ???
B0h 80 BYTEs unused???
SeeAlso: #0585,#0597

Bitfields for Intel 82425EX PCI control register:
Bit(s) Description (Table 0599)
0 CPU-to-PCI byte merging
1 CPU-to-PCI bursting enable
2 PCI posted-write buffer enable
4-3 subtractive decode sampling point
00 slow
01 typical
10 fast
11 reserved
5 DRAM parity error enable
6 target abort error enable
7 reserved
SeeAlso: #0598,#0600,#0601,#0602

Bitfields for Intel 82425EX host device control register:
Bit(s) Description (Table 0600)
0 HRDY# maximum signal sampling point
0 slow timing
1 fast timing
1 HDEV# signal sampling point

0 slow timing
1 fast timing
2 host device present
7-3 reserved
SeeAlso: #0598,#0599

Bitfields for Intel 82425EX local-bus IDE control register:
Bit(s) Description (Table 0601)
1-0 primary/secondary PCI IDE enable
00 IDE disabled
01 primary (ports 01F0h-01F7h,03F6,03F7h)
10 secondary (ports 0170h-017Fh,0376h,0377h)
11 reserved
3-2 fast timing bank drive select 1
bit 2 = drive 0 enabled
bit 3 = drive 1 enabled
5-4 IORDY sample point Enable Drive Select
bit 4 = drive 0 enabled
bit 5 = drive 1 enabled
7-6 reserved
9-8 IORDY sample point
00 6 clocks
01 5 clocks
10 4 clocks
11 3 clocks
12-10 recover time (000 = 8 PCI clocks, 001 = 7, ..., 101 = 3, 110/111 = 3)
15-13 reserved
SeeAlso: #0598,#0599

Bitfields for Intel 82425EX ISA I/O recovery timer register:
Bit(s) Description (Table 0602)
1-0 16-bit I/O recovery time
00 = 4 SYSCLKs
01-11 = 1-3 SYSCLKs
2 16-bit I/O recovery enable
5-3 8-bit I/O recovery time
000 = 8 SYSCLKs
001-110 = 1-7 SYSCLKs
6 8-bit I/O recovery select
7 DMA reserved page register aliasing disable
=0 ports 0090h-009Fh alias ports 0080h-008Fh
=1 ports 0090h-009Fh forwarded to ISA bus
SeeAlso: #0598,#0599

Bitfields for Intel 82425EX part revision register:
Bit(s) Description (Table 0603)
7-5 fabrication house identifier (read-only)
4 E0000h-EFFFFh ISA-to-main-memory forwarding enabled
3-0 revision ID (read-only)
SeeAlso: #0598,#0604

Bitfields for Intel 82425EX X-bus Chip Select A register:
Bit(s) Description (Table 0604)
7 extended BIOS enabled at FFF80000h-FFFDFFFFh
6 lower (E000h) BIOS enabled
5 trigger IRQ13 on FERR#
4 IRQ12 mouse function enabled
3 reserved (0)
2 BIOS memory write protect
1 keyboard controller addresses (60h,62h,64h,66h) enabled
0 RTC addresses (70h-77h) enabled
SeeAlso: #0598,#0603
--------X-1AB10B-----------------------------
INT 1A - Intel PCI BIOS v2.0c - WRITE CONFIGURATION BYTE
AX = B10Bh
BH = bus number
BL = device/function number (bits 7-3 device, bits 2-0 function)
DI = register number (0000h-00FFh)
CL = byte to write
Return: CF clear if successful
CF set on error
AH = status (00h,87h) (see #0582)
EAX, EBX, ECX, and EDX may be modified
all other flags (except IF) may be modified
Notes: this function may require up to 1024 byte of stack; it will not enable
interrupts if they were disabled before making the call
the meanings of BL and BH on entry were exchanged between the initial
drafts of the specification and final implementation
SeeAlso: AX=B18Bh
--------X-1AB10C-----------------------------
INT 1A - Intel PCI BIOS v2.0c - WRITE CONFIGURATION WORD
AX = B10Ch
BH = bus number
BL = device/function number (bits 7-3 device, bits 2-0 function)
DI = register number (multiple of 2 less than 0100h)
CX = word to write
Return: CF clear if successful
CF set on error
AH = status (00h,87h) (see #0582)
EAX, EBX, ECX, and EDX may be modified
all other flags (except IF) may be modified
Notes: this function may require up to 1024 byte of stack; it will not enable
interrupts if they were disabled before making the call
the meanings of BL and BH on entry were exchanged between the initial
drafts of the specification and final implementation
SeeAlso: AX=B18Ch
--------X-1AB10D-----------------------------
INT 1A - Intel PCI BIOS v2.0c - WRITE CONFIGURATION DWORD
AX = B10Dh
BH = bus number
BL = device/function number (bits 7-3 device, bits 2-0 function)
DI = register number (multiple of 4 less than 0100h)
ECX = dword to write
Return: CF clear if successful
CF set on error
AH = status (00h,87h) (see #0582)
EAX, EBX, ECX, and EDX may be modified
all other flags (except IF) may be modified
Notes: this function may require up to 1024 byte of stack; it will not enable
interrupts if they were disabled before making the call
the meanings of BL and BH on entry were exchanged between the initial
drafts of the specification and final implementation
SeeAlso: AX=B18Dh
--------X-1AB10EBX0000-----------------------
INT 1A - Intel PCI BIOS v2.1+ - GET IRQ ROUTING INFORMATION
AX = B10Eh
BX = 0000h
DS = segment/selector for PCI BIOS data
(real mode: F000h; 16-bit PM: physical 000F0000h; 32-bit PM: as
specified by BIOS32 services directory)
ES:(E)DI -> IRQ routing table header (see #0621 at AX=B406h)
Return: CF clear if successful
AH = 00h
BX = bit map of IRQ channels permanently dedicated to PCI
WORD ES:[DI] = size of returned data
CF set on error
AH = error code (59h) (see #0605)
WORD ES:[DI] = required size of buffer
SeeAlso: AX=B10Fh,AX=B406h
--------X-1AB10F-----------------------------
INT 1A - Intel PCI BIOS v2.1+ - SET PCI IRQ
AX = B10Fh
BH = bus number
BL = device/function number (bits 7-3 device, bits 2-0 function)
CH = number of IRQ to connect
CL = number of interrupt pin (0Ah=INTA# to 0Dh=INTD#) to reprogram
DS = segment/selector for PCI BIOS data
(real mode: F000h; 16-bit PM: physical 000F0000h; 32-bit PM: as
specified by BIOS32 services directory)
Return: CF clear if successful
AH = 00h
CF set on error
AH = error code (59h) (see #0605)
Note: assumes that the calling application has determined the IRQ routing
topology (see AX=B10Eh), has ensured that the selected IRQ will not
cause a conflict, and will update the interrupt line configuration
register on all devices which currently use the IRQ line
SeeAlso: AX=B10Eh
--------X-1AB181-----------------------------
INT 1A - Intel PCI BIOS v2.0c - INSTALLATION CHECK (32-bit)
AX = B181h
Return: as for AX=B101h
SeeAlso: AX=B101h
--------X-1AB182-----------------------------
INT 1A - Intel PCI BIOS v2.0c - FIND PCI DEVICE (32-bit)
AX = B182h
CX = device ID
DX = vendor ID
SI = device index (0-n)
Return: as for AX=B102h
SeeAlso: AX=B102h
--------X-1AB183-----------------------------
INT 1A - Intel PCI BIOS v2.0c - FIND PCI CLASS CODE (32-bit)
AX = B183h
ECX = class code (bits 23-0)
SI = device index (0-n)
Return: as for AX=B103h
SeeAlso: AX=B103h
--------X-1AB186-----------------------------
INT 1A - Intel PCI BIOS v2.0c - PCI BUS-SPECIFIC OPERATIONS (32-bit)
AX = B186h
BH = bus number
EDX = Special Cycle data
Return: as for AX=B106h
Note: the meanings of BL and BH on return were exchanged between the initial
drafts of the specification and final implementation
SeeAlso: AX=B106h
--------X-1AB188-----------------------------
INT 1A - Intel PCI BIOS v2.0c - READ CONFIGURATION BYTE (32-bit)
AX = B188h
BH = bus number
BL = device/function number (bits 7-3 device, bits 2-0 function)
DI = register number (0000h-00FFh)
Return: as for AX=B108h
Note: the meanings of BL and BH on return were exchanged between the initial
drafts of the specification and final implementation
SeeAlso: AX=B108h
--------X-1AB189-----------------------------
INT 1A - Intel PCI BIOS v2.0c - READ CONFIGURATION WORD (32-bit)
AX = B189h
BH = bus number
BL = device/function number (bits 7-3 device, bits 2-0 function)
DI = register number (0000h-00FFh)
Return: as for AX=B109h
Note: the meanings of BL and BH on return were exchanged between the initial
drafts of the specification and final implementation
SeeAlso: AX=B109h
--------X-1AB18A-----------------------------
INT 1A - Intel PCI BIOS v2.0c - READ CONFIGURATION DWORD (32-bit)
AX = B18Ah
BH = bus number
BL = device/function number (bits 7-3 device, bits 2-0 function)
DI = register number (0000h-00FFh)
Return: as for AX=B10Ah
Note: the meanings of BL and BH on return were exchanged between the initial
drafts of the specification and final implementation
SeeAlso: AX=B10Ah
--------X-1AB18B-----------------------------
INT 1A - Intel PCI BIOS v2.0c - WRITE CONFIGURATION BYTE (32-bit)
AX = B18Bh
BH = bus number
BL = device/function number (bits 7-3 device, bits 2-0 function)
DI = register number (0000h-00FFh)
CL = byte to write
Return: as for AX=B10Bh
Note: the meanings of BL and BH on return were exchanged between the initial
drafts of the specification and final implementation
SeeAlso: AX=B10Bh
--------X-1AB18C-----------------------------
INT 1A - Intel PCI BIOS v2.0c - WRITE CONFIGURATION WORD (32-bit)
AX = B18Ch
BH = bus number
BL = device/function number (bits 7-3 device, bits 2-0 function)
DI = register number (multiple of 2 less than 0100h)
CX = word to write
Return: as for AX=B10Ch
Note: the meanings of BL and BH on return were exchanged between the initial
drafts of the specification and final implementation
SeeAlso: AX=B10Ch
--------X-1AB18D-----------------------------
INT 1A - Intel PCI BIOS v2.0c - WRITE CONFIGURATION DWORD (32-bit)
AX = B18Dh
BH = bus number
BL = device/function number (bits 7-3 device, bits 2-0 function)
DI = register number (multiple of 4 less than 0100h)
ECX = dword to write
Return: as for AX=B10Dh
Note: the meanings of BL and BH on return were exchanged between the initial
drafts of the specification and final implementation
SeeAlso: AX=B10Dh
--------X-1AB400-----------------------------
INT 1A - Intel Plug-and-Play AUTO-CONFIGURATION - INSTALLATION CHECK
AX = B400h
Return: CF clear if installed
AX = 0000h if installed
BH = ??? (02h)
BL = ??? (08h)
CX = ??? (0002h)
EDX = 47464341h ('GFCA', which is byte-swapped 'ACFG')
SI = ??? (001Fh)
SeeAlso: AX=B401h,AX=B402h,AX=B403h,AX=B404h,AX=B405h,AX=B406h,AX=B407h
SeeAlso: @xxxxh:xxxxh"Plug-and-Play"

(Table 0605)
Values for Intel Plug-and-Play AUTO-CONFIGURATION error codes:
0000h successful
0001h specified action could not be completed
0051h ???
0055h unable to read/write configuration table from/to nonvolatile storage
0056h not a valid configuration table or wrong table version
0059h buffer too small
0081h unsupported function
FFFFh ???
SeeAlso: #F052
--------X-1AB401-----------------------------
INT 1A - Intel Plug-and-Play AUTO-CONFIGURATION - GET DEFAULT CONFIG TABLE
AX = B401h
Return: CF clear if successful
AX = 0000h
BX = maximum size of configuration table in bytes
CX = required configuration buffer size
(includes scratch space used by ACFG code)
EDI = linear/physical address of ESCD table (see #0606)
CF set on error
AX = error code (see #0605)
SeeAlso: AX=B400h,AX=B402h,@xxxxh:xxxxh"Plug-and-Play"

Format of Intel Plug-and-Play Extended System Configuration Data table:
Offset Size Description (Table 0606)
00h WORD total length of this table
02h 4 BYTEs signature "ACFG"
06h BYTE minor version number
07h BYTE major version number (currently 02h)
08h BYTE number of boards listed in the configuration data
09h 3 BYTEs reserved (00h)
0Ch var board data
WORD checksum
Notes: this table contains information about the standard devices in the
system, such as serial ports, parallel ports, etc. For each device,
it includes at least the I/O port address (03F8h,02F8h,0378h,etc).
the sum of all words in the table, including the checksum field (with
implied zero padding if the length is odd), must equal 0000h
SeeAlso: #0607

Format of Extended System Configuration Data Board Header:
Offset Size Description (Table 0607)
00h WORD length of this header in bytes
02h BYTE slot number
00h motherboard
01h-0Fh ISA/EISA
10h-40h PCI
03h BYTE reserved (00h)
SeeAlso: #0606,#0608

Format of Extended System Configuration Data Freeform Board Header:
Offset Size Description (Table 0608)
00h 4 BYTEs signature "ACFG"
04h BYTE minor version number
05h BYTE major version number (currently 02h)
06h BYTE board type
01h ISA
02h EISA
04h PCI
08h PCMCIA
10h PnPISA
20h MCA
07h BYTE reserved (00h)
08h WORD disabled functions (bit N set = function N disabled)
0Ah WORD configuration error functions
0Ch WORD reconfigurable functions (bit N set = function N reconfig'able)
0Eh 2 BYTEs reserved (00h)
SeeAlso: #0611,#0612

Format of Extended System Configuration Data Freeform PCI Device Data:
Offset Size Description (Table 0609)
00h BYTE PCI bus number
01h BYTE PCI device and function number
02h WORD PCI device identifier
04h WORD PCI vendor ID (see #0586)
06h 2 BYTEs reserved (00h)
SeeAlso: #0609,#0612

Format of Extended System Configuration Data Freeform PnP ISA Board ID:
Offset Size Description (Table 0610)
00h DWORD vendor ID (EISA device identifier)
04h DWORD serial number
SeeAlso: #0610,#0611

Format of Extended System Configuration Data PnP ISA ECD Extension Function:
Offset Size Description (Table 0611)
00h WORD 001Eh (length of this structure)
02h BYTE 01h (selection size)
03h BYTE 00h (selection data)
04h BYTE C0h (function information byte) (see #0614)
05h BYTE 18h (size of following free-format data)
06h 16 BYTEs freeform board header (see #0608)
16h 8 BYTEs Plug-and-Play board ID (see #0610)
Note: ECD = Extended Configuration Data; this structure must be the last
"function" for a particular ISA Plug-and-Play board
SeeAlso: #0612

Format of Extended System Configuration Data PCI ECD Extension Function:
Offset Size Description (Table 0612)
00h WORD length of this structure (at least 001Eh, up to 0056h)
02h BYTE 01h (selection size)
03h BYTE 00h (selection data)
04h BYTE C0h (function information byte) (see #0614)
05h BYTE size of following free-format data (at least 18h, max 50h)
06h 16 BYTEs freeform board header (see #0608)
16h 8N BYTEs PCI board ID (see #0609) for one to eight boards
Notes: ECD = Extended Configuration Data; this structure must be the last
"function" for a particular PCI board
AMI BIOS v1.00.05.AX1 sets the length field to 001Ch for entries with
a single board ID, apparently treating the field as the length of
the remainder of the structure instead of the full structure's length
SeeAlso: #0611

Bitfields for EISA ID and Slot Information:
Bit(s) Description (Table 0613)
3-0 selector among duplicate configuration file names (0000 if no dups)
5-4 slot type
00 expansion slot
01 embedded
10 virtual slot
11 reserved
6 ID is readable
7 duplicate IDs present
8 board can be disabled
9 IOCHKERR supported
10 board or entries locked
13-11 reserved
14 board does not have or need configuration file
15 configuration not complete
SeeAlso: #0614

Bitfields for EISA Function Information:
Bit(s) Description (Table 0614)
0 subtype data
1 memory information (see #0615)
2 IRQ information (see #0617)
3 DMA information (see #0618)
4 port range information (see #0619)
5 port initialization data (see #0620)
6 free form data
7 function disabled
SeeAlso: #0611,#0612,#0613

Format of EISA Memory Information:
Offset Size Description (Table 0615)
00h WORD memory information flags (see #0616)
02h 3 BYTEs high 24 bits of memory start address (LSB first)
05h WORD memory size in K (0000h = 65536K)
SeeAlso: #0614

Bitfields for EISA Memory Information Flags:
Bit(s) Description (Table 0616)
0 writable (RAM rather than ROM)
1 cached
2 write-back cache rather than write-through
4-3 memory type
00 system
01 expantion
10 virtual
11 other
5 shared
6 reserved (0)
7 more entries follow
9-8 memory width
00 byte
01 word
10 dword
11 reserved
11-10 decoded address lines
00 = 20
01 = 24
10 = 32
11 reserved
15-12 reserved (0)
SeeAlso: #0615

Bitfields for EISA IRQ Information:
Bit(s) Description (Table 0617)
3-0 IRQ number
4 reserved (0)
5 IRQ triggering (0 = edge, 1 = level)
6 IRQ is shareable
7 more entries follow
15-8 reserved (0)
SeeAlso: #0614

Bitfields for EISA DMA Information:
Bit(s) Description (Table 0618)
2-0 DMA channel number
5-3 reserved (0)
6 shareable
7 more entries follow
9-8 reserved
11-10 DMA transfer size
00 byte
01 word
10 dword
11 word, but count in bytes
13-12 DMA timing
00 ISA-compatible
01 EISA type "A"
10 EISA type "B"
11 EISA type "C"/"F" (burst)
15-14 reserved (0)
SeeAlso: #0614

Format of EISA Port Range Information:
Offset Size Description (Table 0619)
00h BYTE port description
bits 4-0: number of sequential ports
bit 5 reserved (0)
bit 6: shareable
bit 7: more entries follow
01h WORD I/O port address
SeeAlso: #0614,#0620

Format of EISA Port Initialization Data:
Offset Size Description (Table 0620)
00h BYTE flags
bits 1-0: port size
00 byte
01 word
10 dword
11 reserved
bit 2: masked write
bits 6-3 reserved (0)
bit 7: more entries follow
01h ???
SeeAlso: #0614,#0619
--------X-1AB402-----------------------------
INT 1A - Intel Plug-and-Play AUTO-CONFIGURATION - COPY AND VERIFY CONFIG TABLE
AX = B402h
DS:SI -> configuration table (see #0606)
ES:DI -> buffer for copy of configuration table
Return: CF clear if successful
AX = 0000h
CF set on error
AX = error code (0055h,0056h) (see #0605)
Note: the buffer pointed at by ES:DI must be at least as large as the
maximum configuration table size reported by AX=B401h
SeeAlso: AX=B400h,AX=B401h,AX=B403h
--------X-1AB403-----------------------------
INT 1A - Intel Plug-and-Play AUTO-CONFIGURATION - STORE ESCD TABLE IN NVRAM
AX = B403h
DS:SI -> configuration table (see #0606)
Return: CF clear if successful
AX = 0000h
CF set on error
AX = error code (0055h) (see #0605)
Note: sets the configuration table's checksum field, then copies the table
into nonvolatile storage (i.e. FlashROM)
SeeAlso: AX=B400h,AX=B402h
--------X-1AB404-----------------------------
INT 1A - Intel Plug-and-Play AUTO-CONFIGURATION - GET AVAILABLE IRQs???
AX = B404h
BX = bitmap of IRQs being used???
Return: CF clear if successful
AX = 0000h
BX = available for ISA??? (not(BXin) & A127h)
CX = available for on-board I/O??? (not(BXin) & 40D8h)
DX = available for PCI??? (either not(BXin) & 0E00h or 0000h)
CF set on error
AX = error code (0051h) (see #0605)
SeeAlso: AX=B400h
--------X-1AB405-----------------------------
INT 1A - Intel Plug-and-Play AUTO-CONFIGURATION - GET ???
AX = B405h
Return: AX = ??? (0008h)
SeeAlso: AX=B400h
--------X-1AB406-----------------------------
INT 1A - Intel Plug-and-Play AUTO-CONFIGURATION - GET PCI IRQ ROUTING TABLE
AX = B406h
ES:DI -> IRQ routing table header (see #0621)
Return: CF clear if successful
AX = 0000h
WORD ES:[DI] = size of returned data
CF set on error
AX = error code (0059h) (see #0605)
WORD ES:[DI] = required size of buffer
SeeAlso: AX=B400h,AX=B10Eh

Format of Intel Plug-and-Play AUTO-CONFIGURATION PCI IRQ routing header:
Offset Size Description (Table 0621)
00h WORD length of IRQ routing table buffer
02h DWORD -> IRQ routing table array buffer (see #0622)

Format of Intel Plug-and-Play ACFG PCI IRQ routing table entry [array]:
Offset Size Description (Table 0622)
00h BYTE PCI bus number
01h BYTE PCI device number (bits 7-3)
02h BYTE link value for INTA#
(if non-zero, wire-ORed together with any other PCI interrupts
with same link value)
03h WORD IRQ connectivity bit map for INTA#
(standard AT IRQs to which PCI interrupt can be routed)
05h BYTE link value for INTB#
06h WORD IRQ connectivity bit map for INTB#
08h BYTE link value for INTC#
09h WORD IRQ connectivity bit map for INTC#
0Bh BYTE link value for INTD#
0Ch WORD IRQ connectivity bit map for INTD#
0Eh BYTE (PCI BIOS v2.1+) device slot number (00h = motherboard)
0Fh BYTE reserved
Note: each item in the routing table corresponds to a motherboard PCI
device or PCI slot
SeeAlso: #0621
--------X-1AB407-----------------------------
INT 1A - Intel Plug-and-Play AUTO-CONFIGURATION - ???
AX = B407h
EDX = length of ???
EDI = physical address of ???
Return: CF clear if successful
AX = 0000h
EDX = ???
EDI = ???
CF set on error
AX = error code (FFFFh) (see #0605)
Notes: returns error if EDI < 000C0000h or EDI+EDX > 00100000h
seems to force EDI and EDX to align to 16K boundaries
SeeAlso: AX=B400h
--------X-1AB4-------------------------------
INT 1A - Intel Plug-and-Play AUTO-CONFIGURATION - 32-BIT API
AH = B4h
AL = function (80h-87h)
further details not yet available
Note: these functions are 32-bit versions of functions 00h-07h
--------c-1AC0-------------------------------
INT 1A U - Disk Spool II v2.07+ - ALTERNATE INSTALLATION CHECK
AH = C0h
Return: (see AH=A0h)
Notes: this call is identical to AH=A0h
this function is also supported by Vertisoft's Emulaser utility ELSPL,
as that is a licensed version of Disk Spool II
SeeAlso: AH=A0h,AH=ABh,AH=D0h
--------U-1ACCCCBXCCCC-----------------------
INT 1A U - DATEFIX - INSTALLATION CHECK
AX = CCCCh
BX = CCCCh
CX = 0000h
Return: CX = CCCCh if installed
ES:BX -> original interrupt handler
Program: DATEFIX is a public-domain TSR to correct the date on AT&T 6300
machines, where the realtime clock's calendar wraps after 1991
SeeAlso: AH=FEh,AH=FFh"AT&T"
--------c-1AD0-------------------------------
INT 1A U - Disk Spool II v2.07+ - FUNCTION CALLS
AH = D0h
AL = function code
01h enable spooler and despooler
02h enable spooler only
03h enable despooler at beginning of file
04h disable the despooler
05h disable the despooler and spooler
06h clear the spool file
08h inhibit the popup menu
09h enable the popup menu
0Ah ??? (called by Disk Spool's INT 21 handler)
0Bh disable the spooler
0Ch start despooler after last successfully printed document
0Dh start despooler at the exact point where it last left off
0Eh pop up the menu
0Fh ???
11h start new spool file??? (called by Disk Spool's INT 21 handler
when a program terminates)
14h ???
15h delete despool file and reset ???
16h ??? (writes something to unknown file)
17h ??? (writes something to despool file, then reads something
else and ???)
18h ??? (reads something from despool file, and then ???)
19h ??? (creates/truncates spool file)
20h clear file pointed to by the despooler
21h ??? (writes something to unknown file)
22h ??? (writes something to spool file if spooler/despooler using
same file)
23h ??? (opens/creates unknown file, then ???)
30h ???
31h ???
32h beep
33h append CRLF to spool file???
34h ???
35h ???
36h ???
37h append CRLF to spool file and start a new spool file???
38h ???
40h ??? (v4.05)
41h ??? (v4.05)
51h ??? (called by Disk Spool's INT 21 handler)
52h ??? (called by Disk Spool's INT 21 handler)
57h ???
5Ah ??? (v4.05)
5Bh ??? (v4.05)
5Ch ??? (v4.05)
Note: this function is also supported by Vertisoft's Emulaser utility ELSPL,
as that is a licensed version of Disk Spool II
SeeAlso: AH=A0h,AH=ADh
--------c-1AE0-------------------------------
INT 1A - Disk Spool II v4.0x - ENABLE/DISABLE
AH = E0h
AL = subfunction
01h enable spooler
02h disable spooler
03h enable despooler
04h disable despooler
CL = printer port (01h COM1, 02h COM2, 05h LPT1, 06h LPT2)
Return: AH = status
00h successful
F0h printer port not managed by Disk Spool II
FFH failed
Note: this function is also supported by Vertisoft's Emulaser utility ELSPL,
as that is a licensed version of Disk Spool II
SeeAlso: AH=A0h,AH=E1h,AX=E301h,AX=E401h
--------c-1AE1-------------------------------
INT 1A - Disk Spool II v4.0x - GET STATUS
AH = E1h
CL = printer port (01h COM1, 02h COM2, 05h LPT1, 06h LPT2)
Return: AH = status
00h successful
CL = despooler state (00h disabled, 41h enabled)
CH = spooler state (00h disabled, 41h enabled)
DL = despooler activity (00h standing by, 41h printing)
ES:BX -> ASCIZ name of current spool file (or next if AutoSpool
or AutoDespool enabled)
ES:SI -> ASCIZ name of current despool file
ES:DI -> 3-byte file extension used by Disk Spool II
F0h printer port not managed by Disk Spool II
Note: this function is also supported by Vertisoft's Emulaser utility ELSPL,
as that is a licensed version of Disk Spool II
SeeAlso: AH=A0h,AH=E0h,AH=E2h
--------U-1AE11B-----------------------------
INT 1A - TheGrab v4.60 - ???
AX = E11Bh
???
Return: ??? (may destroy all registers)
SeeAlso: AX=E11Dh
--------U-1AE11D-----------------------------
INT 1A - TheGrab v4.60 - INSTALLATION CHECK
AX = E11Dh
Return: ES:DI -> signature block (see #0623) if installed
CX = length of signature block (000Fh)
Program: TheGrab is a resident ANSI screen grabber bundled with TheDraw
SeeAlso: AX=E11Bh

Format of TheGrab signature block:
Offset Size Description (Table 0623)
00h BYTE 08h
01h 8 BYTEs ASCIZ "THEGRAB"
09h 6 BYTEs ??? (zeros)
--------c-1AE2-------------------------------
INT 1A - Disk Spool II v4.0x - GET SPOOL FILES
AH = E2h
AL = which
01h first
02h next (can only call after "first")
CL = printer port (01h COM1, 02h COM2, 05h LPT1, 06h LPT2)
Return: AH = status
00h successful
ES:BX -> ASCIZ filename
F0h no (more) spool files
FFh failed
Note: this function is also supported by Vertisoft's Emulaser utility ELSPL,
as that is a licensed version of Disk Spool II
SeeAlso: AH=E0h,AH=E1h
--------c-1AE301-----------------------------
INT 1A - Disk Spool II v4.0x - GET SPOOL FILE STATUS
AX = E301h
ES:BX -> ASCIZ filename (max 32 chars)
Return: AH = status
00h successful
ES:SI -> spool file status record (see #0624)
F0h not a spool file
FFh failed
Note: this function is also supported by Vertisoft's Emulaser utility ELSPL,
as that is a licensed version of Disk Spool II
SeeAlso: AH=E0h,AX=E302h,AX=E401h

Format of Disk Spool II spool file status record:
Offset Size Description (Table 0624)
00h BYTE hour of creation or last update
01h BYTE minute of creation or last update
02h BYTE year-1980 of creation or last update
03h BYTE month of creation or last update
04h BYTE day of creation or last update
05h BYTE total number of copies to print
06h BYTE number of copies already printed
07h BYTE printer port (01h COM1, 02h COM2, 05h LPT1, 06h LPT2)
08h BYTE save status (00h delete after printing, 01h save)
09h BYTE file status
01h done printing, but being saved
02h on hold
03h queued for printing
04h being spooled
05h being despooled (i.e. printed)
0Ah 16 BYTEs ASCIZ description
1Ah 2 WORDs file size in bytes (high,low)
1Eh 2 WORDs bytes left to print (high,low)
--------c-1AE302-----------------------------
INT 1A - Disk Spool II v4.0x - UPDATE SPOOL FILE
AX = E302h
ES:BX -> ASCIZ filename (max 32 chars)
ES:SI -> spool file status record (see #0624)
Return: AH = status
00h successful
F0h not a spool file
FFh failed
Note: this function is also supported by Vertisoft's Emulaser utility ELSPL,
as that is a licensed version of Disk Spool II
SeeAlso: AH=E0h,AX=E301h,AX=E401h
--------c-1AE401-----------------------------
INT 1A - Disk Spool II v4.0x - SPOOL EXISTING FILE
AX = E401h
ES:BX -> ASCIZ filename (max 32 chars)
CL = printer port (01h COM1, 02h COM2, 05h LPT1, 06h LPT2)
Return: AH = status
00h successful
FFh failed
Note: this function is also supported by Vertisoft's Emulaser utility ELSPL,
as that is a licensed version of Disk Spool II
SeeAlso: AH=E1h,AX=E302h,AX=E402h
--------c-1AE402-----------------------------
INT 1A U - Disk Spool II v4.0x - SPOOL EXISTING FILE???
AX = E402h
ES:BX -> ASCIZ filename (max 32 chars)
CL = printer port (01h COM1, 02h COM2, 05h LPT1, 06h LPT2)
Return: AH = status
00h successful
FFh failed
Note: this function is also supported by Vertisoft's Emulaser utility ELSPL,
as that is a licensed version of Disk Spool II
SeeAlso: AH=E1h,AX=E302h,AX=E401h
--------c-1AE5-------------------------------
INT 1A U - Emulaser ELSPL.COM - ???
AH = E5h
???
Return: ???
Program: ELSPL.COM is a licensed version of Disk Spool II which is distributed
as part of Vertisoft's Emulaser PostScript emulator
SeeAlso: AH=A0h,INT 17/AH=03h
--------c-1AEE-------------------------------
INT 1A U - Disk Spool II v4.05 - ???
AH = EEh
AL = printer port???
???
Return: ???
Note: this function is also supported by Vertisoft's Emulaser utility ELSPL,
as that is a licensed version of Disk Spool II
SeeAlso: AH=E1h
--------U-1AF7-------------------------------
INT 1A - RighTime v1.1 - TEMPORARILY DISABLE
AH = F7h
Program: RighTime is a TSR by G.T. Becker which continuously adjusts the system
time to correct for clock drift
Note: any AH value from F0h-F7h or F9h-FEh will perform this function in
version 1.1, but F7h is the function called by transient portion
SeeAlso: AH=F8h,AH=FFh"RighTime"
--------U-1AF8-------------------------------
INT 1A - RighTime v1.1 - ENABLE
AH = F8h
Program: RighTime is a TSR by G.T. Becker which continuously adjusts the system
time to correct for clock drift
Note: RighTime is TeSseRact-compatible (see INT 2F/AX=5453h) and modifies its
TeSseRact program identifier based on its current state: "RighTime"
when enabled, "RighTim"F7h when disabled.
SeeAlso: AH=F7h,AH=FFh"RighTime"
--------b-1AFE-------------------------------
INT 1A - AT&T 6300 - READ TIME AND DATE
AH = FEh
Return: BX = day count (0 = Jan 1, 1984)
CH = hour
CL = minute
DH = second
DL = hundredths
SeeAlso: AX=CCCCh/BX=CCCCh,AH=FFh"AT&T",INT 21/AH=2Ah,INT 21/AH=2Ch
--------b-1AFF-------------------------------
INT 1A - AT&T 6300 - SET TIME AND DATE
AH = FFh
BX = day count (0 = Jan 1, 1984)
CH = hour
CL = minute
DH = second
DL = hundredths
Return: ???
SeeAlso: AX=CCCCh/BX=CCCCh,AH=FEh,INT 21/AH=2Bh,INT 21/AH=2Dh
--------U-1AFF-------------------------------
INT 1A - RighTime v1.1 - PERMANENTLY DISABLE
AH = FFh
Program: RighTime is a TSR by G.T. Becker which continuously adjusts the system
time to correct for clock drift
Note: upon being permanently disabled, RighTime closes the file handle
referencing its executable (which is updated with time correction
information every two minutes while RighTime is enabled).
--------s-1AFF00-----------------------------
INT 1A - SND - INSTALLATION CHECK???
AX = FF00h
Return: AL = version??? (02h)
AH = busy flag (00h if not in a SND call, 01h if SND currently active)
Note: the SND API is also supported by IC (Internal Commands) v2.0, a
shareware TSR by Geoff Friesen which extends COMMAND.COM's internal
command set
SeeAlso: AX=FF01h,AX=FF02h,AX=FF04h,AX=FF05h
--------s-1AFF01-----------------------------
INT 1A - SND - PAUSE
AX = FF01h
DX = number of clock ticks to delay
Return: AH = status
00h successful
01h SND busy
Notes: if successful, execution returns to the caller after the delay expires;
if SND is busy, execution returns immediately
the IC v2.0 implementation of this API makes no special allowance for
time rollover at midnight, which can cause the delay to be over one
hour if this function is called just before the BIOS time count
rolls over and the delay extends into the next day
SeeAlso: AX=FF00h,INT 15/AH=86h,INT 62/AX=0096h,INT 7F/AH=E8h,INT 80/BX=0009h
SeeAlso: INT E0/CL=BDh
--------s-1AFF02-----------------------------
INT 1A - SND - START SOUND
AX = FF02h
DX = frequency in Hertz (14h-FFFFh)
Return: AH = status
00h successful
01h SND busy
SeeAlso: AX=FF00h,AX=FF01h,AX=FF03h
--------s-1AFF03-----------------------------
INT 1A - SND - STOP SOUND
AX = FF03h
Return: AH = status
00h successful
01h busy
Note: turns off any sound currently being emitted by the PC's speaker unless
SND is currently busy processing an API call (this includes
background music). Use AX=FF05h to stop the sound even if an API
call is in progress.
SeeAlso: AX=FF00h,AX=FF02h,AX=FF05h
--------s-1AFF04-----------------------------
INT 1A - SND - PLAY MUSIC STRING IN BACKGROUND
AX = FF04h
DS:DX -> ASCIZ music string
Return: AH = status
00h successful (music begins playing in background)
01h busy
Note: the music string accepted by SND is not the same as that accepted by
BASIC and other programs which process music strings
SeeAlso: AX=FF00h,AX=FF05h,INT 80/BX=0006h
--------s-1AFF05-----------------------------
INT 1A - SND - UNCONDITIONALLY STOP SOUND
AX = FF05h
Return: AH = 00h (successful)
Note: this function is the same as AX=FF03h, but will stop the sound even if
SND is currently busy, such as playing background music
SeeAlso: AX=FF00h,AX=FF03h,INT 80/BX=0007h
--------B-1B---------------------------------
INT 1B C - KEYBOARD - CONTROL-BREAK HANDLER
Desc: this interrupt is automatically called when INT 09 determines that
Control-Break has been pressed
Note: normally points to a short routine in DOS which sets the Ctrl-C flag,
thus invoking INT 23h the next time DOS checks for Ctrl-C.
SeeAlso: INT 23
--------B-1C---------------------------------
INT 1C - TIME - SYSTEM TIMER TICK
Desc: this interrupt is automatically called on each clock tick by the INT 08
handler
Notes: this is the preferred interrupt to chain when a program needs to be
invoked regularly
not available on NEC 9800-series PCs
SeeAlso: INT 08,INT E2"PC Cluster"
--------B-1D---------------------------------
INT 1D - SYSTEM DATA - VIDEO PARAMETER TABLES
Note: the default parameter table (see #0625) is located at F000h:F0A4h for
100% compatible BIOSes
SeeAlso: INT 10/AH=00h

Format of video parameters:
Offset Size Description (Table 0625)
00h 16 BYTEs 6845 register values for modes 00h and 01h
10h 16 BYTEs 6845 register values for modes 02h and 03h
20h 16 BYTEs 6845 register values for modes 04h and 05h
30h 16 BYTEs 6845 register values for modes 06h and 07h
40h WORD bytes in video buffer for modes 00h and 01h (0800h)
42h WORD bytes in video buffer for modes 02h and 03h (1000h)
44h WORD bytes in video buffer for modes 04h and 05h (4000h)
46h WORD bytes in video buffer for mode 06h (4000h)
48h 8 BYTEs columns on screen for each of modes 00h through 07h
50h 8 BYTEs CRT controller mode bytes for each of modes 00h through 07h
Note: QEMM v7.5 Stealth appears to copy only the first 40h bytes of this
table into always-accessible memory
--------B-1E---------------------------------
INT 1E - SYSTEM DATA - DISKETTE PARAMETERS
Notes: the default parameter table (see #0626) is located at F000h:EFC7h for
100% compatible BIOSes
if the table is changed, INT 13/AH=00h should be called to ensure that
the floppy-disk controller is appropriately reprogrammed
SeeAlso: INT 13/AH=0Fh,INT 41,INT 4D/AH=0Ah

Format of diskette parameter table:
Offset Size Description (Table 0626)
00h BYTE first specify byte
bits 7-4: step rate
bits 3-0: head unload time (0Fh = 240 ms)
01h BYTE second specify byte
bits 7-1: head load time (01h = 4 ms)
bit 0: non-DMA mode (always 0)
02h BYTE delay until motor turned off (in clock ticks)
03h BYTE bytes per sector (00h = 128, 01h = 256, 02h = 512, 03h = 1024)
04h BYTE sectors per track
05h BYTE length of gap between sectors (2Ah for 5.25", 1Bh for 3.5")
06h BYTE data length (ignored if bytes-per-sector field nonzero)
07h BYTE gap length when formatting (50h for 5.25", 6Ch for 3.5")
08h BYTE format filler byte (default F6h)
09h BYTE head settle time in milliseconds
0Ah BYTE motor start time in 1/8 seconds
SeeAlso: #2365 at INT 4D/AH=09h
--------B-1F---------------------------------
INT 1F - SYSTEM DATA - 8x8 GRAPHICS FONT
Desc: this vector points at 1024 bytes of graphics data, 8 bytes for each
character 80h-FFh
Note: graphics data for characters 00h-7Fh stored at F000h:FA6Eh in 100%
compatible BIOSes
SeeAlso: INT 10/AX=5000h,INT 43
--------b-1F12-------------------------------
INT 1F U - C&T "SuperState" BIOS - POWER OFF
AH = 12h
Return: none
Note: POWER OFF
--------b-1F17-------------------------------
INT 1F U - C&T "SuperState" BIOS - EXECUTE FAR PROC ROUTINE ON SuperState
AH = 17h
ES:DI -> far procedure
Return: all registers except AH,ES,DI
Note: You can change the BIOS area (F000h:0000h - F000h:FFFFh) only through
this function
--------b-1F19-------------------------------
INT 1F U - C&T "SuperState" BIOS - ENABLE AUTO WAKEUP AND SET TIME AND DATE
AH = 19h
AL = hour in BCD
BH = minutes in BCD
BL = seconds in BCD
CH = year century in BCD (must be 19h)
CL = year low in BCD
DH = month in BCD
DL = date in BCD
Return: CF clear
--------b-1F1C-------------------------------
INT 1F U - C&T "SuperState" BIOS - SET SUSPEND TIMEOUT
AH = 1Ch
BX = sec until suspend starts
Return: None
--------b-1F1D-------------------------------
INT 1F U - C&T "SuperState" BIOS - SET SLEEP TIMEOUT
AH = 1Dh
BX = sec until sleep starts
Return: None
--------J-1F90-------------------------------
INT 1F - NEC PC-9801 - COPY EXTENDED MEMORY
AH = 90h
ES:BX -> global descriptor table (see #0393 at INT 15/AH=87h)
CX = number of bytes to copy
SI = 0000h
DI = 0000h
Return: CF clear if successful
CF set on error
???
SeeAlso: INT 15/AH=87h
--------b-1FF5--BLFA-------------------------
INT 1F U - C&T "SuperState" BIOS - REQUEST PASSWORD INPUT
AH = F5h
BL = FAh
Return: none
Note: this function will not return until the correct password is entered
SeeAlso: AH=F5h/BL=FDh,AX=F5h/BL=FEh
--------b-1FF5--BLFD-------------------------
INT 1F U - C&T "SuperState" BIOS - ENCRYPT PASSWORD
AH = F5h
BL = FDh
CX:SI = input string
DX:DI = encrypted string
BH = length of input string
Return: CF set on error
SeeAlso: AH=F5h/BL=FAh,AX=F5h/BL=FEh
--------b-1FF5--BLFE-------------------------
INT 1F U - C&T "SuperState" BIOS - SET PASSWORD
AH = F5h
BL = FEh
CX:SI -> input string
BH = length of input string (if BH = 00h, clear password)
Return: CF set on error
Note: the input string must be encrypted by INT 1Fh/AH=F5h/BL=FDh
SeeAlso: AH=F5h/BL=FDh,AX=F5h/BL=FFh
--------b-1FF5--BLFF-------------------------
INT 1F U - C&T "SuperState" BIOS - GET ENCRYPTED PASSWORD
AH = F5h
BL = FFh
DX:DI = string buffer
Return: CF set on error
CF clear if successful
BH = length of input string (if BH = 00h, password is not valid)
DX:DI -> encrypted password string
SeeAlso: AH=F5h/BL=FDh,AX=F5h/BL=FEh
--------b-1FFB-------------------------------
INT 1F U - C&T "SuperState" BIOS - GET/SET CPU SPEED
AH = FBh
BL = function
00h get CPU speed
Return: AL = current CPU speed (00h = fast, 01h = slow)
01h set CPU speed
AL = new CPU speed (00h = fast, 01h = slow)
SeeAlso: AH=FCh/BL=00h
--------b-1FFC--BL00-------------------------
INT 1F U - C&T "SuperState" BIOS - GET ALARM STATUS
AH = FCh
BL = 00h
Return: AL = current alarm state (00h = disabled, 01h = enabled)
SeeAlso: AH=FCh/BL=01h,AH=FCh/BL=02h
--------b-1FFC--BL01-------------------------
INT 1F U - C&T "SuperState" BIOS - SET ALARM STATUS
AH = FCh
BL = 01h
AL = new alarm state (00h = disabled, 01h = enabled)
SeeAlso: AH=FCh/BL=00h,AH=FCh/BL=03h
--------b-1FFC--BL02-------------------------
INT 1F U - C&T "SuperState" BIOS - GET ALARM TIME
AH = FCh
BL = 02h
Return: CH = hour by BCD
CL = min by BCD
DH = sec by BCD
SeeAlso: AH=FCh/BL=00h,AH=FCh/BL=03h,AH=FCh/BL=04h
--------b-1FFC--BL03-------------------------
INT 1F U - C&T "SuperState" BIOS - SET ALARM TIME
AH = FCh
BL = 03h
CH = hour by BCD
CL = min by BCD
DH = sec by BCD
Return: CF set on error (incorrect time format or Alarm is not enable)
SeeAlso: AH=FCh/BL=01h,AH=FCh/BL=02h,AH=FCh/BL=05h
--------b-1FFC--BL04-------------------------
INT 1F U - C&T "SuperState" BIOS - GET ALARM DATE
AH = FCh
BL = 04h
Return: CH = year century by BCD
CL = year low by BCD
DH = month by BCD
DL = date by BCD
SeeAlso: AH=FCh/BL=02h,AH=FCh/BL=05h
--------b-1FFC--BL05-------------------------
INT 1F U - C&T "SuperState" BIOS - SET ALARM DATE
AH = FCh
BL = 05h
CH = year century by BCD
CL = year low by BCD
DH = month by BCD
DL = date by BCD
Return: CF set on error (incorrect date format or Alarm is not enable)
SeeAlso: AH=FCh/BL=03h,AH=FCh/BL=04h
--------b-1FFD--BL00-------------------------
INT 1F U - C&T "SuperState" BIOS - GET AUTO WAKE UP STATUS
AH = FDh
BL = 00h
Return: AL = current wake-up state (00h = disabled, 01h = enabled)
SeeAlso: AH=FDh/BL=01h,AH=FDh/BL=02h
--------b-1FFD--BL01-------------------------
INT 1F U - C&T "SuperState" BIOS - SET AUTO WAKE UP STATUS
AH = FDh
BL = 01h
AL = new wake-up state (00h = disabled, 01h = enabled)
SeeAlso: AH=FDh/BL=00h,AH=FDh/BL=03h
--------b-1FFD--BL02-------------------------
INT 1F U - C&T "SuperState" BIOS - GET AUTO WAKE UP TIME
AH = FDh
BL = 02h
Return: CH = hour by BCD
CL = min by BCD
DH = sec by BCD
SeeAlso: AH=FDh/BL=00h,AH=FDh/BL=03h
--------b-1FFD-------------------------------
INT 1F U - C&T "SuperState" BIOS - SET AUTO WAKE UP TIME
AH = FDh
BL = 3h
CH = hour by BCD
CL = min by BCD
DH = sec by BCD
Return: CF set on error (incorrect Time format or Auto Wake up is not enable)
SeeAlso: AH=FDh/BL=01h,AH=FDh/BL=02h
--------b-1FFD--BL04-------------------------
INT 1F U - C&T "SuperState" BIOS - GET AUTO WAKE UP DATE
AH = FDh
BL = 04h
Return: CH = year century in BCD
CL = year low in BCD
DH = month in BCD
DL = date in BCD
SeeAlso: AH=FDh/BL=02h,AH=FDh/BL=05h
--------b-1FFD--BL05-------------------------
INT 1F U - C&T "SuperState" BIOS - SET AUTO WAKE UP DATE
AH = FDh
BL = 05h
CH = year century in BCD
CL = year low in BCD
DH = month in BCD
DL = date in BCD
Return: CF set on error (incorrect date format or Auto Wake up is not enable)
SeeAlso: AH=FDh/BL=03h,AH=FDh/BL=04h
--------O-20---------------------------------
INT 20 - Minix - SEND/RECEIVE MESSAGE
AX = process ID of other process
BX -> message
CX = operation (1 send, 2 receive, 3 send&receive)
Program: Minix is a Version 7 Unix-compatible operating system by Andrew
Tanenbaum
Note: the message contains the system call number (numbered as in V7
Unix(tm)) and the call parameters
--------D-20---------------------------------
INT 20 - DOS 1+ - TERMINATE PROGRAM
CS = PSP segment
Return: never
Note: (see INT 21/AH=00h)
SeeAlso: INT 21/AH=00h,INT 21/AH=4Ch
--------G-20---------------------------------
INT 20 - COMTROL HOSTESS i/ISA DEBUGGER - INVOKE FIRMWARE DEBUGGER
???
Return: ???
SeeAlso: INT 21"COMTROL"
--------W-20---------------------------------
INT 20 P - Microsoft Windows - VxD FUNCTIONS
Note: the desired VxD and function are identified by the data immediately
following the INT 20 instruction, as in:
INT 20h
DW function number
DW VxD identifier

(Table 0627)
Values for VMM (VxD ID 0001h) function number:
00h get version
01h get current VM handle
02h test current VM handle
03h get system VM handle
04h test system VM handle
05h validate VM handle
06h get VMM reenter count
07h begin reentrant execution
08h end reentrant execution
09h install V86 breakpoint
0Ah remove V86 breakpoint
0Bh allocate V86 callback
0Ch allocation PM callback
0Dh call when VM returns
0Eh schedule global event
0Fh schedule VM event
10h call global event
11h call VM event
12h cancel global event
13h cancel VM event
14h call priority VM event
15h cancel priority VM event
16h get NMI handler address
17h set NMI handler address
18h hook NMI event
19h call when VM interrupts enabled
1Ah enable VM interrupts
1Bh disable VM interrupts
1Ch map flat
1Dh map linear to VM address
1Eh adjust execution priority
1Fh begin critical section
20h end critical section
21h end critical section and suspend
22h claim critical section
23h release critical section
24h call when not critical
25h create semaphore
26h destroy semaphore
27h wait on semaphore
28h signal semaphore
29h get critical section status
2Ah call when task switched
2Bh suspend VM
2Ch resume VM
2Dh no-fail resume VM
2Eh nuke VM
2Fh crash current VM
30h get execution focus
31h set execution focus
32h get time slice priority
33h set time slice priority
34h get time slice granularity
35h set time slice granularity
36h get time slice information
37h adjust execution time
38h release time slice
39h wake up VM
3Ah call when idle
3Bh get next VM handle
3Ch set global timeout
3Dh set VM timeout
3Eh cancel timeout
3Fh get system time
40h get VM execution time
41h hook V86 interrupt chain
42h get V86 interrupt vector
43h set V86 interrupt vector
44h get PM interrupt vector
45h set PM interrupt vector
46h simulate interrupt
47h simulate IRET
48h simulate far call
49h simulate far jump
4Ah simulate far RET
4Bh simulate far RET N
4Ch build interrupt stack frame
4Dh simulate push
4Eh simulate pop
4Fh _HeapAllocate
50h _HeapReAllocate
51h _HeapFree
52h _HeapGetSize
53h _PageAllocate
54h _PageReAllocate
55h _PageFree
56h _PageLock
57h _PageUnLock
58h _PageGetSizeAddr
59h _PageGetAllocInfo
5Ah _GetFreePageCount
5Bh _GetSysPageCount
5Ch _GetVMPgCount
5Dh _MapIntoV86
5Eh _PhysIntoV86
5Fh _TestGlobalV86Mem
60h _ModifyPageBits
61h copy page table
62h map linear into V86
63h linear page lock
64h linear page unlock
65h _SetResetV86Pageabl
66h _GetV86PageableArray
67h _PageCheckLinRange
68h page out dirty pages
69h discard pages
6Ah _GetNulPageHandle
6Bh get first V86 page
6Ch map physical address to linear address
6Dh _GetAppFlatDSAlias
6Eh _SelectorMapFlat
6Fh _GetDemandPageInfo
70h _GetSetPageOutCount
71h hook V86 page
72h assign device V86 pages
73h deassign device V86 pages
74h get array of V86 pages for device
75h _SetNULPageAddr
76h allocate GDT selector
77h free GDT selector
78h allocate LDT selector
79h free LDT selector
7Ah _BuildDescriptorDWORDs
7Bh get descriptor
7Ch set descriptor
7Dh toggle HMA
7Eh get fault hook addresses
7Fh hook V86 fault
80h hook PM fault
81h hook VMM fault
82h begin nested V86 execution
83h begin nested execution
84h execute interrupt
85h resume execution
86h end nested execution
87h allocate PM application callback area
88h get current PM application callback area
89h set V86 execution mode
8Ah set PM execution mode
8Bh begin using locked PM stack
8Ch end using locked PM stack
8Dh save client state
8Eh restore client state
8Fh execute VxD interrupt
90h hook device service
91h hook device V86 API
92h hook device PM API
93h system control
94h simulate I/O
95h install multiple I/O handlers
96h install I/O handler
97h enable global trapping
98h enable local trapping
99h disable global trapping
9Ah disable local trapping
9Bh create list
9Ch destroy list
9Dh allocate list
9Eh attach list
9Fh attach list tail
A0h insert into list
A1h remove from list
A2h deallocate list
A3h get first item in list
A4h get next item in list
A5h remove first item in list
A6h add instance item
A7h allocate device callback area
A8h allocate global V86 data area
A9h allocate temporary V86 data area
AAh free temporary V86 data area
ABh get decimal integer from profile
ACh convert decimal string to integer
ADh get fixed-point number from profile
AEh convert fixed-point string
AFh get hex integer from profile
B0h convert hex string to integer
B1h get boolean value from profile
B2h convert boolean string
B3h get string from profile
B4h get next string from profile
B5h get environment string
B6h get exec path
B7h get configuration directory
B8h open file
B9h get PSP segment
BAh get DOS vectors
BBh get machine information
BCh get/set HMA information
BDh set system exit code
BEh fatal error handler
BFh fatal memory error
C0h update system clock
C1h test if debugger installed
C2h output debugger string
C3h output debugger character
C4h input debugger character
C5h debugger convert hex to binary
C6h debugger convert hex to decimal
C7h debugger test if valid handle
C8h validate client pointer
C9h test reentry
CAh queue debugger string
CBh log procedure call
CCh debugger test current VM
CDh get PM interrupt type
CEh set PM interrupt type
CFh get last updated system time
D0h get last updated VM execution time
D1h test if double-byte character-set lead byte
D2h _AddFreePhysPage
D3h _PageResetHandlePAddr
D4h _SetLastV86Page
D5h _GetLastV86Page
D6h _MapFreePhysReg
D7h _UnmapFreePhysReg
D8h _XchgFreePhysReg
D9h _SetFreePhysRegCalBk
DAh get next arena (MCB)
DBh get name of ugly TSR
DCh get debug options
DDh set physical HMA alias
DEh _GetGlblRng0V86IntBase
DFh add global V86 data area
E0h get/set detailed VM error
E1h Is_Debug_Chr
E2h clear monochrome screen
E3h output character to mono screen
E4h output string to mono screen
E5h set current position on mono screen
E6h get current position on mono screen
E7h get character from mono screen
E8h locate byte in ROM
E9h hook invalid page fault
EAh unhook invalid page fault
EBh set delete on exit file
SeeAlso: #0628

(Table 0628)
Values for VPICD (VxD ID 0003h) function number:
00h get version
01h virtualize IRQ
02h set interrupt request
03h clear interrupt request
04h physical EOI
05h get complete status
06h get status
07h test physical request
08h physically mask
09h physically unmask
0Ah set automatic masking
0Bh get IRQ complete status
0Ch convert handle to IRQ
0Dh convert IRQ to interrupt
0Eh convert interrupt to IRQ
0Fh call on hardware interrupt
10h force default owner
11h force default behavior
SeeAlso: #0627,#0629

(Table 0629)
Values for VDMAD (VxD ID 0004h) function number:
00h get version
01h virtualize channel
02h get region information
03h set region information
04h get virtual state
05h set virtual state
06h set physical state
07h mask channel
08h unmask channel
09h lock DMA region
0Ah unlock DMA region
0Bh scatter lock
0Ch scatter unlock
0Dh reserve buffer space
0Eh request buffer
0Fh release buffer
10h copy to buffer
11h copy from buffer
12h default handler
13h disable translation
14h enable translation
15h get EISA address mode
16h set EISA address mode
17h unlock DMA region (ND)
SeeAlso: #0628,#1883,#1895 at INT 2F/AX=1684h/BX=0444h

(Table 0630)
Values for VTD (VxD ID 0005h) function number:
0000h get version
0001h update system clock
0002h get interrupt period
0003h begin minimum interrupt period
0004h end minimum interrupt period
0005h disable trapping
0006h enable trapping
0007h get real time
SeeAlso: #1883 at INT 2F/AX=1684h/BX=0005h

(Table 0631)
Values for V86MMGR (VxD ID 0006h) function number:
00h get version
01h allocate V86 pages
02h set EMS and XMS limits
03h get EMS and XMS limits
04h set mapping information
05h get mapping information
06h Xlat API
07h load client pointer
08h allocate buffer
09h free buffer
0Ah get Xlat buffer state
0Bh set Xlat buffer state
0Ch get VM flat selector
0Dh map pages
0Eh free page map region
0Fh _LocalGlobalReg
10h get page status
11h set local A20
12h reset base pages
13h set available mapped pages
SeeAlso: #1883,#0632

(Table 0632)
Values for PageSwap (VxD ID 0007h) function number:
00h get version
01h test create
02h create swap file
03h destroy swap file
04h in
05h out
06h test if I/O valid
SeeAlso: #0631,#0633,#1884

(Table 0633)
Values for VDD (VxD ID 000Ah) function number:
00h get version
01h PIF state
02h get GrabRtn
03h hide cursor
04h set VM type
05h get ModTime
06h set HCurTrk
07h message clear screen
08h message foreground color
09h message background color
0Ah message output text
0Bh message set cursor position
0Ch query access
SeeAlso: #0632,#0634,#1884

(Table 0634)
Values for VSD (VxD ID 000Bh) function number:
00h get version
01h bell
SeeAlso: #0633,#0635

(Table 0635)
Values for VMD (VxD ID 000Ch) function number:
00h get version
01h set mouse type
02h get mouse owner
SeeAlso: #0634,#0636

(Table 0636)
Values for VKD (VxD ID 000Dh) function number:
00h get version
01h define hotkey
02h remove hotkey
03h locally enable hotkey
04h locally disable hotkey
05h reflect hotkey
06h cancel hotkey state
07h force keys
08h get keyboard owner
09h define paste mode
0Ah start pasting
0Bh cancel paste
0Ch get message key
0Dh peek message key
0Eh flush message key queue
SeeAlso: #0635,#0637

(Table 0637)
Values for VCD (VxD ID 000Eh) function number:
00h get version
01h set port global
02h get focus
03h virtualize port
SeeAlso: #0636,#0638

(Table 0638)
Values for BlockDev (VxD ID 0010h) function number:
00h get version
01h register device
02h find INT 13 drive
03h get device list
04h send command
05h command complete
06h synchronous command
SeeAlso: #0637,#0639

(Table 0639)
Values for EBIOS (VxD ID 0012h) function number:
00h get version
01h get unused memory
SeeAlso: #0638,#0640

(Table 0640)
Values for VNETBIOS (VxD ID 0014h) function number:
00h get version
SeeAlso: #0639,#0641

(Table 0641)
Values for DOSMGR (VxD ID 0015h) function number:
00h get version
01h set exec VM data
02h coyp VM drive state
03h execute VM
04h get InDOS pointer
05h add device
06h remove device
07h instance device
08h get DOS critical status
09h enable InDOS polling
0Ah backfill allowed
0Bh "LocalGlobalReg"
SeeAlso: #0640,#1885 at INT 2F/AX=1684h/BX=0015h

(Table 0642)
Values for SHELL (VxD ID 0017h) function number:
00h get version
01h resolve contention
02h event
03h SYSMODAL message
04h message
05h get VM information
SeeAlso: #0641,#0643,#1886 at INT 2F/AX=1684h/BX=0017h

(Table 0643)
Values for VMPoll (VxD ID 0018h) function number:
00h get version
01h enable/disable
02h reset detection
SeeAlso: #0630,#1886 at INT 2F/AX=1684h/BX=0017h

(Table 0644)
Values for DOSNET (VxD ID 001Ah) function number:
00h get version
01h send FILESYSCHANGE
02h do PSP adjust
SeeAlso: #0643,#0645

(Table 0645)
Values for Int13 (VxD ID 0020h) function number:
00h get version
01h device registered
02h translate VM interrupt
03h hooking BIOS interrupt
04h unhooking BIOS interrupt
SeeAlso: #0644,#0646

(Table 0646)
Values for PAGEFILE (VxD ID 0021h) function number:
00h get version
01h init file
02h clean up
03h grow file
04h read or write
05h cancel
06h test I/O valid
SeeAlso: #0645,#1890 at INT 2F/AX=1684h/BX=0021h
--------G-21---------------------------------
INT 21 - COMTROL HOSTESS i/ISA DEBUGGER - GET SEGMENT FOR CONTROL PROGRAM USE
???
Return: AX = first segment available for control program use
SeeAlso: INT 20"COMTROL",INT 22"COMTROL"
--------D-2100-------------------------------
INT 21 - DOS 1+ - TERMINATE PROGRAM
AH = 00h
CS = PSP segment
Notes: Microsoft recommends using INT 21/AH=4Ch for DOS 2+
execution continues at the address stored in INT 22 after DOS performs
whatever cleanup it needs to do
if the PSP is its own parent, the process's memory is not freed; if
INT 22 additionally points into the terminating program, the
process is effectively NOT terminated
not supported by MS Windows 3.0 DOSX.EXE DOS extender
SeeAlso: AH=26h,AH=31h,AH=4Ch,INT 20,INT 22
--------D-2101-------------------------------
INT 21 - DOS 1+ - READ CHARACTER FROM STANDARD INPUT, WITH ECHO
AH = 01h
Return: AL = character read
Notes: ^C/^Break are checked, and INT 23 executed if read
character is echoed to standard output
standard input is always the keyboard and standard output the screen
under DOS 1.x, but they may be redirected under DOS 2+
SeeAlso: AH=06h,AH=07h,AH=08h,AH=0Ah
--------D-2102-------------------------------
INT 21 - DOS 1+ - WRITE CHARACTER TO STANDARD OUTPUT
AH = 02h
DL = character to write
Return: AL = last character output (despite the official docs which state
nothing is returned) (at least DOS 3.3-5.0)
Notes: ^C/^Break are checked, and INT 23 executed if pressed
standard output is always the screen under DOS 1.x, but may be
redirected under DOS 2+
the last character output will be the character in DL unless DL=09h
on entry, in which case AL=20h as tabs are expanded to blanks
SeeAlso: AH=06h,AH=09h
--------D-2103-------------------------------
INT 21 - DOS 1+ - READ CHARACTER FROM STDAUX
AH = 03h
Return: AL = character read
Notes: keyboard checked for ^C/^Break, and INT 23 executed if detected
STDAUX is usually the first serial port
SeeAlso: AH=04h,INT 14/AH=02h,INT E0/CL=03h
--------D-2104-------------------------------
INT 21 - DOS 1+ - WRITE CHARACTER TO STDAUX
AH = 04h
DL = character to write
Notes: keyboard checked for ^C/^Break, and INT 23 executed if detected
STDAUX is usually the first serial port
if STDAUX is busy, this function will wait until it becomes free
SeeAlso: AH=03h,INT 14/AH=01h,INT E0/CL=04h
--------D-2105-------------------------------
INT 21 - DOS 1+ - WRITE CHARACTER TO PRINTER
AH = 05h
DL = character to print
Notes: keyboard checked for ^C/^Break, and INT 23 executed if detected
STDPRN is usually the first parallel port, but may be redirected under
DOS 2+
if the printer is busy, this function will wait
SeeAlso: INT 17/AH=00h
--------D-2106-------------------------------
INT 21 - DOS 1+ - DIRECT CONSOLE OUTPUT
AH = 06h
DL = character (except FFh)
Return: AL = character output (despite official docs which state nothing is
returned) (at least DOS 3.3-5.0)
Notes: does not check ^C/^Break
writes to standard output, which is always the screen under DOS 1.x,
but may be redirected under DOS 2+
SeeAlso: AH=02h,AH=09h
--------D-2106--DLFF-------------------------
INT 21 - DOS 1+ - DIRECT CONSOLE INPUT
AH = 06h
DL = FFh
Return: ZF set if no character available
AL = 00h
ZF clear if character available
AL = character read
Notes: ^C/^Break are NOT checked
if the returned character is 00h, the user pressed a key with an
extended keycode, which will be returned by the next call of this
function
this function reads from standard input, which is always the keyboard
under DOS 1.x, but may be redirected under DOS 2+
although the return of AL=00h when no characters are available is not
documented, some programs rely on this behavior
SeeAlso: AH=0Bh
--------D-2107-------------------------------
INT 21 - DOS 1+ - DIRECT CHARACTER INPUT, WITHOUT ECHO
AH = 07h
Return: AL = character read from standard input
Notes: does not check ^C/^Break
standard input is always the keyboard under DOS 1.x, but may be
redirected under DOS 2+
if the interim console flag is set (see AX=6301h), partially-formed
double-byte characters may be returned
SeeAlso: AH=01h,AH=06h,AH=08h,AH=0Ah
--------D-2108-------------------------------
INT 21 - DOS 1+ - CHARACTER INPUT WITHOUT ECHO
AH = 08h
Return: AL = character read from standard input
Notes: ^C/^Break are checked, and INT 23 executed if detected
standard input is always the keyboard under DOS 1.x, but may be
redirected under DOS 2+
if the interim console flag is set (see AX=6301h), partially-formed
double-byte characters may be returned
SeeAlso: AH=01h,AH=06h,AH=07h,AH=0Ah,AH=64h
--------D-2109-------------------------------
INT 21 - DOS 1+ - WRITE STRING TO STANDARD OUTPUT
AH = 09h
DS:DX -> '$'-terminated string
Return: AL = 24h (the '$' terminating the string, despite official docs which
state that nothing is returned) (at least DOS 3.3-5.0)
Notes: ^C/^Break are checked, and INT 23 is called if either pressed
standard output is always the screen under DOS 1.x, but may be
redirected under DOS 2+
under the FlashTek X-32 DOS extender, the pointer is in DS:EDX
SeeAlso: AH=02h,AH=06h"OUTPUT"
--------D-210A-------------------------------
INT 21 - DOS 1+ - BUFFERED INPUT
AH = 0Ah
DS:DX -> buffer (see #0647)
Return: buffer filled with user input
Notes: ^C/^Break are checked, and INT 23 is called if either detected
reads from standard input, which may be redirected under DOS 2+
if the maximum buffer size (see #0647) is set to 00h, this call returns
immediately without reading any input
SeeAlso: AH=0Ch,INT 2F/AX=4810h

Format of DOS input buffer:
Offset Size Description (Table 0647)
00h BYTE maximum characters buffer can hold
01h BYTE (call) number of chars from last input which may be recalled
(ret) number of characters actually read, excluding CR
02h N BYTEs actual characters read, including the final carriage return
--------K-210A00-----------------------------
INT 21 - WCED v1.6+ - INSTALLATION CHECK
AX = 0A00h
DS:DX -> 6-byte buffer whose first two bytes must be 00h
Return: buffer offset 02h-05h filled with "Wced" if installed
Program: WCED is a free command-line editor and history utility by Stuart
Russell
SeeAlso: AH=FFh"CED"
--------D-210B-------------------------------
INT 21 - DOS 1+ - GET STDIN STATUS
AH = 0Bh
Return: AL = status
00h if no character available
FFh if character is available
Notes: ^C/^Break are checked, and INT 23 is called if either pressed
standard input is always the keyboard under DOS 1.x, but may be
redirected under DOS 2+
if the interim console flag is set (see AX=6301h), this function
returns AL=FFh if a partially-formed double-byte character is
available
SeeAlso: AH=06h"INPUT",AX=4406h
--------v-210B56-----------------------------
INT 21 - VIRUS - "Perfume" - INSTALLATION CHECK
AX = 0B56h
Return: AX = 4952h if resident
SeeAlso: AX=0D20h,INT 12/AX=4350h/BX=4920h,INT 13/AH=F2h
--------D-210C-------------------------------
INT 21 - DOS 1+ - FLUSH BUFFER AND READ STANDARD INPUT
AH = 0Ch
AL = STDIN input function to execute after flushing buffer
other registers as appropriate for the input function
Return: as appropriate for the specified input function
Note: if AL is not one of 01h,06h,07h,08h, or 0Ah, the buffer is flushed but
no input is attempted
SeeAlso: AH=01h,AH=06h"INPUT",AH=07h,AH=08h,AH=0Ah
--------D-210D-------------------------------
INT 21 - DOS 1+ - DISK RESET
AH = 0Dh
Return: (DOS 6 only) CF clear (earlier versions preserve CF)
Notes: This function writes all modified disk buffers to disk, but does not
update the directory information (that is only done when files are
closed or a SYNC call is issued)
SeeAlso: AX=5D01h,INT 13/AH=00h,INT 2F/AX=1120h
--------v-210D20-----------------------------
INT 21 - VIRUS - "Crazy Imp" - INSTALLATION CHECK
AX = 0D20h
Return: AX = 1971h if resident
SeeAlso: AX=0B56h,AX=1812h,AX=2C2Ch,AH=30h/DX=ABCDh
--------D-210E-------------------------------
INT 21 - DOS 1+ - SELECT DEFAULT DRIVE
AH = 0Eh
DL = new default drive (00h = A:, 01h = B:, etc)
Return: AL = number of potentially valid drive letters
Notes: under Novell NetWare, the return value is always 32, the number of
drives that NetWare supports
under DOS 3.0+, the return value is the greatest of 5, the value of
LASTDRIVE= in CONFIG.SYS, and the number of drives actually present
on a DOS 1.x/2.x single-floppy system, AL returns 2 since the floppy
may be accessed as either A: or B:
otherwise, the return value is the highest drive actually present
DOS 1.x supports a maximum of 16 drives, 2.x a maximum of 63 drives,
and 3+ a maximum of 26 drives
under Novell DOS 7, this function returns the correct LASTDRIVE value
even when the undocumented LASTDRIVE=32 directive was used in
CONFIG.SYS
SeeAlso: AH=19h,AH=3Bh,AH=DBh
--------v-210E--DLAD-------------------------
INT 21 U - Novell DOS 7 - SDRes v27.03 - INSTALLATION CHECK
AH = 0Eh
DL = ADh
Return: AL = BAh if installed
Program: SDRes is the resident portion of the Search&Destroy antiviral by
Fifth Generation Systems, as bundled with Novell DOS 7
Note: SDRes will terminate programs which test for the presence of viruses
using interrupt-based installation calls, saying that the program
may be infected
SeeAlso: AH=0Eh/DL=AEh,AH=0Eh/DL=AFh,AH=4Ah/BX=00B6h,INT 13/AX=A759h
--------v-210E--DLAE-------------------------
INT 21 U - Novell DOS 7 - SDRes v27.03 - CLEAR ??? FLAG
AH = 0Eh
DL = AEh
SeeAlso: AH=0Eh/DL=ADh,AH=0Eh/DL=AFh,INT 13/AX=A759h
--------v-210E--DLAF-------------------------
INT 21 U - Novell DOS 7 - SDRes v27.03 - SET ??? FLAG
AH = 0Eh
DL = AFh
SeeAlso: AH=0Eh/DL=ADh,AH=0Eh/DL=AEh,INT 13/AX=A759h
--------D-210F-------------------------------
INT 21 - DOS 1+ - OPEN FILE USING FCB
AH = 0Fh
DS:DX -> unopened File Control Block (see #0648)
Return: AL = status
00h successful
FFh file not found or access denied
Notes: (DOS 3.1+) file opened for read/write in compatibility mode
an unopened FCB has the drive, filename, and extension fields filled
in and all other bytes cleared
not supported by MS Windows 3.0 DOSX.EXE DOS extender
DR-DOS checks password attached with AX=4303h
BUG: APPEND for DOS 3.3+ corrupts DX if the file is not found
SeeAlso: AH=10h,AH=16h,AH=3Dh,AX=4303h

Format of File Control Block:
Offset Size Description (Table 0648)
-7 BYTE extended FCB if FFh
-6 5 BYTEs reserved
-1 BYTE file attribute if extended FCB
00h BYTE drive number (0 = default, 1 = A, etc)
01h 8 BYTEs blank-padded file name
09h 3 BYTEs blank-padded file extension
0Ch WORD current block number
0Eh WORD logical record size
10h DWORD file size
14h WORD date of last write (see #0952 at AX=5700h)
16h WORD time of last write (see #0951 at AX=5700h) (DOS 1.1+)
18h 8 BYTEs reserved (see #0649,#0650,#0651,#0652,#0653)
20h BYTE record within current block
21h DWORD random access record number (if record size is > 64 bytes, high
byte is omitted)
Note: to use an extended FCB, you must specify the address of the FFh flag at
offset -7, rather than the address of the drive number field

Format of FCB reserved field for DOS 1.0:
Offset Size Description (Table 0649)
16h WORD location in directory (if high byte = FFh, low byte is device
ID)
18h WORD number of first cluster in file
1Ah WORD current absolute cluster number on disk
1Ch WORD current relative cluster number within file
(0 = first cluster of file, 1 = second cluster, etc.)
1Eh BYTE dirty flag (00h = not dirty)
1Fh BYTE unused

Format of FCB reserved field for DOS 1.10-1.25:
Offset Size Description (Table 0650)
18h BYTE bit 7: set if logical device
bit 6: not dirty
bits 5-0: disk number or logical device ID
19h WORD starting cluster number on disk
1Bh WORD current absolute cluster number on disk
1Dh WORD current relative cluster number within file
1Fh BYTE unused

Format of FCB reserved field for DOS 2.x:
Offset Size Description (Table 0651)
18h BYTE bit 7: set if logical device
bit 6: set if open???
bits 5-0: ???
19h WORD starting cluster number on disk
1Bh WORD ???
1Dh BYTE ???
1Eh BYTE ???
1Fh BYTE ???

Format of FCB reserved field for DOS 3.x:
Offset Size Description (Table 0652)
18h BYTE number of system file table entry for file
19h BYTE attributes
bits 7,6: 00 = SHARE.EXE not loaded, disk file
01 = SHARE.EXE not loaded, character device
10 = SHARE.EXE loaded, remote file
11 = SHARE.EXE loaded, local file or device
bits 5-0: low six bits of device attribute word
---SHARE.EXE loaded, local file---
1Ah WORD starting cluster of file on disk
1Ch WORD (DOS 3.x) offset within SHARE of sharing record
(see #0924 at AH=52h)
1Eh BYTE file attribute
1Fh BYTE ???
---SHARE.EXE loaded, remote file---
1Ah WORD number of sector containing directory entry
1Ch WORD relative cluster within file of last cluster accessed
1Eh BYTE absolute cluster number of last cluster accessed
1Fh BYTE ???
---SHARE.EXE not loaded---
1Ah BYTE (low byte of device attribute word AND 0Ch) OR open mode
1Bh WORD starting cluster of file
1Dh WORD number of sector containing directory entry
1Fh BYTE number of directory entry within sector
Note: if FCB opened on character device, DWORD at 1Ah is set to the address
of the device driver header, then the BYTE at 1Ah is overwritten.

Format of FCB reserved field for DOS 5.0:
Offset Size Description (Table 0653)
18h BYTE number of system file table entry for file
19h BYTE attributes
bits 7,6: 00 = SHARE.EXE not loaded, disk file
01 = SHARE.EXE not loaded, character device
10 = SHARE.EXE loaded, remote file
11 = SHARE.EXE loaded, local file or device
bits 5-0: low six bits of device attribute word
---SHARE.EXE loaded, local file---
1Ah WORD starting cluster of file on disk
1Ch WORD unique sequence number of sharing record
1Eh BYTE file attributes
1Fh BYTE unused???
---SHARE.EXE loaded, remote file---
1Ah WORD network handle
1Ch DWORD network ID
---SHARE not loaded, local device---
1Ah DWORD pointer to device driver header
1Eh 2 BYTEs unused???
---SHARE not loaded, local file---
1Ah BYTE extra info
bit 7: read-only attribute from SFT
bit 6: archive attribute from SFT
bits 5-0: high bits of sector number
1Bh WORD starting cluster of file
1Dh WORD low word of sector number containing directory entry
1Fh BYTE number of directory entry within sector
--------D-2110-------------------------------
INT 21 - DOS 1+ - CLOSE FILE USING FCB
AH = 10h
DS:DX -> File Control Block (see #0648)
Return: AL = status
00h successful
FFh failed
Notes: a successful close forces all disk buffers used by the file to be
written and the directory entry to be updated
not supported by MS Windows 3.0 DOSX.EXE DOS extender
SeeAlso: AH=0Fh,AH=16h,AH=3Eh
--------D-2111-------------------------------
INT 21 - DOS 1+ - FIND FIRST MATCHING FILE USING FCB
AH = 11h
DS:DX -> unopened FCB (see #0648), may contain '?' wildcards
Return: AL = status
00h successful
[DTA] unopened FCB for first matching file
FFh no matching filename, or bad FCB
Notes: the type of the returned FCB depends on whether the input FCB was a
normal or an extended FCB
the data returned in the DTA is actually the drive number (or extended
FCB header and drive number) followed by the file's directory entry
(see #0654); this format happens to be compatible with an unopened
FCB
for extended FCBs with search attribute 08h, the volume label (if any)
will be returned even if the current directory is not the root dir.
DOS 3.0+ also allows the '*' wildcard
the search FCB must not be modified if AH=12h will be used to continue
searching; DOS 3.3 has set the following parts of the FCB:
0Ch BYTE ???
0Dh WORD directory entry number of matching file
0Fh WORD cluster number of current directory
11h 4 BYTEs ???
15h BYTE drive number (1=A:)
this function is used by many copy protection schemes to obtain the
starting cluster of a file
SeeAlso: AH=12h,AH=1Ah,AH=4Eh,INT 2F/AX=111Bh

Format of DOS directory entry:
Offset Size Description (Table 0654)
00h 8 BYTEs blank-padded filename
08h 3 BYTEs blank-padded file extension
0Bh BYTE attributes
0Ch 10 BYTEs reserved
used by DR-DOS to store file password
16h WORD time of creation or last update (see #0951 at AX=5700h)
18h WORD date of creation or last update (see #0952 at AX=5700h)
1Ah WORD starting cluster number
1Ch DWORD file size
--------D-2112-------------------------------
INT 21 - DOS 1+ - FIND NEXT MATCHING FILE USING FCB
AH = 12h
DS:DX -> unopened FCB (see #0648)
Return: AL = status
00h successful
[DTA] = unopened FCB
FFh no more matching filenames
Note: (see AH=11h)
assumes that successful FindFirst executed on search FCB before call
SeeAlso: AH=1Ah,AH=4Fh,INT 2F/AX=111Ch
--------D-2113-------------------------------
INT 21 - DOS 1+ - DELETE FILE USING FCB
AH = 13h
DS:DX -> unopened FCB (see #0648), filename filled with template for
deletion ('?' wildcards allowed)
Return: AL = status
00h one or more files successfully deleted
FFh no matching files or all were read-only or locked
Notes: DOS 1.25+ deletes everything in the current directory (including
subdirectories) and sets the first byte of the name to 00h (entry
never used) instead of E5h if called on an extended FCB with
filename '???????????' and bits 0-4 of the attribute set (bits 1 and
2 for DOS 1.x). This may have originally been an optimization to
minimize directory searching after a mass deletion (DOS 1.25+ stop
the directory search upon encountering a never-used entry), but can
corrupt the filesystem under DOS 2+ because subdirectories are
removed without deleting the files they contain.
currently-open files should not be deleted
MS-DOS allows deletion of read-only files with an extended FCB, whereas
Novell NetWare, DR-DOS 6, and Novell DOS 7 do not
SeeAlso: AH=41h,INT 2F/AX=1113h
--------D-2114-------------------------------
INT 21 - DOS 1+ - SEQUENTIAL READ FROM FCB FILE
AH = 14h
DS:DX -> opened FCB (see #0648)
Return: AL = status
00h successful
01h end of file (no data)
02h segment wrap in DTA
03h end of file, partial record read
[DTA] = record read from file
Notes: reads a record of the size specified in the FCB beginning at the
current file position, then updates the current block and current
record fields in the FCB
if a partial record was read, it is zero-padded to the full size
not supported by MS Windows 3.0 DOSX.EXE DOS extender
SeeAlso: AH=0Fh,AH=15h,AH=1Ah,AH=3Fh,INT 2F/AX=1108h
--------D-2115-------------------------------
INT 21 - DOS 1+ - SEQUENTIAL WRITE TO FCB FILE
AH = 15h
DS:DX -> opened FCB (see #0648)
[DTA] = record to write
Return: AL = status
00h successful
01h disk full
02h segment wrap in DTA
Notes: writes a record of the size specified in the FCB beginning at the
current file position, then updates the current block and current
record fields in the FCB
if less than a full sector is written, the data is placed in a DOS
buffer to be written out at a later time
not supported by MS Windows 3.0 DOSX.EXE DOS extender
SeeAlso: AH=0Fh,AH=14h,AH=1Ah,AH=40h,INT 2F/AX=1109h
--------D-2116-------------------------------
INT 21 - DOS 1+ - CREATE OR TRUNCATE FILE USING FCB
AH = 16h
DS:DX -> unopened FCB (see #0648), wildcards not allowed
Return: AL = status
00h successful
FFh directory full or file exists and is read-only or locked
Notes: if file already exists, it is truncated to zero length
if an extended FCB is used, the file is given the attribute in the
FCB; this is how to create a volume label in the disk's root dir
not supported by MS Windows 3.0 DOSX.EXE DOS extender
SeeAlso: AH=0Fh,AH=10h,AH=3Ch
--------D-2117-------------------------------
INT 21 - DOS 1+ - RENAME FILE USING FCB
AH = 17h
DS:DX -> modified FCB (see also #0648)
the old filename ('?' wildcards OK) is in the standard location
while the new filename ('?' wildcards OK, no drive) is stored
in the 11 bytes beginning at offset 11h
Return: AL = status
00h successfully renamed
FFh no matching files,file is read-only, or new name already exists
Notes: subdirectories may be renamed using an extended FCB with the
appropriate attribute, as may volume labels
DR-DOS checks password attached with AX=4303h before permitting rename
SeeAlso: AH=0Fh,AH=13h,AX=4303h,AH=56h,INT 2F/AX=1111h
--------D-2118-------------------------------
INT 21 - DOS 1+ - NULL FUNCTION FOR CP/M COMPATIBILITY
AH = 18h
Return: AL = 00h
Note: corresponds to the CP/M BDOS function "get bit map of logged drives",
which is meaningless under MS-DOS
SeeAlso: AH=1Dh,AH=1Eh,AH=20h,AX=4459h,INT 60/DI=0513h
--------v-211812------------------------
INT 21 - VIRUS - "Tasha Yar" - INSTALLATION CHECK
AX = 1812h
Return: AL = 00h if resident
DX = 4310h if resident
SeeAlso: INT 16/AH=DDh"VIRUS",INT 21/AX=2C2Ch"VIRUS"
--------D-2119-------------------------------
INT 21 - DOS 1+ - GET CURRENT DEFAULT DRIVE
AH = 19h
Return: AL = drive (00h = A:, 01h = B:, etc)
Note: Novell NetWare uses the fact that DOS 2.x COMMAND.COM issues this call
from a particular location every time it starts a command to
determine when to issue an automatic EOJ
SeeAlso: AH=0Eh,AH=47h,AH=BBh
--------D-211A-------------------------------
INT 21 - DOS 1+ - SET DISK TRANSFER AREA ADDRESS
AH = 1Ah
DS:DX -> Disk Transfer Area (DTA)
Notes: the DTA is set to PSP:0080h when a program is started
under the FlashTek X-32 DOS extender, the pointer is in DS:EDX
SeeAlso: AH=11h,AH=12h,AH=2Fh,AH=4Eh,AH=4Fh
--------D-211B-------------------------------
INT 21 - DOS 1+ - GET ALLOCATION INFORMATION FOR DEFAULT DRIVE
AH = 1Bh
Return: AL = sectors per cluster (allocation unit)
CX = bytes per sector
DX = total number of clusters
DS:BX -> media ID byte (see #0655)
Note: under DOS 1.x, DS:BX points at an actual copy of the FAT; later
versions return a pointer to a copy of the FAT's ID byte
SeeAlso: AH=1Ch,AH=36h

(Table 0655)
Values for media ID byte:
FFh floppy, double-sided, 8 sectors per track (320K)
FEh floppy, single-sided, 8 sectors per track (160K)
FDh floppy, double-sided, 9 sectors per track (360K)
FCh floppy, single-sided, 9 sectors per track (180K)
FAh HP 200LX D: ROM disk, 16 sectors per track (995K)
HP 200LX E: (Stacker host drive ???)
F9h floppy, double-sided, 15 sectors per track (1.2M)
floppy, double-sided, 9 sectors per track (720K,3.5")
F8h hard disk
F0h other media
(e.g. floppy, double-sized, 18 sectors per track -- 1.44M,3.5")
--------D-211C-------------------------------
INT 21 - DOS 1+ - GET ALLOCATION INFORMATION FOR SPECIFIC DRIVE
AH = 1Ch
DL = drive (00h = default, 01h = A:, etc)
Return: AL = sectors per cluster (allocation unit), or FFh if invalid drive
CX = bytes per sector
DX = total number of clusters
DS:BX -> media ID byte (see #0655)
Notes: under DOS 1.x, DS:BX points at an actual copy of the FAT; later
versions return a pointer to a copy of the FAT's ID byte
on a DBLSPACE drive, the total number of clusters is based on the
estimated compression ratio
SeeAlso: AH=1Bh,AH=36h
--------D-211D-------------------------------
INT 21 - DOS 1+ - NULL FUNCTION FOR CP/M COMPATIBILITY
AH = 1Dh
Return: AL = 00h
Note: corresponds to the CP/M BDOS function "get bit map of read-only
drives", which is meaningless under MS-DOS
SeeAlso: AH=18h,AH=1Eh,AH=20h,AX=4459h
--------D-211E-------------------------------
INT 21 - DOS 1+ - NULL FUNCTION FOR CP/M COMPATIBILITY
AH = 1Eh
Return: AL = 00h
Note: corresponds to the CP/M BDOS function "set file attributes" which was
meaningless under MS-DOS 1.x
SeeAlso: AH=18h,AH=1Dh,AH=20h
--------D-211F-------------------------------
INT 21 - DOS 1+ - GET DRIVE PARAMETER BLOCK FOR DEFAULT DRIVE
AH = 1Fh
Return: AL = status
00h successful
DS:BX -> Drive Parameter Block (DPB) (see #0656 for DOS 1.x,
AH=32h for DOS 2+)
FFh invalid drive
Note: this call was undocumented prior to the release of DOS 5.0; however,
only the DOS 4.0+ version of the DPB has been documented
SeeAlso: AH=32h

Format of DOS 1.1 and MS-DOS 1.25 drive parameter block:
Offset Size Description (Table 0656)
00h BYTE sequential device ID
01h BYTE logical drive number (0=A:)
02h WORD bytes per sector
04h BYTE highest sector number within a cluster
05h BYTE shift count to convert clusters into sectors
06h WORD starting sector number of first FAT
08h BYTE number of copies of FAT
09h WORD number of directory entries
0Bh WORD number of first data sector
0Dh WORD highest cluster number (number of data clusters + 1)
0Fh BYTE sectors per FAT
10h WORD starting sector of directory
12h WORD address of allocation table
Note: the DOS 1.0 table is the same except that the first and last fields
are missing; see INT 21/AH=32h for the DOS 2+ version

--------D-2120-------------------------------
INT 21 - DOS 1+ - NULL FUNCTION FOR CP/M COMPATIBILITY
AH = 20h
Return: AL = 00h
Note: corresponds to the CP/M BDOS function "get/set default user
(sublibrary) number", which is meaningless under MS-DOS
SeeAlso: AH=18h,AH=1Dh,AH=1Eh,AX=4459h
--------D-2121-------------------------------
INT 21 - DOS 1+ - READ RANDOM RECORD FROM FCB FILE
AH = 21h
DS:DX -> opened FCB (see #0648)
Return: AL = status
00h successful
01h end of file, no data read
02h segment wrap in DTA, no data read
03h end of file, partial record read
[DTA] = record read from file
Notes: the record is read from the current file position as specified by the
random record and record size fields of the FCB
the file position is not updated after reading the record
if a partial record is read, it is zero-padded to the full size
not supported by MS Windows 3.0 DOSX.EXE DOS extender
SeeAlso: AH=14h,AH=22h,AH=27h,AH=3Fh
--------D-2122-------------------------------
INT 21 - DOS 1+ - WRITE RANDOM RECORD TO FCB FILE
AH = 22h
DS:DX -> opened FCB (see #0648)
[DTA] = record to write
Return: AL = status
00h successful
01h disk full
02h segment wrap in DTA
Notes: the record is written to the current file position as specified by the
random record and record size fields of the FCB
the file position is not updated after writing the record
if the record is located beyond the end of the file, the file is
extended but the intervening data remains uninitialized
if the record only partially fills a disk sector, it is copied to a
DOS disk buffer to be written out to disk at a later time
not supported by MS Windows 3.0 DOSX.EXE DOS extender
SeeAlso: AH=15h,AH=21h,AH=28h,AH=40h
--------D-2123-------------------------------
INT 21 - DOS 1+ - GET FILE SIZE FOR FCB
AH = 23h
DS:DX -> unopened FCB (see #0648), wildcards not allowed
Return: AL = status
00h successful (matching file found)
FCB random record field filled with size in records, rounded up
to next full record
FFh failed (no matching file found)
Notes: not supported by MS Windows 3.0 DOSX.EXE DOS extender
MS-DOS returns nonsense if the FCB record number field is set to a very
large positive number, and status FFh if negative; DR-DOS returns the
correct file size in both cases
BUG: APPEND for DOS 3.3+ corrupts DX if the file is not found
SeeAlso: AH=42h
--------D-2124-------------------------------
INT 21 - DOS 1+ - SET RANDOM RECORD NUMBER FOR FCB
AH = 24h
DS:DX -> opened FCB (see #0648)
Notes: computes the random record number corresponding to the current record
number and record size, then stores the result in the FCB
normally used when switching from sequential to random access
not supported by MS Windows 3.0 DOSX.EXE DOS extender
SeeAlso: AH=21h,AH=27h,AH=42h
--------D-2125-------------------------------
INT 21 - DOS 1+ - SET INTERRUPT VECTOR
AH = 25h
AL = interrupt number
DS:DX -> new interrupt handler
Notes: this function is preferred over direct modification of the interrupt
vector table
some DOS extenders place an API on this function, as it is not
directly meaningful in protected mode
under DR-DOS 5.0+, this function does not use any of the DOS-internal
stacks and may thus be called at any time
Novell NetWare (except the new DOS Requester) monitors the offset of
any INT 24 set, and if equal to the value at startup, substitutes
its own handler to allow handling of network errors; this introduces
the potential bug that any program whose INT 24 handler offset
happens to be the same as COMMAND.COM's will not have its INT 24
handler installed
SeeAlso: AX=2501h,AH=35h
--------E-212501-----------------------------
INT 21 P - Phar Lap 386/DOS-Extender - RESET DOS EXTENDER DATA STRUCTURES
AX = 2501h
SS = application's original SS or DS (FlashTek X-32VM)
Return: CF clear if successful
CF set on error
caller is operating on X-32 stack (FlashTek X-32VM)
Notes: Phar Lap uses INT 21/AH=25h as the entry point for all 386/DOS-Extender
system calls. Only available when directly using 386/DOS-Extender or
a compatible DOS extender, or when using a product that was created
using 386-DOS/Extender or a compatible
this function is also supported by FlashTek X-32VM
SeeAlso: AH=30h"Phar Lap"
--------E-212502-----------------------------
INT 21 P - Phar Lap 386/DOS-Extender - GET PROTECTED-MODE INTERRUPT VECTOR
AX = 2502h
CL = interrupt number
Return: CF clear
ES:EBX = CS:EIP of protected-mode interrupt handler
Note: this function is also supported by FlashTek X-32VM
SeeAlso: AX=2503h,AX=2504h,INT 31/AX=0204h
--------E-212503-----------------------------
INT 21 P - Phar Lap 386/DOS-Extender - GET REAL-MODE INTERRUPT VECTOR
AX = 2503h
CL = interrupt number
Return: CF clear
EBX = CS:IP of real-mode interrupt handler
Note: this function is also supported by FlashTek X-32VM
SeeAlso: AX=2502h,AX=2504h,AH=35h,INT 31/AX=0200h
--------E-212504-----------------------------
INT 21 P - Phar Lap 386/DOS-Extender - SET PROTECTED-MODE INTERRUPT VECTOR
AX = 2504h
CL = interrupt number
DS:EDX = CS:EIP of protected-mode interrupt handler
Return: CF clear
Note: this function is also supported by FlashTek X-32VM
SeeAlso: AX=2502h,AX=2505h,INT 31/AX=0205h
--------E-212505-----------------------------
INT 21 P - Phar Lap 386/DOS-Extender - SET REAL-MODE INTERRUPT VECTOR
AX = 2505h
CL = interrupt number
EBX = CS:IP of real-mode interrupt handler
Return: CF clear
Note: this function is also supported by FlashTek X-32VM
SeeAlso: AX=2503h,AX=2504h,INT 31/AX=0201h
--------E-212506-----------------------------
INT 21 P - Phar Lap 386/DOS-Extender - SET INT TO ALWAYS GAIN CNTRL IN PR. MODE
AX = 2506h
CL = interrupt number
DS:EDX = CS:EIP of protected-mode interrupt handler
Return: CF clear
Notes: this function modifies both the real-mode low-memory interrupt
vector table and the protected-mode Interrupt Descriptor Table (IDT)
interrupts occurring in real mode are resignaled in protected mode
this function is also supported by FlashTek X-32VM
--------E-212507-----------------------------
INT 21 P - Phar Lap 386/DOS-Extender - SET REAL- & PROTECTED-MODE INT VECTORS
AX = 2507h
CL = interrupt number
DS:EDX = CS:EIP of protected-mode interrupt handler
EBX = CS:IP of real-mode interrupt handler
Return: CF clear
Notes: interrupts are disabled until both vectors have been modified
this function is also supported by FlashTek X-32VM
SeeAlso: AX=2504h,AX=2505h
--------E-212508-----------------------------
INT 21 P - Phar Lap 386/DOS-Extender - GET SEGMENT LINEAR BASE ADDRESS
AX = 2508h
BX = segment selector
Return: CF clear if successful
ECX = linear base address of segment
CF set if invalid segment selector
Note: this function is also supported by FlashTek X-32VM
SeeAlso: AX=2509h
--------E-212509-----------------------------
INT 21 P - Phar Lap 386/DOS-Extender - CONVERT LINEAR TO PHYSICAL ADDRESS
AX = 2509h
EBX = linear address to convert
Return: CF clear if successful
ECX = physical address (carry flag clear)
CF set if linear address not mapped in page tables
SeeAlso: AX=2508h
--------E-212509-----------------------------
INT 21 P - FlashTek X-32VM - GET SYSTEM SEGMENTS AND SELECTORS
AX = 2509h
Return: CF clear
EAX high word = default DS
AX = alias for 16-bit data segment
BX = real mode code segment
EDX high word = selector covering full 4GB address space
DX = default SS
ESI high word = PSP selector
SI = environment selector
--------E-21250A-----------------------------
INT 21 P - Phar Lap 386/DOS-Extender - MAP PHYSICAL MEMORY AT END OF SEGMENT
AX = 250Ah
ES = segment selector in the Local Descriptor Table (LDT) of segment
to modify
EBX = physical base address of memory to map (multiple of 4K)
ECX = number of physical 4K pages to map
Return: CF clear if successful
EAX = 32-bit offset in segment of mapped memory
CF set on error
EAX = error code
08h insufficient memory to create page tables
09h invalid segment selector
SeeAlso: INT 31/AX=0800h
--------E-21250C-----------------------------
INT 21 P - Phar Lap 386/DOS-Extender - GET HARDWARE INTERRUPT VECTORS
AX = 250Ch
Return: CF clear
AL = base interrupt vector for IRQ0-IRQ7
AH = base interrupt vector for IRQ8-IRQ15
BL = interrupt vector for BIOS print screen function (Phar Lap only)
Note: this function is also supported by FlashTek X-32VM
SeeAlso: INT 31/AX=0400h,INT 67/AX=DE0Ah
--------E-21250D-----------------------------
INT 21 P - Phar Lap 386/DOS-Extender - GET REAL-MODE LINK INFORMATION
AX = 250Dh
Return: CF clear
EAX = CS:IP of real-mode callback procedure (see #0657) that will
call through from real mode to a protected-mode routine
EBX = 32-bit real-mode address of intermode call data buffer
ECX = size in bytes of intermode call data buffer
ES:EDX = protected-mode address of intermode call data buffer
Notes: this function is also supported by FlashTek X-32VM
X-32VM guarantees the intermode buffer to be at least 4 KB
SeeAlso: AX=250Eh

(Table 0657)
Call Phar Lap real-mode callback with:
STACK: DWORD offset to protected-mode code
WORD placeholder for protected-mode CS
DWORD pointer to selector structure (see #0658)
or 0000h:0000h for defaults
var parameters for protected-mode procedure
Return: via FAR return

Format of Phar Lap selector structure:
Offset Size Description (Table 0658)
00h WORD protected-mode GS selector
02h WORD protected-mode FS selector
04h WORD protected-mode ES selector
06h WORD protected-mode DS selector
--------E-21250E-----------------------------
INT 21 P - Phar Lap 386/DOS-Extender - CALL REAL-MODE PROCEDURE
AX = 250Eh
EBX = CS:IP of real-mode procedure to call
ECX = number of two-byte words to copy from protected-mode stack
to real-mode stack
Return: CF clear if successful
all segment registers unchanged
all general registers contain values set by real-mode procedure
all other flags set as they were left by real-mode procedure
stack unchanged
CF set on error
EAX = error code
01h not enough real-mode stack space
Note: this function is also supported by FlashTek X-32VM; under X-32VM, the
call will fail if ECX > 0000003Fh
SeeAlso: AX=250Dh,AX=2510h,AH=E1h"OS/286",INT 31/AX=0301h
--------E-21250F-----------------------------
INT 21 P - Phar Lap 386/DOS-Extender - CONVERT PROTECTED-MODE ADDRESS TO MS-DOS
AX = 250Fh
ES:EBX = 48-bit protected-mode address to convert
ECX = 00000000h or length of data in bytes
Return: CF clear if successful (address < 1MB and contiguous)
ECX = 32-bit real-mode MS-DOS address
CF set on error (address >= 1MB or not contiguous)
ECX = linear address
Note: this function is also supported by FlashTek X-32VM
SeeAlso: AX=2510h
--------E-212510-----------------------------
INT 21 P - Phar Lap 386/DOS-Extender - CALL REAL-MODE PROCEDURE, REGISTERS
AX = 2510h
EBX = CS:IP of real-mode procedure to call
ECX = number of two-byte words to copy to protected-mode stack to
real-mode stack
DS:EDX -> pointer to parameter block (see #0659)
Return: CF clear if successful
all segment registers unchanged,
EDX unchanged
all other general registers contain values set by real-mode proc
all other flags are set as they were left by real-mode procedure
real-mode register values are returned in the parameter block
CF set on error
EAX = error code
01h not enough real-mode stack space
Note: unlike most of the preceding 25xxh functions, this one is not
supported by FlashTek X-32VM
SeeAlso: AX=250Eh,AX=250Fh

Format of Phar Lap real-mode call parameter block:
Offset Size Description (Table 0659)
00h WORD real-mode DS value
02h WORD real-mode ES value
04h WORD real-mode FS value
06h WORD real-mode GS value
08h DWORD real-mode EAX value
0Ch DWORD real-mode EBX value
10h DWORD real-mode ECX value
14h DWORD real-mode EDX value
--------E-212511-----------------------------
INT 21 P - Phar Lap 386/DOS-Extender - ISSUE REAL-MODE INTERRUPT
AX = 2511h
DS:EDX -> parameter block (see #0660)
Return: all segment registers unchanged
EDX unchanged
all other registers contain values set by the real-mode int handler
the flags are set as they were left by the real-mode interrupt handler
real-mode register values are returned in the parameter block
Note: this function is also supported by FlashTek X-32VM
SeeAlso: AX=2503h,AX=2505h,AX=250Eh,AH=E3h"OS/286",INT 31/AX=0300h

Format of Phar Lap real-mode interrupt parameter block:
Offset Size Description (Table 0660)
00h WORD interrupt number
02h WORD real-mode DS value
04h WORD real-mode ES value
06h WORD real-mode FS value
08h WORD real-mode GS value
0Ah DWORD real-mode EAX value
0Eh DWORD real-mode EDX value
Note: all other real-mode values set from protected-mode registers
--------E-212512-----------------------------
INT 21 P - Phar Lap 386/DOS-Extender - LOAD PROGRAM FOR DEBUGGING
AX = 2512h
DS:EDX -> pointer to ASCIZ program name
ES:EBX -> pointer to parameter block (see #0662)
ECX = size in bytes of LDT buffer
Return: CF clear if successful
EAX = number of segment descriptors in LDT
CF set on error
EAX = error code (see #0661)
SeeAlso: AX=2517h

(Table 0661)
Values for Phar Lap error code:
02h file not found or path invalid
05h access denied
08h insufficient memory
0Ah environment invalid
0Bh invalid file format
80h LDT too small

Format of Phar Lap program load parameter block:
Offset Size Description (Table 0662)
Input:
00h DWORD 32-bit offset of environment string
04h WORD segment of environment string
06h DWORD 32-bit offset of command-tail string
0Ah WORD segment of command-tail string
0Ch DWORD 32-bit offset of LDT buffer (size in ECX)
10h WORD segment of LDT buffer
Output:
12h WORD real-mode paragraph address of PSP (see also AH=26h)
14h WORD real/protected mode flag
0000h real mode
0001h protected mode
16h DWORD initial EIP value
1Ah WORD initial CS value
1Ch DWORD initial ESP value
20h WORD initial SS value
22h WORD initial DS value
24h WORD initial ES value
26h WORD initial FS value
28h WORD initial GS value
--------E-212513-----------------------------
INT 21 P - Phar Lap 386/DOS-Extender - ALIAS SEGMENT DESCRIPTOR
AX = 2513h
BX = segment selector of descriptor in GDT or LDT
CL = access-rights byte for alias descriptor
CH = use-type bit (USE16 or USE32) for alias descriptor
Return: CF clear if successful
AX = segment selector for created alias
CF set on error
EAX = error code
08h insufficient memory (can't grow LDT)
09h invalid segment selector in BX
--------E-212514-----------------------------
INT 21 P - Phar Lap 386/DOS-Extender - CHANGE SEGMENT ATTRIBUTES
AX = 2514h
BX = segment selector of descriptor in GDT or LDT
CL = new access-rights byte
CH = new use-type bit (USE16 or USE32)
Return: CF clear if successful
CF set on error
EAX = error code
09h invalid selector in BX
SeeAlso: AX=2515h,INT 31/AX=0009h
--------E-212515-----------------------------
INT 21 P - Phar Lap 386/DOS-Extender - GET SEGMENT ATTRIBUTES
AX = 2515h
BX = segment selector of descriptor in GDT or LDT
Return: CF clear if successful
CL = access-rights byte for segment
CH = use-type bit (USE16 or USE32)
ECX<16-31> destroyed
CF set on error
EAX = error code
09h invalid segment selector in BX
SeeAlso: AX=2514h
--------E-212516-----------------------------
INT 21 P - Phar Lap 386/DOS-Extender v2.2+ - FREE ALL MEMORY OWNED BY LDT
AX = 2516h
Return: CF clear
Note: this function must be called from Ring 0 or the CS descriptor is freed
--------E-212517-----------------------------
INT 21 P - Phar Lap 386/DOS-Extender v2.1c+ - GET INFO ON DOS DATA BUFFER
AX = 2517h
Return: CF clear
ES:EBX -> data buffer (protected mode address)
ECX -> data buffer (real mode address)
EDX = size of data buffer in bytes
Note: the data buffer's address changes after calls to AX=2512h and AX=252Ah
SeeAlso: AX=2512h,AX=252Ah,AX=2530h
--------E-212518-----------------------------
INT 21 P - Phar Lap 386/DOS-Extender 2.1c+ - SPECIFY HANDLER FOR MOVED SEGMENTS
AX = 2518h
ES:EBX -> function to call when a segment is moved
Return: CF clear
ES:EBX -> previous handler
--------E-212519-----------------------------
INT 21 P - Phar Lap 386/DOS-Extender VMM - GET ADDITIONAL MEMORY ERROR INFO
AX = 2519h
Return: CF clear
EAX = error code
0000h no error
0001h out of physical memory
0002h out of swap space (unable to grow swap file)
0003h out of LDT entries and unable to grow LDT
0004h unable to change extended memory allocation mark
FFFFFFFFh paging disabled
Note: VMM is the Virtual Memory Manager option
--------E-21251A-----------------------------
INT 21 P - Phar Lap 386/DOS-Extender VMM - LOCK PAGES IN MEMORY
AX = 251Ah
EDX = number of 4k pages to lock
if BL = 00h
ECX = linear address of first page to lock
if BL = 01h
ES:ECX -> pointer to first page to lock
Return: CF clear if successful
CF set on error
EAX = error code
08h insufficient memory
09h invalid address range
SeeAlso: AX=251Bh,AX=EB06h,INT 31/AX=0600h
--------E-21251B-----------------------------
INT 21 P - Phar Lap 386/DOS-Extender VMM - UNLOCK PAGES
AX = 251Bh
EDX = number of pages to unlock
if BL = 00h
ECX = linear address of first page to unlock
if BL = 01h
ES:ECX -> pointer to first page to unlock
Return: CF clear if successful
CF set on error
EAX = error code
09h invalid address range
SeeAlso: AX=251Ah,AX=EB07h,INT 31/AX=0601h
--------E-21251C-----------------------------
INT 21 P - Phar Lap 386/DOS-Extender VMM v2.1c+ - FREE PHYSICAL MEMORY PAGES
AX = 251Ch
BH = preservation flag (00h preserve contents, 01h discard contents)
EDX = number of pages to free
BL = address type
00h linear address
ECX = linear address of first page to be freed
01h pointer
ES:ECX -> first page to be freed
Return: CF clear if successful
CF set on error
EAX = error code
08h memory error, swap space full, no VMM or DPMI
09h invalid address
--------E-21251D-----------------------------
INT 21 OP - Phar Lap 386/DOS-Extender VMM v2.1c - READ PAGE-TABLE ENTRY
AX = 251Dh
BL = address type
00h linear address
ECX = linear address of page table entry to read
01h pointer
ES:ECX -> page table entry to read
Return: CF clear if successful
EAX = contents of page table entry
CF set on error
EAX = error code
09h invalid address or NOPAGE option set
78h invalid under DPMI
Note: this function is obsolete; use AX=252Bh/BH=09h instead
SeeAlso: AX=251Eh,AX=252Bh/BH=09h,AX=EB00h,INT 31/AX=0506h
--------E-21251E-----------------------------
INT 21 OP - Phar Lap 386/DOS-Extender VMM v2.1c - WRITE PAGE-TABLE ENTRY
AX = 251Eh
BL = address type
00h linear address
ECX = linear address of page table entry to read
01h pointer
ES:ECX -> page table entry to read
EDX = new value for page table entry
Return: CF clear if successful
CF set on error
EAX = error code
09h invalid address or NOPAGE option set
82h not compatible with DPMI
Note: this call is obsolete; use AX=252Bh/BH=0Ah instead
SeeAlso: AX=251Dh,AX=252Bh/BH=0Ah,INT 31/AX=0507h
--------E-21251F-----------------------------
INT 21 P - Phar Lap 386/DOS-Extender VMM - EXHANGE TWO PAGE-TABLE ENTRIES
AX = 251Fh
BL = address type
00h linear address
ECX = linear address of first page table entry
EDX = linear address of second page table entry
01h pointer
ES:ECX -> first page table entry
ES:EDX -> second page table entry
Return: CF clear if successful
CF set on error
EAX = error code
09h invalid address or NOPAGE option set
82h not compatible with DPMI
SeeAlso: AX=251Dh,AX=251Eh
--------E-212520-----------------------------
INT 21 P - Phar Lap 386/DOS-Extender VMM - GET MEMORY STATISTICS
AX = 2520h
DS:EDX -> pointer to buffer at least 100 bytes in size (see #0663)
BL = 0 (don't reset VM stats), 1 (reset VM stats)
Return: carry flag clear

Format of Phar Lap VM statistics buffer:
Offset Size Description (Table 0663)
00h DWORD VM status
0001h VM subsystem is present
0000h VM not present
04h DWORD "nconvpg" number of conventional memory pages available
08h DWORD "nbimpg" number of Compaq built-in memory pages available
0Ch DWORD "nextpg" total number of extended memory pages
10h DWORD "extlim" extender memory pages limit
14h DWORD "aphyspg" number of physical memory pages allocated to appl
18h DWORD "alockpg" number of locked pages owned by application
1Ch DWORD "sysphyspg" number physical memory pages allocated to system
20h DWORD "nfreepg" number of free physical pages; approx if EMS VCPI
24h DWORD linear address of beginning of application address space
28h DWORD linear address of end of application address space
2Ch DWORD number of seconds since last time VM stats were reset
30h DWORD number of page faults since last time
34h DWORD number of pages written to swap file since last time
38h DWORD number of reclaimed pages (page faults on swapped pages)
3Ch DWORD number of virtual pages allocated to the application
40h DWORD size in pages of swap file
44h DWORD number of system pages allocated with EMS calls
48h DWORD minimum number of conventional memory pages
4Ch DWORD maximum size in pages to which swap file can be increased
50h DWORD "vmflags"
bit 0 = 1 if page fault in progress
---v4.0+ ---
54h DWORD number of physical pages guaranteed to be free
58h DWORD number of free physical pages currently available
5Ch DWORD size in pages of largest free block of memory (including disk
swap space)
60h DWORD reserved
--------E-212521-----------------------------
INT 21 P - Phar Lap 386/DOS-Extender VMM - LIMIT PROGRAM'S EXTENDED MEM USAGE
AX = 2521h
EBX = max 4k pages of physical extended memory which program may use
Return: CF clear if successful
EBX = maximum limit in pages
ECX = minimum limit in pages
CF set on error
EAX = error code
08h insufficient memory or -nopage switch used
SeeAlso: AX=2522h
--------E-212522-----------------------------
INT 21 P - Phar Lap 386/DOS-Ext VMM v2.2+ - SPECIFY ALTERNATE PAGE-FAULT HANDLR
AX = 2522h
ES:EBX -> alternate handler for page faults
Return: CF clear
ES:EBX -> previous page-fault handler
SeeAlso: AX=2523h
--------E-212523-----------------------------
INT 21 P - Phar Lap 386/DOS-Ext VMM v2.2+ - SPECIFY OUT-OF-SWAP-SPACE HANDLER
AX = 2523h
???
Return: ???
Note: this function takes a DWORD pointer and a DWORD pointer to a DWORD
pointer as arguments
SeeAlso: AX=2522h
--------E-212524-----------------------------
INT 21 P - Phar Lap 386/DOS-Ext VMM v2.2+ - INSTALL PAGE-REPLACEMENT HANDLERS
AX = 2524h
???
Return: ???
Note: this function takes three DWORD pointers and three DWORD pointers to
DWORD pointers as arguments
--------E-212525-----------------------------
INT 21 P - Phar Lap 386/DOS-Extender VMM - LIMIT PROGRAM'S CONVENT'L MEM USAGE
AX = 2525h
EBX = limit in 4k pages of physical conventional memory which program
may use
Return: CF clear if successful
EBX = maximum limit in pages
ECX = minimum limit in pages
CF set on error
EAX = error code
08h insufficient memory or -nopage switch used
SeeAlso: AX=2521h
--------E-212526-----------------------------
INT 21 P - Phar Lap 386/DOS-Extender - GET CONFIGURATION INFORMATION
AX = 2526h
???
Return: ???
Notes: details are not yet available
this function takes a pointer to the configuration buffer (see #0664)
and a poitner to a BYTE as arguments

Format of Phar Lap configuration buffer:
Offset Size Description (Table 0664)
00h DWORD flags 1 (see #0665)
04h DWORD flags 2 (unused through v5.0)
08h DWORD flags 3 (unused through v5.0)
0Ch DWORD 386|DOS-Extender major version
10h DWORD 386|DOS-Extender minor version
14h DWORD first letter of text after minor version number in version str
18h DWORD beta flag (00h normal release, 01h beta release)
1Ch DWORD processor (3 = 386, 4 = 486)
20h DWORD coprocessor (4 = none, 6 = 287, 7 = 387/486)
24h DWORD Weitek coprocessor flag (0 = none, 1 = present)
28h DWORD machine type (0 = IBM PC compatible, 1 = NEC 9800 series)
2Ch DWORD machine class
IBM: bus type (0=ISA, 1=MCA, 2=XT, 3=EISA)
NEC: 0=normal mode, 1=high-res mode
30h DWORD VCPI flag (0 = none, 1 = present)
34h DWORD -WEITEK/-1167 switch (0 = AUTO, 1 = ON, 2 = OFF)
38h DWORD -MINREAL setting
3Ch DWORD -MAXREAL setting
40h DWORD -MINIBUF setting
44h DWORD -MAXIBUF setting
48h DWORD size in bytes of DOS call data buffer
4Ch DWORD number of interrupt stacks (-NISTACK)
50h DWORD interrupt stack size (-ISTKSIZE)
54h DWORD -REALBREAK setting
58h DWORD -CALLBUFS
5Ch DWORD -HWIVEC
60h DWORD -PRIVEC
64h DWORD -INTMAP
68h DWORD -PRIMAP
6Ch DWORD VCPI: master 8259 interrupt vector base (IRQ0 mapping)
70h DWORD VCPI: slave 8259 interrupt vector base (IRQ8 mapping)
74h DWORD BIOS print screen interrupt vector (0 if NEC)
78h DWORD -EXTLOW setting
7Ch DWORD -EXTHIGH setting
80h DWORD lowest physical extended-memory address allocatable
84h DWORD highest physical extended-memory address allocatable + 1
88h DWORD special memory's physical base address (00000000h if none)
8Ch DWORD special memory size in bytes (00000000h if none)
90h DWORD -MAXVCPIMEM setting
94h DWORD -VSCAN
98h DWORD -SWAPCHK (0 = OFF, 1 = ON, 2 = FORCE, 3 = MAX)
9Ch DWORD -CODESIZE setting
A0h DWORD minimum swap file size (-MINSWFSIZE)
A4h DWORD maximum swap fiel size (-MAXSWFSIZE)
A8h DWORD page replacement policy (0 = LFU, 1 = NUR)
ACh DWORD number of GDT entries (-NGDTENT)
B0h DWORD number of LDT entries (-NLDTENT)
B4h DWORD program's privilege level (0-3)
---386|DOS-Extender v3.0+ ---
B8h DWORD -LOCKSTACK setting
BCh DWORD -MAXEXTMEM
C0h DWORD -MAXXMSMEM
C4h DWORD -MAXPGMMEM
C8h DWORD -DATATHRESHOLD
CCh DWORD virtual memory manager flag (0 = not present, 1 = present)
D0h DWORD Cyrix coprocessor flag (0 = no Cyrix EMC387, 1 = present)
D4h DWORD -CYRIX setting (0 = AUTO, 1 = ON, 2 = OFF)
D8h DWORD DPMI flag (0 = not present, 1 = present)
DCh DWORD DPMI major version
E0h DWORD DPMI minor version
E4h DWORD DPMI capabilities flags (see #0666)
E8h DWORD VCPI major version
ECh DWORD VCPI minor version
F0h WORD VCPI: IRQ0-7 physical base interrupt vector
F2h WORD VCPI: IRQ8-15 physical base interrupt vector
F4h DWORD XMS flag (0 = none, 1 = present)
F8h DWORD XMS major version
FCh DWORD XMS minor version
100h WORD application's CS selector
102h WORD application's DS selector
104h WORD application's PSP selector
106h WORD application's environment selector
108h WORD selector mapping entire first megabyte
10Ah WORD selector mapping text video memory
10Ch WORD selector mapping video memory (text for IBM, graphics for NEC)
10Eh WORD selector mapping Weitek address space, 0000h if not present
110h WORD selector mapping Cyrix EMC387 address space, 0000h if none
112h WORD reserved (0)
114h DWORD real-mode FAR entry point to call to switch to protected mode
with no saved context
118h DWORD size of LDT in bytes
---386|DOS-Extender v5.0+ ---
11Ch DWORD Windows flag (0 = not present, 1 = Windows present)
120h DWORD Windows major version
124h DWORD Windows minor version
128h DWORD Windows mode (0 = real/standard, 1 = enhanced)
12Ch DWORD OS/2 flag (0 = not present, 1 = OS/2 present)
130h DWORD OS/2 major version
134h DWORD OS/2 minor version
138h 50 DWORDs reserved (0)

Bitfields for flags 1:
Bit(s) Description (Table 0665)
0 -NOPAGE specified
1 -A20 specified
2 -VDISK specified
3 -XT specified
4 -AT specified
5 -MCA specified
6 -EISA specified
7 -NORMRES specified (NEC only)
8 -HIGHRES specified (NEC only)
9 set if -SWFGROW1ST, clear if -NOSWFGROW1ST
10 -NOVM specified
11 -SAVEREGS specified
12 unused (clear)
13 -NOVCPI specified
14 -NOMUL specified
15 -NOBMCHK specified
16 -NOSPCLMEM or -NOBIM
17 -NOPGEXP specified
18 -SWAPDEFDISK specified
---v3.0+ ---
19 -SAVEINTS specified
20 -NOLOAD specified
21 -PAGELOG specified
22 -OPENDENY specified
23 -ERRATA17 specified
---v4.1+ ---
24 -NESTDPMI specified
25 -NONESTDPMI specified
26 -NODPMI specified
27 -NOPCDWEITEK specified
---v4.2+ ---
28 -WININT21 specified

Bitfields for DPMI capabilities flags:
Bit(s) Description (Table 0666)
0 paging supported
1 physical device mapping
2 conventional memory mapping
3 exceptions restartable
--------E-212527-----------------------------
INT 21 P - Phar Lap 386/DOS-Extender VMM - EN/DISABLE STATE SAVE ON INTERRUPTS
AX = 2527h
EBX = new status (00h disabled, 01h enabled)
Return: CF clear
EBX = previous state save flag
SeeAlso: AX=2528h
--------E-212528-----------------------------
INT 21 P - Phar Lap 386/DOS-Extender VMM - READ REGISTERS AFTER CTRL-C INT
AX = 2528h
DS:EBX -> buffer for registers (see #0667)
Return: CF clear if successful
DS:EBX buffer filled
CF set on error
EAX = error code
83h interrupt state save not enabled
84h no active interrupt
SeeAlso: AX=2527h

Format of Phar Lap buffer for registers:
Offset Size Description (Table 0667)
00h 8 BYTEs unused
08h 4 DWORDs EAX,EBX,ECX,EDX
18h 4 DWORDs ESI,EDI,EBP,ESP
28h 6 WORDs CS,DS,SS,ES,FS,GS
34h DWORD EIP
38h DWORD EFLAGS
--------E-212529-----------------------------
INT 21 P - Phar Lap 386/DOS-Extender - LOAD FLAT MODEL .EXP or .REX FILE
AX = 2529h
???
Return: ES:EBX -> parameter block (see #0668)
???
Note: details not available at this time
SeeAlso: AX=252Ah

Format of Phar Lap program load parameter block:
Offset Size Description (Table 0668)
00h DWORD initial EIP
04h WORD initial CS
06h DWORD initial ESP
0Ah WORD initial SS
0Ch 4 WORDs initial DS, ES, FS, GS
14h DWORD minimum size in bytes of program segment
18h DWORD bytes of additional memory allocated
1Ch DWORD flags
bit 0: child linked with -UNPRIVILEGED
---v6.0+ ---
bit 1: child is PE file instead of .EXP
bit 2: loaded file is a DLL
bits 3-31 reserved
---v6.0+ ---
20h DWORD module handles (PE files only)
24h 7 DWORDs reserved (0)
--------E-21252A-----------------------------
INT 21 P - Phar Lap 386/DOS-Extender VMM - NEW LOAD PROGRAM FOR DEBUG
AX = 252Ah
DS:EDX -> ASCIZ program name
ES:EBX -> parameter block (see #0662)
ECX = size of LDT buffer in bytes
ESI = bit flags
bit 0: allow demand paging rather than loading entire program
bit 1: demand page from swap file rather than from .EXP
Return: CF clear if successful
EAX = VMM handle or FFFFFFFFh if none
ECX = number of descriptors in LDT buffer
CF set on error
EAX = error code
02h file error
EBX = file error code (see #0669)
ECX = DOS error code if EBX=1,2,3, or 8
08h insufficient memory
EBX = memory error code (see #0670)
80h LDT buffer too small
87h called twice without intervening call to AX=2531h
SeeAlso: AX=2512h,AX=2517h,AX=2529h,AX=2531h

(Table 0669)
Values for Phar Lap file error code:
01h DOS open error
02h DOS seek error
03h DOS read error
04h not an .EXP or .REX file
05h invalid file format
06h -OFFSET is not a multiple of 64K
07h -NOPAGE incompatible with -REALBREAK/-OFFSET
08h DOS error loading .EXE file

(Table 0670)
Values for Phar Lap memory error code:
01h out of physical memory
02h out of swap space
04h unable to change extended memory allocation
05h -MAXPGMMEM exceeded
06h insufficient low memory to REALBREAK value
07h insufficient low memory for PSP and environment
--------E-21252BBH00-------------------------
INT 21 Pu - Phar Lap 386/DOS-Extender - CREATE UNMAPPED PAGES
AX = 252Bh
BH = 00h
???
Return: ???
--------E-21252BBH01-------------------------
INT 21 Pu - Phar Lap 386/DOS-Extender - CREATE ALLOCATED PAGES
AX = 252Bh
BH = 01h
???
Return: ???
--------E-21252BBH02-------------------------
INT 21 Pu - Phar Lap 386/DOS-Extender - CREATE PHYSICAL DEVICE PAGES
AX = 252Bh
BH = 02h
???
Return: ???
--------E-21252BBH03-------------------------
INT 21 Pu - Phar Lap 386/DOS-Extender - MAP DATA FILE
AX = 252Bh
BH = 03h
???
Return: ???
SeeAlso: AX=252Bh/BL=0Bh
--------E-21252BBH04-------------------------
INT 21 Pu - Phar Lap 386/DOS-Extender - GET PAGE TYPES
AX = 252Bh
BH = 04h
???
Return: ???
Note: returns one word per page
SeeAlso: #0671

Bitfields for Phar Lap page information:
Bit(s) Description (Table 0671)
7 mapped to read/write data file
6 mapped to read-only data file
5 swapped to disk
4 locked
3-0 page type
0 unmapped
1 allocated
2 physical device page
--------E-21252B-----------------------------
INT 21 P - Phar Lap 386/DOS-Extender - VIRTUAL MEMORY MANAGEMENT - PAGE LOCKING
AX = 252Bh
BH = function
05h lock pages
06h unlock pages
BL = address type
00h linear address
ECX = linear start address of memory region
01h segmented address
ES:ECX -> start of memory region
EDX = size of memory region in bytes
Return: CF clear if successful
CF set on error
Note: this function is also supported by FlashTek X-32VM; if X-32 is not
using virtual memory, this function always succeeds
--------E-21252B-----------------------------
INT 21 Pu - Phar Lap 386/DOS-Extender - FREE PHYSICAL PAGES
AX = 252Bh
BH = function (07h,08h)
???
Return: ???
--------E-21252BBH09-------------------------
INT 21 P - Phar Lap 386/DOS-Extender v4.1 - GET PAGETABLE ENTRY/PAGE TABLE INFO
AX = 252Bh
BH = 09h
BL = subfunction
00h get page table entry by linear address
ECX = linear address for which to get page table entry
01h get page table entry by logical address
ES:ECX = address for which to get page table entry
Return: CF clear if successful
EAX = page table entry
EBX = additional page table information
CF set on error
EAX = error code
0009h invalid address
0082h running under DPMI
SeeAlso: AX=251Dh,AX=252Bh/BH=0Ah
--------E-21252BBH0A-------------------------
INT 21 P - Phar Lap 386/DOS-Extender v4.1 - SET PAGETABLE ENTRY/PAGE TABLE INFO
AX = 252Bh
BH = 0Ah
BL = subfunction
00h set page table entry for linear address
ECX = linear address for which to get page table entry
01h set page table entry for logical address
ES:ECX = address for which to get page table entry
ESI = page table entry
EDI = additional page table information
Return: CF clear if successful
CF set on error
EAX = error code
0009h invalid address
0082h running under DPMI
SeeAlso: AX=252Bh/BH=09h
--------E-21252BBH0B-------------------------
INT 21 P - Phar Lap 386/DOS-Extender v4.1+ - MAP DATA FILE AT FILE OFFSET
AX = 252Bh
BH = 0Bh
BL = subfunction
00h by linear address
ECX = linear address at which to map data file
01h by logical address
ES:ECX = logical address at which to map data file
EDX = number of bytes to map
DS:ESI -> mapping structure (see #0672)
DS:EDI -> ASCIZ filename
Return: CF clear if successful
CF set on error
EAX = error code
0002h file error
ECX = phase (01h opening file, 02h seeking, 03h reading)
EDX = error code returned by DOS
0009h invalid address
0081h invalid parameters or 386|VMM not present
0086h all 386|VMM file handles already in use
SeeAlso: AX=252Bh/BH=03h,AX=252Bh/BH=09h

Format of Phar Lap mapping structure:
Offset Size Description (Table 0672)
00h DWORD starting file offset to be mapped
04h DWORD DOS file access and sharing modes (see #0702 at INT 21/AH=3Dh)
--------E-21252C-----------------------------
INT 21 P - Phar Lap 386/DOS-Ext VMM v3.0 - ADD UNMAPPED PAGES AT END OF SEGMENT
AX = 252Ch
BX = segment selector
ECX = number of 4K pages to add
Return: CF clear if successful
EAX = offset in segment of beginning of unmapped pages
CF set on error
EAX = error code
08h insufficent memory
09h invalid selector
82h not supported by current DPMI
--------E-21252D-----------------------------
INT 21 P - Phar Lap 386/DOS-Extender VMM v2.3+ - CLOSE VMM FILE HANDLE
AX = 252Dh
EBX = VMM file handle
Return: CF clear if successful
CF set on error
EAX = error code (81h invalid VMM handle)
--------E-21252E-----------------------------
INT 21 P - Phar Lap 386/DOS-Extender VMM v2.3+ - GET/SET VMM PARAMETERS
AX = 252Eh
CL = direction (00h get parameters, 01h set parameters)
DS:EBX -> parameter buffer (see #0673)
Return: CF clear if successful
CF set on error
EAX = error code (81h bad parameter value)

Format of Phar Lap VMM parameter buffer:
Offset Size Description (Table 0673)
00h DWORD flags
bit 0: page fault logging enabled
---v5.0+ ---
bit 1: swap extender to disk during DOS EXEC call
bit 2: don't zero allocated memory
04h DWORD scan period for page aging, in milliseconds
08h DWORD maximum size (in bytes) to check on each page scan
0Ch 52 BYTEs unused
--------E-21252F-----------------------------
INT 21 P - Phar Lap 386/DOS-Ext VMM v3.0 - WRITE RECORD TO VMM PAGE LOG FILE
AX = 252Fh
DS:EBX -> data to be written
CX = size of data in bytes
Return: CF clear if successful
CF set on error
EAX = error code (85h no page log file or not 386/VMM)
--------E-212530-----------------------------
INT 21 P - Phar Lap 386/DOS-Ext VMM v2.3+ - SET SIZE OF BUFFER FOR DOS CALLS
AX = 2530h
ECX = size of data buffer in bytes (1024 to 65536)
Return: CF clear if successful
CF set on error
EAX = error code
08h insufficient low memory
81h invalid size
SeeAlso: AX=2517h
--------E-212531-----------------------------
INT 21 P - Phar Lap 386/DOS-Extender VMM v3.0 - READ/WRITE LDT DESCRIPTOR
AX = 2531h
BX = segment selector
ECX = direction (00h read, 01h write)
DS:EDX -> 8-byte buffer for descriptor contents
Return: CF clear if successful
CF set on error
EAX = error code
81h invalid selector
82h DPMI running, or not a code or data segment
--------E-212532-----------------------------
INT 21 P - Phar Lap 386/DOS-Extender - GET EXCEPTION HANDLER VECTOR
AX = 2532h
CL = exception number (00h-0Fh)
Return: CF clear if successful
ES:EBX = CS:EIP of current exception handler
CF set on error (CL > 0Fh)
Notes: this call is also supported by the FlashTek X-32VM extender
this function is incompatible with 386|VMM; use AX=2522h instead
SeeAlso: AX=2522h,AX=2533h
--------E-212533-----------------------------
INT 21 P - Phar Lap 386/DOS-Extender - SET EXCEPTION HANDLER VECTOR
AX = 2533h
CL = exception number (00h-0Fh)
DS:EDX = CS:EIP of new exception handler
Return: CF clear if successful
CF set on error (CL > 0Fh)
Notes: this call is also supported by the FlashTek X-32VM extender
this function is incompatible with 386|VMM; use AX=2522h instead
SeeAlso: AX=2522h,AX=2532h
--------E-212534-----------------------------
INT 21 P - Phar Lap 386/DOS-Extender v3.0+ - GET INTERRUPT FLAG
AX = 2534h
Return: CF clear
EAX = interrupt state (00h disabled, 01h enabled)
--------E-212535-----------------------------
INT 21 P - Phar Lap 386/DOS-Extender v3.0+ - READ/WRITE SYSTEM REGISTERS
AX = 2535h
EBX = direction (00h read registers, 01h write)
DS:EDX -> system register record (see #0674)
Return: CF clear
Note: this call is only available under MS Windows if PHARLAP.386 VDD is
installed

Format of Phar Lap system register record:
Offset Size Description (Table 0674)
00h DWORD CR0
04h 4 DWORDs DR0,DR1,DR2,DR3
14h 2 DWORDs reserved
1Ch 2 DWORDs DR6,DR7
24h 3 DWORDs reserved
--------E-212536----------------------------
INT 21 P - Phar Lap 386/DOS-Ext VMM v3.0+ - MIN/MAX EXTENDED/CONV MEMORY USAGE
AX = 2536h
EBX = bit flags
bit 0: modifying conventional memory rather than extended memory
bit 1: setting maximum memory usage rather than minimum
ECX = new limit in 4K pages
Return: CF clear if successful
EAX = new limit
CF set on error
EAX = error code (08h memory error or -NOPAGE set)
EBX = maximum limit in pages
ECX = minimum limit in pages
--------E-212537----------------------------
INT 21 P - Phar Lap 386/DOS-Ext VMM v3.0 - ALLOCATE DOS MEMORY ABOVE DOS BUFFER
AX = 2537h
BX = number of paragraphs to allocate
Return: CF clear if successful
AX = real-mode segment of allocated block
CF set on error
AX = error code
07h MS-DOS memory chain corrupted
08h insufficient low memory
BX = size in paragraphs of largest free block
SeeAlso: AH=48h
--------E-212538----------------------------
INT 21 P - Phar Lap 386/DOS-Ext VMM v3.0 - READ PROTMODE REGS AFTER SFTWARE INT
AX = 2538h
DS:EBX -> buffer for registers (see #0667)
ECX = register record to retrieve
00h first interrupt state
01h next interrupt state
EDX = handle for current interrupt state
Return: CF clear if successful
DS:EBX buffer filled
EDX = handle of current interrupt state
ESI = number of interrupt which occurred
CF set on error
EAX = error code
81h invalid handle in EDX
83h register saving not enabled
84h no more interrupt states
SeeAlso: AX=2527h,AX=2528h
--------E-212539----------------------------
INT 21 P - Phar Lap 386/DOS-Ext VMM v3.0 - GET OFFSET OF .EXP FILE HEADER
AX = 2539h
BX = MS-DOS file handle for open file
Return: CF clear if successful
EAX = offset of .EXP header in file
CF set on error
EAX = error code (02h file error)
EBX = file error code
02h DOS error seeking
03h DOS error reading
04h invalid file type
05h invalid file format
ECX = DOS error code if EBX=02h or 03h
current file position in file modified
--------E-21253A----------------------------
INT 21 P - Phar Lap 386/DOS-Extender v3.0+ - INSTALL MOD. SEG FAILURE HANDLER
AX = 253Ah
ES:EBX -> function to be called when INT 21/AH=4Ah is about to return
an error
Return: CF clear
ES:EBX -> previous handler
SeeAlso: AH=4Ah
--------E-21253B----------------------------
INT 21 P - Phar Lap 386/DOS-Extender v3.0+ - JUMP TO REAL MODE CODE, NO CONTEXT
AX = 253Bh
DS:EBX -> buffer containing register contents (see #0667)
Return: never returns
SeeAlso: AX=2528h
--------E-21253C-----------------------------
INT 21 P - Phar Lap 386/DOS-Extender VMM v3.0+ - SHRINK 386|VMM SWAP FILE
AX = 253Ch
Return: CF clear
EAX = old size of swap file in bytes
EBX = new size of swap file in bytes
--------E-21253D-----------------------------
INT 21 P - Phar Lap 386/DOS-Extender v4.0+ - READ/WRITE IDT DESCRIPTOR
AX = 253Dh
BL = interrupt number
ECX = direction (0 = read, 1 = write)
DS:EDX -> 8-byte buffer for descriptor
Return: CF clear if successful
DS:EDX filled if reading
CF set on error
EAX = error code (0082h if running under DPMI)
Desc: access hardware-level IDT rather than the internal 386/DOS-Extender
shadow IDT
Notes: this call will always fail under DPMI because it is not possible to
access the IDT
the descriptor is not checked when writing
this call can normally be used only by programs running in ring 0
because the processor does not allow an interrupt to be vectored to
a less privileged ring
--------E-21253F-----------------------------
INT 21 Pu - Phar Lap 386/DOS-Extender v6.0+ - ALLOCATE LDT DESCRIPTOR
AX = 253Fh
BX = LDT descriptor to allocate (0000h for any)
???
Return: ???
--------E-212540-----------------------------
INT 21 Pu - Phar Lap 386/DOS-Extender v6.0+ - FORCE ALIAS OF SEGMENT
AX = 2540h
???
Return: ???
--------E-212544-----------------------------
INT 21 Pu - Phar Lap 386/DOS-Extender v6.0+ - FREE DLL
AX = 2544h
???
Return: ???
--------E-212545-----------------------------
INT 21 Pu - Phar Lap 386/DOS-Extender v6.0+ - GET/SET PROCEDURE ADDRESS
AX = 2545h
ECX = direction (00h get, 01h set)
???
Return: ???
--------E-212546-----------------------------
INT 21 Pu - Phar Lap 386/DOS-Extender v6.0+ - GET MODULE HANDLE
AX = 2546h
???
Return: ???
--------E-2125C0-----------------------------
INT 21 P - Phar Lap 386/DOS-Extender - ALLOCATE MS-DOS MEMORY BLOCK
AX = 25C0h
BX = number of 16-byte paragraphs of MS-DOS memory requested
Return: CF clear if successful
AX = real-mode paragraph address of memory
CF set on error
AX = error code
07h MS-DOS memory control blocks destroyed
08h insufficient memory
BX = size in paragraphs of largest available memory block
SeeAlso: AX=25C1h,AX=25C2h
--------E-2125C1-----------------------------
INT 21 P - Phar Lap 386/DOS-Extender - RELEASE MS-DOS MEMORY BLOCK
AX = 25C1h
CX = real-mode paragraph address of memory block to free
Return: CF clear if successful
EAX destroyed
CF set on error
AX = error code
07h MS-DOS memory control blocks destroyed
09h invalid memory block address in CX
SeeAlso: AX=25C0h,AX=25C2h
--------E-2125C2-----------------------------
INT 21 P - Phar Lap 386/DOS-Extender - MODIFY MS-DOS MEMORY BLOCK
AX = 25C2h
BX = new requested block size in paragraphs
CX = real-mode paragraph address of memory block to modify
Return: CF clear if successful
EAX destroyed
CF set on error
AX = error code
07h MS-DOS memory control blocks destroyed
08h insufficient memory
09h invalid memory block address in CX
BX = size in paragraphs of largest available memory block
SeeAlso: AX=25C0h,AX=25C1h
--------E-2125C3-----------------------------
INT 21 P - Phar Lap 386/DOS-Extender - EXECUTE PROGRAM
AX = 25C3h
ES:EBX -> pointer to parameter block (see #0676)
DS:EDX -> pointer to ASCIZ program filename
Return: CF clear if successful
all registers unchanged
CF set on error
EAX = error code (see #0675)

(Table 0675)
Values for Phar Lap error code:
01h function code in AL is invalid ???
02h file not found or path invalid
05h access denied
08h insufficient memory to load program
0Ah environment invalid
0Bh invalid file format

Format of parameter block:
Offset Size Description (Table 0676)
00h DWORD 32-bit offset of environment string
04h WORD segment selector of environment string
06h DWORD 32-bit offset of command-tail string
0Ah WORD segment selector of command-tail string
--------D-2126-------------------------------
INT 21 - DOS 1+ - CREATE NEW PROGRAM SEGMENT PREFIX
AH = 26h
DX = segment at which to create PSP (see #0677)
Notes: new PSP is updated with memory size information; INTs 22h, 23h, 24h
taken from interrupt vector table; the parent PSP field is set to 0
(DOS 2+) DOS assumes that the caller's CS is the segment of the PSP to
copy
SeeAlso: AH=4Bh,AH=50h,AH=51h,AH=55h,AH=62h,AH=67h

Format of Program Segment Prefix (PSP):
Offset Size Description (Table 0677)
00h 2 BYTEs INT 20 instruction for CP/M CALL 0 program termination
the CDh 20h here is often used as a signature for a valid PSP
02h WORD segment of first byte beyond memory allocated to program
04h BYTE (DOS) unused filler
(OS/2) count of fake DOS version returns
05h BYTE CP/M CALL 5 service request (FAR CALL to absolute 000C0h)
BUG: (DOS 2+ DEBUG) PSPs created by DEBUG point at 000BEh
06h WORD CP/M compatibility--size of first segment for .COM files
08h 2 BYTEs remainder of FAR JMP at 05h
0Ah DWORD stored INT 22 termination address
0Eh DWORD stored INT 23 control-Break handler address
12h DWORD DOS 1.1+ stored INT 24 critical error handler address
16h WORD segment of parent PSP
18h 20 BYTEs DOS 2+ Job File Table, one byte per file handle, FFh = closed
2Ch WORD DOS 2+ segment of environment for process (see #0678)
2Eh DWORD DOS 2+ process's SS:SP on entry to last INT 21 call
32h WORD DOS 3+ number of entries in JFT (default 20)
34h DWORD DOS 3+ pointer to JFT (default PSP:0018h)
38h DWORD DOS 3+ pointer to previous PSP (default FFFFFFFFh in 3.x)
used by SHARE in DOS 3.3
3Ch BYTE DOS 4+ (DBCS) interim console flag (see AX=6301h)
3Dh BYTE (APPEND) TrueName flag (see INT 2F/AX=B711h)
3Eh BYTE (Novell NetWare) flag: next byte initialized if CEh
(OS/2) capabilities flag
3Fh BYTE (Novell NetWare) Novell task number if previous byte is CEh
40h 2 BYTEs DOS 5+ version to return on INT 21/AH=30h
42h WORD (MSWindows3) selector of next PSP (PDB) in linked list
Windows keeps a linked list of Windows programs only
44h WORD (MSWindows3) "PDB_Partition"
46h WORD (MSWindows3) "PDB_NextPDB"
48h BYTE (MSWindows3) bit 0 set if non-Windows application (WINOLDAP)
49h BYTE unused by DOS versions <= 6.00
4Ch WORD (MSWindows3) "PDB_EntryStack"
4Eh 2 BYTEs unused by DOS versions <= 6.00
50h 3 BYTEs DOS 2+ service request (INT 21/RETF instructions)
53h 2 BYTEs unused in DOS versions <= 6.00
55h 7 BYTEs unused in DOS versions <= 6.00; can be used to make first FCB
into an extended FCB
5Ch 16 BYTEs first default FCB, filled in from first commandline argument
overwrites second FCB if opened
6Ch 16 BYTEs second default FCB, filled in from second commandline argument
overwrites beginning of commandline if opened
7Ch 4 BYTEs unused
80h 128 BYTEs commandline / default DTA
command tail is BYTE for length of tail, N BYTEs for the tail,
followed by a BYTE containing 0Dh
Notes: in DOS v3+, the limit on simultaneously open files may be increased by
allocating memory for a new open file table, filling it with FFh,
copying the first 20 bytes from the default table, and adjusting the
pointer and count at 34h and 32h. However, DOS will only copy the
first 20 file handles into a child PSP (including the one created on
EXEC).
network redirectors based on the original MS-Net implementation use
values of 80h-FEh in the open file table to indicate remote files;
Novell NetWare also uses values from FEh down to 80h or one more than
FILES= (whichever is greater) to indicate remote files
MS-DOS 5.00 incorrectly fills the FCB fields when loading a program
high; the first FCB is empty and the second contains the first
parameter
some DOS extenders place protected-mode values in various PSP fields
such as the "parent" field, which can confuse PSP walkers. Always
check either for the CDh 20h signature or that the suspected PSP is
at the beginning of a memory block which owns itself (the preceding
paragraph should be a valid MCB with "owner" the same as the
suspected PSP).
Novell NetWare updates the fields at offsets 3Eh and 3Fh without
checking that a legal PSP segment is current; see AH=50h for further
discussion

Format of environment block:
Offset Size Description (Table 0678)
00h N BYTEs first environment variable, ASCIZ string of form "var=value"
N BYTEs second environment variable, ASCIZ string
...
N BYTEs last environment variable, ASCIZ string of form "var=value"
BYTE 00h
---DOS 3.0+ ---
WORD number of strings following environment (normally 1)
N BYTEs ASCIZ full pathname of program owning this environment
other strings may follow
--------D-2127-------------------------------
INT 21 - DOS 1+ - RANDOM BLOCK READ FROM FCB FILE
AH = 27h
CX = number of records to read
DS:DX -> opened FCB (see #0648)
Return: AL = status
00h successful, all records read
01h end of file, no data read
02h segment wrap in DTA, no data read
03h end of file, partial read
[DTA] = records read from file
CX = number of records read (return AL = 00h or 03h)
Notes: read begins at current file position as specified in FCB; the file
position is updated after reading
not supported by MS Windows 3.0 DOSX.EXE DOS extender
SeeAlso: AH=21h,AH=28h,AH=3Fh
--------D-2128-------------------------------
INT 21 - DOS 1+ - RANDOM BLOCK WRITE TO FCB FILE
AH = 28h
CX = number of records to write
DS:DX -> opened FCB (see #0648)
[DTA] = records to write
Return: AL = status
00h successful
01h disk full or file read-only
02h segment wrap in DTA
CX = number of records written
Notes: write begins at current file position as specified in FCB; the file
position is updated after writing
if CX = 0000h on entry, no data is written; instead the file size is
adjusted to be the same as the file position specified by the random
record and record size fields of the FCB
if the data to be written is less than a disk sector, it is copied into
a DOS disk buffer, to be written out to disk at a later time
not supported by MS Windows 3.0 DOSX.EXE DOS extender
SeeAlso: AH=22h,AH=27h,AH=40h,AH=59h
--------D-2129-------------------------------
INT 21 - DOS 1+ - PARSE FILENAME INTO FCB
AH = 29h
AL = parsing options (see #0679)
DS:SI -> filename string (both '*' and '?' wildcards OK)
ES:DI -> buffer for unopened FCB
Return: AL = result code
00h successful parse, no wildcards encountered
01h successful parse, wildcards present
FFh failed (invalid drive specifier)
DS:SI -> first unparsed character
ES:DI buffer filled with unopened FCB (see #0648)
Notes: asterisks expanded to question marks in the FCB
all processing stops when a filename terminator is encountered
cannot be used with filespecs which include a path (DOS 2+)
Novell NetWare monitors the result code since an 'invalid drive' may
signal an attempt to reconnect a network drive; if there are no
connections to the specified drive, NetWare attempts to build a
connection and map the drive to the SYS:LOGIN directory
SeeAlso: AH=0Fh,AH=16h,AH=26h

Bitfields for parsing options:
Bit(s) Description (Table 0679)
0 skip leading separators
1 use existing drive number in FCB if no drive is specified, instead of
setting field to zero
2 use existing filename in FCB if no base name is specified, instead of
filling field with blanks
3 use existing extension in FCB if no extension is specified, instead of
filling field with blanks
4-7 reserved (0)
--------D-212A-------------------------------
INT 21 - DOS 1+ - GET SYSTEM DATE
AH = 2Ah
Return: CX = year (1980-2099)
DH = month
DL = day
---DOS 1.10+---
AL = day of week (00h=Sunday)
SeeAlso: AH=2Bh"DOS",AH=2Ch,AH=E7h,INT 1A/AH=04h,INT 2F/AX=120Dh
--------D-212B-------------------------------
INT 21 - DOS 1+ - SET SYSTEM DATE
AH = 2Bh
CX = year (1980-2099)
DH = month
DL = day
Return: AL = status
00h successful
FFh invalid date, system date unchanged
Note: DOS 3.3+ also sets CMOS clock
SeeAlso: AH=2Ah,AH=2Dh,INT 1A/AH=05h
--------E-212B--CX4149-----------------------
INT 21 - AI Architects - ??? - INSTALLATION CHECK
AH = 2Bh
CX = 4149h ('AI')
DX = 413Fh ('A?')
Return: AL <> FFh if installed
Note: Borland's TKERNEL makes this call
--------c-212B--CX4358-----------------------
INT 21 - Super PC-Kwik v3.20+ - INSTALLATION CHECK
AH = 2Bh
CX = 4358h ('CX')
Return: AL = FFh if PC-Kwik/PC-Cache not installed
AL = 00h if installed
CF clear
CX = 6378h ('cx')
BX = ???
DX = version (DH = major version, DL = binary minor version)
Note: PC Tools PC-Cache v5.x and Qualitas Qcache v4.00 are OEM versions of
Super PC-Kwik, and thus support this call (PC-Cache 5.1 corresponds
to PC-Kwik v3.20)
SeeAlso: INT 13/AH=A0h,INT 13/AH=B0h,INT 16/AX=FFA5h/CX=1111h
Index: PC-Cache;installation check|Qualitas Qcache;installation check
Index: installation check;PC-Cache 5.x|installation check;Qualitas Qcache
--------Q-212B--CX4445-----------------------
INT 21 - DESQview - INSTALLATION CHECK
AH = 2Bh
CX = 4445h ('DE')
DX = 5351h ('SQ')
AL = subfunction (DV v2.00+)
01h get version
Return: BX = version (BH = major, BL = minor)
Note: early copies of v2.00 return 0002h
02h get shadow buffer info, and start shadowing
Return: BH = rows in shadow buffer
BL = columns in shadow buffer
DX = segment of shadow buffer
04h get shadow buffer info
Return: BH = rows in shadow buffer
BL = columns in shadow buffer
DX = segment of shadow buffer
05h stop shadowing
Return: AL = FFh if DESQview not installed
Notes: in DESQview v1.x, there were no subfunctions; this call only identified
whether or not DESQview was loaded. DESQview v2.52 performs function
01h for all subfunction requests 0Ch and higher and appears to ignore
all lower-numbered functions not listed here.
DESQview versions 2.50-2.52 are part of DESQview/X v1.0x; version 2.53
is part of DESQview/X v1.10; and version 2.63 is part of DESQview/X
v2.00.
BUG: subfunction 05h does not appear to work correctly in DESQview 2.52
SeeAlso: INT 10/AH=FEh,INT 10/AH=FFh,INT 15/AX=1024h,INT 15/AX=DE30h
--------U-212B--CX454C-----------------------
INT 21 - ELRES v1.1 - INSTALLATION CHECK
AH = 2Bh
CX = 454Ch ('EL')
DX = 5253h ('RS')
Return: ES:BX -> ELRES history structure (see #0680)
DX = DABEh (signature, DAve BEnnett)
Program: ELRES is an MS-DOS return code (errorlevel) recorder by David H.
Bennett which stores recent errorlevel values, allows them to be
retrieved for use in batch files, and can place them in an
environment variable
SeeAlso: AH=4Bh"ELRES",AH=4Dh

Format of ELRES history structure:
Offset Size Description (Table 0680)
00h WORD number of return codes which can be stored by following buffer
02h WORD current position in buffer (treated as a ring)
04h N BYTEs ELRES buffer
--------m-212B01CX444D-----------------------
INT 21 - Quarterdeck DOS-UP.SYS v2.00 - INSTALLATION CHECK
AX = 2B01h
CX = 444Dh ('DM')
DX = 4158h ('AX')
Return: AX = 0000h if installed
BX = version??? (0002h)
CX = 4845h ('HE')
DX = 5245h ('RE')
ES = DOS-UP driver segment
--------T-212B01CX5441-----------------------
INT 21 - TAME v2.10+ - INSTALLATION CHECK
AX = 2B01h
CX = 5441h ('TA')
DX = 4D45h ('ME')
---v2.60---
BH = ???
00h skip ???, else do
Return: AL = 02h if installed
ES:DX -> data area in TAME-RES (see #0681,#0685,#0687)
Program: TAME is a shareware program by David G. Thomas which gives up CPU time
to other partitions under a multitasker when the current partition's
program incessantly polls the keyboard or system time

Format of TAME 2.10-2.20 data area:
Offset Size Description (Table 0681)
00h BYTE data structure minor version number (01h in TAME 2.20)
01h BYTE data structure major version number (07h in TAME 2.20)
02h DWORD number of task switches
06h DWORD number of keyboard polls
0Ah DWORD number of time polls
0Eh DWORD number of times DESQview told program runs only in foreground
12h DWORD original INT 10h
16h DWORD original INT 14h
1Ah DWORD original INT 15h
1Eh DWORD original INT 16h
22h DWORD original INT 17h
26h DWORD original INT 21h
2Ah DWORD original INT 28h
2Eh WORD offset of TAME INT 10h handler
30h WORD offset of TAME INT 14h handler
32h WORD offset of TAME INT 15h handler
34h WORD offset of TAME INT 16h handler
36h WORD offset of TAME INT 17h handler
38h WORD offset of TAME INT 21h handler
3Ah WORD offset of TAME INT 28h handler
3Ch WORD X in /max:X,Y or /freq:X,Y
3Eh WORD Y in /max:X,Y or /freq:X,Y
40h WORD number of polls remaining before next task switch
42h WORD /KEYIDLE value
44h BYTE interrupts already grabbed by TAME (see #0682)
45h BYTE flags for interrupts which may be acted on (same bits as above)
46h BYTE TAME enabled (01h) or disabled (00h)
47h BYTE /TIMEPOLL (01h) or /NOTIMEPOLL (00h)
48h BYTE /NOTIMER (01h) or /TIMER (00h)
49h BYTE window or task number for this task
4Ah BYTE multitasker type (see #0683)
4Bh BYTE type of task switching selected
bit 0: DESQview???
bit 1: DoubleDOS???
bit 2: TopView???
bit 3: KeySwitch
bit 4: HLT instruction
4Ch BYTE ???
4Dh BYTE flags
bit 1: /FREQ instead of /MAX
4Eh BYTE /FG: value
4Fh BYTE task switches left until next FGONLY DESQview API call
50h BYTE ???

Bitfields for interrupts already grabbed by TAME:
Bit(s) Description (Table 0682)
0 INT 10h
1 INT 14h
2 INT 15h
3 INT 16h
4 INT 17h
5 INT 21h
6 INT 28h

(Table 0683)
Values for multitasker type:
01h DESQview
02h DoubleDOS
03h TopView
04h OmniView
05h VM/386

Bitfields for type of task switching selected:
Bit(s) Description (Table 0684)
0 DESQview
1 DoubleDOS
2 TopView
3 OmniView
4 KeySwitch
5 HLT instruction

Format of TAME 2.30 data area:
Offset Size Description (Table 0685)
00h BYTE data structure minor version number (02h in TAME 2.30)
01h BYTE data structure major version number (0Ah in TAME 2.30)
02h DWORD number of task switches
06h DWORD number of keyboard polls
0Ah DWORD number of time polls
0Eh DWORD number of times DESQview told program runs only in foreground
12h DWORD time of last /CLEAR or TAME-RES load
16h DWORD time yielded
1Ah DWORD time spent polling
1Eh DWORD time spent waiting on key input with INT 16/AH=01h,11h
22h DWORD original INT 10h
26h DWORD original INT 14h
2Ah DWORD original INT 15h
2Eh DWORD original INT 16h
32h DWORD original INT 17h
36h DWORD original INT 21h
3Ah DWORD original INT 28h
3Eh WORD offset of TAME INT 10h handler
40h WORD offset of TAME INT 14h handler
42h WORD offset of TAME INT 15h handler
44h WORD offset of TAME INT 16h handler
46h WORD offset of TAME INT 17h handler
48h WORD offset of TAME INT 21h handler
4Ah WORD offset of TAME INT 28h handler
4Ch WORD X in /max:X,Y or /freq:X,Y
4Eh WORD Y in /max:X,Y or /freq:X,Y
50h WORD number of polls remaining before next task switch
52h WORD /KEYIDLE value
54h WORD /FG: value
56h WORD task switches left until next FGONLY DESQview API call
58h WORD multitasker version
5Ah WORD virtual screen segment
5Ch BYTE interrupts already grabbed by TAME (see #0682)
5Dh BYTE flags for interrupts which may be acted on (same bits as above)
5Eh BYTE window or task number for this task
5Fh BYTE multitasker type (see #0683)
60h BYTE type of task switching selected (bit flags) (see #0684)
61h BYTE watch_DOS
62h BYTE action flags (see #0686)
63h BYTE old status
64h WORD signature DA34h

Bitfields for TAME action flags:
Bit(s) Description (Table 0686)
0 TAME enabled
1 /FREQ instead of /MAX (X and Y count fields are per tick)
2 /TIMEPOLL
3 /KEYPOLL
4 inhibit timer
5 enable status monitoring
SeeAlso: #0685,#0687

Format of TAME 2.60 data area:
Offset Size Description (Table 0687)
00h BYTE data structure minor version number (02h in TAME 2.60)
01h BYTE data structure major version number (0Bh in TAME 2.60)
02h DWORD number of task switches
06h DWORD number of keyboard polls
0Ah DWORD number of time polls
0Eh DWORD number of times DESQview told program runs only in foreground
12h DWORD time of last /CLEAR or TAME-RES load
16h DWORD time yielded
1Ah DWORD time spent polling
1Eh DWORD time spent waiting on key input with INT 16/AH=01h,11h
22h 4 BYTEs ???
26h DWORD original INT 10h
2Ah DWORD original INT 14h
2Eh DWORD original INT 15h
32h DWORD original INT 16h
36h DWORD original INT 17h
3Ah DWORD original INT 21h
3Eh DWORD original INT 28h
42h WORD offset of TAME INT 10h handler
44h WORD offset of TAME INT 14h handler
46h WORD offset of TAME INT 15h handler
48h WORD offset of TAME INT 16h handler
4Ah WORD offset of TAME INT 17h handler
4Ch WORD offset of TAME INT 21h handler
4Eh WORD offset of TAME INT 28h handler
50h WORD X in /max:X,Y or /freq:X,Y
52h WORD Y in /max:X,Y or /freq:X,Y
54h WORD number of polls remaining before next task switch
56h WORD /KEYIDLE value
58h 4 BYTEs ???
5Ch WORD X in /boost:X,Y
5Eh WORD Y in /boost:X,Y
60h WORD /FG: value
62h WORD task switches remaining until next FGONLY DESQview API call
64h WORD multitasker version ???
66h WORD virtual screen segment
68h BYTE interrupts already grabbed by TAME (see #0682)
69h BYTE flags for interrupts which may be acted on (same bits as above)
6Ah BYTE window or task number for this task
6Bh BYTE multitasker type (see #0683)
6Ch BYTE type of task switching selected (bit flags) (see #0684)
6Dh BYTE watch_DOS
6Eh BYTE action flags (see #0686)
6Fh BYTE old status
70h WORD signature DA34h
--------v-212B16CX0643-----------------------
INT 21 - VIRUS - "Maltese Amoeba" - INSTALLATION CHECK
AX = 2B16h
CX = 0643h
Return: AX = 1603h if installed
--------R-212B44BX4D41-----------------------
INT 21 - pcANYWHERE IV/LAN - INSTALLATION CHECK
AX = 2B44h ('D')
BX = 4D41h ('MA')
CX = 7063h ('pc')
DX = 4157h ('AW')
Return: AX = resident program
4F4Bh ('OK') if large host resident
6F6Bh ('ok') if small host resident
CX:DX -> API entry point (see #0688)
SeeAlso: INT 16/AH=79h

(Table 0688)
Call pcANYWHERE API entry point with:
AX = 0000h get pcANYWHERE IV version
DS:SI -> BYTE buffer for host type code
Return: AH = version number
AL = revision number
DS:DI buffer byte filled with
00h full-featured host
01h limited-feature LAN host
other API may not be supported
AX = 0001h initialize operation
DS:SI -> initialization request structure (see #0689)
Return: AX = function status (see #0692)
AX = 0002h get status
Return: AH = current operating mode (see init req structure below)
AL = current connection status (see #0691)
AX = 0003h suspend remote screen updates
Return: AX = function status (see #0692)
AX = 0004h resume screen updates
Return: AX = function status (see #0692)
AX = 0005h end current remote access session
DS:SI -> termination request structure (see #0690)
Return: AX = function status (see #0692)
AX = 0006h remove pcANYWHERE IV from memory
Return: AX = status (see #0692)
AX = 8000h read data from communications channel
DS:BX -> buffer
CX = buffer size
Return: AX >= number of characters read/available
AX < 0 on error
AX = 8001h write data to communications channel
DS:BX -> buffer
CX = buffer size
Return: AX >= number of characters written
AX < 0 on error
AX = 8002h get connection status
Return: AX = status
> 0000h if connection active
= 0000h if connection lost
< 0000h on error

Format of pcANYWHERE initialization request structure:
Offset Size Description (Table 0689)
00h BYTE operating mode
00h wait for a call
01h hot key activates
02h incoming call activates
03h initiate a call
01h 3 BYTEs user ID to append to config file names
04h WORD DS-relative pointer to path for config files
06h WORD DS-relative pointer to path for program files

Format of pcANYWHERE termination request structure:
Offset Size Description (Table 0690)
00h BYTE operating mode after termination
00h wait for a call
01h hot key activates
02h incoming call activates
80h use current mode
FFh remove from memory

Bitfields for current connection status:
Bit(s) Description (Table 0691)
0 a physical connection is active
1 remove screen updating is active
2 connection checking is active
3 hot key detection is active
4 background file transfer is active

(Table 0692)
Values for pcANYWHERE function status:
0000h function completed successfully
FFD1h unable to release interrupt vectors
FFD2h unable to release allocated memory
FFF2h unable to establish a connection when operating mode is
"Initiate a call"
FFF3h modem configuration is invalid (corrupt config)
FFF4h modem initialization failed (no modem response)
FFF5h the communications device could not be initialized
FFF6h the host operator aborted the function
FFF7h the communications driver type specified in the configuration file is
different than the one loaded when pcANYWHERE IV was started
FFF9h the configuration file is invalid
FFFAh the configuration file could not be found
FFFBh no session is active
FFFCh a remote access session is active
FFFDh the specified operating mode is invalid
--------G-212B--CX6269-----------------------
INT 21 - WDTSR.COM - INSTALLATION CHECK
AH = 2Bh
CX = 6269h ('bi')
DX = 742Dh ('t-')
Return: AL = FFh if not installed
AL = 77h ('w') if WDTSR is installed
CX = 6174h ('at')
DX = 6368h ('ch')
ES = resident code segment
ES:DI -> identification and configuration data
Program: WDTSR is a driver for the bitWatch watchdog hardware by bit-design
GmbH
SeeAlso: AH=2Bh/CX=6269h"bitFOSSI",INT 14/AH=14h"FOSSIL",INT 15/AH=C3h
--------S-212B--CX6269-----------------------
INT 21 - bitFOSS - INSTALLATION CHECK
AH = 2Bh
CX = 6269h ('bi')
DX = 7446h ('tF')
Return: AL = FFh if not installed

AL = 4Fh ('O') if bitFOSS is installed
CX = 5353h ('SS')
DX = 494Ch ('IL')
ES = resident code segment
ES:DI -> identification data
Program: bitFOSS is a revision 5 FOSSIL driver
SeeAlso: AH=2Bh/CX=6269h"bitFOSSI",INT 11/AH=BCh
--------S-212B--CX6269-----------------------
INT 21 - bitFOSSI - INSTALLATION CHECK
AH = 2Bh
CX = 6269h ('bi')
DX = 7449h ('tI')
Return: AL = FFh if not installed
AL = 53h ('S') if bitFOSSI is installed
CX = 444Eh ('DN')
DX = 2D46h ('-F')
ES = resident code segment
ES:DI -> identification data
Program: bitFOSSI is a revision 5 FOSSIL driver for ???'s ISDN board
SeeAlso: AH=2Bh/CX=6269h/DX=7446h,INT 11/AH=BCh
--------D-212C-------------------------------
INT 21 - DOS 1+ - GET SYSTEM TIME
AH = 2Ch
Return: CH = hour
CL = minute
DH = second
DL = 1/100 seconds
Note: on most systems, the resolution of the system clock is about 5/100sec,
so returned times generally do not increment by 1
on some systems, DL may always return 00h
SeeAlso: AH=2Ah,AH=2Dh,AH=E7h,INT 1A/AH=00h,INT 1A/AH=02h,INT 1A/AH=FEh
SeeAlso: INT 2F/AX=120Dh
--------v-212C--------------------------
INT 21 - VIRUS - "Anti Pode 2.0" - INSTALLATION CHECK
AH = 2Ch
Return: DL = F2h if resident
SeeAlso: AX=1812h"VIRUS",AX=2C2Ch
--------v-212C00CX534B-----------------------
INT 21 - SKUDO - INSTALLATION CHECK
AX = 2C00h
CX = 534Bh ('SK')
DX = 5544h ('UD')
BX = 4F21h ('O!')
Return: AX = 5349h ('SI') if installed
CH = version number
CL = subversion
Program: SKUDO is an antivirus TSR by Jordi Mas
--------v-212C2C------------------------
INT 21 - VIRUS - "LockJaw/Proto-T" - INSTALLATION CHECK
AX = 2C2Ch
Return: AX = 0DCDh if resident
SeeAlso: AH=2Ch"VIRUS",AX=3000h"VIRUS"
--------D-212D-------------------------------
INT 21 - DOS 1+ - SET SYSTEM TIME
AH = 2Dh
CH = hour
CL = minute
DH = second
DL = 1/100 seconds
Return: AL = result
00h successful
FFh invalid time, system time unchanged
Note: DOS 3.3+ also sets CMOS clock
SeeAlso: AH=2Bh"DOS",AH=2Ch,INT 1A/AH=01h,INT 1A/AH=03h,INT 1A/AH=FFh"AT&T"
--------T-212D01CX7820-----------------------
INT 21 - PC-Mix - INSTALLATION CHECK
AX = 2D01h
CX = 7820h ('X ')
DX = 6D69h ('MI')
Return: AL = 00h if installed
--------D-212E--DL00-------------------------
INT 21 - DOS 1+ - SET VERIFY FLAG
AH = 2Eh
DL = 00h (DOS 1.x/2.x only)
AL = new state of verify flag
00h off
01h on
Notes: default state at system boot is OFF
when ON, all disk writes are verified provided the device driver
supports read-after-write verification
SeeAlso: AH=54h
--------D-212F-------------------------------
INT 21 - DOS 2+ - GET DISK TRANSFER AREA ADDRESS
AH = 2Fh
Return: ES:BX -> current DTA
Note: under the FlashTek X-32 DOS extender, the pointer is in ES:EBX
SeeAlso: AH=1Ah
--------D-2130-------------------------------
INT 21 - DOS 2+ - GET DOS VERSION
AH = 30h
---DOS 5+ ---
AL = what to return in BH
00h OEM number (as for DOS 2.0-4.0x)
01h version flag
Return: AL = major version number (00h if DOS 1.x)
AH = minor version number
BL:CX = 24-bit user serial number (most versions do not use this)
---if DOS <5 or AL=00h---
BH = MS-DOS OEM number (see #0693)
---if DOS 5+ and AL=01h---
BH = version flag
bit 3: DOS is in ROM
other: reserved (0)
Notes: the OS/2 v1.x Compatibility Box returns major version 0Ah (10)
the OS/2 v2.x Compatibility Box returns major version 14h (20)
OS/2 Warp 3.0 Virtual DOS Machines report v20.30.
the Windows/NT DOS box returns version 5.00, subject to SETVER
DOS 4.01 and 4.02 identify themselves as version 4.00; use
INT 21/AH=87h to distinguish between the original European MS-DOS 4.0
and the later PC-DOS 4.0x and MS-DOS 4.0x
IBM DOS 6.1 reports its version as 6.00; use the OEM number to
distinguish between MS-DOS 6.00 and IBM DOS 6.1 (there was never an
IBM DOS 6.0)
MS-DOS 6.21 reports its version as 6.20; version 6.22 returns the
correct value
the "Chicago" beta returns version 7.00 (reported in
_Microsoft_Systems_Journal_, August 1994).
DR-DOS 5.0 and 6.0 report version 3.31; Novell DOS 7 reports IBM v6.00,
which some software displays as IBM DOS v6.10 (because of the version
mismatch in true IBM DOS, as mentioned above)
generic MS-DOS 3.30, Compaq MS-DOS 3.31, and others identify themselves
as PC-DOS by returning OEM number 00h
the version returned under DOS 4.0x may be modified by entries in
the special program list (see #0949 at AH=52h); the version returned
under DOS 5+ may be modified by SETVER--use AX=3306h to get the true
version number
SeeAlso: AX=3000h/BX=3000h,AX=3306h,AX=4452h,AH=87h,INT 15/AX=4900h
SeeAlso: INT 2F/AX=122Fh,INT 2F/AX=4010h,INT 2F/AX=E002h

(Table 0693)
Values for DOS OEM number:
00h IBM
01h Compaq
02h MS Packaged Product
04h AT&T
05h ZDS (Zenith Electronics)
06h Hewlett-Packard
07h ZDS (Groupe Bull)
0Dh Packard-Bell
16h DEC
23h Olivetti
28h Texas Instruments
29h Toshiba
33h Novell (Windows/386 device IDs only)
34h MS Multimedia Systems (Windows/386 device IDs only)
35h MS Multimedia Systems (Windows/386 device IDs only)
4Dh Hewlett-Packard
5Eh RxDOS
66h PhysTechSoft (PTS-DOS)
99h General Software's Embedded DOS
EEh DR-DOS
EFh Novell DOS
FDh FreeDOS
FFh Microsoft, Phoenix
--------E-2130-------------------------------
INT 21 - Phar Lap 386/DOS-Extender, Intel Code Builder - INSTALLATION CHECK
AH = 30h
EAX = 00003000h
EBX = 50484152h ("PHAR")
Return: AL = major DOS version
AH = minor DOS version
EAX bits 31-16 = 4458h ('DX') if 386/DOS-extender installed
BL = ASCII major version number
EAX bits 31-16 = 4243h ('BC') if Intel Code Builder installed
EDX = address of GDA
SeeAlso: AX=2501h,AX=FF00h,INT 2F/AX=F100h
--------v-2130--DXABCD-----------------------
INT 21 - VIRUS - "Possessed" - INSTALLATION CHECK
AH = 30h
DX = ABCDh
Return: DX = DCBAh if installed
SeeAlso: AX=0D20h,AH=30h/SI=1234h,AX=3000h"VIRUS",AX=30F1h
--------v-2130--SI1234---------------------
INT 21 - VIRUS - "ANDROMEDA-758" -INSTALLATION CHECK
AH = 30h
SI = 1234h
Return: AX = FFDDh if resident
SeeAlso: AH=30h/DX=ABCDh,AX=3000h"VIRUS"
--------T-213000BX1234-----------------------
INT 21 - CTask 2.0+ - INSTALLATION CHECK
AX = 3000h
BX = 1234h
DS:DX -> 8-byte version string (DX < FFF0h) "CTask21",00h for v2.1-2.2
Return: AL = DOS major version
AH = DOS minor version
CX:BX -> Ctask global data block
Program: CTask is a multitasking kernel for C written by Thomas Wagner
Note: if first eight bytes of returned data block equal eight bytes passed
in, CTask is resident
--------O-213000BX3000-----------------------
INT 21 - PC-MOS/386 v3.0 - INSTALLATION CHECK/GET VERSION
AX = 3000h
BX = 3000h
CX = DX = 3000h
Return: AX = PC-MOS version
Program: PC-MOS/386 is a multitasking/multiuser MS-DOS-compatible operating
system by The Software Link, Inc.
SeeAlso: AH=30h,INT 38/AH=02h,INT 38/AH=10h
--------v-213000BX614A------------------
INT 21 - VIRUS - "Jackal" - INSTALLATION CHECK
AX = 3000h
BX = 614Ah ('aJ')
CX = 6B63h ('kc')
DX = 6C61h ('la')
Return: BX = ???
SeeAlso: AX=2C2Ch"VIRUS",AX=33DAh"VIRUS"
--------G-213022-----------------------------
INT 21 - StopPrg v2.0 - INSTALLATION CHECK
AX = 3022h
Return: AX = DOS version (see AH=30h)
CX = 1112h if StopPrg installed
BX = segment of resident code
Program: StopPrg is a resident program aborter by MAK-TRAXON's Prophet
Note: StopPrg may be temporarily disabled by storing 9090h in the word at
0000h:04FEh
--------v-2130F1-----------------------------
INT 21 - VIRUS - "Dutch-555"/"Quit 1992" - INSTALLATION CHECK
AX = 30F1h
Return: AL = 00h if resident
SeeAlso: AH=30h/DX=ABCDh,AX=330Fh,AX=33DAh
----------2130FFCX4445-----------------------
INT 21 - DESQ??? - INSTALLATION CHECK
AX = 30FFh
CX = 4445h ("DE")
DX = 5351h ("SQ")
Return: BH = 05h if installed
???
Note: called by DUBLDISK.COM v2.6; this function is not supported by
DESQview, so it may be for DESQview's precursor DESQ.
SeeAlso: AX=4404h"DUBLDISK"
--------D-2131-------------------------------
INT 21 - DOS 2+ - TERMINATE AND STAY RESIDENT
AH = 31h
AL = return code
DX = number of paragraphs to keep resident
Return: never
Notes: the value in DX only affects the memory block containing the PSP;
additional memory allocated via AH=48h is not affected
the minimum number of paragraphs which will remain resident is 11h
for DOS 2.x and 06h for DOS 3.0+
most TSRs can save some memory by releasing their environment block
before terminating (see #0677 at AH=26h,AH=49h)
SeeAlso: AH=00h,AH=4Ch,AH=4Dh,INT 20,INT 22,INT 27
--------D-2132-------------------------------
INT 21 - DOS 2+ - GET DOS DRIVE PARAMETER BLOCK FOR SPECIFIC DRIVE
AH = 32h
DL = drive number (00h = default, 01h = A:, etc)
Return: AL = status
00h successful
DS:BX -> Drive Parameter Block (DPB) (see #0694) for specified
drive
FFh invalid or network drive
Notes: the OS/2 compatibility box supports the DOS 3.3 version of this call
except for the DWORD at offset 12h
this call updates the DPB by reading the disk; the DPB may be accessed
via the DOS list of lists (see #0914 at AH=52h) if disk access is not
desirable.
undocumented prior to the release of DOS 5.0; only the DOS 4.0+
version of the DPB has been documented, however
supported by DR-DOS 3.41+; DR-DOS 3.41-6.0 return the same data as
MS-DOS 3.31
SeeAlso: AH=1Fh,AH=52h

Format of DOS Drive Parameter Block:
Offset Size Description (Table 0694)
00h BYTE drive number (00h = A:, 01h = B:, etc)
01h BYTE unit number within device driver
02h WORD bytes per sector
04h BYTE highest sector number within a cluster
05h BYTE shift count to convert clusters into sectors
06h WORD number of reserved sectors at beginning of drive
08h BYTE number of FATs
09h WORD number of root directory entries
0Bh WORD number of first sector containing user data
0Dh WORD highest cluster number (number of data clusters + 1)
16-bit FAT if greater than 0FF6h, else 12-bit FAT
0Fh BYTE number of sectors per FAT
10h WORD sector number of first directory sector
12h DWORD address of device driver header
16h BYTE media ID byte (see #0655)
17h BYTE 00h if disk accessed, FFh if not
18h DWORD pointer to next DPB
---DOS 2.x---
1Ch WORD cluster containing start of current directory, 0000h=root,
FFFFh = unknown
1Eh 64 BYTEs ASCIZ pathname of current directory for drive
---DOS 3.x---
1Ch WORD cluster at which to start search for free space when writing
1Eh WORD number of free clusters on drive, FFFFh = unknown
---DOS 4.0-6.0---
0Fh WORD number of sectors per FAT
11h WORD sector number of first directory sector
13h DWORD address of device driver header
17h BYTE media ID byte (see #0655)
18h BYTE 00h if disk accessed, FFh if not
19h DWORD pointer to next DPB
1Dh WORD cluster at which to start search for free space when writing,
usually the last cluster allocated
1Fh WORD number of free clusters on drive, FFFFh = unknown
SeeAlso: #0950
--------D-2133-------------------------------
INT 21 - DOS 2+ - EXTENDED BREAK CHECKING
AH = 33h
AL = subfunction
00h get current extended break state
Return: DL = current state, 00h = off, 01h = on
01h set state of extended ^C/^Break checking
DL = new state
00h off, check only on character I/O functions
01h on, check on all DOS functions
Return: (Novell DOS 7) DL = old state of extended Break checks
Note: under DOS 3.1+ and DR-DOS, this function does not use any of the
DOS-internal stacks and may thus be called at any time
SeeAlso: AX=3302h
--------D-213302-----------------------------
INT 21 - DOS 3.x+ internal - GET AND SET EXTENDED CONTROL-BREAK CHECKING STATE
AX = 3302h
DL = new state (00h for OFF, 01h for ON)
Return: DL = old state of extended BREAK checking
Notes: this function does not use any of the DOS-internal stacks and may thus
be called at any time; one possible use is modifying Control-Break
checking from within an interrupt handler or TSR
not supported by DR-DOS through version 6.0; newly-supported by
Novell DOS 7
SeeAlso: AH=33h
--------D-213303-----------------------------
INT 21 - DOS 4.0+ - UNUSED
AX = 3303h
Return: nothing
Note: this function and AX=3304h were apparently intended to support a
code-page switching flag for OS/2 compatibility (OS/2 allows a file
to have a code page as an attribute); however, this function has
always been a NOP in public releases of DOS. See _DOS_Internals_
Chapter 2 for more information
SeeAlso: AX=3304h
--------D-213304-----------------------------
INT 21 - DOS 4.0+ - UNUSED
AX = 3304h
Return: nothing
Note: this function and AX=3303h were apparently intended to support a
code-page switching flag for OS/2 compatibility (OS/2 allows a file
to have a code page as an attribute); however, this function has
always been a NOP in public releases of DOS. See _DOS_Internals_
Chapter 2 for more information
SeeAlso: AX=3303h
--------D-213305-----------------------------
INT 21 - DOS 4.0+ - GET BOOT DRIVE
AX = 3305h
Return: DL = boot drive (1=A:,...)
Notes: fully reentrant
NEC 9800-series PCs always call the boot drive A: and assign the other
drive letters sequentially to the other drives in the system
this call is supported by OS/2 Warp 3.0, but not earlier versions of
OS/2; it is also supported by Novell DOS 7
--------D-213306-----------------------------
INT 21 - DOS 5+ - GET TRUE VERSION NUMBER
AX = 3306h
Return: BL = major version
BH = minor version
DL = revision (bits 2-0, all others 0)
DH = version flags
bit 3: DOS is in ROM
bit 4: DOS is in HMA
AL = FFh if true DOS version < 5.0
Notes: this function always returns the true version number, unlike AH=30h,
whose return value may be changed with SETVER
because of the conflict from the CBIS redirector (see next
entry), programs should check whether BH is less than 100 (64h)
and BL is at least 5 before accepting the returned BX as the true
version number; however, even this is not entirely reliable when
that redirector is loaded
fully reentrant
OS/2 v2.1 will return BX=0A14h (version 20.10)
the Windows NT DOS box returns BX=3205h (version 5.50)
Novell DOS 7 returns IBM v6.00, which some software displays as
IBM DOS v6.10 (because of the version mismatch in true IBM DOS
mentioned for INT 21/AH=30h)
BUG: DR-DOS 5.0 and 6.0 return CF set/AX=0001h for INT 21/AH=33h
subfunctions other than 00h-02h and 05h, while MS-DOS returns AL=FFh
for invalid subfunctions
SeeAlso: AH=30h,INT 2F/AX=122Fh
--------N-213306-----------------------------
INT 21 - CBIS network - NETWORK REDIRECTOR - ???
AX = 3306h
Return: AX = 3306h
BL = ??? (usually 00h)
BH = ??? (usually 00h or FFh)
Note: unknown function, is in conflict with DOS 5+ version call
SeeAlso: AX=3306h"DOS"
--------v-21330F-----------------------------
INT 21 - VIRUS - "Burghofer" - INSTALLATION CHECK
AX = 330Fh
Return: AL = 0Fh if resident (DOS returns AL=FFh)
SeeAlso: AX=30F1h,AX=33DAh,AX=33E0h
--------k-213341-----------------------------
INT 21 - Diet Disk v1.0 - INSTALLATION CHECK
AX = 3341h
Return: DX = 1234h if installed
CX = resident code segment
Program: Diet Disk is a public domain transparent data file compressor by
Barry Nance
--------v-2133DA------------------------
INT 21 - VIRUS - "CoffeeShop" - INSTALLATION CHECK
AX = 33DAh
Return: AH = A5h if resident
AL = virus version
SeeAlso: AX=330Fh,AX=33E0h,AX=5643h"VIRUS"
--------v-2133E0-----------------------------
INT 21 - VIRUS - "Oropax" - INSTALLATION CHECK
AX = 33E0h
Return: AL = E0h if resident (DOS returns AL=FFh)
SeeAlso: AX=330Fh,AX=33DAh,AX=357Fh
--------D-2134-------------------------------
INT 21 - DOS 2+ - GET ADDRESS OF INDOS FLAG
AH = 34h
Return: ES:BX -> one-byte InDOS flag
Notes: this function executes on the DOS stack, and thus cannot be called
while another DOS function is already executing; you should use
this function once at the beginning of the program and store the
returned pointer rather than calling it when requiring DOS access
the value of InDOS is incremented whenever an INT 21 function begins
and decremented whenever one completes
during an INT 28 call, it is safe to call some INT 21 functions even
though InDOS may be 01h instead of zero
InDOS alone is not sufficient for determining when it is safe to
enter DOS, as the critical error handling decrements InDOS and
increments the critical error flag for the duration of the critical
error. Thus, it is possible for InDOS to be zero even if DOS is
busy.
SMARTDRV 4.0 sets the InDOS flag while flushing its buffers to disk,
then zeros it on completion
the critical error flag is the byte immediately following InDOS in
DOS 2.x, and the byte BEFORE the InDOS flag in DOS 3.0+ and
DR-DOS 3.41+ (except COMPAQ DOS 3.0, where the critical error flag
is located 1AAh bytes BEFORE the critical section flag)
for DOS 3.1+, an undocumented call exists to get the address of the
critical error flag (see AX=5D06h)
this function was undocumented prior to the release of DOS 5.0.
SeeAlso: AX=5D06h,AX=5D0Bh,INT 15/AX=DE1Fh,INT 28
--------D-2135-------------------------------
INT 21 - DOS 2+ - GET INTERRUPT VECTOR
AH = 35h
AL = interrupt number
Return: ES:BX -> current interrupt handler
Note: under DR-DOS 5.0+, this function does not use any of the DOS-internal
stacks and may thus be called at any time
SeeAlso: AH=25h,AX=2503h
--------E-213501-----------------------------
INT 21 P - FlashTek X-32VM - ALLOCATE PROTECTED-MODE SELECTOR
AX = 3501h
Return: CF clear if successful
BX = new selector
CF set on error (no more selectors available)
Note: the new selector will be an expand-up read/write data selector with
undefined base and limit
SeeAlso: AX=3502h,INT 31/AX=0000h
--------E-213502-----------------------------
INT 21 P - FlashTek X-32VM - DEALLOCATE PROTECTED-MODE SELECTOR
AX = 3502h
BX = selector
Return: CF clear if successful
CF set on error (invalid selector)
Note: only selectors allocated via AX=3501h should be deallocated
SeeAlso: AX=3501h,INT 31/AX=0001h
--------E-213503-----------------------------
INT 21 P - FlashTek X-32VM - SET SELECTOR BASE ADDRESS
AX = 3503h
BX = selector
ECX = base address
Return: CF clear if successful
CF set on error (invalid selector)
SeeAlso: AX=3504h,AX=3505h,INT 31/AX=0007h
--------E-213504-----------------------------
INT 21 P - FlashTek X-32VM - GET SELECTOR BASE ADDRESS
AX = 3504h
BX = selector
Return: CF clear if successful
ECX = absolute base address of selector
CF set on error (invalid selector)
SeeAlso: AX=3503h,INT 31/AX=0006h
--------E-213505-----------------------------
INT 21 P - FlashTek X-32VM - SET SELECTOR LIMIT
AX = 3505h
BX = selector
ECX = desired limit
Return: CF clear if successful
ECX = actual limit set
CF set on error (no more selectors available)
Note: the limit will be rounded down to nearest 4K boundary if the requested
limit is greater than 1MB
SeeAlso: AX=3503h,INT 31/AX=0008h
--------E-21350A-----------------------------
INT 21 P - FlashTek X-32VM - PHYSICAL ADDRESS MAPPING
AX = 350Ah
EBX = absolute physical address
ECX = size in bytes of area to map
Return: CF clear if successful
CF set on error (insufficient memory or service refused by DPMI host)
Notes: should not make repeated calls for the same physical address
there is no provision for unmapping memory
--------E-21350B-----------------------------
INT 21 P - FlashTek X-32VM - UPDATE AND RETURN AVAILABLE FREE MEMORY
AX = 350Bh
DS = default selector for DS
Return: CF clear
EAX = maximum amount of memory which can be allocated via AX=350Ch
SeeAlso: AX=350Ch
--------E-21350C-----------------------------
INT 21 P - FlashTek X-32VM - ALLOCATE A BLOCK OF MEMORY
AX = 350Ch
ECX = size of block in bytes
DS = default DS
Return: CF clear if successful
EAX = near pointer to new block
EDX = new lowest legal value for stack
CF set on error (requested size not multiple of 4K)
SeeAlso: AX=350Bh,AX=350Dh
--------E-21350D-----------------------------
INT 21 P - FlashTek X-32VM - RESERVE BLOCK OF MEMORY FOR 32-BIT STACK
AX = 350Dh
EBX = current ESP value
ECX = size of block in bytes
DS = default DS
Return: CF clear if successful
EBX = new value for ESP
EDX = suggested new limit for SS
CF set on error
Note: this function should only be called once during initialization
SeeAlso: AX=350Bh,AX=350Ch
--------v-21357F-----------------------------
INT 21 - VIRUS - "Agiplan"/"Month 4-6" - INSTALLATION CHECK
AX = 357Fh
Return: DX = FFFFh if installed
SeeAlso: AX=33E0h,AX=3DFFh
--------D-2136-------------------------------
INT 21 - DOS 2+ - GET FREE DISK SPACE
AH = 36h
DL = drive number (00h = default, 01h = A:, etc)
Return: AX = FFFFh if invalid drive
else
AX = sectors per cluster
BX = number of free clusters
CX = bytes per sector
DX = total clusters on drive
Notes: free space on drive in bytes is AX * BX * CX
total space on drive in bytes is AX * CX * DX
"lost clusters" are considered to be in use
according to Dave Williams' MS-DOS reference, the value in DX is
incorrect for non-default drives after ASSIGN is run
SeeAlso: AH=1Bh,AH=1Ch
--------D-213700-----------------------------
INT 21 - DOS 2+ - "SWITCHAR" - GET SWITCH CHARACTER
AX = 3700h
Return: AL = status
00h successful
DL = current switch character
FFh unsupported subfunction
Desc: Determine the character which is used to introduce command switches.
This setting is ignored by MS-DOS commands in version 4.0 and higher,
but is honored by many third-party programs and by Novell DOS 7
external commands
BUG: Novell DOS 7's COMMAND.COM fails to honor the SwitChar setting for
internal commands even though COMMAND.COM honors it in its own
command tail (i.e. COMMAND /?)
Notes: documented in some OEM versions of some releases of DOS
supported by OS/2 compatibility box
always returns AL=00h/DL=2Fh for MS-DOS 5+ and DR-DOS 3.41-6.0
Novell DOS 7 COMMAND.COM indicates switch characters other than '/'
by changing the first backslash (and only the first one) in the
path it prints for PROMPT $p with a forward slash
SeeAlso: AX=3701h
--------D-213701-----------------------------
INT 21 - DOS 2+ - "SWITCHAR" - SET SWITCH CHARACTER
AX = 3701h
DL = new switch character
Return: AL = status
00h successful
FFh unsupported subfunction
Notes: documented in some OEM versions of some releases of DOS
supported by OS/2 compatibility box and Novell DOS 7
ignored by MS-DOS 5+ and DR-DOS 3.41-6.0; DR-DOS 6.0 and Novell DOS 7
leave AX unchanged
SeeAlso: AX=3700h
--------D-2137-------------------------------
INT 21 - DOS 2.x and 3.3+ only - "AVAILDEV" - SPECIFY \DEV\ PREFIX USE
AH = 37h
AL = subfunction
02h get availdev flag
Return: DL = 00h \DEV\ must precede character device names
= nonzero \DEV\ is optional
03h set availdev flag
DL = new state
00h \DEV\ is mandatory
nonzero \DEV\ is optional
Return: AL = status
00h successful
FFh unsupported subfunction
Notes: all versions of DOS from 2.00 allow \DEV\ to be prepended to device
names without generating an error even if the directory \DEV does
not actually exist (other paths generate an error if they do not
exist).
although MS-DOS 3.3+, DR-DOS 3.41+, and Novell DOS 7 accept these
calls, they have no effect, and AL=02h always returns DL=FFh (except
for Novell DOS 7, which leaves AX unchanged for both subfunctions)
--------k-2137D0BX899D-----------------------
INT 21 - DIET v1.43e - TSR INSTALLATION CHECK
AX = 37D0h
BX = 899Dh ('DI' + 'ET')
Return: AL = FFh if not present as TSR (default return value from DOS)
AX = 0000h if installed as a TSR
CX = 899Dh
DX = version ID
Program: DIET is a transparent file copressor/decompressor by Teddy Matsumoto
SeeAlso: AX=37D1h,AX=37D2h,AX=37D4h,AX=37D6h,AX=37DFh,AX=4BF0h,AX=4BF1h
--------k-2137D1BX899D-----------------------
INT 21 - DIET v1.43e - GET DIET.EXE RESIDENT SEGMENT
AX = 37D1h
BX = 899Dh ('DI' + 'ET')
Return: AX = 0000h
CX = code segment of TSR part of DIET.EXE
DX = memory block segment of TSR DIET.EXE
(0000h if installed as device driver)
SeeAlso: AX=37D0h,AX=37DFh
--------k-2137D2BX899D-----------------------
INT 21 - DIET v1.43e - GET TSR CONTROL FLAGS
AX = 37D2h
BX = 899Dh ('DI' + 'ET')
Return: AX = 0000h
DL = control flag (00h active, else disabled)
DH = skip flag (nonzero while TSR active)
SeeAlso: AX=37D0h,AX=37D3h,AX=37D4h
--------k-2137D3BX899D-----------------------
INT 21 - DIET v1.43e - SET TSR CONTROL FLAGS
AX = 37D3h
BX = 899Dh ('DI' + 'ET')
DL = control flag (00h active, else disabled)
DH = skip flag (00h)
Return: AX = 0000h
SeeAlso: AX=37D0h,AX=37D2h,AX=37D5h
--------k-2137D4BX899D-----------------------
INT 21 - DIET v1.43e - GET TSR OPTIONS
AX = 37D4h
BX = 899Dh ('DI' + 'ET')
Return: AX = 0000h
DX = TSR options (see #0695)
SeeAlso: AX=37D0h,AX=37D2h,AX=37D5h

Bitfields for DIET TSR options:
Bit(s) Description (Table 0695)
0 automated compression of DIETed file
1 automated compression of newly-created file
2 suppress DIET message
3 display original file size
4-15 reserved (0)
--------k-2137D5BX899D-----------------------
INT 21 - DIET v1.43e - SET TSR OPTIONS
AX = 37D5h
BX = 899Dh ('DI' + 'ET')
DX = TSR options (see #0695)
Return: AX = 0000h
Program: DIET is a transparent file copressor/decompressor by Teddy Matsumoto
SeeAlso: AX=37D0h,AX=37D3h,AX=37D4h
--------k-2137D6BX899D-----------------------
INT 21 - DIET v1.43e - GET TEMPORARY DIRECTORY NAMES
AX = 37D6h
BX = 899Dh ('DI' + 'ET')
Return: AX = 0000h
DS:DX -> name of temporary directory or 0000h:0000h for current dir
SeeAlso: AX=37D0h,AX=37D7h
--------k-2137D7BX899D-----------------------
INT 21 - DIET v1.43e - SET TEMPORARY DIRECTORY NAMES
AX = 37D7h
BX = 899Dh ('DI' + 'ET')
DS:DX -> ASCIZ name of temporary directory (max 61 chars)
0000h:0000h for current directory
Return: AX = 0000h
Note: the specified directory name must include a drive letter and end with
a backslash
SeeAlso: AX=37D0h,AX=37D6h
--------k-2137DCBX899D-----------------------
INT 21 - DIET v1.43e - SET ADDRESS OF EXTERNAL PROCEDURE
AX = 37DCh
BX = 899Dh ('DI' + 'ET')
DS:DX -> external procedure (see #0696)
Return: AX = 0000h
Note: the resident code will call the specified external procedure at the
beginning of decompression and when compression is exited on failure
SeeAlso: AX=37DDh

(Table 0696)
Values DIET external procedure is called with:
STACK: WORD class
FFFDh creation failed for unknown reasons
FFFEh creation failed due to lack of space
FFFFh file creation error
else file handle of DIETed file to be decompressed
DWORD -> compressed filename
DWORD -> decompressed or temporary filename
Return: SI,DI,BP,DS,ES must be preserved by external procedure
--------k-2137DDBX899D-----------------------
INT 21 - DIET v1.43e - RELEASE EXTERNAL PROCEDURE
AX = 37DDh
BX = 899Dh ('DI' + 'ET')
Program: DIET is a transparent file copressor/decompressor by Teddy Matsumoto
Note: unlinks the external procedure specified by AX=37DCh
SeeAlso: AX=37DCh
--------k-2137DEBX899D-----------------------
INT 21 - DIET v1.43e - READ EMS STATUS
AX = 37DEh
BX = 899Dh ('DI' + 'ET')
Return: AX = 0000h
CX = EMS status
0000h not used
0001h used as work area
0002h used for code and as work area
DX = EMM handle when EMS is in use
--------k-2137DFBX899D-----------------------
INT 21 - DIET v1.43e - UNLOAD TSR
AX = 37DFh
BX = 899Dh ('DI' + 'ET')
Return: AX = status
0000h successful
00FFh failed
Program: DIET is a transparent file copressor/decompressor by Teddy Matsumoto
SeeAlso: AX=37D0h
Index: uninstall;DIET
--------D-2138-------------------------------
INT 21 - DOS 2+ - GET COUNTRY-SPECIFIC INFORMATION
AH = 38h
--DOS 2.x--
AL = 00h get current-country info
DS:DX -> buffer for returned info (see #0697,#0698)
Return: CF set on error
AX = error code (02h)
CF clear if successful
AX = country code (MS-DOS 2.11 only)
buffer at DS:DX filled
--DOS 3.0+--
AL = 00h for current country
AL = 01h thru 0FEh for specific country with code <255 (see #0699)
AL = 0FFh for specific country with code >= 255
BX = 16-bit country code (see #0699)
DS:DX -> buffer for returned info (see #0698)
Return: CF set on error
AX = error code (02h)
CF clear if successful
AX = country code (Novell NWDOS v7.0)
BX = country code
DS:DX buffer filled
Note: this function is not supported by the Borland DPMI host, but no error
is returned; as a workaround, one should allocate a buffer in
conventional memory with INT 31/AX=0100h and simulate an INT 21 with
INT 31/AX=0300h
SeeAlso: AH=65h,INT 10/AX=5001h,INT 2F/AX=110Ch,INT 2F/AX=1404h

Format of DOS 2.00-2.10 country info:
Offset Size Description (Table 0697)
00h WORD date format 0 = USA mm dd yy
1 = Europe dd mm yy
2 = Japan yy mm dd
02h BYTE currency symbol
03h BYTE 00h
04h BYTE thousands separator char
05h BYTE 00h
06h BYTE decimal separator char
07h BYTE 00h
08h 24 BYTEs reserved

Format of DOS 2.11+ country info:
Offset Size Description (Table 0698)
00h WORD date format (see #0697)
02h 5 BYTEs ASCIZ currency symbol string
07h 2 BYTEs ASCIZ thousands separator
09h 2 BYTEs ASCIZ decimal separator
0Bh 2 BYTEs ASCIZ date separator
0Dh 2 BYTEs ASCIZ time separator
0Fh BYTE currency format
bit 2 = set if currency symbol replaces decimal point
bit 1 = number of spaces between value and currency symbol
bit 0 = 0 if currency symbol precedes value
1 if currency symbol follows value
10h BYTE number of digits after decimal in currency
11h BYTE time format
bit 0 = 0 if 12-hour clock
1 if 24-hour clock
12h DWORD address of case map routine
(FAR CALL, AL = character to map to upper case [>= 80h])
16h 2 BYTEs ASCIZ data-list separator
18h 10 BYTEs reserved

(Table 0699)
Values for country code:
001h United States
002h Canadian-French
003h Latin America
01Fh Netherlands
020h Belgium
021h France
022h Spain
024h Hungary (not supported by DR-DOS 5.0)
026h Yugoslavia (not supported by DR-DOS 5.0)
027h Italy
029h Switzerland
02Ah Czechoslovakia/Tjekia (not supported by DR-DOS 5.0)
02Bh Austria (DR-DOS 5.0)
02Ch United Kingdom
02Dh Denmark
02Eh Sweden
02Fh Norway
030h Poland (not supported by DR-DOS 5.0)
031h Germany
037h Brazil (not supported by DR-DOS 5.0)
03Dh International English [Australia in DR-DOS 5.0]
051h Japan (DR-DOS 5.0, MS-DOS 5.0+)
052h Korea (DR-DOS 5.0)
056h China (MS-DOS 5.0+)
058h Taiwan (MS-DOS 5.0+)
05Ah Turkey (MS-DOS 5.0+)
15Fh Portugal
162h Iceland
166h Finland
311h Middle East/Saudi Arabia (DR-DOS 5.0,MS-DOS 5.0+)
3CCh Israel (DR-DOS 5.0,MS-DOS 5.0+)
--------D-2138--DXFFFF-----------------------
INT 21 - DOS 3.0+ - SET COUNTRY CODE
AH = 38h
DX = FFFFh
AL = 01h thru FEh for specific country with code <255
AL = FFh for specific country with code >= 255
BX = 16-bit country code (see #0699)
Return: CF set on error
AX = error code (see #0960 at AH=59h)
CF clear if successful
Note: not supported by OS/2
SeeAlso: INT 2F/AX=1403h
--------D-2139-------------------------------
INT 21 - DOS 2+ - "MKDIR" - CREATE SUBDIRECTORY
AH = 39h
DS:DX -> ASCIZ pathname
Return: CF clear if successful
AX destroyed
CF set on error
AX = error code (03h,05h) (see #0960 at AH=59h)
Notes: all directories in the given path except the last must exist
fails if the parent directory is the root and is full
DOS 2.x-3.3 allow the creation of a directory sufficiently deep that
it is not possible to make that directory the current directory
because the path would exceed 64 characters
under the FlashTek X-32 DOS extender, the pointer is in DS:EDX
SeeAlso: AH=3Ah,AH=3Bh,AH=6Dh,AH=71h,AH=E2h/SF=0Ah,INT 2F/AX=1103h
SeeAlso: INT 60/DI=0511h
--------D-213A-------------------------------
INT 21 - DOS 2+ - "RMDIR" - REMOVE SUBDIRECTORY
AH = 3Ah
DS:DX -> ASCIZ pathname of directory to be removed
Return: CF clear if successful
AX destroyed
CF set on error
AX = error code (03h,05h,06h,10h) (see #0960 at AH=59h)
Notes: directory must be empty (contain only '.' and '..' entries)
under the FlashTek X-32 DOS extender, the pointer is in DS:EDX
SeeAlso: AH=39h,AH=3Bh,AH=71h,AH=E2h/SF=0Bh,INT 2F/AX=1101h,INT 60/DI=0512h
--------D-213B-------------------------------
INT 21 - DOS 2+ - "CHDIR" - SET CURRENT DIRECTORY
AH = 3Bh
DS:DX -> ASCIZ pathname to become current directory (max 64 bytes)
Return: CF clear if successful
AX destroyed
CF set on error
AX = error code (03h) (see #0960 at AH=59h)
Notes: if new directory name includes a drive letter, the default drive is
not changed, only the current directory on that drive
changing the current directory also changes the directory in which
FCB file calls operate
under the FlashTek X-32 DOS extender, the pointer is in DS:EDX
SeeAlso: AH=47h,AH=71h,INT 2F/AX=1105h
--------D-213C-------------------------------
INT 21 - DOS 2+ - "CREAT" - CREATE OR TRUNCATE FILE
AH = 3Ch
CX = file attributes (see #0700)
DS:DX -> ASCIZ filename
Return: CF clear if successful
AX = file handle
CF set on error
AX = error code (03h,04h,05h) (see #0960 at AH=59h)
Notes: if a file with the given name exists, it is truncated to zero length
under the FlashTek X-32 DOS extender, the pointer is in DS:EDX
DR-DOS checks the system password or explicitly supplied password at
the end of the filename against the reserved field in the directory
entry before allowing access
SeeAlso: AH=16h,AH=3Dh,AH=5Ah,AH=5Bh,AH=93h,INT 2F/AX=1117h

Bitfields for file attributes:
Bit(s) Description (Table 0700)
0 read-only
1 hidden
2 system
3 volume label (ignored)
4 reserved, must be zero (directory)
5 archive bit
7 if set, file is shareable under Novell NetWare
--------D-213D-------------------------------
INT 21 - DOS 2+ - "OPEN" - OPEN EXISTING FILE
AH = 3Dh
AL = access and sharing modes (see #0701)
DS:DX -> ASCIZ filename
CL = attribute mask of files to look for (server call only)
Return: CF clear if successful
AX = file handle
CF set on error
AX = error code (01h,02h,03h,04h,05h,0Ch,56h) (see #0960 at AH=59h)
Notes: file pointer is set to start of file
file handles which are inherited from a parent also inherit sharing
and access restrictions
files may be opened even if given the hidden or system attributes
under the FlashTek X-32 DOS extender, the pointer is in DS:EDX
DR-DOS checks the system password or explicitly supplied password at
the end of the filename against the reserved field in the directory
entry before allowing access
sharing modes are only effective on local drives if SHARE is loaded
BUG: Novell DOS 7 SHARE v1.00 would refuse file access in the cases in
#0702 marked with [1] (read-only open of a read-only file
which had previously been opened in compatibility mode); this was
fixed in SHARE v1.01 of 09/29/94
SeeAlso: AH=0Fh,AH=3Ch,AX=4301h,AX=5D00h,INT 2F/AX=1116h,INT 2F/AX=1226h

Bitfields for access and sharing modes:
Bit(s) Description (Table 0701)
2-0 access mode
000 read only
001 write only
010 read/write
011 (DOS 5+ internal) passed to redirector on EXEC to allow
case-sensitive filenames
3 reserved (0)
6-4 sharing mode (DOS 3.0+) (see #0702)
000 compatibility mode
001 "DENYALL" prohiboth read and write access by others
010 "DENYWRITE" prohiwrite access by others
011 "DENYREAD" prohiread access by others
100 "DENYNONE" allow full access by others
111 network FCB (only available during server call)
7 inheritance
if set, file is private to current process and will not be inherited
by child processes

(Table 0702)
Values of DOS file sharing behavior:
| Second and subsequent Opens
First |Compat Deny Deny Deny Deny
Open | All Write Read None
|R W RW R W RW R W RW R W RW R W RW
- - - - -| - - - - - - - - - - - - - - - - -
Compat R |Y Y Y N N N 1 N N N N N 1 N N
W |Y Y Y N N N N N N N N N N N N
RW|Y Y Y N N N N N N N N N N N N
- - - - -|
Deny R |C C C N N N N N N N N N N N N
All W |C C C N N N N N N N N N N N N
RW|C C C N N N N N N N N N N N N
- - - - -|
Deny R |2 C C N N N Y N N N N N Y N N
Write W |C C C N N N N N N Y N N Y N N
RW|C C C N N N N N N N N N Y N N
- - - - -|
Deny R |C C C N N N N Y N N N N N Y N
Read W |C C C N N N N N N N Y N N Y N
RW|C C C N N N N N N N N N N Y N
- - - - -|
Deny R |2 C C N N N Y Y Y N N N Y Y Y
None W |C C C N N N N N N Y Y Y Y Y Y
RW|C C C N N N N N N N N N Y Y Y
Legend: Y = open succeeds, N = open fails with error code 05h
C = open fails, INT 24 generated
1 = open succeeds if file read-only, else fails with error code
2 = open succeeds if file read-only, else fails with INT 24
SeeAlso: #0923
--------v-213D76-----------------------------
INT 21 - VIRUS - "GT-SPOOF" -INSTALLATION CHECK
AX = 3D76h
Return: AX = 763Dh if resident
SeeAlso: AX=357Fh,AX=3DFFh
--------v-213DFF-----------------------------
INT 21 - VIRUS - "JD-448" - INSTALLATION CHECK
AX = 3DFFh
Return: AX = 4A44h if resident
SeeAlso: AX=3D76h,AX=4203h
--------D-213E-------------------------------
INT 21 - DOS 2+ - "CLOSE" - CLOSE FILE
AH = 3Eh
BX = file handle
Return: CF clear if successful
AX destroyed
CF set on error
AX = error code (06h) (see #0960 at AH=59h)
Note: if the file was written to, any pending disk writes are performed, the
time and date stamps are set to the current time, and the directory
entry is updated
SeeAlso: AH=10h,AH=3Ch,AH=3Dh,INT 2F/AX=1106h,INT 2F/AX=1227h
--------!---Section--------------------------