Category : Assembly Language Source Code
Archive   : APL2EM.ZIP
Filename : TTY.ASM

Page 58,132
Title TTY.ASM TTY Interface Routines
;******************************************************************************
;
; Name: TTY.ASM TTY Interface Routines
;
; Group: Emulator
;
; Revision: 1.00
;
; Date: January 30, 1988
;
; Author: Randy W. Spurlock
;
;******************************************************************************
;
; Module Functional Description:
;
; This module contains all the code for the TTY interface
; used by the Apple emulator.
;
;******************************************************************************
;
; Changes:
;
; DATE REVISION DESCRIPTION
; -------- -------- -------------------------------------------------------
; 1/30/88 1.00 Original
;
;******************************************************************************
Page
;
; Public Declarations
;
Public TTY_Init ; Initialize TTY mode routine
Public TTY_Reset ; Reset TTY mode routine
Public Write_TTY ; Write TTY routine
Public Set_Position ; Set current position routine
Public Set_Row ; Set current row routine
Public Set_Column ; Set current column routine
Public Set_Attribute ; Set current attribute routine
Public Set_Foreground ; Set current foreground routine
Public Set_Background ; Set current background routine
Public Set_Cursor ; Set cursor position routine
Public Set_Type ; Set cursor type routine
Public Get_Position ; Get current position routine
Public Get_Row ; Get current row routine
Public Get_Column ; Get current column routine
Public Get_Attribute ; Get current attribute routine
Public Get_Foreground ; Get current foreground routine
Public Get_Background ; Get current background routine
Public Get_Cursor ; Get cursor position routine
Public Get_Type ; Get cursor type routine
Public Clear_Screen ; Clear screen routine
Public Current_Row ; Current screen row number
Public Current_Col ; Current screen column number
Public Current_Fore ; Current foreground color value
Public Current_Back ; Current background color value
;
; External Declarations
;
Extrn Clear_Window:Near ; Clear window routine (WINDOW)
Extrn Cursor_Off:Near ; Turn cursor off routine (VIDEO)
Extrn Cursor_On:Near ; Turn cursor on routine (VIDEO)
Extrn Blink_Off:Near ; Turn blink off routine (VIDEO)
Extrn Blink_On:Near ; Turn blink on routine (VIDEO)
Extrn CGA_Restore:Near ; CGA restore screen routine (CGA)
Extrn EGA_Restore:Near ; EGA restore screen routine (EGA)
Extrn System_Flag:Byte ; Apple emulator system flag byte(DATA)
Extrn Video_Flag:Byte ; Video system flag byte (DATA)
;
; LOCAL Equates
;
TEXT_MODE Equ 00h ; Text mode value (40 x 25)
GRAPH_MODE Equ 04h ; Graphics mode value (320 x 200)
BACK_SHIFT Equ 04h ; Background attribute shift value
MAX_ROW Equ 19h ; Maximum row number value (25)
MAX_COLUMN Equ 28h ; Maximum column number value (40)
CURSOR_MASK Equ 07h ; Cursor type mask value
ATTRIBUTE_MASK Equ 0Fh ; Foreground/background attribute mask
MAX_TAB Equ 24h ; Maximum horizontal tab position (36)
TAB_SIZE Equ 04h ; Tab stop size value (4)
TAB_MASK Equ 03h ; Tab count mask value
VIDEO_MEMORY Equ 0B800h ; Start of video memory segment
;
; Define any include files needed
;
Include Macros.inc ; Include the macro definitions
Include Equates.inc ; Include the equate definitions
.286c ; Include 80286 instructions
Page
;
; Define the emulator code segment
;
Emulate Segment Word Public 'EMULATE' ; Emulator code segment
Assume cs:Emulate, ds:Nothing, es:Nothing
Subttl TTY_Init Initialize TTY Mode Routine
Page +
;******************************************************************************
;
; TTY_Init()
;
; Save the required registers
; Set text mode 0 (40x25)
; Call routine to turn off cursor
; Call routine to disable blink (Intensity)
; Restore the required registers
; Return to the caller
;
; Registers on Entry:
;
; None
;
; Registers on Exit:
;
; None
;
;******************************************************************************
Even ; Force procedure to even address
TTY_Init Proc Near ; Initialize TTY mode procedure
Save ax ; Save the required registers
mov ah,SET_MODE ; Get set mode video sub-function code
mov al,TEXT_MODE ; Get the 40x25 text mode value
int VIDEO ; Set video mode to 40x25 text mode
call Cursor_Off ; Call routine to turn cursor off
call Blink_Off ; Call routine to turn blink off
Restore ax ; Restore the required registers
ret ; Return to the caller
TTY_Init Endp ; End of the TTY_Init procedure
Subttl TTY_Reset Reset TTY Mode Routine
Page +
;******************************************************************************
;
; TTY_Reset()
;
; If this is a CGA type video
; Call routine to restore CGA screen
; Else this is an EGA type video
; Call routine to restore EGA screen
; Endif for video type
; Return to the caller
;
; Registers on Entry:
;
; None
;
; Registers on Exit:
;
; None
;
;******************************************************************************
Even ; Force procedure to even address
TTY_Reset Proc Near ; Reset TTY mode procedure
test cs:[System_Flag],EGA_TYPE
jnz Reset_Ega ; Jump if this is an EGA type video
Reset_CGA:
call CGA_Restore ; Call routine to restore CGA
jmp Short Reset_Exit ; Go return to the caller
Reset_EGA:
call EGA_Restore ; Call routine to restore EGA
Reset_Exit:
ret ; Return to the caller
TTY_Reset Endp ; End of the TTY_Reset procedure
Subttl Write_TTY Write TTY Routine
Page +
;******************************************************************************
;
; Write_TTY(Character)
;
; Save the required registers
; If special character
; Call routine to handle special character
; Else
; Calculate the current screen position
; Get current screen colors (Foreground/Background)
; Put requested character on the screen
; Endif
; Restore the required registers
; Return to the caller
;
; Registers on Entry:
;
; AL - Character to write
;
; Registers on Exit:
;
; None
;
;******************************************************************************
Even ; Force procedure to even address
Write_TTY Proc Near ; Write TTY procedure
Save ax,bx,cx,dx,di,es ; Save the required registers
mov bx,cs ; Setup access to
mov es,bx ; character table
mov cx,SPECIAL_LENGTH ; Get length of special character table
lea di,cs:[Special_Table] ; Get pointer to character table
repne scasb ; Check for a special character
jne Write_Character ; Jump if NOT a special character
lea ax,cs:[Special_Table] ; Calculate
sub di,ax ; matching
dec di ; character value
shl di,1 ; Convert matching number to table index
call cs:[di + Special_Jump] ; Call correct special character routine
jmp Short Write_Exit ; Go return control to the caller
Write_Character:
mov cx,cs:[Current_Row] ; Get the current row number
mov bx,cx ; Compute
shl bx,2 ; row number
add bx,cx ; times five (*80)
add bx,VIDEO_MEMORY ; Compute actual video memory segment
mov es,bx ; Setup to access video memory
mov di,cs:[Current_Col] ; Compute the actual
shl di,1 ; memory address
mov ah,Byte Ptr cs:[Current_Back]
shl ah,BACK_SHIFT ; Shift background into position
or ah,Byte Ptr cs:[Current_Fore]
stosw ; Store character into memory
mov ax,cs:[Current_Row] ; Get the current
mov bx,cs:[Current_Col] ; row/column values
inc bx ; Increment the column number
cmp bx,MAX_COLUMN ; Check against maximum column value
jb Write_Update ; Jump if column number valid
xor bx,bx ; Reset current column number
inc ax ; Increment the row number
cmp ax,MAX_ROW ; Check against maximum row value
jae Write_Exit ; Jump if invalid row/column values
Write_Update:
mov cs:[Current_Row],ax ; Update the current
mov cs:[Current_Col],bx ; row/column values
Write_Exit:
Restore ax,bx,cx,dx,di,es ; Restore the required registers
ret ; Return to the caller
Write_TTY Endp ; End of the Write_TTY procedure
Subttl Special_NULL Special NULL Character Routine
Page +
;******************************************************************************
;
; Special_NULL()
;
; Return to the caller
;
; Registers on Entry:
;
; None
;
; Registers on Exit:
;
; None
;
;******************************************************************************
Even ; Force procedure to even address
Special_NULL Proc Near ; Special NULL character procedure
ret ; Return to the caller
Special_NULL Endp ; End of the Special_NULL procedure
Subttl Special_BELL Special BELL Character Routine
Page +
;******************************************************************************
;
; Special_BELL()
;
; Save the required registers
;
; Restore the required registers
; Return to the caller
;
; Registers on Entry:
;
; None
;
; Registers on Exit:
;
; None
;
;******************************************************************************
Even ; Force procedure to even address
Special_BELL Proc Near ; Special BELL character procedure
Save ; Save the required registers



Restore ; Restore the required registers
ret ; Return to the caller
Special_BELL Endp ; End of the Special_BELL procedure
Subttl Special_BS Special BS Character Routine
Page +
;******************************************************************************
;
; Special_BS()
;
; Save the required registers
; If current column number greater than zero
; Decrement the current column number
; Calculate the current screen position
; Get current screen colors (Foreground/Background)
; Put space character on the screen
; Endif
; Restore the required registers
; Return to the caller
;
; Registers on Entry:
;
; None
;
; Registers on Exit:
;
; None
;
;******************************************************************************
Even ; Force procedure to even address
Special_BS Proc Near ; Special BS character procedure
Save ax,bx,di,es ; Save the required registers
mov ax,cs:[Current_Col] ; Get the current column number
or ax,ax ; Check for in column zero
jz BS_Exit ; Jump if currently in column zero
dec cs:[Current_Col] ; Decrement the current column value
mov ax,cs:[Current_Row] ; Get the current row number
mov bx,ax ; Compute
shl bx,2 ; row number
add ax,bx ; times five (*80)
add ax,VIDEO_MEMORY ; Compute actual video memory segment
mov es,ax ; Setup to access video memory
mov di,cs:[Current_Col] ; Compute the actual
shl di,1 ; memory address
mov al,SPACE ; Setup to write a space character
mov ah,Byte Ptr cs:[Current_Back]
shl ah,BACK_SHIFT ; Shift background into position
or ah,Byte Ptr cs:[Current_Fore]
stosw ; Store character into memory
BS_Exit:
Restore ax,bx,di,es ; Restore the required registers
ret ; Return to the caller
Special_BS Endp ; End of the Special_BS procedure
Subttl Special_HT Special HT Character Routine
Page +
;******************************************************************************
;
; Special_HT()
;
; Save the required registers
; If current column less than maximum tab position
; Calculate number of pad characters required (Spaces)
; Calculate the current screen position
; Get current screen colors (Foreground/Background)
; Update the current column position
; While more pad characters to display
; Put pad character on the screen (Space)
; Decrement the pad counter
; EndWhile
; Endif
; Restore the required registers
; Return to the caller
;
; Registers on Entry:
;
; None
;
; Registers on Exit:
;
; None
;
;******************************************************************************
Even ; Force procedure to even address
Special_HT Proc Near ; Special HT character procedure
Save ax,bx,cx,di,es ; Save the required registers
mov ax,cs:[Current_Col] ; Get the current column position
cmp ax,MAX_TAB ; Check against maximum tab position
jae HT_Exit ; Jump if past maximum tab position
and ax,TAB_MASK ; Compute
mov cx,TAB_SIZE ; the actual
sub cx,ax ; tab count value
mov ax,cs:[Current_Row] ; Get the current row number
mov bx,ax ; Compute
shl bx,2 ; row number
add ax,bx ; times five (*80)
add ax,VIDEO_MEMORY ; Compute actual video memory segment
mov es,ax ; Setup to access video memory
mov di,cs:[Current_Col] ; Compute the actual
shl di,1 ; memory address
mov al,SPACE ; Setup to write a space character
mov ah,Byte Ptr cs:[Current_Back]
shl ah,BACK_SHIFT ; Shift background into position
or ah,Byte Ptr cs:[Current_Fore]
add cs:[Current_Col],cx ; Update the current column position
rep stosw ; Store the horizontal pad characters
HT_Exit:
Restore ax,bx,cx,di,es ; Restore the required registers
ret ; Return to the caller
Special_HT Endp ; End of the Special_HT procedure
Subttl Special_LF Special LF Character Routine
Page +
;******************************************************************************
;
; Special_LF()
;
; Save the required registers
; If not on the bottom row
; Increment the current row value
; Endif
; Restore the required registers
; Return to the caller
;
; Registers on Entry:
;
; None
;
; Registers on Exit:
;
; None
;
;******************************************************************************
Even ; Force procedure to even address
Special_LF Proc Near ; Special LF character procedure
Save ax ; Save the required registers
mov ax,cs:[Current_Row] ; Get the current row position
cmp ax,MAX_ROW - 1 ; Check for on the bottom row
jae LF_Exit ; Jump if currently on the last row
inc cs:[Current_Row] ; Increment to the next row
LF_Exit:
Restore ax ; Restore the required registers
ret ; Return to the caller
Special_LF Endp ; End of the Special_LF procedure
Subttl Special_VT Special VT Character Routine
Page +
;******************************************************************************
;
; Special_VT()
;
; Save the required registers
; If not on the bottom row
; Increment the current row value
; Endif
; Restore the required registers
; Return to the caller
;
; Registers on Entry:
;
; None
;
; Registers on Exit:
;
; None
;
;******************************************************************************
Even ; Force procedure to even address
Special_VT Proc Near ; Special VT character procedure
Save ax ; Save the required registers
mov ax,cs:[Current_Row] ; Get the current row position
cmp ax,MAX_ROW - 1 ; Check for on the bottom row
jae VT_Exit ; Jump if currently on the last row
inc cs:[Current_Row] ; Increment to the next row
VT_Exit:
Restore ax ; Restore the required registers
ret ; Return to the caller
Special_VT Endp ; End of the Special_VT procedure
Subttl Special_FF Special FF Character Routine
Page +
;******************************************************************************
;
; Special_FF()
;
; Save the required registers
; Call routine to clear the screen
; Set row position to zero
; Set column position to zero
; Restore the required registers
; Return to the caller
;
; Registers on Entry:
;
; None
;
; Registers on Exit:
;
; None
;
;******************************************************************************
Even ; Force procedure to even address
Special_FF Proc Near ; Special FF character procedure
Save ax ; Save the required registers
call Clear_Screen ; Call routine to clear the screen
xor ax,ax ; Setup to zero current position (Home)
mov cs:[Current_Row],ax ; Zero the current
mov cs:[Current_Col],ax ; row/column position
Restore ax ; Restore the required registers
ret ; Return to the caller
Special_FF Endp ; End of the Special_FF procedure
Subttl Special_CR Special CR Character Routine
Page +
;******************************************************************************
;
; Special_CR()
;
; Save the required registers
; Set current column position to zero
; Restore the required registers
; Return to the caller
;
; Registers on Entry:
;
; None
;
; Registers on Exit:
;
; None
;
;******************************************************************************
Even ; Force procedure to even address
Special_CR Proc Near ; Special CR character procedure
Save ax ; Save the required registers
xor ax,ax ; Setup to zero column position
mov cs:[Current_Col],ax ; Zero current column position value
Restore ax ; Restore the required registers
ret ; Return to the caller
Special_CR Endp ; End of the Special_CR procedure
Subttl Set_Position Set Current Position Routine
Page +
;******************************************************************************
;
; Set_Position(Row, Column)
;
; If new row position is valid
; If new column position is valid
; Set current row to new row
; Set current column to new column
; Endif
; Endif
; Return to the caller
;
; Registers on Entry:
;
; AX - New row number
; BX - New column number
;
; Registers on Exit:
;
; None
;
;******************************************************************************
Even ; Force procedure to even address
Set_Position Proc Near ; Set current position procedure
cmp ax,MAX_ROW ; Check the new row number value
jae Position_Exit ; Jump if new row value is invalid
cmp bx,MAX_COLUMN ; Check the new column number value
jae Position_Exit ; Jump if new column value is invalid
mov cs:[Current_Row],ax ; Update the current
mov cs:[Current_Col],bx ; row/column values
Position_Exit:
ret ; Return to the caller
Set_Position Endp ; End of the Set_Position procedure
Subttl Set_Row Set Current Row Position Routine
Page +
;******************************************************************************
;
; Set_Row(Row)
;
; If new row position is valid
; Set current row to new row
; Endif
; Return to the caller
;
; Registers on Entry:
;
; AX - New row number
;
; Registers on Exit:
;
; None
;
;******************************************************************************
Even ; Force procedure to even address
Set_Row Proc Near ; Set current row position procedure
cmp ax,MAX_ROW ; Check the new row number value
jae Row_Exit ; Jump if new row value is invalid
mov cs:[Current_Row],ax ; Update the current row value
Row_Exit:
ret ; Return to the caller
Set_Row Endp ; End of the Set_Row procedure
Subttl Set_Column Set Current Column Position Routine
Page +
;******************************************************************************
;
; Set_Column(Column)
;
; If new column position is valid
; Set current column to new column
; Endif
; Return to the caller
;
; Registers on Entry:
;
; AX - New column number
;
; Registers on Exit:
;
; None
;
;******************************************************************************
Even ; Force procedure to even address
Set_Column Proc Near ; Set current column position procedure
cmp ax,MAX_COLUMN ; Check the new column number value
jae Column_Exit ; Jump if new column value is invalid
mov cs:[Current_Col],ax ; Update the current column value
Column_Exit:
ret ; Return to the caller
Set_Column Endp ; End of the Set_Column procedure
Subttl Set_Attribute Set Current Attribute Routine
Page +
;******************************************************************************
;
; Set_Attribute(Foreground, Background)
;
; Set current foreground color to new value
; Set current background color to new value
; Mask off the foreground value
; Mask off the background value
; Return to the caller
;
; Registers on Entry:
;
; AX - New foreground color
; BX - New background color
;
; Registers on Exit:
;
; None
;
;******************************************************************************
Even ; Force procedure to even address
Set_Attribute Proc Near ; Set current attribute procedure
mov cs:[Current_Fore],ax ; Save new foreground
mov cs:[Current_Back],bx ; background colors
and cs:[Current_Fore],ATTRIBUTE_MASK
and cs:[Current_Back],ATTRIBUTE_MASK
ret ; Return to the caller
Set_Attribute Endp ; End of the Set_Attribute procedure
Subttl Set_Foreground Set Current Foreground Routine
Page +
;******************************************************************************
;
; Set_Foreground(Foreground)
;
; Set current foreground color to new value
; Mask off the foreground value
; Return to the caller
;
; Registers on Entry:
;
; AX - New foreground color
;
; Registers on Exit:
;
; None
;
;******************************************************************************
Even ; Force procedure to even address
Set_Foreground Proc Near ; Set current foreground procedure
mov cs:[Current_Fore],ax ; Save new foreground color value
and cs:[Current_Fore],ATTRIBUTE_MASK
ret ; Return to the caller
Set_Foreground Endp ; End of the Set_Foreground procedure
Subttl Set_Background Set Current Background Routine
Page +
;******************************************************************************
;
; Set_Background(Background)
;
; Set current background color to new value
; Mask off the background value
; Return to the caller
;
; Registers on Entry:
;
; AX - New background color
;
; Registers on Exit:
;
; None
;
;******************************************************************************
Even ; Force procedure to even address
Set_Background Proc Near ; Set current background procedure
mov cs:[Current_Back],ax ; Save new background color value
and cs:[Current_Back],ATTRIBUTE_MASK
ret ; Return to the caller
Set_Background Endp ; End of the Set_Background procedure
Subttl Set_Cursor Set Cursor Position Routine
Page +
;******************************************************************************
;
; Set_Cursor(Row, Column)
;
; Save the required registers
; If new row position is valid
; If new column position is valid
; Set new cursor position
; Endif
; Endif
; Restore the required registers
; Return to the caller
;
; Registers on Entry:
;
; AX - Cursor row number
; BX - Cursor column number
;
; Registers on Exit:
;
; None
;
;******************************************************************************
Even ; Force procedure to even address
Set_Cursor Proc Near ; Set cursor position procedure
Save ax,bx,dx ; Save the required registers
cmp ax,MAX_ROW ; Check the new row number value
jae Cursor_Exit ; Jump if new row value is invalid
cmp bx,MAX_COLUMN ; Check the new column number value
jae Cursor_Exit ; Jump if new column value is invalid
mov dh,al ; Setup the cursor
mov dl,bl ; row and column values
xor bh,bh ; Setup for video page zero
mov ah,WRITE_CURSOR ; Get write cursor position function
int VIDEO ; Set the new cursor position
Cursor_Exit:
Restore ax,bx,dx ; Restore the required registers
ret ; Return to the caller
Set_Cursor Endp ; End of the Set_Cursor procedure
Subttl Set_Type Set Cursor Type Routine
Page +
;******************************************************************************
;
; Set_Type(Start, End)
;
; Save the required registers
; Mask off the cursor start value
; Mask off the cursor end value
; Set the new cursor type value
; Restore the required registers
; Return to the caller
;
; Registers on Entry:
;
; AX - Cursor start row number (0 - 7)
; BX - Cursor end row number (0 - 7)
;
; Registers on Exit:
;
; None
;
;******************************************************************************
Even ; Force procedure to even address
Set_Type Proc Near ; Set cursor type procedure
Save ax,cx ; Save the required registers
mov ch,al ; Get and mask
and ch,CURSOR_MASK ; cursor start value
mov cl,bl ; Get and mask
and cl,CURSOR_MASK ; cursor end value
mov ah,CURSOR_TYPE ; Get set cursor type function code
int VIDEO ; Set the new cursor type value
Restore ax,cx ; Restore the required registers
ret ; Return to the caller
Set_Type Endp ; End of the Set_Type procedure
Subttl Get_Position Get Current Position Routine
Page +
;******************************************************************************
;
; Get_Position()
;
; Get the current row value
; Get the current column vlaue
; Return to the caller
;
; Registers on Entry:
;
; None
;
; Registers on Exit:
;
; AX - Current row number
; BX - Current column number
;
;******************************************************************************
Even ; Force procedure to even address
Get_Position Proc Near ; Get current position procedure
mov ax,cs:[Current_Row] ; Get the current
mov bx,cs:[Current_Col] ; row/column values
ret ; Return to the caller
Get_Position Endp ; End of the Get_Position procedure
Subttl Get_Row Get Current Row Position Routine
Page +
;******************************************************************************
;
; Get_Row()
;
; Get the current row value
; Return to the caller
;
; Registers on Entry:
;
; None
;
; Registers on Exit:
;
; AX - Current row number
;
;******************************************************************************
Even ; Force procedure to even address
Get_Row Proc Near ; Get current row position procedure
mov ax,cs:[Current_Row] ; Get the current row value
ret ; Return to the caller
Get_Row Endp ; End of the Get_Row procedure
Subttl Get_Column Get Current Column Position Routine
Page +
;******************************************************************************
;
; Get_Column()
;
; Get the current column vlaue
; Return to the caller
;
; Registers on Entry:
;
; None
;
; Registers on Exit:
;
; AX - Current column number
;
;******************************************************************************
Even ; Force procedure to even address
Get_Column Proc Near ; Get current column position procedure
mov ax,cs:[Current_Col] ; Get the current column value
ret ; Return to the caller
Get_Column Endp ; End of the Get_Column procedure
Subttl Get_Attribute Get Current Attribute Routine
Page +
;******************************************************************************
;
; Get_Attribute()
;
; Get the current foreground color
; Get the current background color
; Return to the caller
;
; Registers on Entry:
;
; None
;
; Registers on Exit:
;
; AX - Current foreground color
; BX - Current background color
;
;******************************************************************************
Even ; Force procedure to even address
Get_Attribute Proc Near ; Get current attribute procedure
mov ax,cs:[Current_Fore] ; Get foreground/
mov bx,cs:[Current_Back] ; background colors
ret ; Return to the caller
Get_Attribute Endp ; End of the Get_Attribute procedure
Subttl Get_Foreground Get Current Foreground Routine
Page +
;******************************************************************************
;
; Get_Foreground()
;
; Get the current foreground color
; Return to the caller
;
; Registers on Entry:
;
; None
;
; Registers on Exit:
;
; AX - Current foreground color
;
;******************************************************************************
Even ; Force procedure to even address
Get_Foreground Proc Near ; Get current foreground procedure
mov ax,cs:[Current_Fore] ; Get the current foreground color
ret ; Return to the caller
Get_Foreground Endp ; End of the Get_Foreground procedure
Subttl Get_Background Get Current Background Routine
Page +
;******************************************************************************
;
; Get_Background()
;
; Get the current background color
; Return to the caller
;
; Registers on Entry:
;
; None
;
; Registers on Exit:
;
; AX - Current background color
;
;******************************************************************************
Even ; Force procedure to even address
Get_Background Proc Near ; Get current background procedure
mov ax,cs:[Current_Back] ; Get the current background color
ret ; Return to the caller
Get_Background Endp ; End of the Get_Background procedure
Subttl Get_Cursor Get Cursor Position Routine
Page +
;******************************************************************************
;
; Get_Cursor()
;
; Save the required registers
; Get current cursor position
; Restore the required registers
; Return to the caller
;
; Registers on Entry:
;
; None
;
; Registers on Exit:
;
; AX - Cursor row number
; BX - Cursor column number
;
;******************************************************************************
Even ; Force procedure to even address
Get_Cursor Proc Near ; Get cursor position procedure
Save cx,dx ; Save the required registers
xor bh,bh ; Setup for video page zero
mov ah,READ_CURSOR ; Get read cursor position function
int VIDEO ; Get the current cursor position
mov al,dh ; Get the current
xor ah,ah ; row position value
mov bl,dl ; Get the current
xor bh,bh ; column position value
Restore cx,dx ; Restore the required registers
ret ; Return to the caller
Get_Cursor Endp ; End of the Get_Cursor procedure
Subttl Get_Type Get Cursor Type Routine
Page +
;******************************************************************************
;
; Get_Type()
;
; Save the required registers
; Get current cursor type
; Restore the required registers
; Return to the caller
;
; Registers on Entry:
;
; None
;
; Registers on Exit:
;
; AX - Cursor start row number (0 - 7)
; BX - Cursor end row number (0 - 7)
;
;******************************************************************************
Even ; Force procedure to even address
Get_Type Proc Near ; Get cursor type procedure
Save cx,dx ; Save the required registers
xor bh,bh ; Setup for video page zero
mov ah,READ_CURSOR ; Get read cursor position function
int VIDEO ; Get the current cursor position
mov al,ch ; Get cursor start
xor ah,ah ; row position value
mov bl,cl ; Get cursor end
xor bh,bh ; row position value
Restore cx,dx ; Restore the required registers
ret ; Return to the caller
Get_Type Endp ; End of the Get_Type procedure
Subttl Clear_Screen Clear Screen Routine
Page +
;******************************************************************************
;
; Clear_Screen()
;
; Save the required registers
; Set window to entire screen
; Call routine to clear window
; Restore the required registers
; Return to the caller
;
; Registers on Entry:
;
; None
;
; Registers on Exit:
;
; None
;
;******************************************************************************
Even ; Force procedure to even address
Clear_Screen Proc Near ; Clear screen procedure
Save ax,bx,cx,dx ; Save the required registers
xor ax,ax ; Setup
xor bx,bx ; window
mov cx,MAX_ROW - 1 ; to the
mov dx,MAX_COLUMN - 1 ; entire screen
call Clear_Window ; Call routine to clear the window
Restore ax,bx,cx,dx ; Restore the required registers
ret ; Return to the caller
Clear_Screen Endp ; End of the Clear_Screen procedure
Subttl TTY Interface Data Areas
Page +
;******************************************************************************
;
; Define any data areas needed by the TTY interface
;
;******************************************************************************
Special_Table Equ This Byte ; Special character table
Db NULL ; Null character
Db BELL ; Bell character
Db BS ; Backspace character
Db HT ; Horizontal tab character
Db LF ; Line feed character
Db VT ; Vertical tab character
Db FF ; Form feed character
Db CR ; Carriage return character
SPECIAL_LENGTH Equ This Byte - Special_Table
Special_Jump Equ This Word ; Special character jump table
Dw Special_NULL ; Null character routine
Dw Special_BELL ; Bell character routine
Dw Special_BS ; Backspace character routine
Dw Special_HT ; Horizontal tab character routine
Dw Special_LF ; Line feed character routine
Dw Special_VT ; Vertical tab character routine
Dw Special_FF ; Form feed character routine
Dw Special_CR ; Carriage return character routine
Current_Row Dw 0 ; Current screen row number
Current_Col Dw 0 ; Current screen column number
Current_Fore Dw INTENSE_WHITE ; Current foreground color value
Current_Back Dw GRAY ; Current background color value
;******************************************************************************
;
; Define the end of the Emulator Code Segment
;
;******************************************************************************
Emulate Ends
End ; End of the TTY module