Category : Alternate Operating Systems - Quarterdeck DesqView, CP/M, etc
Archive   : CHKDV102.ZIP
Filename : CHECKDV.ASM

comment ~
/*@H************************ < Mylibrary > ****************************
* *
* CHECKDV : checkdv.asm API routines to check for Desqview *
* *
* Author : Donald J. Gloistein *
* *
* Program, Source, Documentation (c) 1987, all rights reserved. *
* *
* Compiled code may be used in your library, and linked to your programs *
* BUT, the source code nor a library based on the compiled modules may be *
* commercially distributed. *
* This is not shareware, no donation is expected. But I do retain rights *
* to the source. *
* *
* See manual for license and information to general public. *
* Any code derived from other sources will be noted in comments. *
* *
* *
*--------------------------- Module Description --------------------------*
* This code was based closely on the samples provided by Quarterdeck for *
* their version 2 Desqview (tm). Modifications made to use C calling *
* conventions and initialize global variables for the program to use. *
* *
* *
* *
* Function names: *
* int dv_get_dv_version(void) *
* unsigned int dv_get_video_buffer(unsigned int) *
* void dv_pause(void) *
* void dv_begin_critical(void) *
* void dv_end_critical(void) *
* Globals that can be used: *
* int in_dv True if dv present *
* unsigned dv_vid_seg segment address of buffer *
* unsigned dv_vid_off offset of buffer (usually 0) *
* int dv_maj_version major version number if in_dv *
* int dv_min_version minor version number if in_dv *
* *
* *
*--------------------------- Implementation Notes --------------------------*
* *
* compiled with : *
* compiled by : MASM v.5.0 *
* *
* linked with : MYLIB.LIB *
* linked by : MICROSOFT LINK *
* *
* As written, this module is set for the C calling conventions of *
* Microsoft C version 5.0, it takes advantage of none of the upgraded *
* options of Masm 5.0, especially the memory model feature. This may not *
* be true in the future. *
* It is designed to be called with model defined or small memory is *
* assumed. This is done on the command line as follows: *
* masm /MX /Dsmall filename ; gives small model *
* mams /MX /Dmedium filename ; gives medium model *
* While it is not necessary to define small, it is included to help in *
* batch files. *
* *
* The dv_get_video_buffer() makes a call to dv_get_version(), so only one *
* need be used. After the call, your program can use the in_dv variable *
* to test if Desqview is present. If your program does direct screen *
* writes, use the get buffer function. Then the shadow area DV uses will *
* be in the variables dv_vid_seg and dv_vid_off. These can be used with *
* straight copying functions. No timing loops are needed, as DV takes *
* care of that. If your program uses only BIOS, DOS or the shadow buffer *
* then it will run in a small window in Desqview. I have modified Windows*
* BOSS for Desqview, and my BATMEN program now runs in DV with no bleeding*
* *
* The other functions are fairly self explanatory. I use the dv_pause() *
* when I am in an inkey loop polling for a key stroke. This speeds up *
* the other programs somewhat. The critical functions would be well used *
* when setting things like interupts and signals. Anytime that you do not *
* want to loose program control. *
* *
* problems: none , I assume people will tell me. Works for me. *
* Desqview version 2.0 has a bug and returns the version in reverse order *
* this version allows for it. *
* *
* I have only tested this under desqview version 2 *
* *
*--------------------------- Author(s) -------------------------*
* Initials ---- Name --------------------------------- *
* DjG Donald J. Gloistein *
* *
*************************************************************************@H*/

/*@R************************< Revision History >*****************************
* *
* version -- date -- init ---Notes---------------------- *
* 1.00 12-14-87 DjG Modified code from DV v2.00 manual *
* 1.01 01-16-88 DjG Fixed bug in interface. My fault. *
* 1.02 01-20-88 DjG Adjusted for DV 2.0 *
* *
*************************************************************************@R*/
~ end_of_comments

TRUE EQU 1
FALSE EQU 0

if1
ifdef SMALL
LDATA EQU FALSE
LCODE EQU FALSE
%out Small model defined
endif
ifdef MEDIUM
LDATA EQU FALSE
LCODE EQU TRUE
%out Medium model defined
endif
ifdef LARGE
LDATA EQU TRUE
LCODE EQU TRUE
%out Large model defined
endif
ifdef COMPACT
LDATA EQU TRUE
LCODE EQU FALSE
%out Compact model defined
endif

ifndef LDATA
LDATA EQU FALSE
LCODE EQU FALSE
%out code not defined assuming small model
endif
if LDATA
%out LARGE DATA
else
%out SMALL DATA
endif
if LCODE
%out LARGE CODE
else
%out SMALL CODE
endif
endif

if LCODE
CHECKDV_TEXT SEGMENT WORD PUBLIC 'CODE'
CHECKDV_TEXT ENDS
else
_TEXT SEGMENT WORD PUBLIC 'CODE'
_TEXT ENDS
endif

CONST SEGMENT WORD PUBLIC 'CONST'
CONST ENDS
_BSS SEGMENT WORD PUBLIC 'BSS'
_BSS ENDS
_DATA SEGMENT WORD PUBLIC 'DATA'
_DATA ENDS

if LCODE
DGROUP GROUP CONST, _BSS, _DATA
ASSUME CS: CHECKDV_TEXT, DS: DGROUP, SS: DGROUP, ES: DGROUP
else
DGROUP GROUP CONST, _BSS, _DATA
ASSUME CS: _TEXT, DS: DGROUP, SS: DGROUP, ES: DGROUP
endif

if LCODE
extrn __chkstk:far
else
extrn __chkstk:near
endif

_DATA segment
public _dv_vid_seg
public _dv_vid_off
public _in_dv
public _dv_maj_version
public _dv_min_version

_dv_vid_seg dw 0
_dv_vid_off dw 0
_in_dv dw 0
_dv_maj_version dw 0
_dv_min_version dw 0
_DATA ends

if LCODE
@AB EQU 6
else
@AB EQU 4
endif

ARG1 EQU @AB
ARG2 EQU @AB+2
ARG3 EQU @AB+4
ARG4 EQU @AB+6
ARG5 EQU @AB+8
ARG6 EQU @AB+10

if LCODE
CHECKDV_TEXT segment
else
_TEXT segment
endif

public _dv_get_version
public _dv_get_video_buffer
public _dv_pause
public _dv_begin_critical
public _dv_end_critical

comment ~
/*@F*************************< dv_get_version>*******************************
* *
* checks for Desqview and version *
* --------------------------------- *
* *
* Checks for presence of desqview. Sets the major and minor version *
* global variables. Sets in_dv variable to true if present *
* *
* Parameters: *
* no parameters *
* ... ... *
* *
* Returns: *
* major version number is returned in AX *
* False (0) is returned if not desqview *
*************************************************************************@F*/
~ end_of_comments


if LCODE
_dv_get_version proc far
else
_dv_get_version proc near
endif
push bp
mov bp,sp
push bx
push cx
push dx
mov cx,'DE' ;set cx and dx to invalid date
mov dx,'SQ'
mov ax,2b01h ;dos set date function
int 21h
cmp al,0ffh ; did dos set date as invalid?
je no_desqview ; if so, desqview isn't there
mov ax,bx ; AH=major version AL = minor version
mov _in_dv,1 ;
cmp ax,0002h ; corrects for bug, version 2.0 reverses the
jne not_20 ; documented version order. Comment out
xchg al,ah ; these three lines if it doesnt matter to you.
not_20:
mov byte ptr _dv_maj_version,ah ; not needed, but I want it
mov byte ptr _dv_min_version,al
xchg al,ah ; get major version in al
cbw ; set up for return
jmp short dvgv_x
no_desqview:
xor ax,ax ;return false (no desqview)
dvgv_x: pop dx
pop cx
pop bx
pop bp
ret
_dv_get_version endp

comment ~
/*@F*************************< dv_get_video_buffer >*************************
* *
* finds the video buffer DV is using *
* --------------------------------- *
* *
* Finds the buffer for direct video screen writing *
* *
* unsigned int dv_get_video_buffer(segment) *
* Parameters: *
* segment unsigned int *
* *
* Returns: *
* the passed segment if no desqview, new segment if DV is there *
* returned value is an unsigned integer. *
* sets up the dv_vid_seg and dv_vid_off to new segments *
* otherwise sets them to the current segment with 0 offset *
* *
*************************************************************************@F*/
~ end_of_comments


if LCODE
_dv_get_video_buffer proc far
else
_dv_get_video_buffer proc near
endif
push bp
mov bp,sp
push di
push si ; lets make sure
push es
mov es,[bp][ARG1]
call _dv_get_version
test ax,ax ; in DV?
jz dvgvb_x
;since DV is running, get the alternate buffer
mov ah,0feh ; DV's get buffer function
int 10h ; returns es:di as alternate buffer
mov _dv_vid_off,di
dvgvb_x:
mov ax,es ;return the video segment
mov _dv_vid_seg,ax ; set up the global
pop es
pop si
pop di
mov sp,bp
pop bp
ret
_dv_get_video_buffer endp


comment ~
/*@F*************************< api_call >*******************************
* *
* invokes a desqview interface func *
* --------------------------------- *
* *
* local procedure to invoke desqview API after switching to a stack that *
* Desqview provides for the programmer *
* *
* Parameters: *
* local procedure, does not follow C calling convention. *
* AX contains the function to be invoked *
* *
* Returns: *
* none *
* *
*************************************************************************@F*/
~ end_of_comments


api_call proc near
mov ax,101ah ; the func to switch to DV's stack
int 15H ; DV's software interupt
mov ax,bx ; move the desired fuction to ax
int 15H
mov ax,1025h ; the func to swith off of DV's stack
int 15H
ret
api_call endp

comment ~
/*@F*************************< dv_pause >*******************************
* *
* gives up programs time slice *
* --------------------------------- *
* *
* When the calling program is just polling the key board waiting for *
* something to happen, it can use up a lot of time. This releases the *
* rest of the time, like if you are using an inkey type loop *
* *
* void dv_pause(void); *
* *
* Parameters: none *
* *
* Returns: nothing *
* *
*************************************************************************@F*/
~ end_of_comments


if LCODE
_dv_pause proc far
else
_dv_pause proc near
endif
cmp byte ptr _in_dv,1 ; are we in desqview ?
jne dvp_x
mov bx,1000h ; put function code in ax
call api_call
dvp_x: ret
_dv_pause endp


comment ~
/*@F*************************< dv_begin_critical >***************************
* *
* keeps time slice in desqview *
* --------------------------------- *
* *
* This function tells Desqview not to give up your time slice. *
* This is used for parts of your program that are critical and you do not *
* want interupted. *
* *
* void dv_begin_critical(void) *
* Parameters: none *
* *
* Returns: nothing *
* *
*************************************************************************@F*/
~ end_of_comments


if LCODE
_dv_begin_critical proc far
else
_dv_begin_critical proc near
endif
cmp byte ptr _in_dv,1
jne dvbc_x
mov bx,101bH ; make the begin critical call
call api_call
dvbc_x: ret
_dv_begin_critical endp


comment ~
/*@F*************************< dv_end_critical >*****************************
* *
* ends the critical time slice *
* --------------------------------- *
* *
* This function tells Desqview to end the critical time slice. *
* *
* void dv_end_critical(void) *
* Parameters: none *
* *
* Returns: nothing *
* *
*************************************************************************@F*/
~ end_of_comments


if LCODE
_dv_end_critical proc far
else
_dv_end_critical proc near
endif
cmp byte ptr _in_dv,1
jne dvec_x
mov bx,101cH ; make the begin critical call
call api_call
dvec_x: ret
_dv_end_critical endp

if LCODE
CHECKDV_TEXT ends
else
_TEXT ends
endif
end