davidsen@steinmetz.UUCP (Davidsen) (08/11/86)
Following is the shar file for switching an EGA board in EGA mode to CGA
mode (and back). It has been tried on IBM and QUAD EGA boards, and seems to
work correctly. It will allow running of programs which will not run when
the CGA mode is selected from switches (S1?).
Included is code to switch into 43 line mode. Now if someone finds this
useful and got all the parts of the 43 line version of emacs, they could
mail it to me as a thank you.
The first file is the (ha) documentation I got with these files.
-bill davidsen
ihnp4!seismo!rochester!steinmetz!--\
\
unirot ------------->---> crdos1!davidsen
chinet ------/
sixhub ---------------------/ (davidsen@ge-crd.ARPA)
"Stupidity, like virtue, is its own reward"
#!/bin/sh
# created from directory /usr2/public/PCsoftware
echo shar created 13:15 on Mon Aug 11, 1986 by davidsen
echo 'x - Xga.doc (text)'
sed << 'E!O!F' 's/^X//' > Xga.doc
XFrom del Fri Mar 28 18:14:26 1986
XTo: davidsen
XSubject: cga.exe and ega.exe
XDate: Fri Mar 28 18:14:25 1986
X
X
XI'd be curious to hear your report on how well (or not well) these two
Xprograms run on some boards other than the "real" EGA. They seem to run
Xflawlessly on it; as a matter of fact, some software which will NOT run
Xon the EGA with Switch 1 set to CGA, WILL run if you set the switch to EGA
Xmode and then reset the mode with this software. I'm interested in
Xknowing if it works that well on other EGA-type boards. Note that I
Xhave also provided source code for both EGA.ASM and CGA.ASM.
X
E!O!F
echo 'x - ega.asm (text)'
sed << 'E!O!F' 's/^X//' > ega.asm
X; (CTRL-OH) IBM PC PRINTER CONDENSED MODE
X page ,132
X title colboot.asm
XRET_FN equ 4CH ;"return to dos" function call
X
X;*********************************************************************
X;
X; LOW MEMORY SEGMENT
X;
X;*********************************************************************
X
X
XLowSeg segment at 00h ;BIOS vectors & DOS variables
X org 487h
XINFO db ?
X org 488h
XINFO3 db ? ;Feature bits, EGA DIP switches
XLowSeg Ends
X
X
X;******************************************************************************
X;
X; DATA SEGMENT
X;
X;******************************************************************************
X
X
XDseg segment para public 'data'
XMSG1 db 'EGA -> EGA mode',10,13,10,13,'$' ;startup message
XDONEMSG db ' *** EGA MODE NOW IN EFFECT ***',10,13,'$' ;ending message
XRET_CD db 0 ;errorlevel return code value
X
XDseg Ends
X
X
X;******************************************************************************
X;
X; CODE SEGMENT
X;
X;******************************************************************************
X
X
XCseg segment para public 'code'
X assume cs:cseg,ss:stack ;already set by dos loader
X
XEntpt proc far ;entry point from dos
X Mov ax,Dseg ;set up addressability to
X Mov ds,ax ; the data segment
X assume ds:Dseg
X Mov ax,LowSeg ;set up addressability to
X Mov es,ax ; the low segment
X assume es:LowSeg
X
X;******************************************************************************
X; set up for EGA mode
X;******************************************************************************
X
X Mov dx,offset MSG1 ;program startup message
X Mov ah,09h ;print string
X Int 21h
X
X mov ah,03h ;read cursor position
X int 10h
X push bx ;save page number
X push dx ;save row,column
X
X mov al,INFO3
X and al,0f0h ;set low nybble to 9
X or al,09h
X mov INFO3,al ;set up for enhanced color display
X mov ax,0082h ;set normal text mode (performs the
X int 10h ; actual mode switch - no cls.)
X
X mov ah,02h ;set cursor position
X pop dx ;restore row,column
X pop bx ;restore page number
X int 10h
X and INFO,07fh ;reset no clear screen bit (fix bug?)
X
X Mov dx,offset DONEMSG ;tell about EGA mode now
X Mov ah,09h ;print string
X Int 21h
X jmp Exit
X
X
X;******************************************************************************
X; RETURN TO DOS
X;******************************************************************************
X
X
XExit: Mov ah,RET_FN ;return to dos function call, and
X Mov al,RET_CD ;value to be passed to errorlevel
X Int 21H ;return to dos
XEntpt Endp ; (version 2.00 or later)
XCseg ENDS
X
XSTACK SEGMENT PARA STACK 'STACK'
XDB 64 DUP("STACK ") ;256 WORD STACK AREA
XSTACK ENDS
XEND ENTPT
E!O!F
echo 'x - cga.asm (text)'
sed << 'E!O!F' 's/^X//' > cga.asm
X; (CTRL-OH) IBM PC PRINTER CONDENSED MODE
X page ,132
X title colboot.asm
XRET_FN equ 4CH ;"return to dos" function call
X
X;*********************************************************************
X;
X; LOW MEMORY SEGMENT
X;
X;*********************************************************************
X
X
XLowSeg segment at 00h ;BIOS vectors & DOS variables
X org 487h
XINFO db ?
X org 488h
XINFO3 db ? ;Feature bits, EGA DIP switches
XLowSeg Ends
X
X
X;******************************************************************************
X;
X; DATA SEGMENT
X;
X;******************************************************************************
X
X
XDseg segment para public 'data'
XMSG1 db 'EGA -> Color Emulator & Reboot',10,13,10,13,'$' ;startup msg
XWAITMSG db 'Press any key to set CGA mode: $' ;wait message
XCGAMSG db ' *** CGA MODE NOW IN EFFECT ***',10,13,10,13,'$'
XBOOTMSG db 'Press ENTER if you wish to boot a floppy now: $'
XCRLF2 db 10,13,10,13,'$'
XRET_CD db 0 ;errorlevel return code value
X
XDseg Ends
X
X
X;******************************************************************************
X;
X; CODE SEGMENT
X;
X;******************************************************************************
X
X
XCseg segment para public 'code'
X assume cs:cseg,ss:stack ;already set by dos loader
X
XEntpt proc far ;entry point from dos
X Mov ax,Dseg ;set up addressability to
X Mov ds,ax ; the data segment
X assume ds:Dseg
X Mov ax,LowSeg ;set up addressability to
X Mov es,ax ; the low segment
X assume es:LowSeg
X
X;******************************************************************************
X; set up for CGA emulation
X;******************************************************************************
X
X Mov dx,offset MSG1 ;program startup message
X Mov ah,09h ;print string
X Int 21h
X
X mov ah,03h ;read cursor position
X int 10h
X push bx ;save page number
X push dx ;save row,column
X
X mov al,INFO3
X and al,0f0h ;set low nybble to 8
X or al,08h
X mov INFO3,al ;set up for color emulation
X mov ax,0082h ;set normal text mode (performs the
X int 10h ; actual mode switch)
X
X mov ah,02h ;set cursor position
X pop dx ;restore row,column
X pop bx ;restore page number
X int 10h
X and INFO,07fh ;reset no clear screen bit (fix bug?)
X
X;******************************************************************************
X; ask for and perform BOOT
X;******************************************************************************
X
X Mov dx,offset CGAMSG ;tell about CGA mode
X Mov ah,09h ;print string
X Int 21h
X
X Mov dx,offset BOOTMSG ;tell to press enter if desire boot
X Mov ah,09h ;print string
X Int 21h
X Mov ax,0C07h ;flush buffer, console input w/o echo
X Int 21h
X push ax
X Mov dx,offset CRLF2 ;print 2 cariage returns
X Mov ah,09h
X Int 21h
X pop ax
X cmp al,0dh ;compare to ENTER
X jnz Exit
X Int 19h ;Dos boot interupt
X jmp Exit
X
X;******************************************************************************
X; RETURN TO DOS
X;******************************************************************************
X
X
XExit: Mov ah,RET_FN ;return to dos function call, and
X Mov al,RET_CD ;value to be passed to errorlevel
X Int 21H ;return to dos
XEntpt Endp ; (version 2.00 or later)
XCseg ENDS
X
XSTACK SEGMENT PARA STACK 'STACK'
XDB 64 DUP("STACK ") ;256 WORD STACK AREA
XSTACK ENDS
XEND ENTPT
E!O!F
echo 'x - EGA43.asm (text)'
sed << 'E!O!F' 's/^X//' > EGA43.asm
XHere is a sample program to put the EGA in 43 line mode. It is also on
XIX/370 under /u1/wheeler.
X
XPAGE 60,132
XTITLE MODE43 - Put EGA with ECD into 43 line mode
X;
XDATA SEGMENT AT 40H
X ORG 88H
XEGAMODE DB ?
XDATA ENDS
X;
XCODE SEGMENT PARA PUBLIC 'CODE'
X ASSUME CS:CODE,DS:CODE
X;
XMODE43 PROC NEAR
X;
X MOV AX,0F00H ; Get current video mode
X INT 10H
X XOR AH,AH ; Now do mode set
X INT 10H
X MOV AX,1112H ; Select 8x8 double dot font
X MOV BL,0
X INT 10H
X MOV AX,DATA ; Change special EGA byte to get cursor
X MOV DS,AX
X ASSUME DS:DATA
X MOV EGAMODE,0F8H ; Set to allow 8x8 cursor
X MOV AX,0100H ; Set cursor type
X MOV CX,0607H ; Select appropriate cursor
X INT 10H
X MOV EGAMODE,0F9H ; Set back
X PUSH CS ; Set DS back to CS
X POP DS
X ASSUME DS:CODE
X MOV AX,1200H ; Select alternate print screen routine
X MOV BL,20H
X INT 10H
X INT 20H ; Return to DOS
XMODE43 ENDP
X;
XCODE ENDS
X;
X END MODE43
E!O!F
--
-bill davidsen
ihnp4!seismo!rochester!steinmetz!--\
\
unirot ------------->---> crdos1!davidsen
chinet ------/
sixhub ---------------------/ (davidsen@ge-crd.ARPA)
"Stupidity, like virtue, is its own reward"