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55 lines
1.4 KiB
NASM
55 lines
1.4 KiB
NASM
TITLE scrn4.asm
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; AUTHOR Tim Spencer - Compuserve [73657,1400]
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; DATE March 19, 1987
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_TEXT SEGMENT BYTE PUBLIC 'CODE'
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_TEXT ENDS
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_DATA SEGMENT WORD PUBLIC 'DATA'
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_DATA ENDS
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DGROUP GROUP _DATA
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ASSUME CS:_TEXT, DS:DGROUP, SS:DGROUP, ES:NOTHING
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_TEXT SEGMENT BYTE PUBLIC 'CODE'
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;-----------------------------------------------------------------------;
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; vcard_type - Tests for type of video card in use ;
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; ;
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; Returns: 0 = MONOCHROME ADAPTER ;
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; 1 = COLOR GRAPHICS ADAPTER ;
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; 2 = ENHANCED GRAPHICS ADAPTER ;
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;-----------------------------------------------------------------------;
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PUBLIC _vcard_type
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_vcard_type PROC NEAR
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push es
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mov ax,40h ; point es to BIOS area
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mov es,ax
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mov al,es:[87h] ; is there an EGA card?
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cmp al,0
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je mono_test ; no ega, check for mono
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test al,00001000b ; test bit 3
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jnz mono_test ; bit 3 was set - ega not active card
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mov ax,2 ; ega is in use...return a 2
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jmp short exit
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mono_test:
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mov al,es:[10h] ; get video status byte
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and al,00110000b ; isolate bits 4 and 5
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cmp al,48 ; is it a mono card?
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jne assume_cga ; no, assume it's a cga
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mov ax,0 ; return 0 for mono card
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jmp short exit
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assume_cga:
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mov ax,1 ; return a 1 for cga card
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exit: pop es
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ret
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_vcard_type ENDP
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_TEXT ENDS
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END
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