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Simtel MSDOS 1996 September
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Simtel-MSDOS-Sep1996-CD1.iso
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swap.a86
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1982-08-13
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737b
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33 lines
.text
.=0x100
| this routine swaps between the b&w display and the color display
| on the IBM personal computer. 80 character width is always selected
start: push ax
push ds
xor ax,ax |zero AX
mov ds,ax |use data at very beginning of memory
xorb 0x410,#0x20 | ?
movb al,0x449 | this is the "current video mode"
cmpb al,#7 | if it is 7, the monochrome display
jz color | is in use, and we swith to color.
mono: mov ax,#3 | AH=0 -> set mode, AL=3 -> 80 column color
int 0x10
j exit
color: mov ax,#7
int 0x10
mov ax,#0x0501
int 0x10
wait: inc ax
jnz wait
mov ax,#0x0500
int 0x10
mov ax,#3 |dont ask me why I have to do it twice...
int 0x10
exit: pop ds
pop ax
int 0x20
ret