44 lines
890 B
NASM
44 lines
890 B
NASM
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;
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progseg segment para public 'CODE'
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public setcom
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assume cs:progseg, ds:progseg, es:progseg
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org 100h
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doscall equ 21h
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oldint equ 16h
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;
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startup proc far
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jmp setup
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;
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setcom proc far
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; jmp cs:[interupt]
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pushf
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call cs:[interupt]
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RET 2
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setcom endp
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;
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save db 0
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interupt label dword
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vector db 8 dup(0) ;only 4 needed 4 more for safety
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;
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setup:
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mov ah,35h ;get interupt vector address function
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mov al,oldint ;keyboard interupt vector
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int doscall ;go get it
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;
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mov word ptr vector,bx ;save offset
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mov bx,es ;get segment address
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mov word ptr vector+2,bx ;save segment
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;
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mov dx,offset setcom ;get new vector address
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mov ax,cs
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mov ds,ax ;set segment
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mov ah,25h ;set interupt vector address function
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mov al,oldint ;set to our new interupt vector
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int doscall ;set the interupt
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;
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mov dx,offset setup ;terminate and stay resident
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int 27h
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startup endp
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progseg ends
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;
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end startup
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