这个都是过去DOS时代的汇编源码，虽然已经过去了，但是对于学习汇编还是有帮助的，汇编语言只是程序员一门基础语言，大多人掌握即可，不一定要深入研究.......
;
progseg segment para public 'CODE'
public setcom
assume cs:progseg, ds:progseg, es:progseg
org 100h
doscall equ 21h
oldint equ 16h
;
startup proc far
jmp setup
;
setcom proc far
; jmp cs:[interupt]
pushf
call cs:[interupt]
RET 2
setcom endp
;
save db 0
interupt label dword
vector db 8 dup(0) ;only 4 needed 4 more for safety
;
setup:
mov ah,35h ;get interupt vector address function
mov al,oldint ;keyboard interupt vector
int doscall ;go get it
;
mov word ptr vector,bx ;save offset
mov bx,es ;get segment address
mov word ptr vector+2,bx ;save segment
;
mov dx,offset setcom ;get new vector address
mov ax,cs
mov ds,ax ;set segment
mov ah,25h ;set interupt vector address function
mov al,oldint ;set to our new interupt vector
int doscall ;set the interupt
;
mov dx,offset setup ;terminate and stay resident
int 27h
startup endp
progseg ends
;
end startup