编写0号中断的处理程序,使得在除法溢出发生时,在屏幕中间显示字符串"divide error!",然后返回到DOS。
程序如下:
assume cs:code
data segment
data ends
code segment
start: mov ax,code
mov ds,ax
mov si,offset do0 ;设置源地址
mov ax,0
mov es,ax
mov di,200h ;设置目标地址
mov cx,offset do0end-offset do0 ;设置长度
cld ;方向为正
rep movsb
mov ax,0
mov ds,ax
mov word ptr ds:[0*4],200h
mov word ptr ds:[0*4+2],0
mov ax,1000h
mov bh,1
div bh ;除法溢出程序
mov ax,4c00h
int 21h
do0: jmp short do0_start
db "divide error!"
do0_start: mov ax,cs
mov ds,ax
mov si,202h
mov ax,0b800h
mov es,ax
mov di,12*160+36*2
mov cx,13
s: mov al,ds:[si]
mov es:[di],al
inc si
add di,2
loop s
mov ax,4c00h
int 21h
do0end: nop
code ends
end start
实验结果: