assume cs:code
code segment
start:
mov ax,cs
mov ds,ax
mov si,offset do7c
mov cx,offset do7cEnd-offset do7c
mov ax,0
mov es,ax
mov di,200h
cld
rep movsb
mov ax,0
mov ds,ax
mov word ptr ds:[7ch*4],200h
mov word ptr ds:[7ch*4+2],0
mov ax,4c00h
int 21h
do7c: push ax
mov al,[si]
cmp al,0
je ok
and al,11011111b
mov [si],al
inc si
jmp short do7c
ok: pop ax
iret
do7cEnd:
nop
code ends
end start
================================
这个中断程序中,为什么
mov word ptr ds:[7ch*4],200h
mov word ptr ds:[7ch*4+2],0
这2句改成: mov word ptr ds:[7ch*4],0
mov word ptr ds:[7ch*4+2],20h
就会出错？
0H:0200H不等于0020H:0H吗？ |
