关于汇编第15.4章的新的int9返回的问题
这是书上的源代码，当运行到新写的int9那里,指令iret运行后ip是不是指向cmp al,1,如过是的话那这段新写的int9 不就一直重复，不好返回了吗？？？assume cs:code
stack segment
db 128 dup (0)
stack ends
data segment
dw 0,0
data ends
code segment
start:
mov ax,stack
mov ss,ax
mov sp,128
mov ax,data
mov ds,ax
mov ax,0
mov es,ax
push es:
pop ds:
push es:
pop ds:
mov word ptr es:,offset int9
mov es:,cs
mov ax,0b800h
mov es,ax
mov ah,'a'
s: mov es:,ah
call delay
inc ah
cmp ah,'z'
jna s
mov ax,0
mov es,ax
push ds:
pop es:
push ds:
pop es:
mov ax,4c00h
int 21h
delay: push ax
push dx
mov dx,1000h
mov ax,0
s1: sub ax,1
sbb dx,0
cmp ax,0
jne s1
cmp dx,0
jne s1
pop dx
pop ax
ret
int9: push ax
push bx
push es
in al,60h
pushf
pushf
pop bx
and bh,11111100b
push bx
popf
call dword ptr ds:
cmp al,1
jne int9ret
mov ax,0b800h
mov es,ax
inc byte ptr es:
int9ret:
pop es
pop bx
pop ax
iret
code ends
end start
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