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:[9*4]
pop ds:[0]
push es:[9*4+2]
pop ds:[2]
;在中断向量表中设置新的int 9中断例程的入口地址
cli ;设置IF=0屏蔽中断
mov word ptr es:[9*4],offset int9
mov word ptr es:[9*4+2],cs
sti ;设置IF=1不屏蔽中断
mov ax,0b800h
mov es,ax
mov ah,'a'
s: mov es:[160*12+40*2],ah ;第12行第40列
inc ah
cmp ah,'z'
jnb s
mov ax,0
mov es,ax
push ds:[0]
pop ss:[9*4]
push ds:[2]
pop es:[9*4+2]
mov ax,4c00h
int 21h
delay: push ax
push dx
mov dx,1000h
mov ax,0
delay1: sub ax,1
sbb dx,0 ;(dx)=(dx)-0-CF
cmp ax,0
jne delay1
cmp dx,0
jne delay1
pop dx
pop ax
ret
int9:push ax
push bx
push es
in al,60h
pushf
call dword ptr ds:[0]
cmp al,1
jne int9ret
mov ax,0b800h
mov es,ax
inc byte ptr es:[160*12+40*2+1]
int9ret:pop es
pop bx
pop ax
iret
code ends
end start
[ 游客 发表于 2012-03-04 09:37 ]
应该有两个地方,一个是设置,另一个是还原。