关于中断的深入学习

assume cs:code,ss:stack

stack segment

dw 8 dup(0)

stack ends

code segment 

start:

mov ax,stack

mov ss,ax

mov sp,10h

;----把存放47号中断的地址指向0:200h处----

mov ax,47h*4

mov di,ax

mov ax,0

mov es,ax

mov es:2[di],ax

;mov ax,200h

mov es:[di],word ptr 200h

;----把47号中断程序存入0:200h处----

mov cx,offset int47end - offset int47

mov ax,cs

mov ds,ax

mov si,offset word ptr int47

mov ax,0

mov es,ax

mov di,word ptr 200h

rep movsb

;----显示位置----

mov ax,0b800h

mov es,ax

mov ax,160*11+80

mov di,ax

;----显示80个!----

mov bx,offset prn - offset lprn ;跳转位置，跟add[bp+2],bx配合--bp+2存放的

mov cx,50h ;是ip,当iret时，回跳的距离

prn:

mov es:[di],byte ptr '!'

add di,2

int 47h

lprn:

nop

mov ax,4c00h

int 21h

;----中断实现程序----

int47:

push bp

mov bp,sp

dec cx

jcxz int47i

add [bp+2],bx

int47i:

pop bp

iret

int47end:nop

code ends

end start