汇编程序45：检测点13.2 (loop指令的中断例程) 

 1 安装程序：
 2 assume cs:code
 3 //loop指令的替代实现
 4 code segment
 5     start:
 6           mov ax,cs
 7           mov ds,ax
 8           mov si,offset sub1
 9           mov ax,0020h
10           mov es,ax
11           mov di,0
12           mov bx,offset sub2 - offset sub1
13           cld
14           rep movsb
15           mov ax,0
16           mov es,ax
17           mov word ptr es:[7ch*4],200h
18           mov word ptr es:[7ch*4+2],0
19           mov ax,4c00h
20           int 21h
21      sub1:
22           push bp
23           mov bp,sp
24           dec cx
25           jcxz s0
26           add [bp+2],bx
27        s0:
28           pop bp
29           iret
30      sub2:
31           nop
32 code ends
33 
34 end start

 

 1 测试程序：
 2 assume cs:code
 3 //将80个!显示在屏幕上
 4 code segment
 5     start:
 6           mov ax,0b800h
 7           mov es,ax
 8           mov di,12*160
 9           mov bx,offset s - offset se
10           mov cx,80
11         s:
12           mov byte ptr es:[di],'!'
13           add di,2
14           int 7ch //安装程序,实现loop s功能
15        se:
16           mov ax,4c00h
17           int 21h
18 code ends
19 
20 end start

 

posted on 2018-02-03 22:07  叶倾仙  阅读(304)  评论(0)    收藏  举报

导航