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
