实验11代码

三田学校

代码如下：

1. 
   
2. assume cs:code,ds:data
   
3. 
   
4. data segment
   
5. db "Beginner's All-purpose Symbolic Instruction Code.",0
   
6. data ends
   
7. 
   
8. code segment
   
9. start:
   
10. mov ax,data
    
11. mov ds,ax
    
12. 
    
13. mov ax,0b878h
    
14. mov es,ax
    
15. 
    
16. mov si,0
    
17. mov di,0
    
18. 
    
19. call letterc
    
20. mov ax,4c00h
    
21. int 21h
    
22. letterc:
    
23. mov al,[si]
    
24. cmp al,0
    
25. je exit
    
26. cmp al,'a'
    
27. jb s0
    
28. cmp al,'z'
    
29. ja s0
    
30. and al,11011111b
    
31. mov byte ptr [si],al
    
32. s0:
    
33. ;显示白底黑字
    
34. mov byte ptr es:[di],al
    
35. mov byte ptr es:1[di],01110000b
    
36. inc si
    
37. add di,2
    
38. jmp short letterc
    
39. exit:
    
40. ret
    
41. code ends
    
42. end start

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