huibianyili.txt

汇编程序从键盘输入一个字符

从键盘输入一个字符，要求调用bios中断，并用八进制的形式显示其扫描码和ascii码


;*************************☆ Keyboard I/O test ☆********************** 
;                                  -(2003 414 901)
;print out scan code and ASCII of any key
;QUFU Normal university 
;Institute of Computer Science and Technology 
;----------------------------------------------------------------------
data segment
msg1  db 0dh,0ah,'        CHAR      Scancode       ASCII',0dh,0ah,'$'
msg2  db '          $' 
data ends
;----------------------------------------------------------------------
stack segment para stack 'stack'
      db 64 DUP(?)
stack ends
;----------------------------------------------------------------------
pro_nam segment 
;----------------------------------------------------------------------
main proc far
     
       assume cs:pro_nam,ds:data
start:
     
       push ds 
       sub ax,ax
       push ax
 
       mov ax,data
       mov ds,ax 

       mov dx, offset msg1
       mov ah,09h
       int 21h     
again:

       mov ah,0
       int 16h   
       cmp ah, 01h  ;is ESC?
       je exit      ;yes,exit to DOS
       mov bx,ax 
       
       mov dx,offset msg2
       mov ah,9h
       int 21h

       mov dl,bl    ; print character
       mov ah,2h
       int 21h     

       call display ; print scancode
     
       mov bh,bl
       call display ; print ASCII
       
       mov dl,0ah   ; print CR 
       mov ah,2h
       int 21h
    
       mov dl,0dh   ; and LF 
       mov ah,2h
       int 21h

       jmp  again

exit:  ret
main   endp
;----------------------------------------------------------------------
display proc near  

       push bx
       
       mov ch,3
       mov cl,3
       shr bx,1

       mov dx,offset msg2
       mov ah,9h
       int 21h

rotate:

       rol bx,cl
       mov al,bl
       and al,07h
       add al,30h

print:

       mov dl,al
       mov ah,2 
       int 21h
       dec ch
       jnz rotate
       pop bx

ret

display endp
;----------------------------------------------------------------------
pro_nam ends
;**********************************************************************
end start
;--------------------------------------