hex_bi.asm

滙編語言的一個應用實例﹐該程序的功能為將十六進制數轉換成二制進數。

; multi-segment executable file template.

data segment
    ; add your data here!
    pkey db "press any key...$"
    
    output db 16 dup(0)
    
    erstatm db 0ah, 0dh, 'WRONG INPUT!!! ', 0ah, 0dh, 'ENTER AGAIN: $'
    
ends

stack segment
    dw   128  dup(0)
ends

code segment
start:
; set segment registers:
    mov ax, data
    mov ds, ax
    mov es, ax

    ; add your code here
    
    input1: mov cx, 4
            mov ah, 01h
            mov di, 15
    
    input: push cx
           mov cx, 4
           int 21h
           cmp al, 30h
           jl error
           cmp al, 39h
           jg test1
           jmp digits
           
    test1: cmp al, 41h
           jl error
           cmp al, 46h
           jg test2
           jmp chars
     
    test2: cmp al, 61h
           jl error
           cmp al, 66h
           jg error
           jmp chars
           
    error: mov dx, offset erstatm
           mov ah, 09h
           int 21h
           pop cx
           mov cx, 16
           mov di, 15
 reassign: mov output[di], 0
           dec di
           loop reassign
           jmp input1
  
   digits: sub al, '0'
   
  digits1: rol al, 3
  
   digit1: rol al, 1
           mov bl, al
           and bl, 80h
           jz add1
           mov output[di], 1
           
     add1: dec di
           loop digit1
           pop cx
           loop input
           jmp print
           
    chars: cmp al, 46h
           jle charsl
           jg charss
           
   charsl: sub al, 37h
           jmp digits1
           
   charss: sub al, 57h
           jmp digits1
           
    print: mov dl, 0ah
           mov ah, 02h
           int 21h
           mov dl, 0dh
           int 21h
           mov di, 16
          
   print1: dec di
           cmp di, 0
           js outos
           test output[di], 1
           jz zero
           mov dl, 31h
           int 21h
           jmp print1
           
     zero: mov dl, 30h
           int 21h
           jmp print1
            
    outos: lea dx, pkey
           mov ah, 9
           int 21h        ; output string at ds:dx
    
    ; wait for any key....    
    mov ah, 1
    int 21h
    
    mov ax, 4c00h ; exit to operating system.
    int 21h    
ends

end start ; set entry point and stop the assembler.