实训汇编语言设计——将bcd码转化为二进制数

将bcd码转化为二进制数

data segment
bcd db 1,2,3,4,5    ;bcd码
a   dw ?              ; 用于存放bcd码转化后的十六进制数
data ends
stack segment para stack'stack'
 stapn dw 50 dup(?)
stack ends
 
code segment
 main proc far
 assume ds:data,cs:code,ss:stack
start: 
 ;set up stack to retuan
    
    
    ;set DS register to current segment
    mov ax,data
    mov ds,ax
    mov ax,stack
    mov ss,ax
    
    ;maim part of the code goes here
   call convert            ;调用子程序
   mov a,bx
   ret
   main endp
   
   
   convert proc near
    push si
    push cx
    push ax
    mov si,4
  l1:mov al,bcd[si]
    cbw 
    ;digit is now in ax
    ;multiply number in bx by 10 decimal 
    xchg ax, bx
    mov cx,10d
    mul cx
    xchg ax,bx
    ;Add digit in ax to number in bx
    add bx,ax
    dec si
    jnz l1
    pop ax
    pop cx
    pop si
exit:mov ah,4ch
     int 21h
convert endp
  
   
 code ends
  
    end start