;把AX中的16进制数转换为ASCII码，放入MEM数组中的四个字节中。
;当(AX)＝2A49H时，程序执行完后，MEM中的4个字节内容为39H,
;34H,41H,32H。
data segment
org 1000h
buf dw 2A49H
mem db 4 dup(?)
data ends
stack segment stack
db 100 dup(?)
stack ends
code segment
assume cs:code,ds:data
start: mov ax,data
       mov ds,ax
       mov ax,buf  
       lea si,mem
       mov bl,al
       and al,0fh
       call z1
       mov al,bl
       mov cl,4
       shr al,cl
       inc si
       call z1
       mov bh,ah
       and ah,0fh
       mov al,ah
       inc si
       call z1    
       mov ah,bh
       shr ah,cl
       mov al,ah
       inc si
       call z1
       mov ah,4ch
       int 21h
z1     proc
       push ax
       push bx
       push cx
       push dx
       cmp al,9
       jbe j1
       add al,7
j1:    add al,30h
       mov [si],al
       pop dx
       pop cx
       pop bx
       pop ax
       ret
z1     endp
code   ends
       end start