汇编高手 看看啊

assume    cs:code
code    segment
start:
    mov ah,1
    int 21h
    cmp al,'0'
    jb exit
    cmp al,'9'
    ja exit
    and al,0fh
    mov bl,3
    mul bl
    add al,5    
    mov dx,ax
    push dx
    mov ah,2
    mov dl,0dh
    int 21h
    mov dl,0ah
    int 21h
    pop dx
    call show
exit:
    mov ah,4ch
    int 21h
;input:dx
show    proc uses ax bx cx dx
    mov ax,dx
    xor dx,dx
    mov bx,10
    mov cx,0
d:    cmp ax,10
    jb ok
    div bx
    add dl,30h
    push dx
    xor dx,dx
    inc cx
    jmp d
ok:    add al,30h
    push ax
    inc cx
d1:    pop dx
    mov ah,2
    int 21h
    loop d1
    ret
show    endp
;
code    ends
end    start