DATAS SEGMENT
    ;此处输入数据段代码  
    x dw 0
    mess1 db 0dh,0ah,'Input DecNumber = $'
    mess2 db 0dh,0ah,'output HexNumber= $'
    hex db '0123456789ABCDEF'
DATAS ENDS

STACKS SEGMENT
    ;此处输入堆栈段代码
STACKS ENDS

CODES SEGMENT
    ASSUME CS:CODES,DS:DATAS,SS:STACKS
START:
    MOV AX,DATAS
    MOV DS,AX
    ;此处输入代码段代码
let0:
    mov x,0
    mov dx,offset mess1;显示输入提示信息
    mov ah,9
    int 21h
    call let1
    call let2
    jmp let0
let1:
    mov ah,1
    int 21h ; 输入->al
    cmp al,27;是ESC？
    jz out1
    sub al,30h
    jl exit;是其它字
    cmp al,9
    jg exit
    mov ah,0
    xchg ax,x;交换x,ax的值，形成十进制数
    mov cx,10
    mul cx
    add x,ax;相加并保存
    jmp let1
exit: 
    ret
let2:
    mov dx,offset mess2;显示输出信息
    mov ah,9
    int 21h
    mov bx,x
    mov ch,4;控制循环次数，显示4位字符
    mov cl,4
rept1:
    rol bx,cl
    mov ax,bx
    and ax,000fh
    mov si,ax
    mov dl,hex[si];查表显示十六进制数字符
    mov ah,2
    int 21h
    dec ch
    jnz rept1
    ret
out1:
    MOV AH,4CH
    INT 21H
CODES ENDS
    END START