输入两个16进制数（两位),求和，并在屏幕上显示16进制的结果，汇编程序

DATA SEGMENT
INPUT1 DB 'PLEASE INPUT THE FIRST XX:','$'
INPUT2 DB 'PLEASE INPUT THE SECOND YY:','$'
X DB ?
Y DB ?
S DW ?
DATA ENDS
CODE SEGMENT
ASSUME CS:CODE,DS:DATA
START: MOV AX,DATA
MOV DS,AX

MOV AH,9
LEA DX,INPUT1
INT 21H

MOV AH,1
INT 21H
CMP AL,'9'
JB NEXT1
SUB AL,55
JMP NEXT2

NEXT1: SUB AL,30H
NEXT2: MOV BL,16
MUL BL
MOV BL,AL

MOV AH,1
INT 21H
CMP AL,'9'
JB NEXT3
SUB AL,55
JMP NEXT4

NEXT3: SUB AL,30H
NEXT4: ADD BL,AL

MOV X,BL ;第一个数存在BX中

MOV AH,2
MOV DL,0DH
INT 21H
MOV D