[求助]用串操作指令编程

;输入一字符串(20个字节),输出时反向输出
.MODEL Small
.DATA
TABLE1 DB 20
DB ?
DB 20 DUP(?)
TABLE2 DB 21 DUP(?)
.STACK 200H
.CODE
MOV AX,@DATA
MOV DS,AX
MOV ES,AX
;输入字符串
LEA DX,TABLE1
MOV AH,0AH
INT 21H

MOV CX,OFFSET TABLE1+1
MOV SI,OFFSET TABLE1+2
ADD SI,CX
DEC SI
LEA DI,TABLE2
;逆向存入字符串TABLE2
CLD
L: MOVSB
SUB SI,2
LOOP L
MOV AX,'$'
MOV [DI],AL

MOV DL,0DH
MOV AH,02H
INT 21H
MOV DL,0AH
INT 21H
;输出
LEA DX,TABLE2
MOV AH,09H
INT 21H

MOV AH,4CH
INT 21H
END