附加段ES的作用是什么。。
DATA SEGMENT
MSG1 DB 'Please input the password:$'
MSG2 DB 'Welcome to use$'
MSG3 DB 'Password error!$'
PASSWORD DB '121212'
STR DB 10,?,10 DUP(?)
CRLF DB 13,10,'$'
DATA ENDS
CODE SEGMENT
ASSUME CS:CODE,DS:DATA
START:MOV AX,DATA
MOV DS,AX
MOV ES,AX
XOR BX,BX
L:
MOV DX,OFFSET MSG1
MOV AH,9
INT 21H
LEA DX,STR
MOV AH,10
INT 21H
LEA DX,CRLF
MOV AH,09H
INT 21H
MOV CX,6
MOV SI,OFFSET PASSWORD
MOV DI,OFFSET STR+2
REPZ CMPSB
JZ LAB1
JNZ LAB2
DEC CX
JCXZ EXIT
LAB1:
MOV DX,OFFSET MSG2
MOV AH,09H
INT 21H
MOV AH,4CH
INT 21H
LAB2:
MOV AL,3
INC BL
CMP AL,BL
JNG EXIT
MOV DX,OFFSET MSG3
MOV AH,09H
INT 21H
LEA DX,CRLF
MOV AH,09H
INT 21H
LOOP L
EXIT:
MOV AH,4CH
INT 21H
CODE ENDS
END START
上面的程序我运行过,去掉ASSUE里面ES段和不去掉ES段运行结果没有差别,我想问问这里加上ES有什么作用?