南邮汇编实验二(用户登录)

.486
DATA SEGMENT USE16
MESG1 DB 'INPUT USER:$'
MESG2 DB 'INPUT PWD:$'
USER  DB 20
DB ?
DB 20 DUP(?)
PWD   DB 20 DUP(?)
PWDLENGTH DB 0

U     DB 'B14040411'
ULENGTH EQU $-U

P     DB 'B14040411'
MLENGTH EQU $-P

WELCOME DB 'WELCOME$'
ERROR DB 'USER ERROR$'
ERROR1 DB 'PASSWORD ERROR$'
DATA ENDS
CODE SEGMENT USE16
ASSUME CS:CODE,DS:DATA
BEG:  MOV AX,DATA
MOV DS,AX

NEXT0:
MOV PWDLENGTH,0
MOV AH,9
MOV DX,OFFSET MESG1
INT 21H

MOV AH,0AH
MOV DX,OFFSET USER
INT 21H

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

MOV AH,9
MOV DX,OFFSET MESG2
INT 21H

MOV CX,MLENGTH
MOV SI,OFFSET PWD
NEXT1:MOV AH,07H       ;无回显从键盘读入一个字符
INT 21H
CMP AL,0DH
JE IND
MOV [SI],AL
MOV AH,2
MOV DX,'*'
INT 21H
INC PWDLENGTH
INC SI
;CMP BYTE PTR [SI-1],0DH
;JNZ NEXT1
JMP NEXT1

IND:  MOV AH,2
MOV DL,0AH
INT 21H

;MOV BX,OFFSET U

MOV BX,OFFSET USER+1
MOV AL,[BX]
CMP AL,ULENGTH        ;比较用户名长度
JNZ UERR

MOV BX,OFFSET U
MOV SI,OFFSET USER+2
MOV CX,ULENGTH
NEXT2:
MOV AL,[BX]
CMP [SI],AL
JNZ UERR
INC SI
INC BX
LOOP NEXT2

MOV BX,OFFSET P
MOV SI,OFFSET PWD
MOV CL,PWDLENGTH
MOV CH,0
CMP CX,MLENGTH      ;比较密码长度
JNZ PERR
MOV CX,MLENGTH
NEXT3:
MOV AL,[BX]
CMP [SI],AL
JNZ PERR
INC SI
INC BX
LOOP NEXT3
JMP WEL

UERR: MOV AH,9
MOV DX,OFFSET ERROR
INT 21H
MOV AH,2
MOV DL,0AH
INT 21H
JMP NEXT0

PERR: MOV AH,9
MOV DX,OFFSET ERROR1
INT 21H
MOV AH,2
MOV DL,0AH
INT 21H
JMP NEXT0

WEL:  MOV AH,9
MOV DX,OFFSET WELCOME
INT 21H
JMP EXIT
EXIT: MOV AH,4CH
INT 21H
CODE ENDS
END BEG