8086-Microprocessor-Basic-Programs/valid_user.asm at main · riman7/8086-Microprocessor-Basic-Programs · GitHub

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;WAP in 8086 which will input the username from the keyboard. If the user is
;"Tribhuvan University" it will display "valid user" else it will display "invalid
;user".

.model small
.stack 64	; Allocates a 64-byte stack for the program.
.data
 	MAXLEN DB 255         ; MAXIMUM BUFFER SIZE (255 CHARACTERS)
	ACTLEN DB ?           ; ACTUAL LENGTH OF INPUT (FILLED AFTER INPUT)
	INPUT DB 255 DUP('$') ; BUFFER TO STORE USER INPUT

	valid_prompt DB "Valid User$"
	invalid_prompt DB "Invalid User$"

	test_string DB "Tribhuvan University$"
	NEW_LINE MACRO
	        mov ah, 02h
	        mov dl, 0ah
	        int 21h

	        mov dl, 0dh
	        int 21h
    	NEW_LINE ENDM

.code
    main proc far

        MOV ax, @data
        MOV ds, ax

        MOV ah, 0ah
        LEA DX, MAXLEN
        INT 21h

        NEW_LINE
        MOV CL, ACTLEN
        CMP CL, 20d
        JZ CONTINUE

        MOV AH, 09h
        LEA DX, invalid_prompt
        int 21h
        ;end program
        mov ax, 4C00h
        int 21h

        CONTINUE:

        MOV CH, 0
        MOV CL, ACTLEN
        LEA DI, test_string
        LEA SI, INPUT ; Skip first two bytes

        L1:
        	MOV Al, [SI]
        	MOV BL, [DI]
        	CMP BL, AL
        	JE CORRECT
        		MOV AH, 09h
        		LEA DX, invalid_prompt
        		int 21h
        		;end program
        		mov ax, 4C00h
        		int 21h
        	CORRECT:
	        	INC SI
	        	INC DI

        LOOP L1

        MOV AH, 09h
        LEA DX, valid_prompt
        int 21h

        mov ax, 4C00h
        int 21h

    main endp

 end