IDEAL
MODEL small
STACK 100h
DATASEG
passnum equ 2
password db 16 dup (?)
actualpassword db '123abc'
enterpassword db 'Enter the password and press ENTER to finish.',13,10,'$'
wrongpassword db 13,10,'You have inserted an incorrect password.',13,10,'$'
rightpassword db 13,10,'You have inserted the right password.',13,10,'$'
CODESEG
start:
mov ax, @data
mov ds, ax

;Ask for password
lea dx, [enterpassword]
mov ah, 9h
int 21h

Getchar:
xor cx, cx

GetcharLoop:

;If user has inserted 16 bytes or more ( 16 characters or more )restart password checking
cmp cx, passnum
jae Getchar

mov ah, 1
int 21h
cmp al, 13
je Checkpass
;If didn't press enter
lea bx, [password]
add bx, cx
mov [bx], al
inc cx
jmp GetcharLoop

;Checking if [password] contains the right password
;Password will be 123abc
Checkpass:
cmp cx, passnum
jne Fail

mov ax, cx; ax = number of times user has inserted a char
xor cx, cx

CheckCharLoop:
lea bx, [password]
add bx, cx
mov bl, [bx]

lea di, [actualpassword]
add di, cx
mov bh, [di]

cmp bl, bh
jne Fail
inc cx
cmp cx, ax
je Success
jmp CheckCharLoop

Fail:
lea dx, [wrongpassword]
mov ah, 9h
int 21h
jmp EndPassCheck
Success:
lea dx, [rightpassword]
mov ah, 9h
int 21h
jmp EndPassCheck

EndPassCheck:
;For nothing
mov ah, 1
int 21h
exit:
	mov ax, 4c00h
	int 21h
END start