.STACK 100H

.DATA
    SPACE DB ' $'
    NLINE DB 0DH, 0AH, '$'
    MSG_INPUT DB 'INPUT A NUMBER: $'
    MSG_OUTPUT DB 'YOUR INPUT IS: $'
    RES DB ?
.CODE

INPUT PROC
    PUSH AX
    PUSH BX
    PUSH CX
    MOV BL, 0
    Loop:
        MOV AH, 1
        INT 21H
        CMP AL, 13
        JZ in

        MOV CL, AL
        SUB CL, '0'
        MOV AL, BL
        MOV BL, 10
        MUL BL
        MOV BL, AL
        ADD BL, CL
        JMP Loop

    in:
        MOV RES, BL
        POP CX
        POP BX
        POP AX
        RET
INPUT ENDP

OUTPUT PROC
    PUSH AX
    PUSH BX
    PUSH CX
    PUSH DX

    MOV BL, RES

    Print:
        MOV AL, BL
        MOV AH, 0
        MOV CL, 10
        DIV CL
        MOV DL, AH
        ADD DL, '0'
        MOV BL, AL

        MOV AH, 2
        INT 21H

        CMP BL, 0
        JZ Exit
        JMP Print
    Exit:
        POP DX
        POP CX
        POP BX
        POP AX
        RET

OUTPUT ENDP

MAIN PROC
    MOV AX, @DATA
    MOV DS, AX

    CALL INPUT

    LEA DX, NLINE
    MOV AH, 9
    INT 21H

    CALL OUTPUT

    MOV AH, 4CH
    INT 21H
MAIN ENDP
END MAIN