.model small
.data
        PA EQU 0E880H
        PB EQU 0E881H
        PC EQU 0E882H
        CWR EQU 0E883H
.code
        MOV AX,@DATA
        MOV DS, AX

        MOV AL, 80H
        mov dx,cwr
        OUT DX, AL

        MOV CX, 99
        MOV AL, 00

        NEXTVAL:
                MOV DX, PA
                OUT DX, AL
                CALL DELAY
                ADD AL, 01
                DAA
                LOOP NEXTVAL

        MOV CX, 99

        NEXTVAL1:
                SUB AL, 01
                DAS
                MOV DX, PA
                OUT DX, AL
                CALL DELAY
                LOOP NEXTVAL1


        DELAY PROC
                PUSH CX
                MOV CX, 0FfFFH
                OUTER:
                        MOV BX, 0FFfH
                        INNER:
                                NOP
                                NOP
                                NOP
                                NOP
                                NOP
                                NOP
                                NOP
                                NOP
                                NOP
                                NOP
                                NOP
                                NOP

                                DEC BX
                                JNZ INNER
                         LOOP OUTER
                POP CX
                RET
        DELAY ENDP
        INT 3
END