0040h:003Fh           Diskette Drive Motor Status

    Length: 1 byte

    This byte indicates which diskette drive is currently selected and
    which diskette drive motors are on.


        Diskette Drive Motor Status

        7 6 5 4 3 2 1 0
        x . . . . . . .      Read/Write Operation
        . x . . . . . .      Reserved
        . . x x . . . .      Diskette Drive Select Status (see below)
        . . . . x . . .      Diskette Drive 3 Motor On Status
        . . . . . x . .      Diskette Drive 2 Motor On Status
        . . . . . . x .      Diskette Drive 1 Motor On Status
        . . . . . . . x      Diskette Drive 0 Motor On Status


    Bits 3 through 0 control the motor status of the different
    diskette drives. If set, then the specified drive motor is on.

                Diskette Drive Select Status (bits 5 and 4)

                00 --  Diskette Drive 0 Selected
                01 --  Diskette Drive 1 Selected
                10 --  Diskette Drive 2 Selected
                11 --  Diskette Drive 3 Selected

    Int 08h will turn the Motor On bits off (bits 3 - 0) when the
    motor counter (0040h:0040h) reaches 0.