NAME
    IND_SETMPORT -- Set the current mouse port

FUNCTION
    This command sets the gameport port at which the mouse is
    connected.

IO REQUEST
    io_Message      mn_ReplyPort set if quick I/O is not possible
    io_Device       preset by the call to opendevice
    io_Unit         preset by the call to opendevice
    io_Command      IND_SETMPORT
    io_Flags        IOB_QUICK set if quick I/O is possible
    io_Length       1
    io_Data         a pointer to a byte that is either 0 or 1,
                    indicating that mouse input should be obtained
                    from either the left or right controller port,
                    respectively.