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INT 15h, C2h (194)         Mouse Interface                        PS/2

     Support for the Mouse.

   AL = 0 Enable/disable Mouse

                 On entry:          AH    C2h
                                    AL    00h
                                    BH    00h . Disable mouse
                                          01h . Enable mouse

                 Returns:       For PCjr and PC:
                                    AH = 80h, CF = 1
                                For PC XT, AT, XT 286, Convertible, PS/2 30:
                                    AH = 86h, CF = 1
                                For All Others:
                                    CF = 0 . Operation successful
                                       = 1 . Operation unsuccessful
                                    AH = Status:
                                        00h No error
                                        01h Invalid function call
                                        02h Invalid input
                                        03h Interface error
                                        04h Resend
                                        05h No far call installed

  ---------------------------------------------------------------------------
   AL = 1 Reset Mouse

                 On entry:          AH    C2h
                                    AL    01h

                 Returns:           See AL = 0 for AH setting.
                                    BH = Device ID

  ---------------------------------------------------------------------------
   AL = 2 Set Sample Rate

                 On entry:          AH    C2h
                                    AL    02h
                                    BH    Sample Rate:
                                        00h 10/sec
                                        01h 20/sec
                                        02h 40/sec
                                        03h 60/sec
                                        04h 80/sec
                                        05h 100/sec
                                        06h 200/sec

                 Returns:           See AL = 0 for AH setting.

  ---------------------------------------------------------------------------
   AL = 3 Set Resolution

                 On entry:          AH    C2h
                                    AL    03h
                                    BH    Sample Rate:
                                        00h 1 count/mm
                                        01h 2 counts/mm
                                        02h 4 counts/mm
                                        03h 8 counts/mm

                 Returns:           See AL = 0 for AH setting.

  ---------------------------------------------------------------------------
   AL = 4 Read Device Type

                 On entry:          AH    C2h
                                    AL    4
                                    AL    04h

                 Returns:           See AL = 0 for AH setting.
                                    BH = Device ID

  ---------------------------------------------------------------------------
   AL = 5 Mouse Interface Initialization

                 On entry:          AH    C2h
                                    AL    5
                                    BH    Data package size
                                        00h reserved
                                        01h 1 byte
                                        02h 2 bytes
                                             :
                                        08h 8 bytes

                 Returns:           See AL = 0 for AH setting.

  ---------------------------------------------------------------------------
   AL = 6 Extended Commands

        BH    00h . return status

                 On entry:          AH    C2h
                                    AL    6
                                    BH    00h . return status

                 Returns:           See AL = 0 for AH setting.
                                    BL = Status Byte 1
                                        Bit 7 = 0 Reserved
                                        Bit 6 = 0 . Stream mode
                                                1 . Remote mode
                                        Bit 5 = 0 .Disable
                                                1 . Enable
                                        Bit 4 = 0 . 1:1 scaling
                                                1 . 2:1 scaling
                                        Bit 3 = 0 Reserved
                                        Bit 2 = 1 . Left button pressed
                                        Bit 1 = 0 Reserved
                                        Bit 0 = 1 . Right button pressed

                                    CL = Status Byte 2
                                          0 . 1 count/mm
                                          1 . 2 counts/mm
                                          2 . 4 counts/mm
                                          3 . 8 counts/mm

        BH    01h . Set Scaling 1:1

                 On entry:          AH    C2h
                                    AL    6
                                    BH    01h . Set scaling 1:1

                 Returns:           See AL = 0 for AH setting.


        BH    02h . Set Scaling 2:1

                 On entry:          AH    C2h
                                    AL    6
                                    BH    02h . Set scaling 2:1

                 Returns:           See AL = 0 for AH setting.

  ---------------------------------------------------------------------------
   AL = 7 Device Driver Far Call Initialization

                 On entry:          AH    C2h
                                    AL    7
                                    ES    Segment
                                    BX    Offset

                 Returns:           See AL = 0 for AH setting.

  ---------------------------------------------------------------------------

     This is the support for the mouse. Each time mouse data is
     available, the mouse interrupt handler calls the device driver
     address (which you pass to BIOS in in Subservice 7) with the
     following information on the stack:

                Word 1 Pushed on Stack:
                        Low Byte = Status
                                Bit 7 = 1 . Y data overflow
                                Bit 6 = 1 . X data overflow
                                Bit 5 = 1 . Y data is negative
                                Bit 4 = 1 . X data is negative
                                Bit 3 reserved (must be 1)
                                Bit 2 reserved (must be 0)
                                Bit 1 = 1 . right button pressed
                                Bit 0 = 1 . left button pressed
                        High Byte = 0

                Word 2 Pushed on the Stack
                        Low Byte = X Data
                                Bit 7 = Most significant bit
                                Bit 0 = Least significant bit
                        High byte = 0


                Word 3 Pushed on the Stack
                        Low Byte = Y Data
                                Bit 7 = Most significant bit
                                Bit 0 = Least significant bit
                        High byte = 0


                Word 4 Pushed on the Stack
                        Low Byte = 0
                        High byte = 0

     This information is followed on the stack by the far return address of
     the mouse interrupt routine.

     Every time there is a mouse event (mouse moved, button pushed, etc),
     the address you passed in Subservice 7 is called with the above
     information. You can examine the words on the stack to get mouse
     pointer location and button information.