2 Mouse Driver

Most GEOS platforms will use some kind of pointing device. On desktop machines, this is most commonly a mouse; in any event, these pointing devices share many similarities with mice. Accordingly, all these devices are driven by drivers known collectively as mouse drivers.

2.1 Mouse Driver Basics

Most mouse drivers behave in very similar ways. For this reason, most GEOS mouse drivers share a lot of code. This code is provided in the SDK in the files \OMNIGO\DRIVER\DDK\MOUSE\MOUSECOM.ASM and …\MOUSE\MOUSESER.ASM . That directory also contains several GEOS mouse drivers; these demonstrate how the drivers actually use the common code to perform such tasks as send mouse movements to the system, handle strategy-routine requests, etc.

2.1.1 Data Structures

All mouse drivers must be extended drivers, even if they support only one kind of mouse. A mouse driver’s dgroup segment must begin with the MouseDriverInfoStruct structure. This structure is based on the DriverExtendedInfoStruct structure, but has some extra fields:

MouseDriverInfoStruct  struct
    MDIS_common        DriverExtendedInfoStruct
        <<0, mask DA_HAS_EXTENDED_INFO,
             DRIVER_TYPE_INPUT>,
        0>
    MDIS_numButtons    word                    ?
    MDIS_xRes          word                    ?
    MDIS_yRes          word                    ?
    MDIS_flags         MouseDriverInfoFlags    0
MouseDriverInfoStruct  ends

MDIS _numButtons
This is the number of buttons the supported mouse has.

MDIS _xRes, MDIS _yRes
This is the number of points per inch, of the points collected by the pointing device. Mouse drivers generally have these set to zero; the fields are used for other input devices that use mouse drivers, such as pen-screens.

MDIS _flags
A record of MouseDriverInfoFlags. These flags store miscellaneous information about the mouse.

Each MouseDriverInfoStruct stores a word of MouseDriverInfoFlags. This record has only a single flag:

MDIF_KEYBOARD_ONLY
This driver is actually a keyboard-driven mouse driver, i.e. the user doesn’t have a real mouse.

Every mouse driver must set up an extended information resource, as described above in “Driver Basics,” Chapter 1. This resource must contain a DriverExtendedInfoTable, which (among other things) contains a pointer to an array of data words, one word for each supported mouse. These data words must contain a MouseExtendedInfo record. This record has the following flags:

MEI_SERIAL
Set if the device is a serial mouse, and needs a COM port to operate.

MEI_GENERIC
Set if this is a generic mouse and needs a DOS -level driver.

MEI_IRQ
This field is four bits wide. If it is set, the mouse needs to be told at what interrupt level it is operating (i.e. it is a “bus” mouse). This field should contain the factory-set default value.

MEI_CALIBRATE
Set if this mouse can be calibrated within GEOS.

2.1.2 Functions

Mouse drivers must be able to handle all four functions defined by DriverFunction, and both functions defined by DriverExtendedFunction. Furthermore, they must be able to handle the functions defined by MouseFunction, a special enumerated type defined in mousedr.def.

As usual, the first of these function names is an enumerated equal to 12 (or two past the last DriverExtendedFunction), and the constants increase by two thereafter. ___

  • DR_MOUSE_SET_RATE
    The mouse should set the number of times it reports per second.

Pass:

  • cx -> The report rate the mouse should be set to, in number of reports per second.

Returns:

  • cx -> The actual new report rate for the mouse, again in number of reports per second.

Destroyed:

  • Allowed to destroy di and ax.

Include:
mousedr.def

  • DR_MOUSE_SET_ACCELERATION
    The mouse should set its acceleration rate.

Pass:

  • Nothing.

Returns:

  • cx -> The threshold for acceleration (i.e. if the mouse moves this many pixels in 1/30 second, acceleration should start).
  • dx -> Acceleration multiplier once threshold is met.

Destroyed:

  • Nothing.

Include:
mousedr.def

  • DR_MOUSE_GET_ACCELERATION
    The mouse should return its current acceleration rate.

Pass:

  • Nothing.

Returns:

  • cx -> The threshold for acceleration (i.e. if the mouse moves this many pixels in 1/30 second, acceleration should start).
  • dx -> Acceleration multiplier once threshold is met.

Destroyed:

  • Nothing.

Include:
mousedr.def

  • DR_MOUSE_COMBINE_MODE
    The mouse should set the mode for combining mouse events. This is a member of the (byte-sized) MouseCombineMode enumerated type:
    MCM_ COMBINE
    MCM_NO_COMBINE
    MCM_COMBINE_COLINEAR_ONLY

Pass:

  • cl –> MouseCombineMode to use.

Returns:

  • Nothing.

Destroyed:

  • Nothing.

Include:
mousedr.def

  • DR_MOUSE_GET_COMBINE_MODE
    The mouse should return the mode it uses for combining mouse events. This is a member of the (byte-sized) MouseCombineMode enumerated type, described above in DR_MOUSE_COMBINE_MODE.

Pass:
Nothing.

Returns:

  • cl -> Current MouseCombineMode.

Destroyed: Nothing.

  • DR_MOUSE_GET_CALIBRATION_POINTS
    This instructs the mouse driver to return its current set of calibration points.

Pass:

  • dx:si -> Buffer to which to write calibration points. This buffer will be long enough to hold nine i.e. MAX_NUM_CALIBRATION_POINTS) calibration points.

Returns:

  • dx:si -> Pointer to same buffer, filled with calibration points
  • cx -> Number of calibration points

Destroyed:

  • Nothing
  • DR_MOUSE_SET_CALIBRATION_POINTS
    This instructs the mouse driver to set its calibration points.

Pass:

  • dx:si -> Buffer filled with adjusted calibration points.
  • cx -> Number of calibration points.

Returns:

  • Nothing.

Destroyed:

  • Nothing.
  • DR_MOUSE_GET_RAW_COORDINATE
    This instructs the mouse driver to return the current calibrated and non-calibrated mouse positions.

Pass:

  • Nothing.

Returns:

  • CF -> Clear if point returned, set otherwise.
  • (ax,bx) -> Current raw (uncalibrated) mouse position, if CF = 0.
  • (cx,dx) -> Current adjusted (calibrated) mouse position, if CF = 0.

Destroyed:

  • Nothing.