Re: Mouse driver for Ada... how?

["J. Marshall" <a_revelation@hotmail.com>]

Thank you very much for the information.  I appreciate your time and input.
Jim Marshall


tmoran@bix.com wrote in message
<8bg53.656$HD.140382@typhoon-sf.snfc21.pbi.net>...
>> So I had hoped to find some existing code examples.
>Here's the spec of a (very old) mouse driver for DOS.  It uses the
>INT 33 services.  In Windows you'd use the WM_MOUSEMOVE,
>WM_LBUTTONDOWN, etc.  events.  If you don't have an OS service
>available, don't have a vendor supplied driver, and are reduced to
>handling a serial byte stream yourself, your first need is to find
>what bytes your mouse (trackball) sends.  It's probably not too
>complex, and thus not too hard to write code to process it.
>
>with system;
>
>package mouse is    -- low level mouse driver interface
>                    -- uses int33 functions
>                    --   16#00#: reset
>                    --   16#0B#: read motion counters
>                    --   16#03#: get mouse position and button status
>                    --               (ignore logical position from this)
>                    -- In 1987 this interface was standard and supported
>                    -- by all PC mice.
>  type state is
>       record
>         x,y:integer;
>         left_button,middle_button,right_button:boolean;
>       end record;
>  -- x,y measured in mickeys
>  -- button flags are true iff button is currently depressed
>
>  current:state :=
>     (x | y => 0,left_button | middle_button | right_button => FALSE);
>
>  driver_missing:exception; -- will be raised at initialization
>                            -- iff mouse driver is detected not present
>                            -- ie if int33=0 or int33 points to an IRET
>
>  procedure check;  -- updates current (nop if mouse driver is missing)
>
>  -- The public record 'current' is used, rather than having 'out'
>  -- parameters to the 'check' routine, for simplicity and efficiency.
>  -- There is no way with this interface to have more than one mouse
>  -- per OS task, so the generality of out parameters, or a generic
>  -- mouse package, would be spurious.
>
>  procedure reset;
>
>  procedure hide_cursor;
>
>  procedure show_cursor;
>
>  procedure horizontal_range(min,max:in natural);
>
>  procedure vertical_range(min,max:in natural);
>
>  type graphic_cursor_bits is array(integer range <>) of system.word;
>  subtype normal_graphic_cursor_bits is graphic_cursor_bits(0 .. 15);
>  subtype hot_spot_offsets is integer range -16 .. 16;
>
>  procedure set_graphic_cursor_words(screen_mask:in graphic_cursor_bits;
>                                     cursor_mask:in graphic_cursor_bits;
>                                     x_hot_spot :in hot_spot_offsets;
>                                     y_hot_spot :in hot_spot_offsets);
>
>  procedure Set_Cursor_Position(X,Y:in Integer);
>
>end mouse;