subsystems/ntvdm/timer.h

   1 /*
   2  * COPYRIGHT:       GPL - See COPYING in the top level directory
   3  * PROJECT:         ReactOS Virtual DOS Machine
   4  * FILE:            timer.h
   5  * PURPOSE:         Programmable Interval Timer emulation (header file)
   6  * PROGRAMMERS:     Aleksandar Andrejevic <theflash AT sdf DOT lonestar DOT org>
   7  */
   8
   9 #ifndef _TIMER_H_
  10 #define _TIMER_H_
  11
  12 /* INCLUDES *******************************************************************/
  13
  14 #include "ntvdm.h"
  15
  16 /* DEFINES ********************************************************************/
  17
  18 #define PIT_CHANNELS 3
  19 #define PIT_BASE_FREQUENCY 1193182LL
  20 #define PIT_DATA_PORT(x) (0x40 + (x))
  21 #define PIT_COMMAND_PORT 0x43
  22
  23 enum
  24 {
  25     PIT_MODE_INT_ON_TERMINAL_COUNT,
  26     PIT_MODE_HARDWARE_ONE_SHOT,
  27     PIT_MODE_RATE_GENERATOR,
  28     PIT_MODE_SQUARE_WAVE,
  29     PIT_MODE_SOFTWARE_STROBE,
  30     PIT_MODE_HARDWARE_STROBE
  31 };
  32
  33 typedef struct _PIT_CHANNEL
  34 {
  35     WORD ReloadValue;
  36     WORD CurrentValue;
  37     WORD LatchedValue;
  38     INT Mode;
  39     BOOLEAN Pulsed;
  40     BOOLEAN LatchSet;
  41     BOOLEAN InputFlipFlop;
  42     BOOLEAN OutputFlipFlop;
  43     BYTE AccessMode;
  44 } PIT_CHANNEL, *PPIT_CHANNEL;
  45
  46 /* FUNCTIONS ******************************************************************/
  47
  48 VOID PitWriteCommand(BYTE Value);
  49 BYTE PitReadData(BYTE Channel);
  50 VOID PitWriteData(BYTE Channel, BYTE Value);
  51 VOID PitDecrementCount();
  52
  53 #endif // _TIMER_H_
  54
  55 /* EOF */