timer.hpp

一个嵌入式系统的C代码

//*************************************************************************
//  MODULE : Timer - Module contains high level Timer class definition.   *
//  AUTHOR : Ron Chernich                                                 *
//  PURPOSE: Definition of classes to provide interrupt service for timer *
//	     events, delays, counts.                                      *
//	     CAUTION: User defined Interrupt service routines require the *
//	     C/C++ stack probes be disabled on all routines which are or  *
//	     may be used during service.  Ensure the appropriate option   *
//	     switch is set (or use MSC #pragma stack_check (off)).	  *
//  HISTORY:                                                              *
//   21-JAN-93	First (MSC/C++ 7.00) version				  *
//   08-APR-93	Start/Stop added and GetTicks adjusted for 1mS (hah!)	  *
//   27-OCT-93  Smart pointer hiding added (mouse int, fn 16)             *
//   30-OCT-93  Massive simplification through the PAL abstraction module * 
//   04-FEB-94  "Tock" size changed to 32 bits                            *
//*************************************************************************

#ifndef _RCOS_TIMER_

  #include "rcos.hpp"
  #include "pal.hpp"
  #include "userip.hpp"


  //////////////////////
  // This module contains a platform dependant routine that must be
  // regularely called.  Under DOS, we can use the "user clock" interrupt..
  //
  // I would dearly love to remove the need for these, but it would
  // require a PAL function that takes a variable number of function
  // pointers as formal params..
  //
  #ifdef MSC700
    #define __CPPARGS	void
    #define INTERRUPT	__cdecl __interrupt __far __loadds
  #endif

  #ifdef BC31
    #define __CPPARGS 	...
    #define INTERRUPT	interrupt
  #endif

  #ifdef SYM60
    extern  "C"
    #define __CPPARGS	void
    #define INTERRUPT
  #endif
  
  #ifdef _DOS_ENV
    #define _DOS_RTC	0x1c
  #endif

  #ifdef UNIX
	#define __CPPARGS void
	#define INTERRUPT
	#define _DOS_RTC 1
  #endif

  ///////////////////////
  // Timer class understates scope of this thing.. as well as providing a
  // mechanism for the kernel to perform time accounting for applications,
  // it also acts as a "hardware interrupt" module by grabbing keyboard
  // input during timer interrupts and storing them for later dispersal
  // within the <main> loop.
  //
  class Timer {
    static UINT32 nTocks;		      // 18 mS interrupt accum.
    INT16  nSenCnt;			      // startable only when zero
    UINT32 OldRTC; 		              // old interrupt handler
    UINT32 mTicks, mofs; 		      // retained timer counts
    friend void INTERRUPT NewRTC (__CPPARGS); // new one (runs first)
  public:
    Timer ();
    ~Timer ();
    void   Stop (void);			      // Stop accumulating
    void   Start (void);		      // Accumulate milliseconds
    UINT32 GetTicks (void);		      // return 1 mS ticks
    UINT32 GetTocks (void);		      // return 18 mS ticks
  };

  //////////////
  // And this should be private to the "App" class, but I can't make it
  // work that way - something to do with variable referencing for ISR's;
  // It's actual instantiation is in <app.cpp>.
  //
  extern Timer  Clock;

  #define _RCOS_TIMER_

#endif

/********************************** eof **********************************/