clock.hxx

ecos为实时嵌入式操作系统

#ifndef CYGONCE_KERNEL_CLOCK_HXX
#define CYGONCE_KERNEL_CLOCK_HXX

//==========================================================================
//
//      clock.hxx
//
//      Clock and Alarm class declaration(s)
//
//==========================================================================
//####COPYRIGHTBEGIN####
//
// -------------------------------------------
// The contents of this file are subject to the Cygnus eCos Public License
// Version 1.0 (the "License"); you may not use this file except in
// compliance with the License.  You may obtain a copy of the License at
// http://sourceware.cygnus.com/ecos
// 
// Software distributed under the License is distributed on an "AS IS"
// basis, WITHOUT WARRANTY OF ANY KIND, either express or implied.  See the
// License for the specific language governing rights and limitations under
// the License.
// 
// The Original Code is eCos - Embedded Cygnus Operating System, released
// September 30, 1998.
// 
// The Initial Developer of the Original Code is Cygnus.  Portions created
// by Cygnus are Copyright (C) 1998,1999 Cygnus Solutions.  All Rights Reserved.
// -------------------------------------------
//
//####COPYRIGHTEND####
//==========================================================================
//#####DESCRIPTIONBEGIN####
//
// Author(s):   nickg
// Contributors:        nickg
// Date:        1997-09-09
// Purpose:     Define Clock and Alarm class interfaces
// Description: The classes defined here collectively implement the
//              internal API used to create, configure and manage Counters,
//              Clocks and Alarms.
// Usage:       #include <cyg/kernel/clock.hxx>
//
//####DESCRIPTIONEND####
//
//==========================================================================

#include <cyg/kernel/ktypes.h>
#include <cyg/infra/cyg_ass.h>            // assertion macros

// -------------------------------------------------------------------------

class Cyg_Alarm;

typedef void cyg_alarm_fn(Cyg_Alarm *alarm, CYG_ADDRWORD data);

// -------------------------------------------------------------------------
// Counter object.

class Cyg_Counter
{

    friend class Cyg_Alarm;

#if defined(CYGIMP_KERNEL_COUNTERS_SINGLE_LIST)

    Cyg_Alarm           *alarm_list;    // Linear list of Alarms

#elif defined(CYGIMP_KERNEL_COUNTERS_MULTI_LIST)

    Cyg_Alarm           *alarm_list[CYGNUM_KERNEL_COUNTERS_MULTI_LIST_SIZE];
    
#endif

    cyg_tick_count      counter;        // counter value

    cyg_uint32          increment;      // increment per tick
    
public:

    CYGDBG_DEFINE_CHECK_THIS
    
    Cyg_Counter(
        cyg_uint32      increment = 1
    );

    ~Cyg_Counter();
    
    // Return current value of counter
    cyg_tick_count current_value();

    // Return low and high halves of the
    // counter value.
    cyg_uint32 current_value_lo();
    cyg_uint32 current_value_hi();
    
    // Set the counter's current value
    void set_value( cyg_tick_count new_value);
        
    // Advance counter by some number of ticks
    void tick( cyg_uint32 ticks = 1);

    // Add an alarm to this counter
    void add_alarm( Cyg_Alarm *alarm );

    // Remove an alarm from this counter
    void rem_alarm( Cyg_Alarm *alarm );

};

// -------------------------------------------------------------------------
// Clock class. This is derived from a Counter and defines extra
// features to support clock-like behaviour.

class Cyg_Clock
    : public Cyg_Counter
{

public:

    CYGDBG_DEFINE_CHECK_THIS

    // This structure allows a more accurate representation
    // of the resolution than a single integer would allow.
    // The resolution is defined as dividend/divisor nanoseconds
    // per tick.
    struct cyg_resolution {
        cyg_uint32  dividend;
        cyg_uint32  divisor;
    };

private:

    cyg_resolution      resolution;     // Current clock resolution

public:

    Cyg_Clock(                          // Create clock with given resolution
        cyg_resolution resolution
        );

    ~Cyg_Clock();                       // Destructor
        
    cyg_resolution get_resolution();    // Return current resolution

    void set_resolution(                // Set new resolution
        cyg_resolution resolution
        ); 

#ifdef CYGVAR_KERNEL_COUNTERS_CLOCK 
    
    // There is a system supplied real time clock...

    static Cyg_Clock *real_time_clock;

#endif    
        
};

// -------------------------------------------------------------------------
// Alarm class. An alarm may be attached to a counter (or a clock) to be
// called when the trigger value is reached.

class Cyg_Alarm
{
    friend class Cyg_Counter;
    
#if defined(CYGIMP_KERNEL_COUNTERS_SINGLE_LIST) || defined(CYGIMP_KERNEL_COUNTERS_MULTI_LIST)

    Cyg_Alarm           *next;          // next alarm in list
    
#endif

protected:
    Cyg_Counter         *counter;       // Attached to this counter/clock

    cyg_alarm_fn        *alarm;         // Call-back function

    CYG_ADDRWORD        data;           // Call-back data

    cyg_tick_count      trigger;        // Absolute trigger time

    cyg_tick_count      interval;       // Retrigger interval

    cyg_bool            enabled;        // True if enabled

    Cyg_Alarm();

    void synchronize( void );           // deal with times in the past,
                                        // make next alarm in synch.
    
public:

    CYGDBG_DEFINE_CHECK_THIS
    
    Cyg_Alarm                           // Constructor
    (
        Cyg_Counter     *counter,       // Attached to this counter
        cyg_alarm_fn    *alarm,         // Call-back function
        CYG_ADDRWORD    data            // Call-back data
        );

    ~Cyg_Alarm();                       // Destructor
        
    void initialize(                    // Initialize Alarm
        cyg_tick_count    trigger,      // Absolute trigger time
        cyg_tick_count    interval = 0  // Relative retrigger interval
        );

    void enable();                      // Ensure alarm enabled

    void disable();                     // Ensure alarm disabled
    
    
};

// -------------------------------------------------------------------------

#endif // ifndef CYGONCE_KERNEL_CLOCK_HXX
// EOF clock.hxx