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[/] [or1k/] [trunk/] [ecos-2.0/] [packages/] [kernel/] [v2_0/] [include/] [clock.hxx] - Rev 1254
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#ifndef CYGONCE_KERNEL_CLOCK_HXX
#define CYGONCE_KERNEL_CLOCK_HXX
//==========================================================================
//
// clock.hxx
//
// Clock and Alarm class declaration(s)
//
//==========================================================================
//####ECOSGPLCOPYRIGHTBEGIN####
// -------------------------------------------
// This file is part of eCos, the Embedded Configurable Operating System.
// Copyright (C) 1998, 1999, 2000, 2001, 2002 Red Hat, Inc.
//
// eCos is free software; you can redistribute it and/or modify it under
// the terms of the GNU General Public License as published by the Free
// Software Foundation; either version 2 or (at your option) any later version.
//
// eCos is distributed in the hope that it will be useful, but WITHOUT ANY
// WARRANTY; without even the implied warranty of MERCHANTABILITY or
// FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
// for more details.
//
// You should have received a copy of the GNU General Public License along
// with eCos; if not, write to the Free Software Foundation, Inc.,
// 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA.
//
// As a special exception, if other files instantiate templates or use macros
// or inline functions from this file, or you compile this file and link it
// with other works to produce a work based on this file, this file does not
// by itself cause the resulting work to be covered by the GNU General Public
// License. However the source code for this file must still be made available
// in accordance with section (3) of the GNU General Public License.
//
// This exception does not invalidate any other reasons why a work based on
// this file might be covered by the GNU General Public License.
//
// Alternative licenses for eCos may be arranged by contacting Red Hat, Inc.
// at http://sources.redhat.com/ecos/ecos-license/
// -------------------------------------------
//####ECOSGPLCOPYRIGHTEND####
//==========================================================================
//#####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
#include <cyg/infra/clist.hxx>
// -------------------------------------------------------------------------
// Forward definitions and typedefs.
class Cyg_Alarm;
typedef void cyg_alarm_fn(Cyg_Alarm *alarm, CYG_ADDRWORD data);
typedef Cyg_CList_T<Cyg_Alarm> Cyg_Alarm_List;
// -------------------------------------------------------------------------
// Counter object.
class Cyg_Counter
{
friend class Cyg_Alarm;
#if defined(CYGIMP_KERNEL_COUNTERS_SINGLE_LIST)
Cyg_Alarm_List alarm_list; // Linear list of Alarms
#elif defined(CYGIMP_KERNEL_COUNTERS_MULTI_LIST)
Cyg_Alarm_List alarm_list[CYGNUM_KERNEL_COUNTERS_MULTI_LIST_SIZE];
#endif
volatile 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
);
// There is a need for converting from "other" ticks to clock ticks.
// We will construct 4 numbers to do the conversion as:
// clock_ticks = (((otherticks*mul1)/div1)*mul2/div2)
// with the values chosen to minimize the possibility of overflow.
// Do the arithmetic in cyg_uint64s throughout.
struct converter {
cyg_uint64 mul1, div1, mul2, div2;
};
// There are two of these because the 4 numbers are different depending
// on the direction of the conversion, to prevent loss of significance.
// NB these relate to the resolution of the clock object they are
// called against, not necessarily "the" system real time clock.
void get_other_to_clock_converter( cyg_uint64 ns_per_other_tick,
struct converter *pcc );
void get_clock_to_other_converter( cyg_uint64 ns_per_other_tick,
struct converter *pcc );
// A utility to perform the conversion in the obvious way, with
// rounding to nearest at each stage. Static because it uses a
// previously acquired converter.
static cyg_tick_count convert( cyg_tick_count value,
struct converter *pcc );
#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
#if defined(CYGIMP_KERNEL_COUNTERS_SINGLE_LIST) || defined(CYGIMP_KERNEL_COUNTERS_MULTI_LIST)
: public Cyg_DNode_T<Cyg_Alarm>
#endif
{
friend class Cyg_Counter;
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
void get_times(
cyg_tick_count *trigger, // Next trigger time
cyg_tick_count *interval // Current interval
);
};
// -------------------------------------------------------------------------
#endif // ifndef CYGONCE_KERNEL_CLOCK_HXX
// EOF clock.hxx
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