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#ifndef CYGONCE_KERNEL_MLQUEUE_HXX

#define CYGONCE_KERNEL_MLQUEUE_HXX

//==========================================================================

//

//      mlqueue.hxx

//

//      Multi-Level Queue scheduler class declarations

//

//==========================================================================

//####ECOSGPLCOPYRIGHTBEGIN####

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

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// Copyright (C) 1998, 1999, 2000, 2001, 2002 Red Hat, Inc.

//

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// 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA.

//

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// or inline functions from this file, or you compile this file and link it

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//####ECOSGPLCOPYRIGHTEND####

//==========================================================================

//#####DESCRIPTIONBEGIN####

//

// Author(s):    nickg

// Contributors: jlarmour

// Date:         1997-09-10

// Purpose:      Define multilevel queue scheduler implementation

// Description:  The classes defined here are used as base classes

//               by the common classes that define schedulers and thread

//               things. The MLQ scheduler in various configurations

//               provides standard FIFO, round-robin and single priority

//               schedulers.

// Usage:        Included according to configuration by

//               

//

//####DESCRIPTIONEND####

//

//==========================================================================

#include 

#include                   // List implementation

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

// The macro CYGNUM_KERNEL_SCHED_PRIORITIES contains the number of priorities

// supported by the scheduler.

#ifndef CYGNUM_KERNEL_SCHED_PRIORITIES

#define CYGNUM_KERNEL_SCHED_PRIORITIES 32       // define a default

#endif

// set bitmap size

#define CYGNUM_KERNEL_SCHED_BITMAP_SIZE CYGNUM_KERNEL_SCHED_PRIORITIES

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

// The macro CYGNUM_KERNEL_SCHED_BITMAP_SIZE contains the number of bits that the

// scheduler bitmap should contain. It is derived from the number of prioirity

// levels defined by the configuration.

#if CYGNUM_KERNEL_SCHED_BITMAP_SIZE <= 8

typedef cyg_ucount8 cyg_sched_bitmap;

#elif CYGNUM_KERNEL_SCHED_BITMAP_SIZE <= 16

typedef cyg_ucount16 cyg_sched_bitmap;

#elif CYGNUM_KERNEL_SCHED_BITMAP_SIZE <= 32

typedef cyg_ucount32 cyg_sched_bitmap;

#else

#error Bitmaps greater than 32 bits not currently allowed

#endif

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

// Customize the scheduler

#define CYGIMP_THREAD_PRIORITY  1       // Threads have changable priorities

#define CYG_THREAD_MIN_PRIORITY (CYGNUM_KERNEL_SCHED_PRIORITIES-1)

#define CYG_THREAD_MAX_PRIORITY 0

// set default scheduling info value for thread constructors.

#define CYG_SCHED_DEFAULT_INFO  CYG_THREAD_MAX_PRIORITY

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

// scheduler Run queue object

typedef Cyg_CList_T Cyg_RunQueue;

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

// Thread queue implementation.

// This class provides the (scheduler specific) implementation of the

// thread queue class.

class Cyg_ThreadQueue_Implementation

    : public Cyg_CList_T

{

    friend class Cyg_Scheduler_Implementation;

    friend class Cyg_SchedThread_Implementation;

    void                set_thread_queue(Cyg_Thread *thread,

                                         Cyg_ThreadQueue *tq );

protected:

    // API used by Cyg_ThreadQueue

    Cyg_ThreadQueue_Implementation() {};   // Constructor

                                        // Add thread to queue

    void                enqueue(Cyg_Thread *thread);

                                        // return first thread on queue

    Cyg_Thread          *highpri();

                                        // remove first thread on queue

    Cyg_Thread          *dequeue();

                                        // Remove thread from queue

    void                remove(Cyg_Thread *thread);

};

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

// This class contains the implementation details of the scheduler, and

// provides a standard API for accessing it.

class Cyg_Scheduler_Implementation

    : public Cyg_Scheduler_Base

{

    friend class Cyg_ThreadQueue_Implementation;

    friend class Cyg_SchedThread_Implementation;

    friend class Cyg_HardwareThread;

    friend void cyg_scheduler_set_need_reschedule();

    // Mask of which run queues have ready threads

    cyg_sched_bitmap    queue_map;

    // Each run queue is a double linked circular list of threads.

    // These pointers point to the head element of each list.

    Cyg_RunQueue run_queue[CYGNUM_KERNEL_SCHED_PRIORITIES];

#ifdef CYGPKG_KERNEL_SMP_SUPPORT

    // In SMP systems we additionally keep a counter for each priority

    // of the number of pending but not running threads in each queue.

    cyg_uint32 pending[CYGNUM_KERNEL_SCHED_PRIORITIES];

    cyg_sched_bitmap pending_map;

#endif

protected:

#ifdef CYGSEM_KERNEL_SCHED_TIMESLICE

    // Timeslice counter. This is decremented on each

    // clock tick, and a timeslice is performed each

    // time it zeroes.

    static cyg_ucount32 timeslice_count[CYGNUM_KERNEL_CPU_MAX]

                                        CYGBLD_ANNOTATE_VARIABLE_SCHED;

    static void reset_timeslice_count();

#endif

    Cyg_Scheduler_Implementation();     // Constructor

    // The following functions provide the scheduler implementation

    // interface to the Cyg_Scheduler class. These are protected

    // so that only the scheduler can call them.

    // choose a new thread

    Cyg_Thread  *schedule();

    // make thread schedulable

    void        add_thread(Cyg_Thread *thread);

    // make thread un-schedulable

    void        rem_thread(Cyg_Thread *thread);

    // register thread with scheduler

    void        register_thread(Cyg_Thread *thread);

    // deregister thread

    void        deregister_thread(Cyg_Thread *thread);

    // Test the given priority for uniqueness

    cyg_bool    unique( cyg_priority priority);

    // Set need_reschedule if the supplied thread is of lower

    // priority than any that are currently running.

    static void set_need_reschedule( Cyg_Thread *thread );

    static void set_need_reschedule();

public:

    void set_idle_thread( Cyg_Thread *thread, HAL_SMP_CPU_TYPE cpu );

#ifdef CYGSEM_KERNEL_SCHED_TIMESLICE

    // If timeslicing is enbled, define a scheduler

    // entry points to do timeslicing. This will be

    // called from the RTC DSR.

public:

    void timeslice();

    void timeslice_cpu();

#endif

};

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

// Cyg_Scheduler_Implementation inlines

inline void Cyg_Scheduler_Implementation::set_need_reschedule()

{

    need_reschedule[CYG_KERNEL_CPU_THIS()] = true;

}

#ifdef CYGSEM_KERNEL_SCHED_TIMESLICE

inline void Cyg_Scheduler_Implementation::reset_timeslice_count()

{

    timeslice_count[CYG_KERNEL_CPU_THIS()] = CYGNUM_KERNEL_SCHED_TIMESLICE_TICKS;

}

#endif

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

// Scheduler thread implementation.

// This class provides the implementation of the scheduler specific parts

// of each thread.

class Cyg_SchedThread_Implementation

    : public Cyg_DNode_T

{

    friend class Cyg_Scheduler_Implementation;

    friend class Cyg_ThreadQueue_Implementation;

protected:

    cyg_priority        priority;       // current thread priority

#ifdef CYGPKG_KERNEL_SMP_SUPPORT

    HAL_SMP_CPU_TYPE    cpu;            // CPU id of cpu currently running

                                        // this thread, or CYG_KERNEL_CPU_NONE

                                        // if not running.

#endif

    Cyg_SchedThread_Implementation(CYG_ADDRWORD sched_info);

    void yield();                       // Yield CPU to next thread

    static void rotate_queue( cyg_priority pri );

                                        // Rotate that run queue

    void to_queue_head( void );         // Move this thread to the head

                                        // of its queue (not necessarily

                                        // a scheduler queue)

#ifdef CYGSEM_KERNEL_SCHED_TIMESLICE_ENABLE

    // This defines whether this thread is subject to timeslicing.

    // If false, timeslice expiry has no effect on the thread.

    cyg_bool            timeslice_enabled;

public:

    void timeslice_enable();

    void timeslice_disable();

#endif

};

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

// Cyg_SchedThread_Implementation inlines.

#ifdef CYGSEM_KERNEL_SCHED_TIMESLICE_ENABLE

inline void Cyg_SchedThread_Implementation::timeslice_enable()

{

    timeslice_enabled = true;

}

inline void Cyg_SchedThread_Implementation::timeslice_disable()

{

    timeslice_enabled = false;

}

#endif

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

#endif // ifndef CYGONCE_KERNEL_MLQUEUE_HXX

// EOF mlqueue.hxx