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+#ifndef CYGONCE_KERNEL_MLQUEUE_HXX
+#define CYGONCE_KERNEL_MLQUEUE_HXX
+
+//==========================================================================
+//
+// mlqueue.hxx
+//
+// Multi-Level Queue scheduler class declarations
+//
+//==========================================================================
+//####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: 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
+// <cyg/kernel/sched.hxx>
+//
+//####DESCRIPTIONEND####
+//
+//==========================================================================
+
+#include <cyg/kernel/ktypes.h>
+
+#include <cyg/infra/clist.hxx> // 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_Thread> 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<Cyg_Thread>
+{
+ 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<Cyg_Thread>
+{
+ 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