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/*

 *  Thread Queue Handler

 *

 *

 *  COPYRIGHT (c) 1989-1999.

 *  On-Line Applications Research Corporation (OAR).

 *

 *  The license and distribution terms for this file may be

 *  found in the file LICENSE in this distribution or at

 *  http://www.OARcorp.com/rtems/license.html.

 *

 *  $Id: threadqdequeuefifo.c,v 1.2 2001-09-27 11:59:34 chris Exp $

 */

#include <rtems/system.h>

#include <rtems/score/chain.h>

#include <rtems/score/isr.h>

#include <rtems/score/object.h>

#include <rtems/score/states.h>

#include <rtems/score/thread.h>

#include <rtems/score/threadq.h>

#include <rtems/score/tqdata.h>

/*PAGE

 *

 *  _Thread_queue_Dequeue_fifo

 *

 *  This routine removes a thread from the specified threadq.

 *

 *  Input parameters:

 *    the_thread_queue - pointer to threadq

 *

 *  Output parameters:

 *    returns - thread dequeued or NULL

 *

 *  INTERRUPT LATENCY:

 *    check sync

 *    FIFO

 */

Thread_Control *_Thread_queue_Dequeue_fifo(

  Thread_queue_Control *the_thread_queue

)

{

  ISR_Level              level;

  Thread_Control *the_thread;

  _ISR_Disable( level );

  if ( !_Chain_Is_empty( &the_thread_queue->Queues.Fifo ) ) {

    the_thread = (Thread_Control *)

       _Chain_Get_first_unprotected( &the_thread_queue->Queues.Fifo );

    if ( !_Watchdog_Is_active( &the_thread->Timer ) ) {

      _ISR_Enable( level );

      _Thread_Unblock( the_thread );

    } else {

      _Watchdog_Deactivate( &the_thread->Timer );

      _ISR_Enable( level );

      (void) _Watchdog_Remove( &the_thread->Timer );

      _Thread_Unblock( the_thread );

    }

#if defined(RTEMS_MULTIPROCESSING)

    if ( !_Objects_Is_local_id( the_thread->Object.id ) )

      _Thread_MP_Free_proxy( the_thread );

#endif

    return the_thread;

  }

  switch ( the_thread_queue->sync_state ) {

    case THREAD_QUEUE_SYNCHRONIZED:

    case THREAD_QUEUE_SATISFIED:

      _ISR_Enable( level );

      return NULL;

    case THREAD_QUEUE_NOTHING_HAPPENED:

    case THREAD_QUEUE_TIMEOUT:

      the_thread_queue->sync_state = THREAD_QUEUE_SATISFIED;

      _ISR_Enable( level );

      return _Thread_Executing;

  }

  return NULL;                /* this is only to prevent warnings */

}