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/*

 *  CORE Semaphore Handler

 *

 *  DESCRIPTION:

 *

 *  This package is the implementation of the CORE Semaphore Handler.

 *  This core object utilizes standard Dijkstra counting semaphores to provide

 *  synchronization and mutual exclusion capabilities.

 *

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

 */

#include <rtems/system.h>

#include <rtems/score/isr.h>

#include <rtems/score/coresem.h>

#include <rtems/score/states.h>

#include <rtems/score/thread.h>

#include <rtems/score/threadq.h>

#if defined(RTEMS_MULTIPROCESSING)

#include <rtems/score/mpci.h>

#endif

/*PAGE

 *

 *  _CORE_semaphore_Surrender

 *

 *  Input parameters:

 *    the_semaphore            - the semaphore to be flushed

 *    id                       - id of parent semaphore

 *    api_semaphore_mp_support - api dependent MP support actions

 *

 *  Output parameters:

 *    CORE_SEMAPHORE_STATUS_SUCCESSFUL - if successful

 *    core error code                  - if unsuccessful

 *

 *  Output parameters:

 */

CORE_semaphore_Status _CORE_semaphore_Surrender(

  CORE_semaphore_Control                *the_semaphore,

  Objects_Id                             id,

  CORE_semaphore_API_mp_support_callout  api_semaphore_mp_support

)

{

  Thread_Control *the_thread;

  ISR_Level       level;

  CORE_semaphore_Status status;

  status = CORE_SEMAPHORE_STATUS_SUCCESSFUL;

  if ( (the_thread = _Thread_queue_Dequeue(&the_semaphore->Wait_queue)) ) {

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

      (*api_semaphore_mp_support) ( the_thread, id );

  } else {

    _ISR_Disable( level );

      if ( the_semaphore->count <= the_semaphore->Attributes.maximum_count )

        the_semaphore->count += 1;

      else

        status = CORE_SEMAPHORE_MAXIMUM_COUNT_EXCEEDED;

    _ISR_Enable( level );

  }

  return status;

}