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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.rtems.com/license/LICENSE.
*
* $Id$
*/
#if HAVE_CONFIG_H
#include "config.h"
#endif
#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>
/*
* _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 defined(RTEMS_MULTIPROCESSING)
if ( !_Objects_Is_local_id( the_thread->Object.id ) )
(*api_semaphore_mp_support) ( the_thread, id );
#endif
} 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;
}
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