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/**
* @file
*
* @brief Thread Queue First
* @ingroup ScoreThreadQ
*/
/*
* COPYRIGHT (c) 1989-2014.
* 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.org/license/LICENSE.
*/
#if HAVE_CONFIG_H
#include "config.h"
#endif
#include <rtems/score/threadqimpl.h>
#include <rtems/score/chainimpl.h>
#include <rtems/score/isrlevel.h>
#include <rtems/score/threadimpl.h>
Thread_Control *_Thread_queue_First(
Thread_queue_Control *the_thread_queue
)
{
ISR_Level level;
Thread_Control *thread;
thread = NULL;
_ISR_Disable( level );
if ( the_thread_queue->discipline == THREAD_QUEUE_DISCIPLINE_FIFO ) {
if ( !_Chain_Is_empty( &the_thread_queue->Queues.Fifo ) )
thread = (Thread_Control *) _Chain_First(&the_thread_queue->Queues.Fifo);
} else { /* must be THREAD_QUEUE_DISCIPLINE_PRIORITY */
RBTree_Node *first;
first = _RBTree_First( &the_thread_queue->Queues.Priority, RBT_LEFT );
if ( first )
thread = THREAD_RBTREE_NODE_TO_THREAD( first );
}
_ISR_Enable( level );
return thread;
}
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