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/*
* Thread Queue Handler - Enqueue By Priority
*
* COPYRIGHT (c) 1989-2009.
* 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/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>
/*
* Support the user forcing the unrolling to be disabled.
*/
#if __RTEMS_DO_NOT_UNROLL_THREADQ_ENQUEUE_PRIORITY__
#undef CPU_UNROLL_ENQUEUE_PRIORITY
#define CPU_UNROLL_ENQUEUE_PRIORITY FALSE
#endif
/*PAGE
*
* _Thread_queue_Enqueue_priority
*
* This routine places a blocked thread on a priority thread queue.
*
* Input parameters:
* the_thread_queue - pointer to threadq
* thread - thread to insert
*
* Output parameters: NONE
*
* INTERRUPT LATENCY:
* forward less than
* forward equal
*/
Thread_blocking_operation_States _Thread_queue_Enqueue_priority (
Thread_queue_Control *the_thread_queue,
Thread_Control *the_thread,
ISR_Level *level_p
)
{
Priority_Control search_priority;
Thread_Control *search_thread;
ISR_Level level;
Chain_Control *header;
uint32_t header_index;
Chain_Node *the_node;
Chain_Node *next_node;
Chain_Node *previous_node;
Chain_Node *search_node;
Priority_Control priority;
States_Control block_state;
_Chain_Initialize_empty( &the_thread->Wait.Block2n );
priority = the_thread->current_priority;
header_index = _Thread_queue_Header_number( priority );
header = &the_thread_queue->Queues.Priority[ header_index ];
block_state = the_thread_queue->state;
if ( _Thread_queue_Is_reverse_search( priority ) )
goto restart_reverse_search;
restart_forward_search:
search_priority = PRIORITY_MINIMUM - 1;
_ISR_Disable( level );
search_thread = (Thread_Control *) header->first;
while ( !_Chain_Is_tail( header, (Chain_Node *)search_thread ) ) {
search_priority = search_thread->current_priority;
if ( priority <= search_priority )
break;
#if ( CPU_UNROLL_ENQUEUE_PRIORITY == TRUE )
search_thread = (Thread_Control *) search_thread->Object.Node.next;
if ( _Chain_Is_tail( header, (Chain_Node *)search_thread ) )
break;
search_priority = search_thread->current_priority;
if ( priority <= search_priority )
break;
#endif
_ISR_Flash( level );
if ( !_States_Are_set( search_thread->current_state, block_state) ) {
_ISR_Enable( level );
goto restart_forward_search;
}
search_thread =
(Thread_Control *)search_thread->Object.Node.next;
}
if ( the_thread_queue->sync_state !=
THREAD_BLOCKING_OPERATION_NOTHING_HAPPENED )
goto synchronize;
the_thread_queue->sync_state = THREAD_BLOCKING_OPERATION_SYNCHRONIZED;
if ( priority == search_priority )
goto equal_priority;
search_node = (Chain_Node *) search_thread;
previous_node = search_node->previous;
the_node = (Chain_Node *) the_thread;
the_node->next = search_node;
the_node->previous = previous_node;
previous_node->next = the_node;
search_node->previous = the_node;
the_thread->Wait.queue = the_thread_queue;
_ISR_Enable( level );
return THREAD_BLOCKING_OPERATION_NOTHING_HAPPENED;
restart_reverse_search:
search_priority = PRIORITY_MAXIMUM + 1;
_ISR_Disable( level );
search_thread = (Thread_Control *) header->last;
while ( !_Chain_Is_head( header, (Chain_Node *)search_thread ) ) {
search_priority = search_thread->current_priority;
if ( priority >= search_priority )
break;
#if ( CPU_UNROLL_ENQUEUE_PRIORITY == TRUE )
search_thread = (Thread_Control *) search_thread->Object.Node.previous;
if ( _Chain_Is_head( header, (Chain_Node *)search_thread ) )
break;
search_priority = search_thread->current_priority;
if ( priority >= search_priority )
break;
#endif
_ISR_Flash( level );
if ( !_States_Are_set( search_thread->current_state, block_state) ) {
_ISR_Enable( level );
goto restart_reverse_search;
}
search_thread = (Thread_Control *)
search_thread->Object.Node.previous;
}
if ( the_thread_queue->sync_state !=
THREAD_BLOCKING_OPERATION_NOTHING_HAPPENED )
goto synchronize;
the_thread_queue->sync_state = THREAD_BLOCKING_OPERATION_SYNCHRONIZED;
if ( priority == search_priority )
goto equal_priority;
search_node = (Chain_Node *) search_thread;
next_node = search_node->next;
the_node = (Chain_Node *) the_thread;
the_node->next = next_node;
the_node->previous = search_node;
search_node->next = the_node;
next_node->previous = the_node;
the_thread->Wait.queue = the_thread_queue;
_ISR_Enable( level );
return THREAD_BLOCKING_OPERATION_NOTHING_HAPPENED;
equal_priority: /* add at end of priority group */
search_node = _Chain_Tail( &search_thread->Wait.Block2n );
previous_node = search_node->previous;
the_node = (Chain_Node *) the_thread;
the_node->next = search_node;
the_node->previous = previous_node;
previous_node->next = the_node;
search_node->previous = the_node;
the_thread->Wait.queue = the_thread_queue;
_ISR_Enable( level );
return THREAD_BLOCKING_OPERATION_NOTHING_HAPPENED;
synchronize:
/*
* An interrupt completed the thread's blocking request.
* For example, the blocking thread could have been given
* the mutex by an ISR or timed out.
*
* WARNING! Returning with interrupts disabled!
*/
*level_p = level;
return the_thread_queue->sync_state;
}
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