forked from Imagelibrary/rtems
80 lines
2.0 KiB
C
80 lines
2.0 KiB
C
/*
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* CORE Semaphore Handler
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*
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* DESCRIPTION:
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*
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* This package is the implementation of the CORE Semaphore Handler.
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* This core object utilizes standard Dijkstra counting semaphores to provide
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* synchronization and mutual exclusion capabilities.
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*
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* COPYRIGHT (c) 1989-1999.
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* On-Line Applications Research Corporation (OAR).
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*
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* The license and distribution terms for this file may be
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* found in the file LICENSE in this distribution or at
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* http://www.rtems.com/license/LICENSE.
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*
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* $Id$
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*/
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#if HAVE_CONFIG_H
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#include "config.h"
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#endif
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#include <rtems/system.h>
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#include <rtems/score/isr.h>
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#include <rtems/score/coresem.h>
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#include <rtems/score/states.h>
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#include <rtems/score/thread.h>
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#include <rtems/score/threadq.h>
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#if defined(RTEMS_MULTIPROCESSING)
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#include <rtems/score/mpci.h>
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#endif
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/*PAGE
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*
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* _CORE_semaphore_Surrender
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*
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* Input parameters:
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* the_semaphore - the semaphore to be flushed
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* id - id of parent semaphore
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* api_semaphore_mp_support - api dependent MP support actions
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*
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* Output parameters:
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* CORE_SEMAPHORE_STATUS_SUCCESSFUL - if successful
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* core error code - if unsuccessful
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*
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* Output parameters:
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*/
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CORE_semaphore_Status _CORE_semaphore_Surrender(
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CORE_semaphore_Control *the_semaphore,
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Objects_Id id,
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CORE_semaphore_API_mp_support_callout api_semaphore_mp_support
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)
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{
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Thread_Control *the_thread;
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ISR_Level level;
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CORE_semaphore_Status status;
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status = CORE_SEMAPHORE_STATUS_SUCCESSFUL;
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if ( (the_thread = _Thread_queue_Dequeue(&the_semaphore->Wait_queue)) ) {
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#if defined(RTEMS_MULTIPROCESSING)
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if ( !_Objects_Is_local_id( the_thread->Object.id ) )
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(*api_semaphore_mp_support) ( the_thread, id );
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#endif
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} else {
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_ISR_Disable( level );
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if ( the_semaphore->count < the_semaphore->Attributes.maximum_count )
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the_semaphore->count += 1;
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else
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status = CORE_SEMAPHORE_MAXIMUM_COUNT_EXCEEDED;
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_ISR_Enable( level );
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}
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return status;
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}
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