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[/] [openrisc/] [trunk/] [rtos/] [rtems/] [c/] [src/] [exec/] [score/] [src/] [coremsgseize.c] - Rev 30
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/* * CORE Message Queue Handler * * DESCRIPTION: * * This package is the implementation of the CORE Message Queue Handler. * This core object provides task synchronization and communication functions * via messages passed to queue objects. * * 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: coremsgseize.c,v 1.2 2001-09-27 11:59:34 chris Exp $ */ #include <rtems/system.h> #include <rtems/score/chain.h> #include <rtems/score/isr.h> #include <rtems/score/object.h> #include <rtems/score/coremsg.h> #include <rtems/score/states.h> #include <rtems/score/thread.h> #include <rtems/score/wkspace.h> #if defined(RTEMS_MULTIPROCESSING) #include <rtems/score/mpci.h> #endif /*PAGE * * _CORE_message_queue_Seize * * This kernel routine dequeues a message, copies the message buffer to * a given destination buffer, and frees the message buffer to the * inactive message pool. The thread will be blocked if wait is TRUE, * otherwise an error will be given to the thread if no messages are available. * * Input parameters: * the_message_queue - pointer to message queue * id - id of object we are waitig on * buffer - pointer to message buffer to be filled * size - pointer to the size of buffer to be filled * wait - TRUE if wait is allowed, FALSE otherwise * timeout - time to wait for a message * * Output parameters: NONE * * NOTE: Dependent on BUFFER_LENGTH * * INTERRUPT LATENCY: * available * wait */ void _CORE_message_queue_Seize( CORE_message_queue_Control *the_message_queue, Objects_Id id, void *buffer, unsigned32 *size, boolean wait, Watchdog_Interval timeout ) { ISR_Level level; CORE_message_queue_Buffer_control *the_message; Thread_Control *executing; Thread_Control *the_thread; executing = _Thread_Executing; executing->Wait.return_code = CORE_MESSAGE_QUEUE_STATUS_SUCCESSFUL; _ISR_Disable( level ); if ( the_message_queue->number_of_pending_messages != 0 ) { the_message_queue->number_of_pending_messages -= 1; the_message = _CORE_message_queue_Get_pending_message( the_message_queue ); _ISR_Enable( level ); *size = the_message->Contents.size; _Thread_Executing->Wait.count = the_message->priority; _CORE_message_queue_Copy_buffer(the_message->Contents.buffer,buffer,*size); /* * There could be a thread waiting to send a message. If there * is not, then we can go ahead and free the buffer. * * NOTE: If we note that the queue was not full before this receive, * then we can avoid this dequeue. */ the_thread = _Thread_queue_Dequeue( &the_message_queue->Wait_queue ); if ( !the_thread ) { _CORE_message_queue_Free_message_buffer( the_message_queue, the_message ); return; } /* * There was a thread waiting to send a message. This code * puts the messages in the message queue on behalf of the * waiting task. */ the_message->priority = the_thread->Wait.count; the_message->Contents.size = (unsigned32)the_thread->Wait.return_argument_1; _CORE_message_queue_Copy_buffer( the_thread->Wait.return_argument, the_message->Contents.buffer, the_message->Contents.size ); _CORE_message_queue_Insert_message( the_message_queue, the_message, the_message->priority ); return; } if ( !wait ) { _ISR_Enable( level ); executing->Wait.return_code = CORE_MESSAGE_QUEUE_STATUS_UNSATISFIED_NOWAIT; return; } _Thread_queue_Enter_critical_section( &the_message_queue->Wait_queue ); executing->Wait.queue = &the_message_queue->Wait_queue; executing->Wait.id = id; executing->Wait.return_argument = (void *)buffer; executing->Wait.return_argument_1 = (void *)size; /* Wait.count will be filled in with the message priority */ _ISR_Enable( level ); _Thread_queue_Enqueue( &the_message_queue->Wait_queue, timeout ); }
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