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/* Shared Memory Lock Routines
*
* This shared memory locked queue support routine need to be
* able to lock the specified locked queue. Interrupts are
* disabled while the queue is locked to prevent preemption
* and deadlock when two tasks poll for the same lock.
* previous level.
*
* 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.
*
* $Id$
*/
#include <bsp.h>
#include <shm.h>
/*
* Shm_Initialize_lock
*
* Initialize the lock for the specified locked queue.
*/
void Shm_Initialize_lock(
Shm_Locked_queue_Control *lq_cb
)
{
lq_cb->lock = lq_cb - Shm_Locked_queues;
}
/* Shm_Lock( &lq_cb )
*
* This shared memory locked queue support routine locks the
* specified locked queue. It disables interrupts to prevent
* a deadlock condition.
*/
void Shm_Lock(
Shm_Locked_queue_Control *lq_cb
)
{
rtems_unsigned32 isr_level;
rtems_interrupt_disable( isr_level );
Shm_isrstat = isr_level;
_CPU_SHM_Lock( lq_cb->lock );
}
/*
* Shm_Unlock
*
* Unlock the lock for the specified locked queue.
*/
void Shm_Unlock(
Shm_Locked_queue_Control *lq_cb
)
{
rtems_unsigned32 isr_level;
_CPU_SHM_Unlock( lq_cb->lock );
isr_level = Shm_isrstat;
rtems_interrupt_enable( isr_level );
}
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