66 lines
2.5 KiB
C
66 lines
2.5 KiB
C
/*
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* Copyright (c) 1997 John Birrell <jb@cimlogic.com.au>.
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* 3. All advertising materials mentioning features or use of this software
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* must display the following acknowledgement:
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* This product includes software developed by John Birrell.
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* 4. Neither the name of the author nor the names of any co-contributors
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* may be used to endorse or promote products derived from this software
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* without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY JOHN BIRRELL AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*
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* $Id: uthread_spinlock.c,v 1.1 1998/04/29 09:59:28 jb Exp $
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*
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*/
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#include <stdio.h>
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#include <sched.h>
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#include <unistd.h>
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#include <pthread.h>
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#include "spinlock.h"
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#include "pthread_private.h"
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/*
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* Lock a location for the running thread. Yield to allow other
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* threads to run if this thread is blocked because the lock is
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* not available. Note that this function does not sleep. It
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* assumes that the lock will be available very soon.
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*/
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void
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_spinlock(volatile long *lck)
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{
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do {
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/*
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* Allow other threads to run if the lock is not
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* available:
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*/
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while (*lck != 0)
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sched_yield();
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/*
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* Try to grab the lock and loop if another thread grabs
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* it before we do.
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*/
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} while(_atomic_lock(lck,(long) _thread_run));
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}
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