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libhermit/include/hermit/islelock.h
2016-12-03 00:43:49 +01:00

78 lines
2.6 KiB
C

/*
* Copyright 2015 Stefan Lankes, RWTH Aachen University
* All rights reserved.
*
* This software is available to you under a choice of one of two
* licenses. You may choose to be licensed under the terms of the GNU
* General Public License (GPL) Version 2 (https://www.gnu.org/licenses/gpl-2.0.txt)
* or the BSD license below:
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are met:
* * Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* * Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* * Neither the name of the University nor the names of its contributors
* may be used to endorse or promote products derived from this
* software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
* WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
* DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE FOR ANY
* DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
* (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
* LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
* ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
* SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
#ifndef __ISLELOCK_H__
#define __ISLELOCK_H__
#include <hermit/stddef.h>
#include <asm/atomic.h>
typedef struct islelock {
/// Internal queue
atomic_int32_t queue;
/// Internal dequeue
atomic_int32_t dequeue;
} islelock_t;
inline static int islelock_init(islelock_t* s)
{
atomic_int32_set(&s->queue, 0);
atomic_int32_set(&s->dequeue, 1);
return 0;
}
inline static int islelock_destroy(islelock_t* s)
{
return 0;
}
static inline int islelock_lock(islelock_t* s)
{
int ticket;
ticket = atomic_int32_inc(&s->queue);
while(atomic_int32_read(&s->dequeue) != ticket) {
PAUSE;
}
return 0;
}
static inline int islelock_unlock(islelock_t* s)
{
atomic_int32_inc(&s->dequeue);
return 0;
}
#endif