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/*
* Copyright (C) 2009 The Android Open Source Project
* All rights reserved.
*
* 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.
*
* 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
* COPYRIGHT OWNER 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.
*/
#include <pthread.h>
#include <linux/futex.h>
#define SWAP_LOCK_COUNT 32U
static pthread_mutex_t _swap_locks[SWAP_LOCK_COUNT];
#define SWAP_LOCK(addr) \
&_swap_locks[((unsigned)(void *)(addr) >> 3U) % SWAP_LOCK_COUNT]
#if 0
/*
* Only this function is moved to atomic_cmpxchg.S, and
* implemented with gUSA framework.
*/
int __atomic_cmpxchg(int old, int _new, volatile int *ptr)
{
int result;
pthread_mutex_t *lock = SWAP_LOCK(ptr);
pthread_mutex_lock(lock);
if (*ptr == old) {
*ptr = _new;
result = 0;
} else {
result = 1;
}
pthread_mutex_unlock(lock);
return result;
}
#else
extern int __atomic_cmpxchg(int old, int _new, volatile int *ptr);
#endif
int __atomic_swap(int _new, volatile int *ptr)
{
int oldValue;
do {
oldValue = *ptr;
} while (__atomic_cmpxchg(oldValue, _new, ptr));
return oldValue;
}
int __atomic_dec(volatile int *ptr)
{
int oldValue;
do {
oldValue = *ptr;
} while (__atomic_cmpxchg(oldValue, oldValue-1, ptr));
return oldValue;
}
int __atomic_inc(volatile int *ptr)
{
int32_t oldValue;
do {
oldValue = *ptr;
} while (__atomic_cmpxchg(oldValue, oldValue+1, ptr));
return oldValue;
}
extern int futex(volatile void *, int, int, void *, void *, int);
int __futex_wait(volatile void *ftx, int val, const struct timespec *timeout)
{
return futex(ftx, FUTEX_WAIT, val, (void *)timeout, NULL, 0);
}
int __futex_wake(volatile void *ftx, int count)
{
return futex(ftx, FUTEX_WAKE, count, NULL, NULL, 0);
}
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