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/*
* Copyright (C) 2008 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.
*/
#ifndef _SYS_ATOMICS_H
#define _SYS_ATOMICS_H
#include <sys/cdefs.h>
#include <sys/time.h>
__BEGIN_DECLS
/* Note: atomic operations that were exported by the C library didn't
* provide any memory barriers, which created potential issues on
* multi-core devices. We now define them as inlined calls to
* GCC sync builtins, which always provide a full barrier.
*
* NOTE: The C library still exports atomic functions by the same
* name to ensure ABI stability for existing NDK machine code.
*
* If you are an NDK developer, we encourage you to rebuild your
* unmodified sources against this header as soon as possible.
*/
#define __ATOMIC_INLINE__ static __inline__ __attribute__((always_inline))
__ATOMIC_INLINE__ int
__atomic_cmpxchg(int old, int _new, volatile int *ptr)
{
/* We must return 0 on success */
return __sync_val_compare_and_swap(ptr, old, _new) != old;
}
__ATOMIC_INLINE__ int
__atomic_swap(int _new, volatile int *ptr)
{
int prev;
do {
prev = *ptr;
} while (__sync_val_compare_and_swap(ptr, prev, _new) != prev);
return prev;
}
__ATOMIC_INLINE__ int
__atomic_dec(volatile int *ptr)
{
return __sync_fetch_and_sub (ptr, 1);
}
__ATOMIC_INLINE__ int
__atomic_inc(volatile int *ptr)
{
return __sync_fetch_and_add (ptr, 1);
}
int __futex_wait(volatile void *ftx, int val, const struct timespec *timeout);
int __futex_wake(volatile void *ftx, int count);
__END_DECLS
#endif /* _SYS_ATOMICS_H */
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