84 lines
2.9 KiB
C
84 lines
2.9 KiB
C
/*
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* Copyright (C) 2008 The Android Open Source Project
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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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* * 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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* * Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in
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* the documentation and/or other materials provided with the
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* distribution.
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*
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* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
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* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
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* FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
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* COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
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* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
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* BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
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* OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
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* AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
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* OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
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* 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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#ifndef _SYS_ATOMICS_H
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#define _SYS_ATOMICS_H
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#include <sys/cdefs.h>
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#include <sys/time.h>
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__BEGIN_DECLS
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/* Note: atomic operations that were exported by the C library didn't
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* provide any memory barriers, which created potential issues on
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* multi-core devices. We now define them as inlined calls to
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* GCC sync builtins, which always provide a full barrier.
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*
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* NOTE: The C library still exports atomic functions by the same
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* name to ensure ABI stability for existing NDK machine code.
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*
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* If you are an NDK developer, we encourage you to rebuild your
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* unmodified sources against this header as soon as possible.
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*/
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#define __ATOMIC_INLINE__ static __inline__ __attribute__((always_inline))
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__ATOMIC_INLINE__ int
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__atomic_cmpxchg(int old_value, int new_value, volatile int* ptr)
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{
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/* We must return 0 on success */
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return __sync_val_compare_and_swap(ptr, old_value, new_value) != old_value;
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}
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__ATOMIC_INLINE__ int
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__atomic_swap(int new_value, volatile int *ptr)
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{
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int old_value;
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do {
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old_value = *ptr;
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} while (__sync_val_compare_and_swap(ptr, old_value, new_value) != old_value);
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return old_value;
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}
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__ATOMIC_INLINE__ int
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__atomic_dec(volatile int *ptr)
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{
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return __sync_fetch_and_sub (ptr, 1);
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}
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__ATOMIC_INLINE__ int
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__atomic_inc(volatile int *ptr)
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{
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return __sync_fetch_and_add (ptr, 1);
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}
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int __futex_wait(volatile void *ftx, int val, const struct timespec *timeout);
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int __futex_wake(volatile void *ftx, int count);
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__END_DECLS
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#endif /* _SYS_ATOMICS_H */
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