/* * 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_value, int new_value, volatile int* ptr) { /* We must return 0 on success */ return __sync_val_compare_and_swap(ptr, old_value, new_value) != old_value; } __ATOMIC_INLINE__ int __atomic_swap(int new_value, volatile int *ptr) { int old_value; do { old_value = *ptr; } while (__sync_val_compare_and_swap(ptr, old_value, new_value) != old_value); return old_value; } __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 */