1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
|
/*
* 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 _TW_SYS_ATOMICS_H
#define _TW_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.
*/
/* This was kanged from Android 4.4 bionic/libc/include/sys/atomics.h
* This header was removed in Android 5.0 in favor of stdatomics.h but
* to maintain compatibility across multiple trees, we are including our
* own copy.
*/
#ifndef __ATOMIC_INLINE__
#define __ATOMIC_INLINE__ static __inline__ __attribute__((always_inline))
#endif
__ATOMIC_INLINE__ int
__tw_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;
}
__END_DECLS
#endif /* _TW_SYS_ATOMICS_H */
|
