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2e362c74 | 1 | // Support for atomic operations -*- C++ -*- |
2c5d0ae8 | 2 | |
a5544970 | 3 | // Copyright (C) 2004-2019 Free Software Foundation, Inc. |
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4 | // |
5 | // This file is part of the GNU ISO C++ Library. This library is free | |
6 | // software; you can redistribute it and/or modify it under the | |
7 | // terms of the GNU General Public License as published by the | |
748086b7 | 8 | // Free Software Foundation; either version 3, or (at your option) |
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9 | // any later version. |
10 | ||
11 | // This library is distributed in the hope that it will be useful, | |
12 | // but WITHOUT ANY WARRANTY; without even the implied warranty of | |
13 | // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
14 | // GNU General Public License for more details. | |
15 | ||
748086b7 JJ |
16 | // Under Section 7 of GPL version 3, you are granted additional |
17 | // permissions described in the GCC Runtime Library Exception, version | |
18 | // 3.1, as published by the Free Software Foundation. | |
2c5d0ae8 | 19 | |
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20 | // You should have received a copy of the GNU General Public License and |
21 | // a copy of the GCC Runtime Library Exception along with this program; | |
22 | // see the files COPYING3 and COPYING.RUNTIME respectively. If not, see | |
23 | // <http://www.gnu.org/licenses/>. | |
2c5d0ae8 | 24 | |
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25 | /** @file ext/atomicity.h |
26 | * This file is a GNU extension to the Standard C++ Library. | |
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27 | */ |
28 | ||
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29 | #ifndef _GLIBCXX_ATOMICITY_H |
30 | #define _GLIBCXX_ATOMICITY_H 1 | |
31 | ||
aeb1f2be PC |
32 | #pragma GCC system_header |
33 | ||
3cbc7af0 | 34 | #include <bits/c++config.h> |
b7ee72de | 35 | #include <bits/gthr.h> |
2c5d0ae8 | 36 | #include <bits/atomic_word.h> |
3cbc7af0 | 37 | |
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38 | namespace __gnu_cxx _GLIBCXX_VISIBILITY(default) |
39 | { | |
40 | _GLIBCXX_BEGIN_NAMESPACE_VERSION | |
3cbc7af0 | 41 | |
2e362c74 | 42 | // Functions for portable atomic access. |
ee5ca789 | 43 | // To abstract locking primitives across all thread policies, use: |
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44 | // __exchange_and_add_dispatch |
45 | // __atomic_add_dispatch | |
a152e96f | 46 | #ifdef _GLIBCXX_ATOMIC_BUILTINS |
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47 | static inline _Atomic_word |
48 | __exchange_and_add(volatile _Atomic_word* __mem, int __val) | |
7dcbaaa9 | 49 | { return __atomic_fetch_add(__mem, __val, __ATOMIC_ACQ_REL); } |
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50 | |
51 | static inline void | |
52 | __atomic_add(volatile _Atomic_word* __mem, int __val) | |
7dcbaaa9 | 53 | { __atomic_fetch_add(__mem, __val, __ATOMIC_ACQ_REL); } |
1b98c24e | 54 | #else |
b7ee72de | 55 | _Atomic_word |
2c5d0ae8 | 56 | __attribute__ ((__unused__)) |
09f2a1e4 | 57 | __exchange_and_add(volatile _Atomic_word*, int) throw (); |
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58 | |
59 | void | |
60 | __attribute__ ((__unused__)) | |
09f2a1e4 | 61 | __atomic_add(volatile _Atomic_word*, int) throw (); |
1b98c24e | 62 | #endif |
9268b7cb | 63 | |
b7ee72de | 64 | static inline _Atomic_word |
b93d5ca9 | 65 | __exchange_and_add_single(_Atomic_word* __mem, int __val) |
b7ee72de PC |
66 | { |
67 | _Atomic_word __result = *__mem; | |
68 | *__mem += __val; | |
69 | return __result; | |
70 | } | |
71 | ||
72 | static inline void | |
b93d5ca9 | 73 | __atomic_add_single(_Atomic_word* __mem, int __val) |
b7ee72de PC |
74 | { *__mem += __val; } |
75 | ||
76 | static inline _Atomic_word | |
77 | __attribute__ ((__unused__)) | |
b93d5ca9 | 78 | __exchange_and_add_dispatch(_Atomic_word* __mem, int __val) |
b7ee72de PC |
79 | { |
80 | #ifdef __GTHREADS | |
b7ee72de | 81 | if (__gthread_active_p()) |
701a3eee | 82 | return __exchange_and_add(__mem, __val); |
b7ee72de PC |
83 | else |
84 | return __exchange_and_add_single(__mem, __val); | |
b7ee72de | 85 | #else |
b7ee72de | 86 | return __exchange_and_add_single(__mem, __val); |
b7ee72de PC |
87 | #endif |
88 | } | |
89 | ||
90 | static inline void | |
91 | __attribute__ ((__unused__)) | |
b93d5ca9 | 92 | __atomic_add_dispatch(_Atomic_word* __mem, int __val) |
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93 | { |
94 | #ifdef __GTHREADS | |
b7ee72de | 95 | if (__gthread_active_p()) |
701a3eee | 96 | __atomic_add(__mem, __val); |
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97 | else |
98 | __atomic_add_single(__mem, __val); | |
b7ee72de | 99 | #else |
b7ee72de | 100 | __atomic_add_single(__mem, __val); |
b7ee72de PC |
101 | #endif |
102 | } | |
103 | ||
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104 | _GLIBCXX_END_NAMESPACE_VERSION |
105 | } // namespace | |
2c5d0ae8 | 106 | |
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107 | // Even if the CPU doesn't need a memory barrier, we need to ensure |
108 | // that the compiler doesn't reorder memory accesses across the | |
109 | // barriers. | |
445cf5eb | 110 | #ifndef _GLIBCXX_READ_MEM_BARRIER |
57e6d9be | 111 | #define _GLIBCXX_READ_MEM_BARRIER __atomic_thread_fence (__ATOMIC_ACQUIRE) |
445cf5eb JM |
112 | #endif |
113 | #ifndef _GLIBCXX_WRITE_MEM_BARRIER | |
57e6d9be | 114 | #define _GLIBCXX_WRITE_MEM_BARRIER __atomic_thread_fence (__ATOMIC_RELEASE) |
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115 | #endif |
116 | ||
2c5d0ae8 | 117 | #endif |