]>
Commit | Line | Data |
---|---|---|
72de368c | 1 | // Support for atomic operations -*- C++ -*- |
94540c6b | 2 | |
f1717362 | 3 | // Copyright (C) 2004-2016 Free Software Foundation, Inc. |
94540c6b | 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 | |
6bc9506f | 8 | // Free Software Foundation; either version 3, or (at your option) |
94540c6b | 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 | ||
6bc9506f | 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. | |
94540c6b | 19 | |
6bc9506f | 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/>. | |
94540c6b | 24 | |
5846aeac | 25 | /** @file ext/atomicity.h |
26 | * This file is a GNU extension to the Standard C++ Library. | |
b2a66747 | 27 | */ |
28 | ||
94540c6b | 29 | #ifndef _GLIBCXX_ATOMICITY_H |
30 | #define _GLIBCXX_ATOMICITY_H 1 | |
31 | ||
a440362f | 32 | #pragma GCC system_header |
33 | ||
1069247d | 34 | #include <bits/c++config.h> |
c360b175 | 35 | #include <bits/gthr.h> |
94540c6b | 36 | #include <bits/atomic_word.h> |
1069247d | 37 | |
2948dd21 | 38 | namespace __gnu_cxx _GLIBCXX_VISIBILITY(default) |
39 | { | |
40 | _GLIBCXX_BEGIN_NAMESPACE_VERSION | |
1069247d | 41 | |
72de368c | 42 | // Functions for portable atomic access. |
fa826926 | 43 | // To abstract locking primitives across all thread policies, use: |
72de368c | 44 | // __exchange_and_add_dispatch |
45 | // __atomic_add_dispatch | |
06bc5cca | 46 | #ifdef _GLIBCXX_ATOMIC_BUILTINS |
6b1464a3 | 47 | static inline _Atomic_word |
48 | __exchange_and_add(volatile _Atomic_word* __mem, int __val) | |
ec9b7e8a | 49 | { return __atomic_fetch_add(__mem, __val, __ATOMIC_ACQ_REL); } |
6b1464a3 | 50 | |
51 | static inline void | |
52 | __atomic_add(volatile _Atomic_word* __mem, int __val) | |
ec9b7e8a | 53 | { __atomic_fetch_add(__mem, __val, __ATOMIC_ACQ_REL); } |
6b1464a3 | 54 | #else |
c360b175 | 55 | _Atomic_word |
94540c6b | 56 | __attribute__ ((__unused__)) |
e49af22b | 57 | __exchange_and_add(volatile _Atomic_word*, int) throw (); |
94540c6b | 58 | |
59 | void | |
60 | __attribute__ ((__unused__)) | |
e49af22b | 61 | __atomic_add(volatile _Atomic_word*, int) throw (); |
6b1464a3 | 62 | #endif |
aa475990 | 63 | |
c360b175 | 64 | static inline _Atomic_word |
cce6f477 | 65 | __exchange_and_add_single(_Atomic_word* __mem, int __val) |
c360b175 | 66 | { |
67 | _Atomic_word __result = *__mem; | |
68 | *__mem += __val; | |
69 | return __result; | |
70 | } | |
71 | ||
72 | static inline void | |
cce6f477 | 73 | __atomic_add_single(_Atomic_word* __mem, int __val) |
c360b175 | 74 | { *__mem += __val; } |
75 | ||
76 | static inline _Atomic_word | |
77 | __attribute__ ((__unused__)) | |
cce6f477 | 78 | __exchange_and_add_dispatch(_Atomic_word* __mem, int __val) |
c360b175 | 79 | { |
80 | #ifdef __GTHREADS | |
c360b175 | 81 | if (__gthread_active_p()) |
3ba82d60 | 82 | return __exchange_and_add(__mem, __val); |
c360b175 | 83 | else |
84 | return __exchange_and_add_single(__mem, __val); | |
c360b175 | 85 | #else |
c360b175 | 86 | return __exchange_and_add_single(__mem, __val); |
c360b175 | 87 | #endif |
88 | } | |
89 | ||
90 | static inline void | |
91 | __attribute__ ((__unused__)) | |
cce6f477 | 92 | __atomic_add_dispatch(_Atomic_word* __mem, int __val) |
c360b175 | 93 | { |
94 | #ifdef __GTHREADS | |
c360b175 | 95 | if (__gthread_active_p()) |
3ba82d60 | 96 | __atomic_add(__mem, __val); |
c360b175 | 97 | else |
98 | __atomic_add_single(__mem, __val); | |
c360b175 | 99 | #else |
c360b175 | 100 | __atomic_add_single(__mem, __val); |
c360b175 | 101 | #endif |
102 | } | |
103 | ||
2948dd21 | 104 | _GLIBCXX_END_NAMESPACE_VERSION |
105 | } // namespace | |
94540c6b | 106 | |
cce6f477 | 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. | |
2ca3d426 | 110 | #ifndef _GLIBCXX_READ_MEM_BARRIER |
60be3999 | 111 | #define _GLIBCXX_READ_MEM_BARRIER __atomic_thread_fence (__ATOMIC_ACQUIRE) |
2ca3d426 | 112 | #endif |
113 | #ifndef _GLIBCXX_WRITE_MEM_BARRIER | |
60be3999 | 114 | #define _GLIBCXX_WRITE_MEM_BARRIER __atomic_thread_fence (__ATOMIC_RELEASE) |
2ca3d426 | 115 | #endif |
116 | ||
94540c6b | 117 | #endif |