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c2ba9709 JS |
1 | // -*- C++ -*- |
2 | ||
a945c346 | 3 | // Copyright (C) 2007-2024 Free Software Foundation, Inc. |
c2ba9709 JS |
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 terms | |
7 | // of the GNU General Public License as published by the Free Software | |
748086b7 | 8 | // Foundation; either version 3, or (at your option) any later |
c2ba9709 JS |
9 | // version. |
10 | ||
11 | // This library is distributed in the hope that it will be useful, but | |
12 | // WITHOUT ANY WARRANTY; without even the implied warranty of | |
13 | // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU | |
14 | // 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. | |
c2ba9709 | 19 | |
748086b7 JJ |
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/>. | |
c2ba9709 JS |
24 | |
25 | /** @file parallel/compatibility.h | |
26 | * @brief Compatibility layer, mostly concerned with atomic operations. | |
693ac783 JW |
27 | * |
28 | * This file is a GNU parallel extension to the Standard C++ Library | |
29 | * and contains implementation details for the library's internal use. | |
c2ba9709 JS |
30 | */ |
31 | ||
32 | // Written by Felix Putze. | |
33 | ||
34 | #ifndef _GLIBCXX_PARALLEL_COMPATIBILITY_H | |
35 | #define _GLIBCXX_PARALLEL_COMPATIBILITY_H 1 | |
36 | ||
37 | #include <parallel/types.h> | |
38 | #include <parallel/base.h> | |
39 | ||
cccc4450 | 40 | #if !defined(_WIN32) || defined (__CYGWIN__) |
c2ba9709 JS |
41 | #include <sched.h> |
42 | #endif | |
43 | ||
cccc4450 DS |
44 | #ifdef __MINGW32__ |
45 | // Including <windows.h> will drag in all the windows32 names. Since | |
46 | // that can cause user code portability problems, we just declare the | |
47 | // one needed function here. | |
48 | extern "C" | |
49 | __attribute((dllimport)) void __attribute__((stdcall)) Sleep (unsigned long); | |
50 | #endif | |
51 | ||
c2ba9709 JS |
52 | namespace __gnu_parallel |
53 | { | |
80241991 JW |
54 | template<typename _Tp> |
55 | inline _Tp | |
56 | __add_omp(volatile _Tp* __ptr, _Tp __addend) | |
c2ba9709 | 57 | { |
80241991 JW |
58 | int64_t __res; |
59 | #pragma omp critical | |
60 | { | |
61 | __res = *__ptr; | |
62 | *(__ptr) += __addend; | |
63 | } | |
64 | return __res; | |
c2ba9709 | 65 | } |
c2ba9709 JS |
66 | |
67 | /** @brief Add a value to a variable, atomically. | |
68 | * | |
1acba85b JS |
69 | * @param __ptr Pointer to a signed integer. |
70 | * @param __addend Value to add. | |
c2ba9709 | 71 | */ |
1acba85b | 72 | template<typename _Tp> |
80241991 JW |
73 | inline _Tp |
74 | __fetch_and_add(volatile _Tp* __ptr, _Tp __addend) | |
75 | { | |
76 | if (__atomic_always_lock_free(sizeof(_Tp), __ptr)) | |
77 | return __atomic_fetch_add(__ptr, __addend, __ATOMIC_ACQ_REL); | |
78 | return __add_omp(__ptr, __addend); | |
79 | } | |
c2ba9709 | 80 | |
80241991 JW |
81 | template<typename _Tp> |
82 | inline bool | |
83 | __cas_omp(volatile _Tp* __ptr, _Tp __comparand, _Tp __replacement) | |
c2ba9709 | 84 | { |
80241991 JW |
85 | bool __res = false; |
86 | #pragma omp critical | |
87 | { | |
88 | if (*__ptr == __comparand) | |
89 | { | |
90 | *__ptr = __replacement; | |
91 | __res = true; | |
92 | } | |
93 | } | |
94 | return __res; | |
c2ba9709 | 95 | } |
c2ba9709 | 96 | |
80241991 JW |
97 | /** @brief Compare-and-swap |
98 | * | |
99 | * Compare @c *__ptr and @c __comparand. If equal, let @c | |
8e32aa11 | 100 | * *__ptr=__replacement and return @c true, return @c false otherwise. |
c2ba9709 | 101 | * |
1acba85b JS |
102 | * @param __ptr Pointer to signed integer. |
103 | * @param __comparand Compare value. | |
693ac783 JW |
104 | * @param __replacement Replacement value. |
105 | */ | |
1acba85b | 106 | template<typename _Tp> |
80241991 JW |
107 | inline bool |
108 | __compare_and_swap(volatile _Tp* __ptr, _Tp __comparand, _Tp __replacement) | |
109 | { | |
110 | if (__atomic_always_lock_free(sizeof(_Tp), __ptr)) | |
111 | return __atomic_compare_exchange_n(__ptr, &__comparand, __replacement, | |
112 | false, __ATOMIC_ACQ_REL, | |
113 | __ATOMIC_RELAXED); | |
114 | return __cas_omp(__ptr, __comparand, __replacement); | |
115 | } | |
c2ba9709 | 116 | |
80241991 | 117 | /** @brief Yield control to another thread, without waiting for |
693ac783 JW |
118 | * the end of the time slice. |
119 | */ | |
c2ba9709 | 120 | inline void |
1acba85b | 121 | __yield() |
c2ba9709 | 122 | { |
cccc4450 | 123 | #if defined (_WIN32) && !defined (__CYGWIN__) |
c2ba9709 JS |
124 | Sleep(0); |
125 | #else | |
126 | sched_yield(); | |
127 | #endif | |
128 | } | |
129 | } // end namespace | |
130 | ||
cbcd1e45 | 131 | #endif /* _GLIBCXX_PARALLEL_COMPATIBILITY_H */ |