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// -*- C++ -*- |
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// Copyright (C) 2007-2021 Free Software Foundation, Inc. |
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// |
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// This file is part of the GNU ISO C++ Library. This library is free |
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// software; you can redistribute it and/or modify it under the terms |
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// of the GNU General Public License as published by the Free Software |
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// Foundation; either version 3, or (at your option) any later |
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// version. |
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|
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// This library is distributed in the hope that it will be useful, but |
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// WITHOUT ANY WARRANTY; without even the implied warranty of |
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// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
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// General Public License for more details. |
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|
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// Under Section 7 of GPL version 3, you are granted additional |
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// permissions described in the GCC Runtime Library Exception, version |
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// 3.1, as published by the Free Software Foundation. |
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|
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// You should have received a copy of the GNU General Public License and |
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// a copy of the GCC Runtime Library Exception along with this program; |
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// see the files COPYING3 and COPYING.RUNTIME respectively. If not, see |
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// <http://www.gnu.org/licenses/>. |
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|
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/** @file parallel/compatibility.h |
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* @brief Compatibility layer, mostly concerned with atomic operations. |
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* |
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* This file is a GNU parallel extension to the Standard C++ Library |
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* and contains implementation details for the library's internal use. |
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*/ |
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|
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// Written by Felix Putze. |
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|
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#ifndef _GLIBCXX_PARALLEL_COMPATIBILITY_H |
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#define _GLIBCXX_PARALLEL_COMPATIBILITY_H 1 |
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|
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#include <parallel/types.h> |
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#include <parallel/base.h> |
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|
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#if !defined(_WIN32) || defined (__CYGWIN__) |
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#include <sched.h> |
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#endif |
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|
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#ifdef __MINGW32__ |
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// Including <windows.h> will drag in all the windows32 names. Since |
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// that can cause user code portability problems, we just declare the |
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// one needed function here. |
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extern "C" |
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__attribute((dllimport)) void __attribute__((stdcall)) Sleep (unsigned long); |
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#endif |
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|
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namespace __gnu_parallel |
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{ |
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template<typename _Tp> |
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inline _Tp |
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__add_omp(volatile _Tp* __ptr, _Tp __addend) |
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{ |
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int64_t __res; |
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#pragma omp critical |
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{ |
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__res = *__ptr; |
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*(__ptr) += __addend; |
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} |
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return __res; |
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} |
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|
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/** @brief Add a value to a variable, atomically. |
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* |
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* @param __ptr Pointer to a signed integer. |
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* @param __addend Value to add. |
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*/ |
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template<typename _Tp> |
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inline _Tp |
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__fetch_and_add(volatile _Tp* __ptr, _Tp __addend) |
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{ |
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if (__atomic_always_lock_free(sizeof(_Tp), __ptr)) |
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return __atomic_fetch_add(__ptr, __addend, __ATOMIC_ACQ_REL); |
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return __add_omp(__ptr, __addend); |
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} |
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|
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template<typename _Tp> |
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inline bool |
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__cas_omp(volatile _Tp* __ptr, _Tp __comparand, _Tp __replacement) |
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{ |
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bool __res = false; |
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#pragma omp critical |
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{ |
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if (*__ptr == __comparand) |
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{ |
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*__ptr = __replacement; |
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__res = true; |
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} |
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} |
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return __res; |
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} |
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|
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/** @brief Compare-and-swap |
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* |
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* Compare @c *__ptr and @c __comparand. If equal, let @c |
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* *__ptr=__replacement and return @c true, return @c false otherwise. |
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* |
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* @param __ptr Pointer to signed integer. |
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* @param __comparand Compare value. |
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* @param __replacement Replacement value. |
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*/ |
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template<typename _Tp> |
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inline bool |
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__compare_and_swap(volatile _Tp* __ptr, _Tp __comparand, _Tp __replacement) |
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{ |
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if (__atomic_always_lock_free(sizeof(_Tp), __ptr)) |
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return __atomic_compare_exchange_n(__ptr, &__comparand, __replacement, |
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false, __ATOMIC_ACQ_REL, |
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__ATOMIC_RELAXED); |
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return __cas_omp(__ptr, __comparand, __replacement); |
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} |
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|
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/** @brief Yield control to another thread, without waiting for |
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* the end of the time slice. |
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*/ |
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inline void |
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__yield() |
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{ |
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#if defined (_WIN32) && !defined (__CYGWIN__) |
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Sleep(0); |
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#else |
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sched_yield(); |
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#endif |
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} |
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} // end namespace |
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|
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#endif /* _GLIBCXX_PARALLEL_COMPATIBILITY_H */ |
