1// Support for atomic operations -*- C++ -*- 2 3// Copyright (C) 2008, 2009 4// Free Software Foundation, Inc. 5// 6// This file is part of the GNU ISO C++ Library. This library is free 7// software; you can redistribute it and/or modify it under the 8// terms of the GNU General Public License as published by the 9// Free Software Foundation; either version 3, or (at your option) 10// any later version. 11 12// This library is distributed in the hope that it will be useful, 13// but WITHOUT ANY WARRANTY; without even the implied warranty of 14// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 15// GNU General Public License for more details. 16 17// Under Section 7 of GPL version 3, you are granted additional 18// permissions described in the GCC Runtime Library Exception, version 19// 3.1, as published by the Free Software Foundation. 20 21// You should have received a copy of the GNU General Public License and 22// a copy of the GCC Runtime Library Exception along with this program; 23// see the files COPYING3 and COPYING.RUNTIME respectively. If not, see 24// <http://www.gnu.org/licenses/>. 25 26#include "gstdint.h" 27#include <atomic> 28#include <mutex> 29 30#define LOGSIZE 4 31 32namespace 33{ 34#if defined(_GLIBCXX_HAS_GTHREADS) && defined(_GLIBCXX_USE_C99_STDINT_TR1) 35 std::mutex& 36 get_atomic_mutex() 37 { 38 static std::mutex atomic_mutex; 39 return atomic_mutex; 40 } 41#endif 42 43 std::__atomic_flag_base flag_table[ 1 << LOGSIZE ] = 44 { 45 ATOMIC_FLAG_INIT, ATOMIC_FLAG_INIT, ATOMIC_FLAG_INIT, ATOMIC_FLAG_INIT, 46 ATOMIC_FLAG_INIT, ATOMIC_FLAG_INIT, ATOMIC_FLAG_INIT, ATOMIC_FLAG_INIT, 47 ATOMIC_FLAG_INIT, ATOMIC_FLAG_INIT, ATOMIC_FLAG_INIT, ATOMIC_FLAG_INIT, 48 ATOMIC_FLAG_INIT, ATOMIC_FLAG_INIT, ATOMIC_FLAG_INIT, ATOMIC_FLAG_INIT, 49 }; 50} // anonymous namespace 51 52namespace std 53{ 54 namespace __atomic0 55 { 56 bool 57 atomic_flag::test_and_set(memory_order) 58 { 59#if defined(_GLIBCXX_HAS_GTHREADS) && defined(_GLIBCXX_USE_C99_STDINT_TR1) 60 lock_guard<mutex> __lock(get_atomic_mutex()); 61#endif 62 bool result = _M_i; 63 _M_i = true; 64 return result; 65 } 66 67 void 68 atomic_flag::clear(memory_order) 69 { 70#if defined(_GLIBCXX_HAS_GTHREADS) && defined(_GLIBCXX_USE_C99_STDINT_TR1) 71 lock_guard<mutex> __lock(get_atomic_mutex()); 72#endif 73 _M_i = false; 74 } 75 } 76 77 extern "C" 78 { 79 bool 80 atomic_flag_test_and_set_explicit(__atomic_flag_base* __a, 81 memory_order __m) throw() 82 { 83 atomic_flag* d = static_cast<volatile atomic_flag*>(__a); 84 return d->test_and_set(__m); 85 } 86 87 void 88 atomic_flag_clear_explicit(__atomic_flag_base* __a, 89 memory_order __m) throw() 90 { 91 atomic_flag* d = static_cast<volatile atomic_flag*>(__a); 92 return d->clear(__m); 93 } 94 95 void 96 __atomic_flag_wait_explicit(__atomic_flag_base* __a, 97 memory_order __x) throw() 98 { 99 while (atomic_flag_test_and_set_explicit(__a, __x)) 100 { }; 101 } 102 103 __atomic_flag_base* 104 __atomic_flag_for_address(const void* __z) throw() 105 { 106 uintptr_t __u = reinterpret_cast<uintptr_t>(__z); 107 __u += (__u >> 2) + (__u << 4); 108 __u += (__u >> 7) + (__u << 5); 109 __u += (__u >> 17) + (__u << 13); 110 if (sizeof(uintptr_t) > 4) 111 __u += (__u >> 31); 112 __u &= ~((~uintptr_t(0)) << LOGSIZE); 113 return flag_table + __u; 114 } 115 } // extern "C" 116} // namespace std 117 118 119// XXX GLIBCXX_ABI Deprecated 120// gcc-4.5.0 121// <atomic> signature changes 122 123// The rename syntax for default exported names is 124// asm (".symver name1,exportedname@GLIBCXX_3.4") 125// asm (".symver name2,exportedname@@GLIBCXX_3.4.5") 126// In the future, GLIBCXX_ABI > 6 should remove all uses of 127// _GLIBCXX_*_SYMVER macros in this file. 128 129#if defined(_GLIBCXX_SYMVER_GNU) && defined(PIC) \ 130 && defined(_GLIBCXX_HAVE_AS_SYMVER_DIRECTIVE) 131 132#define _GLIBCXX_ASM_SYMVER(cur, old, version) \ 133 asm (".symver " #cur "," #old "@@" #version); 134 135_GLIBCXX_ASM_SYMVER(_ZNSt9__atomic011atomic_flag5clearESt12memory_order, _ZNVSt9__atomic011atomic_flag5clearESt12memory_order, GLIBCXX_3.4.11) 136 137_GLIBCXX_ASM_SYMVER(_ZNSt9__atomic011atomic_flag12test_and_setESt12memory_order, _ZNVSt9__atomic011atomic_flag12test_and_setESt12memory_order, GLIBCXX_3.4.11) 138 139#endif 140