1 // Low-level functions for atomic operations: x86, x >= 4 version -*- C++ -*- 2 3 // Copyright (C) 1999, 2000, 2001, 2004, 2005, 2009 Free Software Foundation, Inc. 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 8 // Free Software Foundation; either version 3, or (at your option) 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 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. 19 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/>. 24 25 #include <ext/atomicity.h> 26 27 namespace __gnu_cxx _GLIBCXX_VISIBILITY(default) 28 { 29 _GLIBCXX_BEGIN_NAMESPACE_VERSION 30 31 _Atomic_word 32 __attribute__ ((__unused__)) 33 __exchange_and_add(volatile _Atomic_word* __mem, int __val) throw () 34 { 35 register _Atomic_word __result; 36 __asm__ __volatile__ ("lock; xadd{l} {%0,%1|%1,%0}" 37 : "=r" (__result), "=m" (*__mem) 38 : "0" (__val), "m" (*__mem)); 39 return __result; 40 } 41 42 void 43 __attribute__ ((__unused__)) 44 __atomic_add(volatile _Atomic_word* __mem, int __val) throw () 45 { 46 __asm__ __volatile__ ("lock; add{l} {%1,%0|%0,%1}" 47 : "=m" (*__mem) : "ir" (__val), "m" (*__mem)); 48 } 49 50 _GLIBCXX_END_NAMESPACE_VERSION 51 } // namespace 52 53