atomicity.h revision 169692
1// Low-level functions for atomic operations: x86, x >= 4 version -*- C++ -*- 2 3// Copyright (C) 1999, 2000, 2001, 2004, 2005 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 2, 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// You should have received a copy of the GNU General Public License along 17// with this library; see the file COPYING. If not, write to the Free 18// Software Foundation, 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, 19// USA. 20 21// As a special exception, you may use this file as part of a free software 22// library without restriction. Specifically, if other files instantiate 23// templates or use macros or inline functions from this file, or you compile 24// this file and link it with other files to produce an executable, this 25// file does not by itself cause the resulting executable to be covered by 26// the GNU General Public License. This exception does not however 27// invalidate any other reasons why the executable file might be covered by 28// the GNU General Public License. 29 30#include <ext/atomicity.h> 31 32_GLIBCXX_BEGIN_NAMESPACE(__gnu_cxx) 33 34 _Atomic_word 35 __attribute__ ((__unused__)) 36 __exchange_and_add(volatile _Atomic_word* __mem, int __val) 37 { 38 register _Atomic_word __result; 39 __asm__ __volatile__ ("lock; xadd{l} {%0,%1|%1,%0}" 40 : "=r" (__result), "=m" (*__mem) 41 : "0" (__val), "m" (*__mem)); 42 return __result; 43 } 44 45 void 46 __attribute__ ((__unused__)) 47 __atomic_add(volatile _Atomic_word* __mem, int __val) 48 { 49 __asm__ __volatile__ ("lock; add{l} {%1,%0|%0,%1}" 50 : "=m" (*__mem) : "ir" (__val), "m" (*__mem)); 51 } 52 53_GLIBCXX_END_NAMESPACE 54 55