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