1 // Low-level type for atomic operations -*- C++ -*-
3 // Copyright (C) 2004-2013 Free Software Foundation, Inc.
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)
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.
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.
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/>.
25 #ifndef _GLIBCXX_ATOMIC_WORD_H
26 #define _GLIBCXX_ATOMIC_WORD_H 1
28 #include <bits/cxxabi_tweaks.h>
30 typedef int _Atomic_word;
32 namespace __gnu_cxx _GLIBCXX_VISIBILITY(default)
34 // Test the first byte of __g and ensure that no loads are hoisted across
37 __test_and_acquire (__cxxabiv1::__guard *__g)
40 unsigned char *__p = reinterpret_cast<unsigned char *>(__g);
41 // ldN.acq is a load with an implied hoist barrier.
42 // would ld8+mask be faster than just doing an ld1?
43 __asm __volatile ("ld1.acq %0 = %1" : "=r"(__c) : "m"(*__p) : "memory");
47 // Set the first byte of __g to 1 and ensure that no stores are sunk
50 __set_and_release (__cxxabiv1::__guard *__g)
52 unsigned char *__p = reinterpret_cast<unsigned char *>(__g);
53 // stN.rel is a store with an implied sink barrier.
54 // could load word, set flag, and CAS it back
55 __asm __volatile ("st1.rel %0 = %1" : "=m"(*__p) : "r"(1) : "memory");
58 // We don't define the _BARRIER macros on ia64 because the barriers are
59 // included in the test and set, above.
60 #define _GLIBCXX_GUARD_TEST_AND_ACQUIRE(G) __gnu_cxx::__test_and_acquire (G)
61 #define _GLIBCXX_GUARD_SET_AND_RELEASE(G) __gnu_cxx::__set_and_release (G)