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1 | // Low-level type for atomic operations -*- C++ -*- |
2 | ||
748086b7 | 3 | // Copyright (C) 2004, 2005, 2006, 2007, 2009 Free Software Foundation, Inc. |
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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 | |
748086b7 | 8 | // Free Software Foundation; either version 3, or (at your option) |
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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 | ||
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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/>. | |
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24 | |
25 | #ifndef _GLIBCXX_ATOMIC_WORD_H | |
26 | #define _GLIBCXX_ATOMIC_WORD_H 1 | |
27 | ||
ddde5c6d | 28 | #include <bits/cxxabi_tweaks.h> |
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29 | |
30 | typedef int _Atomic_word; | |
31 | ||
12ffa228 | 32 | namespace __gnu_cxx _GLIBCXX_VISIBILITY(default) |
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33 | { |
34 | // Test the first byte of __g and ensure that no loads are hoisted across | |
35 | // the test. | |
36 | inline bool | |
37 | __test_and_acquire (__cxxabiv1::__guard *__g) | |
38 | { | |
39 | unsigned char __c; | |
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"); | |
44 | return __c != 0; | |
45 | } | |
46 | ||
47 | // Set the first byte of __g to 1 and ensure that no stores are sunk | |
48 | // across the store. | |
49 | inline void | |
50 | __set_and_release (__cxxabiv1::__guard *__g) | |
51 | { | |
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"); | |
56 | } | |
57 | ||
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) | |
62 | } | |
63 | ||
64 | #endif |