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27ca74f7 | 1 | // Low-level functions for atomic operations: x86, x >= 3 version -*- C++ -*- |
2 | ||
71e45bc2 | 3 | // Copyright (C) 2003, 2004, 2005, 2009, 2011 Free Software Foundation, Inc. |
27ca74f7 | 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 | |
6bc9506f | 8 | // Free Software Foundation; either version 3, or (at your option) |
27ca74f7 | 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 | ||
6bc9506f | 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. | |
27ca74f7 | 19 | |
6bc9506f | 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/>. | |
27ca74f7 | 24 | |
72de368c | 25 | #include <ext/atomicity.h> |
27ca74f7 | 26 | |
2948dd21 | 27 | namespace __gnu_cxx _GLIBCXX_VISIBILITY(default) |
28 | { | |
29 | _GLIBCXX_BEGIN_NAMESPACE_VERSION | |
1069247d | 30 | |
94540c6b | 31 | template<int __inst> |
d9323516 | 32 | struct _Atomicity_lock |
94540c6b | 33 | { |
34 | static volatile _Atomic_word _S_atomicity_lock; | |
35 | }; | |
36 | ||
37 | template<int __inst> | |
d9323516 | 38 | volatile _Atomic_word _Atomicity_lock<__inst>::_S_atomicity_lock = 0; |
94540c6b | 39 | |
d9323516 | 40 | template volatile _Atomic_word _Atomicity_lock<0>::_S_atomicity_lock; |
94540c6b | 41 | |
42 | _Atomic_word | |
43 | __attribute__ ((__unused__)) | |
e49af22b | 44 | __exchange_and_add(volatile _Atomic_word* __mem, int __val) throw () |
94540c6b | 45 | { |
46 | register _Atomic_word __result, __tmp = 1; | |
47 | ||
48 | // Obtain the atomic exchange/add spin lock. | |
49 | do | |
50 | { | |
51 | __asm__ __volatile__ ("xchg{l} {%0,%1|%1,%0}" | |
d9323516 | 52 | : "=m" (_Atomicity_lock<0>::_S_atomicity_lock), |
94540c6b | 53 | "+r" (__tmp) |
d9323516 | 54 | : "m" (_Atomicity_lock<0>::_S_atomicity_lock)); |
94540c6b | 55 | } |
56 | while (__tmp); | |
57 | ||
58 | __result = *__mem; | |
59 | *__mem += __val; | |
60 | ||
61 | // Release spin lock. | |
d9323516 | 62 | _Atomicity_lock<0>::_S_atomicity_lock = 0; |
94540c6b | 63 | |
64 | return __result; | |
65 | } | |
66 | ||
67 | void | |
68 | __attribute__ ((__unused__)) | |
e49af22b | 69 | __atomic_add(volatile _Atomic_word* __mem, int __val) throw () |
94540c6b | 70 | { __exchange_and_add(__mem, __val); } |
1069247d | 71 | |
2948dd21 | 72 | _GLIBCXX_END_NAMESPACE_VERSION |
73 | } // namespace |