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94540c6b | 1 | // Low-level functions for atomic operations -*- C++ -*- |
2 | ||
c360b175 | 3 | // Copyright (C) 2004, 2005, 2006 Free Software Foundation, Inc. |
94540c6b | 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 | |
23f75131 | 18 | // Software Foundation, 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, |
94540c6b | 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 | ||
b2a66747 | 30 | /** @file atomicity.h |
31 | * This is an internal header file, included by other library headers. | |
32 | * You should not attempt to use it directly. | |
33 | */ | |
34 | ||
94540c6b | 35 | #ifndef _GLIBCXX_ATOMICITY_H |
36 | #define _GLIBCXX_ATOMICITY_H 1 | |
37 | ||
1069247d | 38 | #include <bits/c++config.h> |
c360b175 | 39 | #include <bits/gthr.h> |
94540c6b | 40 | #include <bits/atomic_word.h> |
1069247d | 41 | |
42 | _GLIBCXX_BEGIN_NAMESPACE(__gnu_cxx) | |
43 | ||
c360b175 | 44 | _Atomic_word |
94540c6b | 45 | __attribute__ ((__unused__)) |
46 | __exchange_and_add(volatile _Atomic_word* __mem, int __val); | |
47 | ||
48 | void | |
49 | __attribute__ ((__unused__)) | |
50 | __atomic_add(volatile _Atomic_word* __mem, int __val); | |
aa475990 | 51 | |
c360b175 | 52 | static inline _Atomic_word |
cce6f477 | 53 | __exchange_and_add_single(_Atomic_word* __mem, int __val) |
c360b175 | 54 | { |
55 | _Atomic_word __result = *__mem; | |
56 | *__mem += __val; | |
57 | return __result; | |
58 | } | |
59 | ||
60 | static inline void | |
cce6f477 | 61 | __atomic_add_single(_Atomic_word* __mem, int __val) |
c360b175 | 62 | { *__mem += __val; } |
63 | ||
64 | static inline _Atomic_word | |
65 | __attribute__ ((__unused__)) | |
cce6f477 | 66 | __exchange_and_add_dispatch(_Atomic_word* __mem, int __val) |
c360b175 | 67 | { |
68 | #ifdef __GTHREADS | |
c360b175 | 69 | if (__gthread_active_p()) |
3ba82d60 | 70 | return __exchange_and_add(__mem, __val); |
c360b175 | 71 | else |
72 | return __exchange_and_add_single(__mem, __val); | |
c360b175 | 73 | #else |
c360b175 | 74 | return __exchange_and_add_single(__mem, __val); |
c360b175 | 75 | #endif |
76 | } | |
77 | ||
78 | static inline void | |
79 | __attribute__ ((__unused__)) | |
cce6f477 | 80 | __atomic_add_dispatch(_Atomic_word* __mem, int __val) |
c360b175 | 81 | { |
82 | #ifdef __GTHREADS | |
c360b175 | 83 | if (__gthread_active_p()) |
3ba82d60 | 84 | __atomic_add(__mem, __val); |
c360b175 | 85 | else |
86 | __atomic_add_single(__mem, __val); | |
c360b175 | 87 | #else |
c360b175 | 88 | __atomic_add_single(__mem, __val); |
c360b175 | 89 | #endif |
90 | } | |
91 | ||
1069247d | 92 | _GLIBCXX_END_NAMESPACE |
94540c6b | 93 | |
cce6f477 | 94 | // Even if the CPU doesn't need a memory barrier, we need to ensure |
95 | // that the compiler doesn't reorder memory accesses across the | |
96 | // barriers. | |
2ca3d426 | 97 | #ifndef _GLIBCXX_READ_MEM_BARRIER |
98 | #define _GLIBCXX_READ_MEM_BARRIER __asm __volatile ("":::"memory") | |
99 | #endif | |
100 | #ifndef _GLIBCXX_WRITE_MEM_BARRIER | |
101 | #define _GLIBCXX_WRITE_MEM_BARRIER __asm __volatile ("":::"memory") | |
102 | #endif | |
103 | ||
94540c6b | 104 | #endif |