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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); | |
1069247d | 51 | |
c360b175 | 52 | static inline _Atomic_word |
53 | __exchange_and_add_single(volatile _Atomic_word* __mem, int __val) | |
54 | { | |
55 | _Atomic_word __result = *__mem; | |
56 | *__mem += __val; | |
57 | return __result; | |
58 | } | |
59 | ||
60 | static inline void | |
61 | __atomic_add_single(volatile _Atomic_word* __mem, int __val) | |
62 | { *__mem += __val; } | |
63 | ||
64 | static inline _Atomic_word | |
65 | __attribute__ ((__unused__)) | |
66 | __exchange_and_add_dispatch(volatile _Atomic_word* __mem, int __val) | |
67 | { | |
68 | #ifdef __GTHREADS | |
69 | ||
70 | if (__gthread_active_p()) | |
71 | return __exchange_and_add(__mem, __val); | |
72 | else | |
73 | return __exchange_and_add_single(__mem, __val); | |
74 | ||
75 | #else | |
76 | ||
77 | return __exchange_and_add_single(__mem, __val); | |
78 | ||
79 | #endif | |
80 | } | |
81 | ||
82 | static inline void | |
83 | __attribute__ ((__unused__)) | |
84 | __atomic_add_dispatch(volatile _Atomic_word* __mem, int __val) | |
85 | { | |
86 | #ifdef __GTHREADS | |
87 | ||
88 | if (__gthread_active_p()) | |
89 | __atomic_add(__mem, __val); | |
90 | else | |
91 | __atomic_add_single(__mem, __val); | |
92 | ||
93 | #else | |
94 | ||
95 | __atomic_add_single(__mem, __val); | |
96 | ||
97 | #endif | |
98 | } | |
99 | ||
1069247d | 100 | _GLIBCXX_END_NAMESPACE |
94540c6b | 101 | |
2ca3d426 | 102 | /* Even if the CPU doesn't need a memory barrier, we need to ensure that |
103 | the compiler doesn't reorder memory accesses across the barriers. */ | |
104 | #ifndef _GLIBCXX_READ_MEM_BARRIER | |
105 | #define _GLIBCXX_READ_MEM_BARRIER __asm __volatile ("":::"memory") | |
106 | #endif | |
107 | #ifndef _GLIBCXX_WRITE_MEM_BARRIER | |
108 | #define _GLIBCXX_WRITE_MEM_BARRIER __asm __volatile ("":::"memory") | |
109 | #endif | |
110 | ||
94540c6b | 111 | #endif |