]>
git.ipfire.org Git - thirdparty/gcc.git/blob - libstdc++-v3/include/ext/atomicity.h
1 // Support for atomic operations -*- C++ -*-
3 // Copyright (C) 2004, 2005, 2006 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 2, 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 // 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
18 // Software Foundation, 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301,
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.
31 * This is an internal header file, included by other library headers.
32 * You should not attempt to use it directly.
35 #ifndef _GLIBCXX_ATOMICITY_H
36 #define _GLIBCXX_ATOMICITY_H 1
38 #include <bits/c++config.h>
39 #include <bits/gthr.h>
40 #include <bits/atomic_word.h>
42 _GLIBCXX_BEGIN_NAMESPACE(__gnu_cxx
)
44 // Functions for portable atomic access.
45 // To abstract locking primatives across all thread policies, use:
46 // __exchange_and_add_dispatch
47 // __atomic_add_dispatch
48 #ifdef _GLIBCXX_ATOMIC_BUILTINS
49 static inline _Atomic_word
50 __exchange_and_add(volatile _Atomic_word
* __mem
, int __val
)
51 { return __sync_fetch_and_add(__mem
, __val
); }
54 __atomic_add(volatile _Atomic_word
* __mem
, int __val
)
55 { __sync_fetch_and_add(__mem
, __val
); }
58 __attribute__ ((__unused__
))
59 __exchange_and_add(volatile _Atomic_word
*, int);
62 __attribute__ ((__unused__
))
63 __atomic_add(volatile _Atomic_word
*, int);
66 static inline _Atomic_word
67 __exchange_and_add_single(_Atomic_word
* __mem
, int __val
)
69 _Atomic_word __result
= *__mem
;
75 __atomic_add_single(_Atomic_word
* __mem
, int __val
)
78 static inline _Atomic_word
79 __attribute__ ((__unused__
))
80 __exchange_and_add_dispatch(_Atomic_word
* __mem
, int __val
)
83 if (__gthread_active_p())
84 return __exchange_and_add(__mem
, __val
);
86 return __exchange_and_add_single(__mem
, __val
);
88 return __exchange_and_add_single(__mem
, __val
);
93 __attribute__ ((__unused__
))
94 __atomic_add_dispatch(_Atomic_word
* __mem
, int __val
)
97 if (__gthread_active_p())
98 __atomic_add(__mem
, __val
);
100 __atomic_add_single(__mem
, __val
);
102 __atomic_add_single(__mem
, __val
);
106 _GLIBCXX_END_NAMESPACE
108 // Even if the CPU doesn't need a memory barrier, we need to ensure
109 // that the compiler doesn't reorder memory accesses across the
111 #ifndef _GLIBCXX_READ_MEM_BARRIER
112 #define _GLIBCXX_READ_MEM_BARRIER __asm __volatile ("":::"memory")
114 #ifndef _GLIBCXX_WRITE_MEM_BARRIER
115 #define _GLIBCXX_WRITE_MEM_BARRIER __asm __volatile ("":::"memory")