1 // Low-level functions for atomic operations: x86, x >= 3 version -*- C++ -*-
3 // Copyright (C) 2003 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, 59 Temple Place - Suite 330, Boston, MA 02111-1307,
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.
30 #ifndef _GLIBCXX_ATOMICITY_H
31 #define _GLIBCXX_ATOMICITY_H 1
33 typedef int _Atomic_word
;
36 struct __Atomicity_lock
38 static volatile _Atomic_word _S_atomicity_lock
;
42 volatile _Atomic_word __Atomicity_lock
<__inst
>::_S_atomicity_lock
= 0;
44 template volatile _Atomic_word __Atomicity_lock
<0>::_S_atomicity_lock
;
46 static inline _Atomic_word
47 __attribute__ ((__unused__
))
48 __exchange_and_add(volatile _Atomic_word
* __mem
, int __val
)
50 register _Atomic_word __result
, __tmp
= 1;
52 /* obtain the atomic exchange/add spin lock */
54 __asm__
__volatile__ ("xchg{l} {%0,%1|%1,%0}"
55 : "=m" (__Atomicity_lock
<0>::_S_atomicity_lock
),
57 : "m" (__Atomicity_lock
<0>::_S_atomicity_lock
));
63 /* release spin lock */
64 __Atomicity_lock
<0>::_S_atomicity_lock
= 0;
70 __attribute__ ((__unused__
))
71 __atomic_add(volatile _Atomic_word
* __mem
, int __val
)
73 __exchange_and_add(__mem
, __val
);
76 #endif /* atomicity.h */