1 // Low-level functions for atomic operations: x86, x >= 4 version -*- C++ -*-
3 // Copyright (C) 1999-2020 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 3, 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 // 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.
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/>.
25 #include <ext/atomicity.h>
27 namespace __gnu_cxx
_GLIBCXX_VISIBILITY(default)
29 _GLIBCXX_BEGIN_NAMESPACE_VERSION
32 __attribute__ ((__unused__
))
33 __exchange_and_add(volatile _Atomic_word
* __mem
, int __val
) throw ()
35 register _Atomic_word __result
;
36 __asm__
__volatile__ ("lock; xadd{l} {%0,%1|%1,%0}"
37 : "=r" (__result
), "=m" (*__mem
)
38 : "0" (__val
), "m" (*__mem
));
43 __attribute__ ((__unused__
))
44 __atomic_add(volatile _Atomic_word
* __mem
, int __val
) throw ()
46 __asm__
__volatile__ ("lock; add{l} {%1,%0|%0,%1}"
47 : "=m" (*__mem
) : "ir" (__val
), "m" (*__mem
));
50 _GLIBCXX_END_NAMESPACE_VERSION