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// Support for atomic operations -*- C++ -*-
// Copyright (C) 2008, 2009
// Free Software Foundation, Inc.
//
// This file is part of the GNU ISO C++ Library. This library is free
// software; you can redistribute it and/or modify it under the
// terms of the GNU General Public License as published by the
// Free Software Foundation; either version 3, or (at your option)
// any later version.
// This library is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
// GNU General Public License for more details.
// Under Section 7 of GPL version 3, you are granted additional
// permissions described in the GCC Runtime Library Exception, version
// 3.1, as published by the Free Software Foundation.
// You should have received a copy of the GNU General Public License and
// a copy of the GCC Runtime Library Exception along with this program;
// see the files COPYING3 and COPYING.RUNTIME respectively. If not, see
// <http://www.gnu.org/licenses/>.
#include "gstdint.h"
#include <cstdatomic>
#include <mutex>
#define LOGSIZE 4
namespace
{
#if defined(_GLIBCXX_HAS_GTHREADS) && defined(_GLIBCXX_USE_C99_STDINT_TR1)
std::mutex&
get_atomic_mutex()
{
static std::mutex atomic_mutex;
return atomic_mutex;
}
#endif
std::__atomic_flag_base volatile flag_table[ 1 << LOGSIZE ] =
{
ATOMIC_FLAG_INIT, ATOMIC_FLAG_INIT, ATOMIC_FLAG_INIT, ATOMIC_FLAG_INIT,
ATOMIC_FLAG_INIT, ATOMIC_FLAG_INIT, ATOMIC_FLAG_INIT, ATOMIC_FLAG_INIT,
ATOMIC_FLAG_INIT, ATOMIC_FLAG_INIT, ATOMIC_FLAG_INIT, ATOMIC_FLAG_INIT,
ATOMIC_FLAG_INIT, ATOMIC_FLAG_INIT, ATOMIC_FLAG_INIT, ATOMIC_FLAG_INIT,
};
} // anonymous namespace
namespace std
{
namespace __atomic0
{
bool
atomic_flag::test_and_set(memory_order) volatile
{
#if defined(_GLIBCXX_HAS_GTHREADS) && defined(_GLIBCXX_USE_C99_STDINT_TR1)
lock_guard<mutex> __lock(get_atomic_mutex());
#endif
bool result = _M_i;
_M_i = true;
return result;
}
void
atomic_flag::clear(memory_order) volatile
{
#if defined(_GLIBCXX_HAS_GTHREADS) && defined(_GLIBCXX_USE_C99_STDINT_TR1)
lock_guard<mutex> __lock(get_atomic_mutex());
#endif
_M_i = false;
}
}
extern "C"
{
bool
atomic_flag_test_and_set_explicit(volatile __atomic_flag_base* __a,
memory_order __m)
{
volatile atomic_flag d(__a->_M_i);
return d.test_and_set(__m);
}
void
atomic_flag_clear_explicit(volatile __atomic_flag_base* __a,
memory_order __m)
{
volatile atomic_flag d(__a->_M_i);
return d.clear(__m);
}
void
__atomic_flag_wait_explicit(volatile __atomic_flag_base* __a,
memory_order __x)
{
while (atomic_flag_test_and_set_explicit(__a, __x))
{ };
}
volatile __atomic_flag_base*
__atomic_flag_for_address(const volatile void* __z)
{
uintptr_t __u = reinterpret_cast<uintptr_t>(__z);
__u += (__u >> 2) + (__u << 4);
__u += (__u >> 7) + (__u << 5);
__u += (__u >> 17) + (__u << 13);
if (sizeof(uintptr_t) > 4)
__u += (__u >> 31);
__u &= ~((~uintptr_t(0)) << LOGSIZE);
return flag_table + __u;
}
} // extern "C"
} // namespace std
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