87 lines
2.9 KiB
C++
87 lines
2.9 KiB
C++
/*
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* Distributed under the Boost Software License, Version 1.0.
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* (See accompanying file LICENSE_1_0.txt or copy at
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* http://www.boost.org/LICENSE_1_0.txt)
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*
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* Copyright (c) 2018 Andrey Semashev
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*/
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/*!
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* \file atomic/detail/fp_ops_generic.hpp
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*
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* This header contains generic implementation of the floating point atomic operations.
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*/
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#ifndef BOOST_ATOMIC_DETAIL_FP_OPS_GENERIC_HPP_INCLUDED_
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#define BOOST_ATOMIC_DETAIL_FP_OPS_GENERIC_HPP_INCLUDED_
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#include <cstddef>
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#include <boost/memory_order.hpp>
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#include <boost/atomic/detail/config.hpp>
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#include <boost/atomic/detail/bitwise_fp_cast.hpp>
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#include <boost/atomic/detail/storage_traits.hpp>
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#include <boost/atomic/detail/fp_operations_fwd.hpp>
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#include <boost/atomic/detail/header.hpp>
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#ifdef BOOST_HAS_PRAGMA_ONCE
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#pragma once
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#endif
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namespace boost {
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namespace atomics {
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namespace detail {
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//! Generic implementation of floating point operations
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template< typename Base, typename Value, std::size_t Size >
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struct fp_operations_generic :
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public Base
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{
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typedef Base base_type;
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typedef typename base_type::storage_type storage_type;
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typedef Value value_type;
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static BOOST_FORCEINLINE value_type fetch_add(storage_type volatile& storage, value_type v, memory_order order) BOOST_NOEXCEPT
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{
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storage_type old_storage, new_storage;
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value_type old_val, new_val;
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atomics::detail::non_atomic_load(storage, old_storage);
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do
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{
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old_val = atomics::detail::bitwise_fp_cast< value_type >(old_storage);
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new_val = old_val + v;
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new_storage = atomics::detail::bitwise_fp_cast< storage_type >(new_val);
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}
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while (!base_type::compare_exchange_weak(storage, old_storage, new_storage, order, memory_order_relaxed));
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return old_val;
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}
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static BOOST_FORCEINLINE value_type fetch_sub(storage_type volatile& storage, value_type v, memory_order order) BOOST_NOEXCEPT
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{
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storage_type old_storage, new_storage;
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value_type old_val, new_val;
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atomics::detail::non_atomic_load(storage, old_storage);
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do
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{
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old_val = atomics::detail::bitwise_fp_cast< value_type >(old_storage);
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new_val = old_val - v;
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new_storage = atomics::detail::bitwise_fp_cast< storage_type >(new_val);
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}
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while (!base_type::compare_exchange_weak(storage, old_storage, new_storage, order, memory_order_relaxed));
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return old_val;
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}
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};
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// Default fp_operations template definition will be used unless specialized for a specific platform
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template< typename Base, typename Value, std::size_t Size >
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struct fp_operations< Base, Value, Size, true > :
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public fp_operations_generic< Base, Value, Size >
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{
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};
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} // namespace detail
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} // namespace atomics
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} // namespace boost
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#include <boost/atomic/detail/footer.hpp>
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#endif // BOOST_ATOMIC_DETAIL_FP_OPS_GENERIC_HPP_INCLUDED_
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