/*
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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) 2014 Andrey Semashev
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*/
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/*!
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* \file atomic/detail/extending_cas_based_arithmetic.hpp
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*
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* This header contains a boilerplate of core atomic operations that require sign/zero extension in arithmetic operations.
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*/
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#ifndef BOOST_ATOMIC_DETAIL_EXTENDING_CAS_BASED_ARITHMETIC_HPP_INCLUDED_
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#define BOOST_ATOMIC_DETAIL_EXTENDING_CAS_BASED_ARITHMETIC_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/storage_traits.hpp>
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#include <boost/atomic/detail/integral_conversions.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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template< typename Base, std::size_t Size, bool Signed >
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struct extending_cas_based_arithmetic :
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public Base
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{
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typedef typename Base::storage_type storage_type;
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typedef typename storage_traits< Size >::type emulated_storage_type;
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static BOOST_FORCEINLINE storage_type fetch_add(storage_type volatile& storage, storage_type v, memory_order order) BOOST_NOEXCEPT
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{
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storage_type old_val;
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atomics::detail::non_atomic_load(storage, old_val);
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storage_type new_val;
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do
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{
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new_val = atomics::detail::integral_extend< Signed, storage_type >(static_cast< emulated_storage_type >(old_val + v));
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}
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while (!Base::compare_exchange_weak(storage, old_val, new_val, order, memory_order_relaxed));
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return old_val;
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}
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static BOOST_FORCEINLINE storage_type fetch_sub(storage_type volatile& storage, storage_type v, memory_order order) BOOST_NOEXCEPT
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{
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storage_type old_val;
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atomics::detail::non_atomic_load(storage, old_val);
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storage_type new_val;
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do
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{
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new_val = atomics::detail::integral_extend< Signed, storage_type >(static_cast< emulated_storage_type >(old_val - v));
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}
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while (!Base::compare_exchange_weak(storage, old_val, new_val, order, memory_order_relaxed));
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return old_val;
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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_EXTENDING_CAS_BASED_ARITHMETIC_HPP_INCLUDED_
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