Chris@102: /*
Chris@102:  * Distributed under the Boost Software License, Version 1.0.
Chris@102:  * (See accompanying file LICENSE_1_0.txt or copy at
Chris@102:  * http://www.boost.org/LICENSE_1_0.txt)
Chris@102:  *
Chris@102:  * Copyright (c) 2014 Andrey Semashev
Chris@102:  */
Chris@102: /*!
Chris@102:  * \file   atomic/detail/ops_extending_cas_based.hpp
Chris@102:  *
Chris@102:  * This header contains a boilerplate of the \c operations template implementation that requires sign/zero extension in arithmetic operations.
Chris@102:  */
Chris@102: 
Chris@102: #ifndef BOOST_ATOMIC_DETAIL_OPS_EXTENDING_CAS_BASED_HPP_INCLUDED_
Chris@102: #define BOOST_ATOMIC_DETAIL_OPS_EXTENDING_CAS_BASED_HPP_INCLUDED_
Chris@102: 
Chris@102: #include <boost/memory_order.hpp>
Chris@102: #include <boost/atomic/detail/config.hpp>
Chris@102: #include <boost/atomic/detail/storage_type.hpp>
Chris@102: 
Chris@102: #ifdef BOOST_HAS_PRAGMA_ONCE
Chris@102: #pragma once
Chris@102: #endif
Chris@102: 
Chris@102: namespace boost {
Chris@102: namespace atomics {
Chris@102: namespace detail {
Chris@102: 
Chris@102: template< typename Base, unsigned int Size, bool Signed >
Chris@102: struct extending_cas_based_operations :
Chris@102:     public Base
Chris@102: {
Chris@102:     typedef typename Base::storage_type storage_type;
Chris@102:     typedef typename make_storage_type< Size, Signed >::type emulated_storage_type;
Chris@102: 
Chris@102:     static BOOST_FORCEINLINE storage_type fetch_add(storage_type volatile& storage, storage_type v, memory_order order) BOOST_NOEXCEPT
Chris@102:     {
Chris@102:         storage_type old_val = Base::load(storage, memory_order_relaxed);
Chris@102:         emulated_storage_type new_val;
Chris@102:         do
Chris@102:         {
Chris@102:             new_val = static_cast< emulated_storage_type >(old_val) + static_cast< emulated_storage_type >(v);
Chris@102:         }
Chris@102:         while (!Base::compare_exchange_weak(storage, old_val, static_cast< storage_type >(new_val), order, memory_order_relaxed));
Chris@102:         return old_val;
Chris@102:     }
Chris@102: 
Chris@102:     static BOOST_FORCEINLINE storage_type fetch_sub(storage_type volatile& storage, storage_type v, memory_order order) BOOST_NOEXCEPT
Chris@102:     {
Chris@102:         storage_type old_val = Base::load(storage, memory_order_relaxed);
Chris@102:         emulated_storage_type new_val;
Chris@102:         do
Chris@102:         {
Chris@102:             new_val = static_cast< emulated_storage_type >(old_val) - static_cast< emulated_storage_type >(v);
Chris@102:         }
Chris@102:         while (!Base::compare_exchange_weak(storage, old_val, static_cast< storage_type >(new_val), order, memory_order_relaxed));
Chris@102:         return old_val;
Chris@102:     }
Chris@102: };
Chris@102: 
Chris@102: } // namespace detail
Chris@102: } // namespace atomics
Chris@102: } // namespace boost
Chris@102: 
Chris@102: #endif // BOOST_ATOMIC_DETAIL_OPS_EXTENDING_CAS_BASED_HPP_INCLUDED_