2 * Distributed under the Boost Software License, Version 1.0.
3 * (See accompanying file LICENSE_1_0.txt or copy at
4 * http://www.boost.org/LICENSE_1_0.txt)
6 * Copyright (c) 2014 Andrey Semashev
9 * \file atomic/detail/ops_extending_cas_based.hpp
11 * This header contains a boilerplate of the \c operations template implementation that requires sign/zero extension in arithmetic operations.
14 #ifndef BOOST_ATOMIC_DETAIL_OPS_EXTENDING_CAS_BASED_HPP_INCLUDED_
15 #define BOOST_ATOMIC_DETAIL_OPS_EXTENDING_CAS_BASED_HPP_INCLUDED_
18 #include <boost/memory_order.hpp>
19 #include <boost/atomic/detail/config.hpp>
20 #include <boost/atomic/detail/storage_type.hpp>
22 #ifdef BOOST_HAS_PRAGMA_ONCE
30 template< typename Base, std::size_t Size, bool Signed >
31 struct extending_cas_based_operations :
34 typedef typename Base::storage_type storage_type;
35 typedef typename make_storage_type< Size, Signed >::type emulated_storage_type;
37 static BOOST_FORCEINLINE storage_type fetch_add(storage_type volatile& storage, storage_type v, memory_order order) BOOST_NOEXCEPT
40 atomics::detail::non_atomic_load(storage, old_val);
41 emulated_storage_type new_val;
44 new_val = static_cast< emulated_storage_type >(old_val) + static_cast< emulated_storage_type >(v);
46 while (!Base::compare_exchange_weak(storage, old_val, static_cast< storage_type >(new_val), order, memory_order_relaxed));
50 static BOOST_FORCEINLINE storage_type fetch_sub(storage_type volatile& storage, storage_type v, memory_order order) BOOST_NOEXCEPT
53 atomics::detail::non_atomic_load(storage, old_val);
54 emulated_storage_type new_val;
57 new_val = static_cast< emulated_storage_type >(old_val) - static_cast< emulated_storage_type >(v);
59 while (!Base::compare_exchange_weak(storage, old_val, static_cast< storage_type >(new_val), order, memory_order_relaxed));
65 } // namespace atomics
68 #endif // BOOST_ATOMIC_DETAIL_OPS_EXTENDING_CAS_BASED_HPP_INCLUDED_