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1 | /* |
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) | |
5 | * | |
6 | * Copyright (c) 2014 Andrey Semashev | |
7 | */ | |
8 | /*! | |
9 | * \file atomic/detail/ops_extending_cas_based.hpp | |
10 | * | |
11 | * This header contains a boilerplate of the \c operations template implementation that requires sign/zero extension in arithmetic operations. | |
12 | */ | |
13 | ||
14 | #ifndef BOOST_ATOMIC_DETAIL_OPS_EXTENDING_CAS_BASED_HPP_INCLUDED_ | |
15 | #define BOOST_ATOMIC_DETAIL_OPS_EXTENDING_CAS_BASED_HPP_INCLUDED_ | |
16 | ||
17 | #include <cstddef> | |
18 | #include <boost/memory_order.hpp> | |
19 | #include <boost/atomic/detail/config.hpp> | |
20 | #include <boost/atomic/detail/storage_type.hpp> | |
21 | ||
22 | #ifdef BOOST_HAS_PRAGMA_ONCE | |
23 | #pragma once | |
24 | #endif | |
25 | ||
26 | namespace boost { | |
27 | namespace atomics { | |
28 | namespace detail { | |
29 | ||
30 | template< typename Base, std::size_t Size, bool Signed > | |
31 | struct extending_cas_based_operations : | |
32 | public Base | |
33 | { | |
34 | typedef typename Base::storage_type storage_type; | |
35 | typedef typename make_storage_type< Size, Signed >::type emulated_storage_type; | |
36 | ||
37 | static BOOST_FORCEINLINE storage_type fetch_add(storage_type volatile& storage, storage_type v, memory_order order) BOOST_NOEXCEPT | |
38 | { | |
39 | storage_type old_val; | |
40 | atomics::detail::non_atomic_load(storage, old_val); | |
41 | emulated_storage_type new_val; | |
42 | do | |
43 | { | |
44 | new_val = static_cast< emulated_storage_type >(old_val) + static_cast< emulated_storage_type >(v); | |
45 | } | |
46 | while (!Base::compare_exchange_weak(storage, old_val, static_cast< storage_type >(new_val), order, memory_order_relaxed)); | |
47 | return old_val; | |
48 | } | |
49 | ||
50 | static BOOST_FORCEINLINE storage_type fetch_sub(storage_type volatile& storage, storage_type v, memory_order order) BOOST_NOEXCEPT | |
51 | { | |
52 | storage_type old_val; | |
53 | atomics::detail::non_atomic_load(storage, old_val); | |
54 | emulated_storage_type new_val; | |
55 | do | |
56 | { | |
57 | new_val = static_cast< emulated_storage_type >(old_val) - static_cast< emulated_storage_type >(v); | |
58 | } | |
59 | while (!Base::compare_exchange_weak(storage, old_val, static_cast< storage_type >(new_val), order, memory_order_relaxed)); | |
60 | return old_val; | |
61 | } | |
62 | }; | |
63 | ||
64 | } // namespace detail | |
65 | } // namespace atomics | |
66 | } // namespace boost | |
67 | ||
68 | #endif // BOOST_ATOMIC_DETAIL_OPS_EXTENDING_CAS_BASED_HPP_INCLUDED_ |