整理

include/boost/atomic/detail/fp_ops_generic.hpp

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+/*
+ * Distributed under the Boost Software License, Version 1.0.
+ * (See accompanying file LICENSE_1_0.txt or copy at
+ * http://www.boost.org/LICENSE_1_0.txt)
+ *
+ * Copyright (c) 2018-2025 Andrey Semashev
+ */
+/*!
+ * \file   atomic/detail/fp_ops_generic.hpp
+ *
+ * This header contains generic implementation of the floating point atomic operations.
+ */
+
+#ifndef BOOST_ATOMIC_DETAIL_FP_OPS_GENERIC_HPP_INCLUDED_
+#define BOOST_ATOMIC_DETAIL_FP_OPS_GENERIC_HPP_INCLUDED_
+
+#include <cstddef>
+#include <boost/memory_order.hpp>
+#include <boost/atomic/detail/config.hpp>
+#include <boost/atomic/detail/bitwise_fp_cast.hpp>
+#include <boost/atomic/detail/storage_traits.hpp>
+#include <boost/atomic/detail/fp_operations_fwd.hpp>
+#include <boost/atomic/detail/header.hpp>
+
+#ifdef BOOST_HAS_PRAGMA_ONCE
+#pragma once
+#endif
+
+namespace boost {
+namespace atomics {
+namespace detail {
+
+//! Generic implementation of floating point operations
+template< typename Base, typename Value, std::size_t Size >
+struct fp_operations_generic :
+    public Base
+{
+    using base_type = Base;
+    using storage_type = typename base_type::storage_type;
+    using value_type = Value;
+
+    static BOOST_FORCEINLINE value_type fetch_add(storage_type volatile& storage, value_type v, memory_order order) noexcept
+    {
+        storage_type old_storage, new_storage;
+        value_type old_val, new_val;
+        atomics::detail::non_atomic_load(storage, old_storage);
+        do
+        {
+            old_val = atomics::detail::bitwise_fp_cast< value_type >(old_storage);
+            new_val = old_val + v;
+            new_storage = atomics::detail::bitwise_fp_cast< storage_type >(new_val);
+        }
+        while (!base_type::compare_exchange_weak(storage, old_storage, new_storage, order, memory_order_relaxed));
+        return old_val;
+    }
+
+    static BOOST_FORCEINLINE value_type fetch_sub(storage_type volatile& storage, value_type v, memory_order order) noexcept
+    {
+        storage_type old_storage, new_storage;
+        value_type old_val, new_val;
+        atomics::detail::non_atomic_load(storage, old_storage);
+        do
+        {
+            old_val = atomics::detail::bitwise_fp_cast< value_type >(old_storage);
+            new_val = old_val - v;
+            new_storage = atomics::detail::bitwise_fp_cast< storage_type >(new_val);
+        }
+        while (!base_type::compare_exchange_weak(storage, old_storage, new_storage, order, memory_order_relaxed));
+        return old_val;
+    }
+};
+
+// Default fp_operations template definition will be used unless specialized for a specific platform
+template< typename Base, typename Value, std::size_t Size >
+struct fp_operations< Base, Value, Size, true > :
+    public fp_operations_generic< Base, Value, Size >
+{
+};
+
+} // namespace detail
+} // namespace atomics
+} // namespace boost
+
+#include <boost/atomic/detail/footer.hpp>
+
+#endif // BOOST_ATOMIC_DETAIL_FP_OPS_GENERIC_HPP_INCLUDED_