third_party/boost/atomic/include/boost/atomic/detail/core_arch_ops_gcc_sparc.hpp

/*
 * 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) 2010 Helge Bahmann
 * Copyright (c) 2013 Tim Blechmann
 * Copyright (c) 2014 Andrey Semashev
 */
/*!
 * \file   atomic/detail/core_arch_ops_gcc_sparc.hpp
 *
 * This header contains implementation of the \c core_arch_operations template.
 */

#ifndef BOOST_ATOMIC_DETAIL_CORE_ARCH_OPS_GCC_SPARC_HPP_INCLUDED_
#define BOOST_ATOMIC_DETAIL_CORE_ARCH_OPS_GCC_SPARC_HPP_INCLUDED_

#include <cstddef>
#include <boost/memory_order.hpp>
#include <boost/atomic/detail/config.hpp>
#include <boost/atomic/detail/storage_traits.hpp>
#include <boost/atomic/detail/core_arch_operations_fwd.hpp>
#include <boost/atomic/detail/core_ops_cas_based.hpp>
#include <boost/atomic/detail/cas_based_exchange.hpp>
#include <boost/atomic/detail/extending_cas_based_arithmetic.hpp>
#include <boost/atomic/detail/header.hpp>

#ifdef BOOST_HAS_PRAGMA_ONCE
#pragma once
#endif

namespace boost {
namespace atomics {
namespace detail {

struct gcc_sparc_cas_base
{
    static BOOST_CONSTEXPR_OR_CONST bool full_cas_based = true;
    static BOOST_CONSTEXPR_OR_CONST bool is_always_lock_free = true;

    static BOOST_FORCEINLINE void fence_before(memory_order order) BOOST_NOEXCEPT
    {
        if (order == memory_order_seq_cst)
            __asm__ __volatile__ ("membar #Sync" ::: "memory");
        else if ((static_cast< unsigned int >(order) & static_cast< unsigned int >(memory_order_release)) != 0u)
            __asm__ __volatile__ ("membar #StoreStore | #LoadStore" ::: "memory");
    }

    static BOOST_FORCEINLINE void fence_after(memory_order order) BOOST_NOEXCEPT
    {
        if (order == memory_order_seq_cst)
            __asm__ __volatile__ ("membar #Sync" ::: "memory");
        else if ((static_cast< unsigned int >(order) & (static_cast< unsigned int >(memory_order_consume) | static_cast< unsigned int >(memory_order_acquire))) != 0u)
            __asm__ __volatile__ ("membar #StoreStore | #LoadStore" ::: "memory");
    }

    static BOOST_FORCEINLINE void fence_after_store(memory_order order) BOOST_NOEXCEPT
    {
        if (order == memory_order_seq_cst)
            __asm__ __volatile__ ("membar #Sync" ::: "memory");
    }
};

template< bool Signed, bool Interprocess >
struct gcc_sparc_cas32 :
    public gcc_sparc_cas_base
{
    typedef typename storage_traits< 4u >::type storage_type;

    static BOOST_CONSTEXPR_OR_CONST std::size_t storage_size = 4u;
    static BOOST_CONSTEXPR_OR_CONST std::size_t storage_alignment = 4u;
    static BOOST_CONSTEXPR_OR_CONST bool is_signed = Signed;
    static BOOST_CONSTEXPR_OR_CONST bool is_interprocess = Interprocess;

    static BOOST_FORCEINLINE void store(storage_type volatile& storage, storage_type v, memory_order order) BOOST_NOEXCEPT
    {
        fence_before(order);
        storage = v;
        fence_after_store(order);
    }

    static BOOST_FORCEINLINE storage_type load(storage_type const volatile& storage, memory_order order) BOOST_NOEXCEPT
    {
        storage_type v = storage;
        fence_after(order);
        return v;
    }

    static BOOST_FORCEINLINE bool compare_exchange_strong(
        storage_type volatile& storage, storage_type& expected, storage_type desired, memory_order success_order, memory_order failure_order) BOOST_NOEXCEPT
    {
        fence_before(success_order);
        storage_type previous = expected;
        __asm__ __volatile__
        (
            "cas [%1], %2, %0"
            : "+r" (desired)
            : "r" (&storage), "r" (previous)
            : "memory"
        );
        const bool success = (desired == previous);
        if (success)
            fence_after(success_order);
        else
            fence_after(failure_order);
        expected = desired;
        return success;
    }

    static BOOST_FORCEINLINE bool compare_exchange_weak(
        storage_type volatile& storage, storage_type& expected, storage_type desired, memory_order success_order, memory_order failure_order) BOOST_NOEXCEPT
    {
        return compare_exchange_strong(storage, expected, desired, success_order, failure_order);
    }

    static BOOST_FORCEINLINE storage_type exchange(storage_type volatile& storage, storage_type v, memory_order order) BOOST_NOEXCEPT
    {
        fence_before(order);
        __asm__ __volatile__
        (
            "swap [%1], %0"
            : "+r" (v)
            : "r" (&storage)
            : "memory"
        );
        fence_after(order);
        return v;
    }
};

template< bool Signed, bool Interprocess >
struct core_arch_operations< 4u, Signed, Interprocess > :
    public core_operations_cas_based< gcc_sparc_cas32< Signed, Interprocess > >
{
};

template< bool Signed, bool Interprocess >
struct core_arch_operations< 1u, Signed, Interprocess > :
    public extending_cas_based_arithmetic< core_arch_operations< 4u, Signed, Interprocess >, 1u, Signed >
{
};

template< bool Signed, bool Interprocess >
struct core_arch_operations< 2u, Signed, Interprocess > :
    public extending_cas_based_arithmetic< core_arch_operations< 4u, Signed, Interprocess >, 2u, Signed >
{
};

template< bool Signed, bool Interprocess >
struct gcc_sparc_cas64 :
    public gcc_sparc_cas_base
{
    typedef typename storage_traits< 8u >::type storage_type;

    static BOOST_CONSTEXPR_OR_CONST std::size_t storage_size = 8u;
    static BOOST_CONSTEXPR_OR_CONST std::size_t storage_alignment = 8u;
    static BOOST_CONSTEXPR_OR_CONST bool is_signed = Signed;
    static BOOST_CONSTEXPR_OR_CONST bool is_interprocess = Interprocess;

    static BOOST_FORCEINLINE void store(storage_type volatile& storage, storage_type v, memory_order order) BOOST_NOEXCEPT
    {
        fence_before(order);
        storage = v;
        fence_after_store(order);
    }

    static BOOST_FORCEINLINE storage_type load(storage_type const volatile& storage, memory_order order) BOOST_NOEXCEPT
    {
        storage_type v = storage;
        fence_after(order);
        return v;
    }

    static BOOST_FORCEINLINE bool compare_exchange_strong(
        storage_type volatile& storage, storage_type& expected, storage_type desired, memory_order success_order, memory_order failure_order) BOOST_NOEXCEPT
    {
        fence_before(success_order);
        storage_type previous = expected;
        __asm__ __volatile__
        (
            "casx [%1], %2, %0"
            : "+r" (desired)
            : "r" (&storage), "r" (previous)
            : "memory"
        );
        const bool success = (desired == previous);
        if (success)
            fence_after(success_order);
        else
            fence_after(failure_order);
        expected = desired;
        return success;
    }

    static BOOST_FORCEINLINE bool compare_exchange_weak(
        storage_type volatile& storage, storage_type& expected, storage_type desired, memory_order success_order, memory_order failure_order) BOOST_NOEXCEPT
    {
        return compare_exchange_strong(storage, expected, desired, success_order, failure_order);
    }
};

template< bool Signed, bool Interprocess >
struct core_arch_operations< 8u, Signed, Interprocess > :
    public core_operations_cas_based< cas_based_exchange< gcc_sparc_cas64< Signed, Interprocess > > >
{
};

} // namespace detail
} // namespace atomics
} // namespace boost

#include <boost/atomic/detail/footer.hpp>

#endif // BOOST_ATOMIC_DETAIL_ARCH_OPS_GCC_SPARC_HPP_INCLUDED_