/*

 * Copyright (c) 2003, 2019, Oracle and/or its affiliates. All rights reserved.

 * Copyright 2007, 2008, 2011, 2015, Red Hat, Inc.

 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.

 *

 * This code is free software; you can redistribute it and/or modify it

 * under the terms of the GNU General Public License version 2 only, as

 * published by the Free Software Foundation.

 *

 * This code is distributed in the hope that it will be useful, but WITHOUT

 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or

 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License

 * version 2 for more details (a copy is included in the LICENSE file that

 * accompanied this code).

 *

 * You should have received a copy of the GNU General Public License version

 * 2 along with this work; if not, write to the Free Software Foundation,

 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.

 *

 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA

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 */

#ifndef OS_CPU_LINUX_ZERO_ATOMIC_LINUX_ZERO_HPP

#define OS_CPU_LINUX_ZERO_ATOMIC_LINUX_ZERO_HPP

#include "runtime/os.hpp"

// Implementation of class atomic

template<size_t byte_size>

struct Atomic::PlatformAdd

  : Atomic::AddAndFetch<Atomic::PlatformAdd<byte_size> >

{

  template<typename D, typename I>

  D add_and_fetch(D volatile* dest, I add_value, atomic_memory_order order) const;

};

template<>

template<typename D, typename I>

inline D Atomic::PlatformAdd<4>::add_and_fetch(D volatile* dest, I add_value,

                                               atomic_memory_order order) const {

  STATIC_ASSERT(4 == sizeof(I));

  STATIC_ASSERT(4 == sizeof(D));

  return __sync_add_and_fetch(dest, add_value);

}

template<>

template<typename D, typename I>

inline D Atomic::PlatformAdd<8>::add_and_fetch(D volatile* dest, I add_value,

                                               atomic_memory_order order) const {

  STATIC_ASSERT(8 == sizeof(I));

  STATIC_ASSERT(8 == sizeof(D));

  return __sync_add_and_fetch(dest, add_value);

}

template<>

template<typename T>

inline T Atomic::PlatformXchg<4>::operator()(T volatile* dest,

                                             T exchange_value,

                                             atomic_memory_order order) const {

  STATIC_ASSERT(4 == sizeof(T));

  // __sync_lock_test_and_set is a bizarrely named atomic exchange

  // operation.  Note that some platforms only support this with the

  // limitation that the only valid value to store is the immediate

  // constant 1.  There is a test for this in JNI_CreateJavaVM().

  T result = __sync_lock_test_and_set (dest, exchange_value);

  // All atomic operations are expected to be full memory barriers

  // (see atomic.hpp). However, __sync_lock_test_and_set is not

  // a full memory barrier, but an acquire barrier. Hence, this added

  // barrier.

  __sync_synchronize();

  return result;

}

template<>

template<typename T>

inline T Atomic::PlatformXchg<8>::operator()(T volatile* dest,

                                             T exchange_value,

                                             atomic_memory_order order) const {

  STATIC_ASSERT(8 == sizeof(T));

  T result = __sync_lock_test_and_set (dest, exchange_value);

  __sync_synchronize();

  return result;

}

// No direct support for cmpxchg of bytes; emulate using int.

template<>

struct Atomic::PlatformCmpxchg<1> : Atomic::CmpxchgByteUsingInt {};

template<>

template<typename T>

                                                T compare_value,

                                                atomic_memory_order order) const {

  STATIC_ASSERT(4 == sizeof(T));

  return __sync_val_compare_and_swap(dest, compare_value, exchange_value);

}

template<>

template<typename T>

                                                T compare_value,

                                                atomic_memory_order order) const {

  STATIC_ASSERT(8 == sizeof(T));

  return __sync_val_compare_and_swap(dest, compare_value, exchange_value);

}

template<>

template<typename T>

inline T Atomic::PlatformLoad<8>::operator()(T const volatile* src) const {

  STATIC_ASSERT(8 == sizeof(T));

  volatile int64_t dest;

  os::atomic_copy64(reinterpret_cast<const volatile int64_t*>(src), reinterpret_cast<volatile int64_t*>(&dest));

  return PrimitiveConversions::cast<T>(dest);

}

template<>

template<typename T>

inline void Atomic::PlatformStore<8>::operator()(T volatile* dest,

                                                 T store_value) const {

  STATIC_ASSERT(8 == sizeof(T));

  os::atomic_copy64(reinterpret_cast<const volatile int64_t*>(&store_value), reinterpret_cast<volatile int64_t*>(dest));

}

#endif // OS_CPU_LINUX_ZERO_ATOMIC_LINUX_ZERO_HPP