/*
//@HEADER
// ************************************************************************
//
//                        Kokkos v. 3.0
//       Copyright (2020) National Technology & Engineering
//               Solutions of Sandia, LLC (NTESS).
//
// Under the terms of Contract DE-NA0003525 with NTESS,
// the U.S. Government retains certain rights in this software.
//
// Redistribution and use in source and binary forms, with or without
// modification, are permitted provided that the following conditions are
// met:
//
// 1. Redistributions of source code must retain the above copyright
// notice, this list of conditions and the following disclaimer.
//
// 2. Redistributions in binary form must reproduce the above copyright
// notice, this list of conditions and the following disclaimer in the
// documentation and/or other materials provided with the distribution.
//
// 3. Neither the name of the Corporation nor the names of the
// contributors may be used to endorse or promote products derived from
// this software without specific prior written permission.
//
// THIS SOFTWARE IS PROVIDED BY NTESS "AS IS" AND ANY
// EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
// IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
// PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL NTESS OR THE
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// SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
//
// Questions? Contact Christian R. Trott (crtrott@sandia.gov)
//
// ************************************************************************
//@HEADER
*/

#if defined(KOKKOS_ENABLE_RFO_PREFETCH)
#include <xmmintrin.h>
#endif

#include <Kokkos_Macros.hpp>
#if defined(KOKKOS_ATOMIC_HPP) && !defined(KOKKOS_ATOMIC_DECREMENT_HPP)
#define KOKKOS_ATOMIC_DECREMENT_HPP

#include "impl/Kokkos_Atomic_Fetch_Sub.hpp"

namespace Kokkos {

// Atomic decrement
template <>
KOKKOS_INLINE_FUNCTION void atomic_decrement<char>(volatile char* a) {
#if defined(KOKKOS_ENABLE_ASM) && defined(KOKKOS_ENABLE_ISA_X86_64) && \
    !defined(_WIN32) && !defined(__CUDA_ARCH__)
#if defined(KOKKOS_ENABLE_RFO_PREFETCH)
  _mm_prefetch((const char*)a, _MM_HINT_ET0);
#endif
  __asm__ __volatile__("lock decb %0"
                       : /* no output registers */
                       : "m"(a[0])
                       : "memory");
#elif defined(KOKKOS_ENABLE_SERIAL_ATOMICS)
  char* a_nv = const_cast<char*>(a);
  --(*a_nv);
#else
  Kokkos::atomic_fetch_sub(a, char(1));
#endif
}

template <>
KOKKOS_INLINE_FUNCTION void atomic_decrement<short>(volatile short* a) {
#if defined(KOKKOS_ENABLE_ASM) && defined(KOKKOS_ENABLE_ISA_X86_64) && \
    !defined(_WIN32) && !defined(__CUDA_ARCH__)
#if defined(KOKKOS_ENABLE_RFO_PREFETCH)
  _mm_prefetch((const char*)a, _MM_HINT_ET0);
#endif
  __asm__ __volatile__("lock decw %0"
                       : /* no output registers */
                       : "m"(a[0])
                       : "memory");
#elif defined(KOKKOS_ENABLE_SERIAL_ATOMICS)
  short* a_nv = const_cast<short*>(a);
  --(*a_nv);
#else
  Kokkos::atomic_fetch_sub(a, short(1));
#endif
}

template <>
KOKKOS_INLINE_FUNCTION void atomic_decrement<int>(volatile int* a) {
#if defined(KOKKOS_ENABLE_ASM) && defined(KOKKOS_ENABLE_ISA_X86_64) && \
    !defined(_WIN32) && !defined(__CUDA_ARCH__)
#if defined(KOKKOS_ENABLE_RFO_PREFETCH)
  _mm_prefetch((const char*)a, _MM_HINT_ET0);
#endif
  __asm__ __volatile__("lock decl %0"
                       : /* no output registers */
                       : "m"(a[0])
                       : "memory");
#elif defined(KOKKOS_ENABLE_SERIAL_ATOMICS)
  int* a_nv = const_cast<int*>(a);
  --(*a_nv);
#else
  Kokkos::atomic_fetch_sub(a, int(1));
#endif
}

template <>
KOKKOS_INLINE_FUNCTION void atomic_decrement<long long int>(
    volatile long long int* a) {
#if defined(KOKKOS_ENABLE_ASM) && defined(KOKKOS_ENABLE_ISA_X86_64) && \
    !defined(_WIN32) && !defined(__CUDA_ARCH__)
#if defined(KOKKOS_ENABLE_RFO_PREFETCH)
  _mm_prefetch((const char*)a, _MM_HINT_ET0);
#endif
  __asm__ __volatile__("lock decq %0"
                       : /* no output registers */
                       : "m"(a[0])
                       : "memory");
#elif defined(KOKKOS_ENABLE_SERIAL_ATOMICS)
  long long int* a_nv = const_cast<long long int*>(a);
  --(*a_nv);
#else
  using T = long long int;
  Kokkos::atomic_fetch_sub(a, T(1));
#endif
}

template <typename T>
KOKKOS_INLINE_FUNCTION void atomic_decrement(volatile T* a) {
#if defined(KOKKOS_ENABLE_SERIAL_ATOMICS)
  T* a_nv = const_cast<T*>(a);
  --(*a_nv);
#else
  Kokkos::atomic_fetch_sub(a, T(1));
#endif
}

}  // End of namespace Kokkos
#endif
