<gh_stars>0
/*
//@HEADER
// ************************************************************************
//
//                        Kokkos v. 2.0
//              Copyright (2014) Sandia Corporation
//
// Under the terms of Contract DE-AC04-94AL85000 with Sandia Corporation,
// 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 SANDIA CORPORATION "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 SANDIA CORPORATION OR THE
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//
// Questions? Contact <NAME> (<EMAIL>)
//
// ************************************************************************
//@HEADER
*/

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

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

#if defined(KOKKOS_ENABLE_CUDA)
#include<Cuda/Kokkos_Cuda_Version_9_8_Compatibility.hpp>
#endif

namespace Kokkos {

//----------------------------------------------------------------------------

#if defined( KOKKOS_ENABLE_CUDA )
#if defined(__CUDA_ARCH__) || defined(KOKKOS_IMPL_CUDA_CLANG_WORKAROUND)

// Support for int, unsigned int, unsigned long long int, and float

__inline__ __device__
int atomic_fetch_sub( volatile int * const dest , const int val )
{ return atomicSub((int*)dest,val); }

__inline__ __device__
unsigned int atomic_fetch_sub( volatile unsigned int * const dest , const unsigned int val )
{ return atomicSub((unsigned int*)dest,val); }

template < typename T >
__inline__ __device__
T atomic_fetch_sub( volatile T * const dest ,
  typename Kokkos::Impl::enable_if< sizeof(T) == sizeof(int) , const T >::type val )
{
  union { int i ; T t ; } oldval , assume , newval ;

  oldval.t = *dest ;

  do {
    assume.i = oldval.i ;
    newval.t = assume.t - val ;
    oldval.i = atomicCAS( (int*)dest , assume.i , newval.i );
  } while ( assume.i != oldval.i );

  return oldval.t ;
}

template < typename T >
__inline__ __device__
T atomic_fetch_sub( volatile T * const dest ,
  typename Kokkos::Impl::enable_if< sizeof(T) != sizeof(int) &&
                                    sizeof(T) == sizeof(unsigned long long int) , const T >::type val )
{
  union { unsigned long long int i ; T t ; } oldval , assume , newval ;

  oldval.t = *dest ;

  do {
    assume.i = oldval.i ;
    newval.t = assume.t - val ;
    oldval.i = atomicCAS( (unsigned long long int*)dest , assume.i , newval.i );
  } while ( assume.i != oldval.i );

  return oldval.t ;
}


//----------------------------------------------------------------------------

template < typename T >
__inline__ __device__
T atomic_fetch_sub( volatile T * const dest ,
    typename Kokkos::Impl::enable_if<
                  ( sizeof(T) != 4 )
               && ( sizeof(T) != 8 )
             , const T >::type& val )
{
  T return_val;
  // This is a way to (hopefully) avoid dead lock in a warp
  int done = 0;
  unsigned int active = KOKKOS_IMPL_CUDA_BALLOT(1);
  unsigned int done_active = 0;
  while (active!=done_active) {
    if(!done) {
      if( Impl::lock_address_cuda_space( (void*) dest ) ) {
        return_val = *dest;
        *dest = return_val - val;
        Impl::unlock_address_cuda_space( (void*) dest );
        done = 1;
      }
    }
    done_active = KOKKOS_IMPL_CUDA_BALLOT(done);
  }
  return return_val;
}
#endif
#endif
//----------------------------------------------------------------------------
#if !defined(KOKKOS_ENABLE_ROCM_ATOMICS)
#if !defined(__CUDA_ARCH__) || defined(KOKKOS_IMPL_CUDA_CLANG_WORKAROUND)
#if defined(KOKKOS_ENABLE_GNU_ATOMICS) || defined(KOKKOS_ENABLE_INTEL_ATOMICS)

inline
int atomic_fetch_sub( volatile int * const dest , const int val )
{
#if defined( KOKKOS_ENABLE_RFO_PREFETCH )
  _mm_prefetch( (const char*) dest, _MM_HINT_ET0 );
#endif
  return __sync_fetch_and_sub(dest,val);
}

inline
long int atomic_fetch_sub( volatile long int * const dest , const long int val )
{
#if defined( KOKKOS_ENABLE_RFO_PREFETCH )
  _mm_prefetch( (const char*) dest, _MM_HINT_ET0 );
#endif
  return __sync_fetch_and_sub(dest,val);
}

#if defined( KOKKOS_ENABLE_GNU_ATOMICS )

inline
unsigned int atomic_fetch_sub( volatile unsigned int * const dest , const unsigned int val )
{
#if defined( KOKKOS_ENABLE_RFO_PREFETCH )
  _mm_prefetch( (const char*) dest, _MM_HINT_ET0 );
#endif
  return __sync_fetch_and_sub(dest,val);
}

inline
unsigned long int atomic_fetch_sub( volatile unsigned long int * const dest , const unsigned long int val )
{
#if defined( KOKKOS_ENABLE_RFO_PREFETCH )
  _mm_prefetch( (const char*) dest, _MM_HINT_ET0 );
#endif
  return __sync_fetch_and_sub(dest,val);
}

#endif

template < typename T >
inline
T atomic_fetch_sub( volatile T * const dest ,
  typename Kokkos::Impl::enable_if< sizeof(T) == sizeof(int) , const T >::type val )
{
  union { int i ; T t ; } assume , oldval , newval ;

#if defined( KOKKOS_ENABLE_RFO_PREFETCH )
  _mm_prefetch( (const char*) dest, _MM_HINT_ET0 );
#endif

  oldval.t = *dest ;

  do {
    assume.i = oldval.i ;
    newval.t = assume.t - val ;
    oldval.i = __sync_val_compare_and_swap( (int*) dest , assume.i , newval.i );
  } while ( assume.i != oldval.i );

  return oldval.t ;
}

template < typename T >
inline
T atomic_fetch_sub( volatile T * const dest ,
  typename Kokkos::Impl::enable_if< sizeof(T) != sizeof(int) &&
                                    sizeof(T) == sizeof(long) , const T >::type val )
{
#if defined( KOKKOS_ENABLE_RFO_PREFETCH )
  _mm_prefetch( (const char*) dest, _MM_HINT_ET0 );
#endif

  union { long i ; T t ; } assume , oldval , newval ;

  oldval.t = *dest ;

  do {
    assume.i = oldval.i ;
    newval.t = assume.t - val ;
    oldval.i = __sync_val_compare_and_swap( (long*) dest , assume.i , newval.i );
  } while ( assume.i != oldval.i );

  return oldval.t ;
}


//----------------------------------------------------------------------------

template < typename T >
inline
T atomic_fetch_sub( volatile T * const dest ,
    typename Kokkos::Impl::enable_if<
                  ( sizeof(T) != 4 )
               && ( sizeof(T) != 8 )
             , const T >::type& val )
{
#if defined( KOKKOS_ENABLE_RFO_PREFETCH )
  _mm_prefetch( (const char*) dest, _MM_HINT_ET0 );
#endif

  while( !Impl::lock_address_host_space( (void*) dest ) );
  T return_val = *dest;
  *dest = return_val - val;
  Impl::unlock_address_host_space( (void*) dest );
  return return_val;
}

//----------------------------------------------------------------------------

#elif defined( KOKKOS_ENABLE_OPENMP_ATOMICS )

template< typename T >
T atomic_fetch_sub( volatile T * const dest , const T val )
{
  T retval;
#pragma omp atomic capture
  {
    retval = dest[0];
    dest[0] -= val;
  }
  return retval;
}

#elif defined( KOKKOS_ENABLE_SERIAL_ATOMICS )

template< typename T >
T atomic_fetch_sub( volatile T * const dest_v , const T val )
{
  T* dest = const_cast<T*>(dest_v);
  T retval = *dest;
  *dest -= val;
  return retval;
}

#endif
#endif
#endif // !defined ROCM_ATOMICS

// Simpler version of atomic_fetch_sub without the fetch
template <typename T>
KOKKOS_INLINE_FUNCTION
void atomic_sub(volatile T * const dest, const T src) {
  atomic_fetch_sub(dest,src);
}

}

#include<impl/Kokkos_Atomic_Assembly.hpp>
#endif

