#ifndef MY_ATOMIC_INCLUDED
#define MY_ATOMIC_INCLUDED

/* Copyright (c) 2006, 2017, Oracle and/or its affiliates. All rights reserved.

   This program is free software; you can redistribute it and/or modify
   it under the terms of the GNU General Public License, version 2.0,
   as published by the Free Software Foundation.

   This program is also distributed with certain software (including
   but not limited to OpenSSL) that is licensed under separate terms,
   as designated in a particular file or component or in included license
   documentation.  The authors of MySQL hereby grant you an additional
   permission to link the program and your derivative works with the
   separately licensed software that they have included with MySQL.

   This program 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 2.0, for more details.

   You should have received a copy of the GNU General Public License
   along with this program; if not, write to the Free Software
   Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301  USA */

/*
  This header defines five atomic operations:

  my_atomic_add#(&var, what)
    'Fetch and Add'
    add 'what' to *var, and return the old value of *var

  my_atomic_fas#(&var, what)
    'Fetch And Store'
    store 'what' in *var, and return the old value of *var

  my_atomic_cas#(&var, &old, new)
    An odd variation of 'Compare And Set/Swap'
    if *var is equal to *old, then store 'new' in *var, and return TRUE
    otherwise store *var in *old, and return FALSE
    Usually, &old should not be accessed if the operation is successful.

  my_atomic_load#(&var)
    return *var

  my_atomic_store#(&var, what)
    store 'what' in *var

  '#' is substituted by a size suffix - 32, 64, or ptr
  (e.g. my_atomic_add64, my_atomic_fas32, my_atomic_casptr).
*/

/*
  We choose implementation as follows:
  ------------------------------------
  On Windows using Visual C++ the native implementation should be
  preferrable. When using gcc we prefer the Solaris implementation
  before the gcc because of stability preference, we choose gcc
  builtins if available. If neither Visual C++ or gcc we still choose
  the Solaris implementation on Solaris (mainly for SunStudio compilers).
*/
#if defined(_MSC_VER)
#  include "atomic/generic-msvc.h"
#elif defined(HAVE_SOLARIS_ATOMIC)
#  include "atomic/solaris.h"
#elif defined(HAVE_GCC_ATOMIC_BUILTINS) /* Use __atomic by default */
#  include "atomic/gcc_atomic.h"
/* Use old __sync if __atomic is unavailable */
#elif defined(HAVE_GCC_SYNC_BUILTINS)
#  include "atomic/gcc_sync.h"
#else
#  error Native atomics support not found!
#endif

/*
  the macro below defines (as an expression) the code that
  will be run in spin-loops. Intel manuals recummend to have PAUSE there.
  It is expected to be defined in include/atomic/ *.h files
*/
#ifndef LF_BACKOFF
#define LF_BACKOFF (1)
#endif

#endif /* MY_ATOMIC_INCLUDED */
