/*

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

 * 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

 * or visit www.oracle.com if you need additional information or have any

 * questions.

 */

#ifndef SHARE_GC_Z_ZMARKTERMINATE_INLINE_HPP

#define SHARE_GC_Z_ZMARKTERMINATE_INLINE_HPP

#include "runtime/atomic.hpp"

inline ZMarkTerminate::ZMarkTerminate() :

    _nworkers(0),

    _nworking_stage0(0),

    _nworking_stage1(0) {}

inline bool ZMarkTerminate::enter_stage(volatile uint* nworking_stage) {

  return Atomic::sub(nworking_stage, 1u) == 0;

}

inline void ZMarkTerminate::exit_stage(volatile uint* nworking_stage) {

  Atomic::add(nworking_stage, 1u);

}

inline bool ZMarkTerminate::try_exit_stage(volatile uint* nworking_stage) {

  uint nworking = Atomic::load(nworking_stage);

  for (;;) {

    if (nworking == 0) {

      return false;

    }

    const uint new_nworking = nworking + 1;

    const uint prev_nworking = Atomic::cmpxchg(nworking_stage, nworking, new_nworking);

    if (prev_nworking == nworking) {

      // Success

      return true;

    }

    // Retry

    nworking = prev_nworking;

  }

}

inline void ZMarkTerminate::reset(uint nworkers) {

  _nworkers = _nworking_stage0 = _nworking_stage1 = nworkers;

}

inline bool ZMarkTerminate::enter_stage0() {

  return enter_stage(&_nworking_stage0);

}

inline void ZMarkTerminate::exit_stage0() {

  exit_stage(&_nworking_stage0);

}

inline bool ZMarkTerminate::try_exit_stage0() {

  return try_exit_stage(&_nworking_stage0);

}

inline bool ZMarkTerminate::enter_stage1() {

  return enter_stage(&_nworking_stage1);

}

inline bool ZMarkTerminate::try_exit_stage1() {

  return try_exit_stage(&_nworking_stage1);

}

#endif // SHARE_GC_Z_ZMARKTERMINATE_INLINE_HPP