/*

 * Copyright (c) 2016, 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

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 */

#ifndef SHARE_GC_Z_ZBITMAP_INLINE_HPP

#define SHARE_GC_Z_ZBITMAP_INLINE_HPP

#include "gc/z/zBitMap.hpp"

#include "runtime/atomic.hpp"

#include "utilities/bitMap.inline.hpp"

#include "utilities/debug.hpp"

inline ZBitMap::ZBitMap(idx_t size_in_bits) :

    CHeapBitMap(size_in_bits, mtGC, false /* clear */) {}

inline BitMap::bm_word_t ZBitMap::bit_mask_pair(idx_t bit) {

  assert(bit_in_word(bit) < BitsPerWord - 1, "Invalid bit index");

  return (bm_word_t)3 << bit_in_word(bit);

}

inline bool ZBitMap::par_set_bit_pair_finalizable(idx_t bit, bool& inc_live) {

  inc_live = par_set_bit(bit);

  return inc_live;

}

inline bool ZBitMap::par_set_bit_pair_strong(idx_t bit, bool& inc_live) {

  verify_index(bit);

  volatile bm_word_t* const addr = word_addr(bit);

  const bm_word_t pair_mask = bit_mask_pair(bit);

  bm_word_t old_val = *addr;

  do {

    const bm_word_t new_val = old_val | pair_mask;

    if (new_val == old_val) {

      // Someone else beat us to it

      inc_live = false;

      return false;

    }

    const bm_word_t cur_val = Atomic::cmpxchg(new_val, addr, old_val);

    if (cur_val == old_val) {

      // Success

      const bm_word_t marked_mask = bit_mask(bit);

      inc_live = !(old_val & marked_mask);

      return true;

    }

    // The value changed, retry

    old_val = cur_val;

  } while (true);

}

inline bool ZBitMap::par_set_bit_pair(idx_t bit, bool finalizable, bool& inc_live) {

  if (finalizable) {

    return par_set_bit_pair_finalizable(bit, inc_live);

  } else {

    return par_set_bit_pair_strong(bit, inc_live);

  }

}

#endif // SHARE_GC_Z_ZBITMAP_INLINE_HPP