/*

 * 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_ZPAGETABLEENTRY_HPP

#define SHARE_GC_Z_ZPAGETABLEENTRY_HPP

#include "gc/z/zBitField.hpp"

#include "memory/allocation.hpp"

//

// Page table entry layout

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

//

//   6

//   3                                                                    1 0

//  +----------------------------------------------------------------------+-+

//  |11111111 11111111 11111111 11111111 11111111 11111111 11111111 1111111|1|

//  +----------------------------------------------------------------------+-+

//  |                                                                      |

//  |                                          0-0 Relocating Flag (1-bit) *

//  |

//  |

//  |

//  * 63-1 Page address (63-bits)

//

class ZPage;

class ZPageTableEntry {

private:

  typedef ZBitField<uint64_t, bool,   0, 1>     field_relocating;

  typedef ZBitField<uint64_t, ZPage*, 1, 63, 1> field_page;

  uint64_t _entry;

public:

  ZPageTableEntry() :

      _entry(0) {}

  ZPageTableEntry(ZPage* page, bool relocating) :

      _entry(field_page::encode(page) |

             field_relocating::encode(relocating)) {}

  bool relocating() const {

    return field_relocating::decode(_entry);

  }

  ZPage* page() const {

    return field_page::decode(_entry);

  }

};

#endif // SHARE_GC_Z_ZPAGETABLEENTRY_HPP