/*

 * Copyright (c) 2017, 2018, 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_ZNMETHODTABLEENTRY_HPP

#define SHARE_GC_Z_ZNMETHODTABLEENTRY_HPP

#include "gc/z/zBitField.hpp"

#include "memory/allocation.hpp"

//

// NMethod table entry layout

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

//

//   6

//   3                                                                   2 1 0

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

//  |11111111 11111111 11111111 11111111 11111111 11111111 11111111 111111|1|1|

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

//  |                                                                     | |

//  |                                                                     | |

//  |                                                                     | |

//  |                                      1-1 Unregistered Flag (1-bits) * |

//  |                                                                       |

//  |                                          0-0 Registered Flag (1-bits) *

//  |

//  * 63-3 NMethod Address (61-bits)

//

class nmethod;

class ZNMethodTableEntry : public CHeapObj<mtGC> {

private:

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

  typedef ZBitField<uint64_t, bool,     1,  1>    field_unregistered;

  typedef ZBitField<uint64_t, nmethod*, 2, 62, 2> field_method;

  uint64_t _entry;

public:

  explicit ZNMethodTableEntry(bool unregistered = false) :

      _entry(field_registered::encode(false) |

             field_unregistered::encode(unregistered) |

             field_method::encode(NULL)) {}

  explicit ZNMethodTableEntry(nmethod* method) :

      _entry(field_registered::encode(true) |

             field_unregistered::encode(false) |

             field_method::encode(method)) {}

  bool registered() const {

    return field_registered::decode(_entry);

  }

  bool unregistered() const {

    return field_unregistered::decode(_entry);

  }

  nmethod* method() const {

    return field_method::decode(_entry);

  }

};

#endif // SHARE_GC_Z_ZNMETHODTABLEENTRY_HPP