/*
 * Copyright Amazon.com Inc. 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 CPU_AARCH64_SPIN_WAIT_AARCH64_HPP
#define CPU_AARCH64_SPIN_WAIT_AARCH64_HPP

#include "utilities/debug.hpp"

class SpinWait {
public:
  enum Inst {
    NONE = -1,
    NOP,
    ISB,
    YIELD,
    SB,
    WFET
  };

private:
  Inst _inst;
  int _count;
  int _delay;

  Inst from_name(const char *name);

public:
  SpinWait(Inst inst = NONE, int count = 0, int delay = -1)
    : _inst(inst), _count(inst == NONE ? 0 : count), _delay(delay) {}
  SpinWait(const char *name, int count, int delay)
    : SpinWait(from_name(name), count, delay) {}

  Inst inst() const { return _inst; }
  int inst_count() const { return _count; }
  int delay() const {
    assert(_inst == WFET, "Specifying the delay value is only supported for WFET");
    assert(_delay > 0, "The delay value must be positive");
    return _delay;
  }

  static bool supports(const char *name);
};

#endif // CPU_AARCH64_SPIN_WAIT_AARCH64_HPP
