ras.hh

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/*
 * Copyright (c) 2004-2005 The Regents of The University of Michigan
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are
 * met: redistributions of source code must retain the above copyright
 * notice, this list of conditions and the following disclaimer;
 * redistributions in binary form must reproduce the above copyright
 * notice, this list of conditions and the following disclaimer in the
 * documentation and/or other materials provided with the distribution;
 * neither the name of the copyright holders nor the names of its
 * contributors may be used to endorse or promote products derived from
 * this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
 * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 *
 * Authors: Kevin Lim
 */

#ifndef __CPU_PRED_RAS_HH__
#define __CPU_PRED_RAS_HH__

#include <vector>

#include "arch/types.hh"
#include "base/types.hh"
#include "config/the_isa.hh"

class ReturnAddrStack
{
  public:
    ReturnAddrStack() {}

    void init(unsigned numEntries);

    void reset();

    TheISA::PCState top()
    { return addrStack[tos]; }

    unsigned topIdx()
    { return tos; }

    void push(const TheISA::PCState &return_addr);

    void pop();

    void restore(unsigned top_entry_idx, const TheISA::PCState &restored);

     bool empty() { return usedEntries == 0; }

     bool full() { return usedEntries == numEntries; }
  private:
    inline void incrTos()
    { if (++tos == numEntries) tos = 0; }

    inline void decrTos()
    { tos = (tos == 0 ? numEntries - 1 : tos - 1); }

    std::vector<TheISA::PCState> addrStack;

    unsigned numEntries;

    unsigned usedEntries;

    unsigned tos;
};

#endif // __CPU_PRED_RAS_HH__