ras.hh

Go to the documentation of this file.

/*
 * 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.
 */
 
#ifndef __CPU_PRED_RAS_HH__
#define __CPU_PRED_RAS_HH__
 
#include <vector>
 
#include "arch/generic/pcstate.hh"
#include "base/types.hh"
 
namespace gem5
{
 
namespace branch_prediction
{
 
class ReturnAddrStack
{
  public:
    ReturnAddrStack() {}
 
    void init(unsigned numEntries);
 
    void reset();
 
    const PCStateBase *top() { return addrStack[tos].get(); }
 
    unsigned topIdx() { return tos; }
 
    void push(const PCStateBase &return_addr);
 
    void pop();
 
    void restore(unsigned top_entry_idx, const PCStateBase *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<std::unique_ptr<PCStateBase>> addrStack;
 
    unsigned numEntries;
 
    unsigned usedEntries;
 
    unsigned tos;
};
 
} // namespace branch_prediction
} // namespace gem5
 
#endif // __CPU_PRED_RAS_HH__