ras.hh

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/*
 * Copyright (c) 2004-2005 The Regents of The University of Michigan
 * All rights reserved.
 *
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 * 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
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#ifndef __CPU_PRED_RAS_HH__
#define __CPU_PRED_RAS_HH__
 
#include <vector>
 
#include "arch/pcstate.hh"
#include "base/types.hh"
#include "config/the_isa.hh"
 
namespace gem5
{
 
namespace branch_prediction
{
 
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;
};
 
} // namespace branch_prediction
} // namespace gem5
 
#endif // __CPU_PRED_RAS_HH__