tournament.hh

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/*
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 * property including but not limited to intellectual property relating
 * to a hardware implementation of the functionality of the software
 * licensed hereunder.  You may use the software subject to the license
 * terms below provided that you ensure that this notice is replicated
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 * modified or unmodified, in source code or in binary form.
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#ifndef __CPU_PRED_TOURNAMENT_PRED_HH__
#define __CPU_PRED_TOURNAMENT_PRED_HH__
 
#include <vector>
 
#include "base/sat_counter.hh"
#include "base/types.hh"
#include "cpu/pred/bpred_unit.hh"
#include "params/TournamentBP.hh"
 
namespace gem5
{
 
namespace branch_prediction
{
 
class TournamentBP : public BPredUnit
{
  public:
    TournamentBP(const TournamentBPParams &params);
 
    bool lookup(ThreadID tid, Addr branch_addr, void * &bp_history);
 
    void uncondBranch(ThreadID tid, Addr pc, void * &bp_history);
    void btbUpdate(ThreadID tid, Addr branch_addr, void * &bp_history);
    void update(ThreadID tid, Addr branch_addr, bool taken, void *bp_history,
                bool squashed, const StaticInstPtr & inst, Addr corrTarget);
 
    void squash(ThreadID tid, void *bp_history);
 
  private:
    inline bool getPrediction(uint8_t &count);
 
    inline unsigned calcLocHistIdx(Addr &branch_addr);
 
    inline void updateGlobalHistTaken(ThreadID tid);
 
    inline void updateGlobalHistNotTaken(ThreadID tid);
 
    inline void updateLocalHistTaken(unsigned local_history_idx);
 
    inline void updateLocalHistNotTaken(unsigned local_history_idx);
 
    struct BPHistory
    {
#ifdef GEM5_DEBUG
        BPHistory()
        { newCount++; }
        ~BPHistory()
        { newCount--; }
 
        static int newCount;
#endif
        unsigned globalHistory;
        unsigned localHistoryIdx;
        unsigned localHistory;
        bool localPredTaken;
        bool globalPredTaken;
        bool globalUsed;
    };
 
    static const int invalidPredictorIndex = -1;
    unsigned localPredictorSize;
 
    unsigned localPredictorMask;
 
    unsigned localCtrBits;
 
    std::vector<SatCounter8> localCtrs;
 
    std::vector<unsigned> localHistoryTable;
 
    unsigned localHistoryTableSize;
 
    unsigned localHistoryBits;
 
    unsigned globalPredictorSize;
 
    unsigned globalCtrBits;
 
    std::vector<SatCounter8> globalCtrs;
 
    std::vector<unsigned> globalHistory;
 
    unsigned globalHistoryBits;
 
    unsigned globalHistoryMask;
 
    unsigned choiceHistoryMask;
 
    unsigned historyRegisterMask;
 
    unsigned choicePredictorSize;
 
    unsigned choiceCtrBits;
 
    std::vector<SatCounter8> choiceCtrs;
 
    unsigned localThreshold;
    unsigned globalThreshold;
    unsigned choiceThreshold;
};
 
} // namespace branch_prediction
} // namespace gem5
 
#endif // __CPU_PRED_TOURNAMENT_PRED_HH__