btb.hh

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#ifndef __CPU_PRED_BTB_HH__
#define __CPU_PRED_BTB_HH__
 
 
#include "arch/generic/pcstate.hh"
#include "base/statistics.hh"
#include "cpu/pred/branch_type.hh"
#include "cpu/static_inst.hh"
#include "params/BranchTargetBuffer.hh"
#include "sim/clocked_object.hh"
 
namespace gem5
{
 
namespace branch_prediction
{
 
class BranchTargetBuffer : public ClockedObject
{
  public:
    typedef BranchTargetBufferParams Params;
    typedef enums::BranchType BranchType;
 
    BranchTargetBuffer(const Params &params);
 
    virtual void memInvalidate() override = 0;
 
    virtual bool valid(ThreadID tid, Addr instPC) = 0;
 
    virtual const PCStateBase *lookup(ThreadID tid, Addr instPC,
                            BranchType type = BranchType::NoBranch) = 0;
 
    virtual const StaticInstPtr getInst(ThreadID tid, Addr instPC) = 0;
 
 
    virtual void update(ThreadID tid, Addr inst_pc,
                          const PCStateBase &target_pc,
                          BranchType type = BranchType::NoBranch,
                          StaticInstPtr inst = nullptr) = 0;
 
    virtual void incorrectTarget(Addr inst_pc,
                                  BranchType type = BranchType::NoBranch)
    {
      stats.mispredict[type]++;
    }
 
  protected:
    const unsigned numThreads;
 
    struct BranchTargetBufferStats : public statistics::Group
    {
        BranchTargetBufferStats(statistics::Group *parent);
 
        statistics::Vector lookups;
        statistics::Vector misses;
        statistics::Vector updates;
        statistics::Vector mispredict;
        statistics::Scalar evictions;
 
    } stats;
 
};
 
} // namespace branch_prediction
} // namespace gem5
 
#endif // __CPU_PRED_BTB_HH__