#ifndef __CPU_BETA_CPU_TOURNAMENT_PRED_HH__ #define __CPU_BETA_CPU_TOURNAMENT_PRED_HH__ // For Addr type. #include "arch/alpha/isa_traits.hh" #include "cpu/beta_cpu/sat_counter.hh" class TournamentBP { public: /** * Default branch predictor constructor. */ TournamentBP(unsigned local_predictor_size, unsigned local_ctr_bits, unsigned local_history_table_size, unsigned local_history_bits, unsigned global_predictor_size, unsigned global_history_bits, unsigned global_ctr_bits, unsigned choice_predictor_size, unsigned choice_ctr_bits, unsigned instShiftAmt); /** * Looks up the given address in the branch predictor and returns * a true/false value as to whether it is taken. * @param branch_addr The address of the branch to look up. * @return Whether or not the branch is taken. */ bool lookup(Addr &branch_addr); /** * Updates the branch predictor with the actual result of a branch. * @param branch_addr The address of the branch to update. * @param taken Whether or not the branch was taken. */ void update(Addr &branch_addr, unsigned global_history, bool taken); inline unsigned readGlobalHist() { return globalHistory; } private: inline bool getPrediction(uint8_t &count); inline unsigned calcLocHistIdx(Addr &branch_addr); inline void updateHistoriesTaken(unsigned local_history_idx); inline void updateHistoriesNotTaken(unsigned local_history_idx); /** Local counters. */ SatCounter *localCtrs; /** Size of the local predictor. */ unsigned localPredictorSize; /** Number of bits of the local predictor's counters. */ unsigned localCtrBits; /** Array of local history table entries. */ unsigned *localHistoryTable; /** Size of the local history table. */ unsigned localHistoryTableSize; /** Number of bits for each entry of the local history table. * @todo Doesn't this come from the size of the local predictor? */ unsigned localHistoryBits; /** Mask to get the proper local history. */ unsigned localHistoryMask; /** Array of counters that make up the global predictor. */ SatCounter *globalCtrs; /** Size of the global predictor. */ unsigned globalPredictorSize; /** Number of bits of the global predictor's counters. */ unsigned globalCtrBits; /** Global history register. */ unsigned globalHistory; /** Number of bits for the global history. */ unsigned globalHistoryBits; /** Mask to get the proper global history. */ unsigned globalHistoryMask; /** Array of counters that make up the choice predictor. */ SatCounter *choiceCtrs; /** Size of the choice predictor (identical to the global predictor). */ unsigned choicePredictorSize; /** Number of bits of the choice predictor's counters. */ unsigned choiceCtrBits; /** Number of bits to shift the instruction over to get rid of the word * offset. */ unsigned instShiftAmt; /** Threshold for the counter value; above the threshold is taken, * equal to or below the threshold is not taken. */ unsigned threshold; }; #endif // __CPU_BETA_CPU_TOURNAMENT_PRED_HH__