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Diffstat (limited to 'src/cpu/o3/tournament_pred.hh')
-rw-r--r-- | src/cpu/o3/tournament_pred.hh | 221 |
1 files changed, 0 insertions, 221 deletions
diff --git a/src/cpu/o3/tournament_pred.hh b/src/cpu/o3/tournament_pred.hh deleted file mode 100644 index 96bd43ed6..000000000 --- a/src/cpu/o3/tournament_pred.hh +++ /dev/null @@ -1,221 +0,0 @@ -/* - * Copyright (c) 2004-2006 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. - * - * Authors: Kevin Lim - */ - -#ifndef __CPU_O3_TOURNAMENT_PRED_HH__ -#define __CPU_O3_TOURNAMENT_PRED_HH__ - -#include <vector> - -#include "base/types.hh" -#include "cpu/o3/sat_counter.hh" - -/** - * Implements a tournament branch predictor, hopefully identical to the one - * used in the 21264. It has a local predictor, which uses a local history - * table to index into a table of counters, and a global predictor, which - * uses a global history to index into a table of counters. A choice - * predictor chooses between the two. Only the global history register - * is speculatively updated, the rest are updated upon branches committing - * or misspeculating. - */ -class TournamentBP -{ - public: - /** - * Default branch predictor constructor. - */ - TournamentBP(unsigned localPredictorSize, - unsigned localCtrBits, - unsigned localHistoryTableSize, - unsigned localHistoryBits, - unsigned globalPredictorSize, - unsigned globalHistoryBits, - unsigned globalCtrBits, - unsigned choicePredictorSize, - unsigned choiceCtrBits, - unsigned instShiftAmt); - - /** - * Looks up the given address in the branch predictor and returns - * a true/false value as to whether it is taken. Also creates a - * BPHistory object to store any state it will need on squash/update. - * @param branch_addr The address of the branch to look up. - * @param bp_history Pointer that will be set to the BPHistory object. - * @return Whether or not the branch is taken. - */ - bool lookup(Addr &branch_addr, void * &bp_history); - - /** - * Records that there was an unconditional branch, and modifies - * the bp history to point to an object that has the previous - * global history stored in it. - * @param bp_history Pointer that will be set to the BPHistory object. - */ - void uncondBr(void * &bp_history); - - /** - * 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. - * @param bp_history Pointer to the BPHistory object that was created - * when the branch was predicted. - */ - void update(Addr &branch_addr, bool taken, void *bp_history); - - /** - * Restores the global branch history on a squash. - * @param bp_history Pointer to the BPHistory object that has the - * previous global branch history in it. - */ - void squash(void *bp_history); - - /** Returns the global history. */ - inline unsigned readGlobalHist() { return globalHistory; } - - private: - /** - * Returns if the branch should be taken or not, given a counter - * value. - * @param count The counter value. - */ - inline bool getPrediction(uint8_t &count); - - /** - * Returns the local history index, given a branch address. - * @param branch_addr The branch's PC address. - */ - inline unsigned calcLocHistIdx(Addr &branch_addr); - - /** Updates global history as taken. */ - inline void updateGlobalHistTaken(); - - /** Updates global history as not taken. */ - inline void updateGlobalHistNotTaken(); - - /** - * Updates local histories as taken. - * @param local_history_idx The local history table entry that - * will be updated. - */ - inline void updateLocalHistTaken(unsigned local_history_idx); - - /** - * Updates local histories as not taken. - * @param local_history_idx The local history table entry that - * will be updated. - */ - inline void updateLocalHistNotTaken(unsigned local_history_idx); - - /** - * The branch history information that is created upon predicting - * a branch. It will be passed back upon updating and squashing, - * when the BP can use this information to update/restore its - * state properly. - */ - struct BPHistory { -#ifdef DEBUG - BPHistory() - { newCount++; } - ~BPHistory() - { newCount--; } - - static int newCount; -#endif - unsigned globalHistory; - bool localPredTaken; - bool globalPredTaken; - bool globalUsed; - }; - - /** Local counters. */ - std::vector<SatCounter> localCtrs; - - /** Size of the local predictor. */ - unsigned localPredictorSize; - - /** Mask to get the proper index bits into the predictor. */ - unsigned localPredictorMask; - - /** Number of bits of the local predictor's counters. */ - unsigned localCtrBits; - - /** Array of local history table entries. */ - std::vector<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. */ - std::vector<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. */ - std::vector<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_O3_TOURNAMENT_PRED_HH__ |