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Diffstat (limited to 'cpu/o3/tournament_pred.cc')
-rw-r--r-- | cpu/o3/tournament_pred.cc | 295 |
1 files changed, 0 insertions, 295 deletions
diff --git a/cpu/o3/tournament_pred.cc b/cpu/o3/tournament_pred.cc deleted file mode 100644 index 8b1af6c7c..000000000 --- a/cpu/o3/tournament_pred.cc +++ /dev/null @@ -1,295 +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. - */ - -#include "base/intmath.hh" -#include "cpu/o3/tournament_pred.hh" - -TournamentBP::TournamentBP(unsigned _localPredictorSize, - unsigned _localCtrBits, - unsigned _localHistoryTableSize, - unsigned _localHistoryBits, - unsigned _globalPredictorSize, - unsigned _globalCtrBits, - unsigned _globalHistoryBits, - unsigned _choicePredictorSize, - unsigned _choiceCtrBits, - unsigned _instShiftAmt) - : localPredictorSize(_localPredictorSize), - localCtrBits(_localCtrBits), - localHistoryTableSize(_localHistoryTableSize), - localHistoryBits(_localHistoryBits), - globalPredictorSize(_globalPredictorSize), - globalCtrBits(_globalCtrBits), - globalHistoryBits(_globalHistoryBits), - choicePredictorSize(_globalPredictorSize), - choiceCtrBits(_choiceCtrBits), - instShiftAmt(_instShiftAmt) -{ - if (!isPowerOf2(localPredictorSize)) { - fatal("Invalid local predictor size!\n"); - } - - //Setup the array of counters for the local predictor - localCtrs.resize(localPredictorSize); - - for (int i = 0; i < localPredictorSize; ++i) - localCtrs[i].setBits(localCtrBits); - - localPredictorMask = floorPow2(localPredictorSize) - 1; - - if (!isPowerOf2(localHistoryTableSize)) { - fatal("Invalid local history table size!\n"); - } - - //Setup the history table for the local table - localHistoryTable.resize(localHistoryTableSize); - - for (int i = 0; i < localHistoryTableSize; ++i) - localHistoryTable[i] = 0; - - // Setup the local history mask - localHistoryMask = (1 << localHistoryBits) - 1; - - if (!isPowerOf2(globalPredictorSize)) { - fatal("Invalid global predictor size!\n"); - } - - //Setup the array of counters for the global predictor - globalCtrs.resize(globalPredictorSize); - - for (int i = 0; i < globalPredictorSize; ++i) - globalCtrs[i].setBits(globalCtrBits); - - //Clear the global history - globalHistory = 0; - // Setup the global history mask - globalHistoryMask = (1 << globalHistoryBits) - 1; - - if (!isPowerOf2(choicePredictorSize)) { - fatal("Invalid choice predictor size!\n"); - } - - //Setup the array of counters for the choice predictor - choiceCtrs.resize(choicePredictorSize); - - for (int i = 0; i < choicePredictorSize; ++i) - choiceCtrs[i].setBits(choiceCtrBits); - - // @todo: Allow for different thresholds between the predictors. - threshold = (1 << (localCtrBits - 1)) - 1; - threshold = threshold / 2; -} - -inline -unsigned -TournamentBP::calcLocHistIdx(Addr &branch_addr) -{ - // Get low order bits after removing instruction offset. - return (branch_addr >> instShiftAmt) & (localHistoryTableSize - 1); -} - -inline -void -TournamentBP::updateGlobalHistTaken() -{ - globalHistory = (globalHistory << 1) | 1; - globalHistory = globalHistory & globalHistoryMask; -} - -inline -void -TournamentBP::updateGlobalHistNotTaken() -{ - globalHistory = (globalHistory << 1); - globalHistory = globalHistory & globalHistoryMask; -} - -inline -void -TournamentBP::updateLocalHistTaken(unsigned local_history_idx) -{ - localHistoryTable[local_history_idx] = - (localHistoryTable[local_history_idx] << 1) | 1; -} - -inline -void -TournamentBP::updateLocalHistNotTaken(unsigned local_history_idx) -{ - localHistoryTable[local_history_idx] = - (localHistoryTable[local_history_idx] << 1); -} - -bool -TournamentBP::lookup(Addr &branch_addr, void * &bp_history) -{ - bool local_prediction; - unsigned local_history_idx; - unsigned local_predictor_idx; - - bool global_prediction; - bool choice_prediction; - - //Lookup in the local predictor to get its branch prediction - local_history_idx = calcLocHistIdx(branch_addr); - local_predictor_idx = localHistoryTable[local_history_idx] - & localPredictorMask; - local_prediction = localCtrs[local_predictor_idx].read() > threshold; - - //Lookup in the global predictor to get its branch prediction - global_prediction = globalCtrs[globalHistory].read() > threshold; - - //Lookup in the choice predictor to see which one to use - choice_prediction = choiceCtrs[globalHistory].read() > threshold; - - // Create BPHistory and pass it back to be recorded. - BPHistory *history = new BPHistory; - history->globalHistory = globalHistory; - history->localPredTaken = local_prediction; - history->globalPredTaken = global_prediction; - history->globalUsed = choice_prediction; - bp_history = (void *)history; - - assert(globalHistory < globalPredictorSize && - local_history_idx < localHistoryTableSize && - local_predictor_idx < localPredictorSize); - - // Commented code is for doing speculative update of counters and - // all histories. - if (choice_prediction) { - if (global_prediction) { -// updateHistoriesTaken(local_history_idx); -// globalCtrs[globalHistory].increment(); -// localCtrs[local_history_idx].increment(); - updateGlobalHistTaken(); - return true; - } else { -// updateHistoriesNotTaken(local_history_idx); -// globalCtrs[globalHistory].decrement(); -// localCtrs[local_history_idx].decrement(); - updateGlobalHistNotTaken(); - return false; - } - } else { - if (local_prediction) { -// updateHistoriesTaken(local_history_idx); -// globalCtrs[globalHistory].increment(); -// localCtrs[local_history_idx].increment(); - updateGlobalHistTaken(); - return true; - } else { -// updateHistoriesNotTaken(local_history_idx); -// globalCtrs[globalHistory].decrement(); -// localCtrs[local_history_idx].decrement(); - updateGlobalHistNotTaken(); - return false; - } - } -} - -void -TournamentBP::uncondBr(void * &bp_history) -{ - // Create BPHistory and pass it back to be recorded. - BPHistory *history = new BPHistory; - history->globalHistory = globalHistory; - history->localPredTaken = true; - history->globalPredTaken = true; - bp_history = static_cast<void *>(history); - - updateGlobalHistTaken(); -} - -void -TournamentBP::update(Addr &branch_addr, bool taken, void *bp_history) -{ - unsigned local_history_idx; - unsigned local_predictor_idx; - unsigned local_predictor_hist; - - // Get the local predictor's current prediction - local_history_idx = calcLocHistIdx(branch_addr); - local_predictor_hist = localHistoryTable[local_history_idx]; - local_predictor_idx = local_predictor_hist & localPredictorMask; - - // Update the choice predictor to tell it which one was correct if - // there was a prediction. - if (bp_history) { - BPHistory *history = static_cast<BPHistory *>(bp_history); - if (history->localPredTaken != history->globalPredTaken) { - // If the local prediction matches the actual outcome, - // decerement the counter. Otherwise increment the - // counter. - if (history->localPredTaken == taken) { - choiceCtrs[globalHistory].decrement(); - } else if (history->globalPredTaken == taken){ - choiceCtrs[globalHistory].increment(); - } - } - - // We're done with this history, now delete it. - delete history; - } - - assert(globalHistory < globalPredictorSize && - local_history_idx < localHistoryTableSize && - local_predictor_idx < localPredictorSize); - - // Update the counters and local history with the proper - // resolution of the branch. Global history is updated - // speculatively and restored upon squash() calls, so it does not - // need to be updated. - if (taken) { - localCtrs[local_predictor_idx].increment(); - globalCtrs[globalHistory].increment(); - - updateLocalHistTaken(local_history_idx); - } else { - localCtrs[local_predictor_idx].decrement(); - globalCtrs[globalHistory].decrement(); - - updateLocalHistNotTaken(local_history_idx); - } -} - -void -TournamentBP::squash(void *bp_history) -{ - BPHistory *history = static_cast<BPHistory *>(bp_history); - - // Restore global history to state prior to this branch. - globalHistory = history->globalHistory; - - // Delete this BPHistory now that we're done with it. - delete history; -} - -#ifdef DEBUG -int -TournamentBP::BPHistory::newCount = 0; -#endif |