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Diffstat (limited to 'cpu/o3/2bit_local_pred.cc')
| -rw-r--r-- | cpu/o3/2bit_local_pred.cc | 129 |
1 files changed, 0 insertions, 129 deletions
diff --git a/cpu/o3/2bit_local_pred.cc b/cpu/o3/2bit_local_pred.cc deleted file mode 100644 index d9744eec7..000000000 --- a/cpu/o3/2bit_local_pred.cc +++ /dev/null @@ -1,129 +0,0 @@ -/* - * Copyright (c) 2004-2005 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/trace.hh" -#include "cpu/o3/2bit_local_pred.hh" - -DefaultBP::DefaultBP(unsigned _localPredictorSize, - unsigned _localCtrBits, - unsigned _instShiftAmt) - : localPredictorSize(_localPredictorSize), - localCtrBits(_localCtrBits), - instShiftAmt(_instShiftAmt) -{ - // Should do checks here to make sure sizes are correct (powers of 2). - - // Setup the index mask. - indexMask = localPredictorSize - 1; - - DPRINTF(Fetch, "Branch predictor: index mask: %#x\n", indexMask); - - // Setup the array of counters for the local predictor. - localCtrs = new SatCounter[localPredictorSize]; - - for (int i = 0; i < localPredictorSize; ++i) - localCtrs[i].setBits(_localCtrBits); - - DPRINTF(Fetch, "Branch predictor: local predictor size: %i\n", - localPredictorSize); - - DPRINTF(Fetch, "Branch predictor: local counter bits: %i\n", localCtrBits); - - DPRINTF(Fetch, "Branch predictor: instruction shift amount: %i\n", - instShiftAmt); -} - -bool -DefaultBP::lookup(Addr &branch_addr) -{ - bool taken; - uint8_t local_prediction; - unsigned local_predictor_idx = getLocalIndex(branch_addr); - - DPRINTF(Fetch, "Branch predictor: Looking up index %#x\n", - local_predictor_idx); - - assert(local_predictor_idx < localPredictorSize); - - local_prediction = localCtrs[local_predictor_idx].read(); - - DPRINTF(Fetch, "Branch predictor: prediction is %i.\n", - (int)local_prediction); - - taken = getPrediction(local_prediction); - -#if 0 - // Speculative update. - if (taken) { - DPRINTF(Fetch, "Branch predictor: Branch updated as taken.\n"); - localCtrs[local_predictor_idx].increment(); - } else { - DPRINTF(Fetch, "Branch predictor: Branch updated as not taken.\n"); - localCtrs[local_predictor_idx].decrement(); - } -#endif - - return taken; -} - -void -DefaultBP::update(Addr &branch_addr, bool taken) -{ - unsigned local_predictor_idx; - - // Update the local predictor. - local_predictor_idx = getLocalIndex(branch_addr); - - DPRINTF(Fetch, "Branch predictor: Looking up index %#x\n", - local_predictor_idx); - - assert(local_predictor_idx < localPredictorSize); - - if (taken) { - DPRINTF(Fetch, "Branch predictor: Branch updated as taken.\n"); - localCtrs[local_predictor_idx].increment(); - } else { - DPRINTF(Fetch, "Branch predictor: Branch updated as not taken.\n"); - localCtrs[local_predictor_idx].decrement(); - } -} - -inline -bool -DefaultBP::getPrediction(uint8_t &count) -{ - // Get the MSB of the count - return (count >> (localCtrBits - 1)); -} - -inline -unsigned -DefaultBP::getLocalIndex(Addr &branch_addr) -{ - return (branch_addr >> instShiftAmt) & indexMask; -} |