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/*
* Copyright 2019 Texas A&M University
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are met:
*
* 1. Redistributions of source code must retain the above copyright notice,
* this list of conditions and the following disclaimer.
*
* 2. 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.
*
* 3. Neither the name of the copyright holder 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
* HOLDER 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.
*
* Author: Daniel A. Jiménez
* Adapted to gem5 by: Javier Bueno Hedo
*
*/
/*
* Multiperspective Perceptron Predictor with TAGE (by Daniel A. Jiménez)
* 8 KB version
*/
#include "cpu/pred/multiperspective_perceptron_tage_8KB.hh"
namespace gem5
{
namespace branch_prediction
{
MPP_StatisticalCorrector_8KB::MPP_StatisticalCorrector_8KB(
const MPP_StatisticalCorrector_8KBParams &p)
: MPP_StatisticalCorrector(p)
{
}
MPP_StatisticalCorrector_8KB::SCThreadHistory*
MPP_StatisticalCorrector_8KB::makeThreadHistory()
{
MPP_SCThreadHistory *sh = new MPP_SCThreadHistory();
sh->setNumOrdinalHistories(1);
sh->initLocalHistory(1, numEntriesFirstLocalHistories, 4);
return sh;
}
void
MPP_StatisticalCorrector_8KB::getBiasLSUM(Addr branch_pc,
StatisticalCorrector::BranchInfo* bi, int &lsum) const
{
int8_t ctr = bias[getIndBias(branch_pc, bi, false /* unused */)];
lsum += 2 * ctr + 1;
ctr = biasSK[getIndBiasSK(branch_pc, bi)];
lsum += 2 * ctr + 1;
}
int
MPP_StatisticalCorrector_8KB::gPredictions(ThreadID tid, Addr branch_pc,
StatisticalCorrector::BranchInfo* bi, int & lsum, int64_t phist)
{
MPP_SCThreadHistory *sh = static_cast<MPP_SCThreadHistory *>(scHistory);
unsigned int pc = branch_pc;
lsum += gPredict((pc << 1) + bi->predBeforeSC, sh->globalHist << 11,
gm, ggehl, gnb, logGnb, wg);
// Local History #1
lsum += 2 * gPredict(branch_pc, sh->getLocalHistory(1, branch_pc),
lm, lgehl, lnb, logLnb, wl);
if (sh->getLocalHistory(1, branch_pc) == 2047) lsum += 4;
if (sh->getLocalHistory(1, branch_pc) == 0) lsum -= 4;
lsum += gPredict(branch_pc, sh->getHistoryStackEntry(),
pm, pgehl, pnb, logPnb, wp);
int thres = pUpdateThreshold[getIndUpd(branch_pc)];
return thres;
}
void
MPP_StatisticalCorrector_8KB::gUpdates(ThreadID tid, Addr pc, bool taken,
StatisticalCorrector::BranchInfo* bi, int64_t phist)
{
MPP_SCThreadHistory *sh = static_cast<MPP_SCThreadHistory *>(scHistory);
gUpdate((pc << 1) + bi->predBeforeSC, taken, sh->globalHist << 11,
gm, ggehl, gnb, logGnb, wg, bi);
gUpdate(pc, taken, sh->getLocalHistory(1, pc),
lm, lgehl, lnb, logLnb, wl, bi);
gUpdate(pc, taken, sh->getHistoryStackEntry(),
pm, pgehl, pnb, logPnb, wp, bi);
}
void
MPP_StatisticalCorrector_8KB::scHistoryUpdate(Addr branch_pc,
const StaticInstPtr &inst, bool taken,
StatisticalCorrector::BranchInfo *bi, Addr corrTarget)
{
int brtype = inst->isDirectCtrl() ? 0 : 2;
if (! inst->isUncondCtrl()) {
++brtype;
}
MPP_SCThreadHistory *sh = static_cast<MPP_SCThreadHistory *>(scHistory);
if (brtype & 1) {
sh->globalHist = (sh->globalHist << 1) + taken;
}
sh->updateHistoryStack(corrTarget, taken, inst->isCall(),
inst->isReturn());
StatisticalCorrector::scHistoryUpdate(branch_pc, inst, taken, bi,
corrTarget);
}
size_t
MPP_StatisticalCorrector_8KB::getSizeInBits() const
{
size_t bits = 16; //global histories
bits += (1 << logSizeUp) * pUpdateThresholdWidth;
bits += scCountersWidth * 2 * (1 << logBias); //2 bias arrays
bits += (gnb - 2) * (1 << logGnb) * (scCountersWidth - 1) +
(1 << (logGnb - 1)) * (2 * scCountersWidth - 1);
bits += (pnb - 2) * (1 << logPnb) * (scCountersWidth - 1) +
(1 << (logPnb - 1)) * (2 * scCountersWidth - 1);
bits += (lnb - 2) * (1 << logLnb) * (scCountersWidth - 1) +
(1 << (logLnb - 1)) * (2 * scCountersWidth - 1);
bits += numEntriesFirstLocalHistories * lm[0];
bits += 16 * 16; // History stack
bits += 4; // History stack pointer
bits += 3 * chooserConfWidth; // 3 chooser counters
return bits;
}
MultiperspectivePerceptronTAGE8KB::MultiperspectivePerceptronTAGE8KB(
const MultiperspectivePerceptronTAGE8KBParams &p)
: MultiperspectivePerceptronTAGE(p)
{
}
void
MultiperspectivePerceptronTAGE8KB::createSpecs()
{
addSpec(new BLURRYPATH(5, 15, -1, 2.25, 0, 6, *this));
addSpec(new RECENCYPOS(31, 3.5, 0, 6, *this));
addSpec(new GHISTMODPATH(3, 7, 1, 2.24, 0, 6, *this));
addSpec(new IMLI(1, 2.23, 0, 6, *this));
addSpec(new IMLI(4, 1.98, 0, 6, *this));
}
} // namespace branch_prediction
} // namespace gem5