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| author | Pau Cabre <pau.cabre@metempsy.com> | 2018-11-07 23:32:55 +0100 |
|---|---|---|
| committer | Pau Cabre <pau.cabre@metempsy.com> | 2018-11-13 22:37:56 +0000 |
| commit | f3016e6846980038a50a66055cd2619df6926207 (patch) | |
| tree | d6f9f03fd75ebea867350e1a61b05366e159c53a | |
| parent | 2f52a9b65ee37ba8f34ac3d46f96dca9afc02c7c (diff) | |
| download | gem5-f3016e6846980038a50a66055cd2619df6926207.tar.xz | |
cpu: Fixed PC shifting on LTAGE branch predictor
The PC needs to be shifted according to the instShiftAmt parameter
Change-Id: I272619c093695b56cf7f8ff7163e3b5d23205d16
Signed-off-by: Pau Cabre <pau.cabre@metempsy.com>
Reviewed-on: https://gem5-review.googlesource.com/c/14035
Reviewed-by: Sudhanshu Jha <sudhanshu.jha@arm.com>
Reviewed-by: Ilias Vougioukas <ilias.vougioukas@arm.com>
Reviewed-by: Nikos Nikoleris <nikos.nikoleris@arm.com>
Maintainer: Andreas Sandberg <andreas.sandberg@arm.com>
| -rw-r--r-- | src/cpu/pred/ltage.cc | 17 |
1 files changed, 10 insertions, 7 deletions
diff --git a/src/cpu/pred/ltage.cc b/src/cpu/pred/ltage.cc index 251fb2e7f..86b9e9993 100644 --- a/src/cpu/pred/ltage.cc +++ b/src/cpu/pred/ltage.cc @@ -138,13 +138,14 @@ LTAGE::LTAGE(const LTAGEParams *params) int LTAGE::bindex(Addr pc_in) const { - return ((pc_in) & ((ULL(1) << (logSizeBiMP)) - 1)); + return ((pc_in >> instShiftAmt) & ((ULL(1) << (logSizeBiMP)) - 1)); } int LTAGE::lindex(Addr pc_in) const { - return (((pc_in) & ((ULL(1) << (logSizeLoopPred - 2)) - 1)) << 2); + return (((pc_in >> instShiftAmt) & + ((ULL(1) << (logSizeLoopPred - 2)) - 1)) << 2); } int @@ -171,7 +172,8 @@ LTAGE::gindex(ThreadID tid, Addr pc, int bank) const int index; int hlen = (histLengths[bank] > 16) ? 16 : histLengths[bank]; index = - (pc) ^ ((pc) >> ((int) abs(tagTableSizes[bank] - bank) + 1)) ^ + (pc >> instShiftAmt) ^ + ((pc >> instShiftAmt) >> ((int) abs(tagTableSizes[bank] - bank) + 1)) ^ threadHistory[tid].computeIndices[bank].comp ^ F(threadHistory[tid].pathHist, hlen, bank); @@ -183,8 +185,9 @@ LTAGE::gindex(ThreadID tid, Addr pc, int bank) const uint16_t LTAGE::gtag(ThreadID tid, Addr pc, int bank) const { - int tag = (pc) ^ threadHistory[tid].computeTags[0][bank].comp - ^ (threadHistory[tid].computeTags[1][bank].comp << 1); + int tag = (pc >> instShiftAmt) ^ + threadHistory[tid].computeTags[0][bank].comp ^ + (threadHistory[tid].computeTags[1][bank].comp << 1); return (tag & ((ULL(1) << tagWidths[bank]) - 1)); } @@ -239,7 +242,7 @@ LTAGE::getLoop(Addr pc, BranchInfo* bi) const bi->loopHit = -1; bi->loopPredValid = false; bi->loopIndex = lindex(pc); - bi->loopTag = ((pc) >> (logSizeLoopPred - 2)); + bi->loopTag = ((pc) >> (instShiftAmt + logSizeLoopPred - 2)); for (int i = 0; i < 4; i++) { if (ltable[bi->loopIndex + i].tag == bi->loopTag) { @@ -630,7 +633,7 @@ LTAGE::updateHistories(ThreadID tid, Addr branch_pc, bool taken, void* b) BranchInfo* bi = (BranchInfo*)(b); ThreadHistory& tHist = threadHistory[tid]; // UPDATE HISTORIES - bool pathbit = ((branch_pc) & 1); + bool pathbit = ((branch_pc >> instShiftAmt) & 1); //on a squash, return pointers to this and recompute indices. //update user history updateGHist(tHist.gHist, taken, tHist.globalHistory, tHist.ptGhist); |