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| author | Mrinmoy Ghosh <mrinmoy.ghosh@arm.com> | 2012-11-02 11:32:00 -0500 |
|---|---|---|
| committer | Mrinmoy Ghosh <mrinmoy.ghosh@arm.com> | 2012-11-02 11:32:00 -0500 |
| commit | 4440332bdd44453e5a301a46eabbab1e85fa8cfb (patch) | |
| tree | 17a31a934a53d4aa710132d3f006585bc7206dad /src | |
| parent | 7e25052feebcc69592e8d40aa085e386ad23b173 (diff) | |
| download | gem5-4440332bdd44453e5a301a46eabbab1e85fa8cfb.tar.xz | |
o3: Fix a couple of issues with the local predictor.
Fix some issues with the local predictor and the way it's indexed.
Diffstat (limited to 'src')
| -rw-r--r-- | src/cpu/pred/tournament.cc | 24 |
1 files changed, 15 insertions, 9 deletions
diff --git a/src/cpu/pred/tournament.cc b/src/cpu/pred/tournament.cc index b6320ca8a..ba2b1decb 100644 --- a/src/cpu/pred/tournament.cc +++ b/src/cpu/pred/tournament.cc @@ -167,7 +167,7 @@ TournamentBP::BTBUpdate(Addr &branch_addr, void * &bp_history) globalHistory = globalHistory & (globalHistoryMask - 1); //Update Local History to Not Taken localHistoryTable[local_history_idx] = - localHistoryTable[local_history_idx] & (localPredictorMask - 1); + localHistoryTable[local_history_idx] & (localPredictorMask & ~ULL(1)); } bool @@ -263,8 +263,14 @@ TournamentBP::update(Addr &branch_addr, bool taken, void *bp_history, // Update may also be called if the Branch target is incorrect even if // the prediction is correct. In that case do not update the counters. bool historyPred = false; - unsigned old_local_pred_index = history->localHistory - & localPredictorMask; + unsigned old_local_pred_index = history->localHistory & + localPredictorMask; + + bool old_local_pred_valid = history->localHistory != + invalidPredictorIndex; + + assert(old_local_pred_index < localPredictorSize); + if (history->globalUsed) { historyPred = history->globalPredTaken; } else { @@ -291,12 +297,12 @@ TournamentBP::update(Addr &branch_addr, bool taken, void *bp_history, // need to be updated. if (taken) { globalCtrs[history->globalHistory].increment(); - if (old_local_pred_index != invalidPredictorIndex) { + if (old_local_pred_valid) { localCtrs[old_local_pred_index].increment(); } } else { globalCtrs[history->globalHistory].decrement(); - if (old_local_pred_index != invalidPredictorIndex) { + if (old_local_pred_valid) { localCtrs[old_local_pred_index].decrement(); } } @@ -305,15 +311,15 @@ TournamentBP::update(Addr &branch_addr, bool taken, void *bp_history, if (taken) { globalHistory = (history->globalHistory << 1) | 1; globalHistory = globalHistory & globalHistoryMask; - if (old_local_pred_index != invalidPredictorIndex) { - localHistoryTable[old_local_pred_index] = + if (old_local_pred_valid) { + localHistoryTable[local_history_idx] = (history->localHistory << 1) | 1; } } else { globalHistory = (history->globalHistory << 1); globalHistory = globalHistory & globalHistoryMask; - if (old_local_pred_index != invalidPredictorIndex) { - localHistoryTable[old_local_pred_index] = + if (old_local_pred_valid) { + localHistoryTable[local_history_idx] = history->localHistory << 1; } } |