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authorMrinmoy Ghosh <mrinmoy.ghosh@arm.com>2012-11-02 11:32:00 -0500
committerMrinmoy Ghosh <mrinmoy.ghosh@arm.com>2012-11-02 11:32:00 -0500
commit4440332bdd44453e5a301a46eabbab1e85fa8cfb (patch)
tree17a31a934a53d4aa710132d3f006585bc7206dad /src
parent7e25052feebcc69592e8d40aa085e386ad23b173 (diff)
downloadgem5-4440332bdd44453e5a301a46eabbab1e85fa8cfb.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.cc24
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;
}
}