summaryrefslogtreecommitdiff
path: root/src/cpu/pred/tournament.cc
diff options
context:
space:
mode:
Diffstat (limited to 'src/cpu/pred/tournament.cc')
-rw-r--r--src/cpu/pred/tournament.cc69
1 files changed, 32 insertions, 37 deletions
diff --git a/src/cpu/pred/tournament.cc b/src/cpu/pred/tournament.cc
index 319606871..ea6be46fa 100644
--- a/src/cpu/pred/tournament.cc
+++ b/src/cpu/pred/tournament.cc
@@ -52,7 +52,6 @@ TournamentBP::TournamentBP(const TournamentBPParams *params)
localHistoryBits(ceilLog2(params->localPredictorSize)),
globalPredictorSize(params->globalPredictorSize),
globalCtrBits(params->globalCtrBits),
- globalHistory(params->numThreads, 0),
globalHistoryBits(
ceilLog2(params->globalPredictorSize) >
ceilLog2(params->choicePredictorSize) ?
@@ -93,6 +92,8 @@ TournamentBP::TournamentBP(const TournamentBPParams *params)
for (int i = 0; i < globalPredictorSize; ++i)
globalCtrs[i].setBits(globalCtrBits);
+ //Clear the global history
+ globalHistory = 0;
// Set up the global history mask
// this is equivalent to mask(log2(globalPredictorSize)
globalHistoryMask = globalPredictorSize - 1;
@@ -144,18 +145,18 @@ TournamentBP::calcLocHistIdx(Addr &branch_addr)
inline
void
-TournamentBP::updateGlobalHistTaken(ThreadID tid)
+TournamentBP::updateGlobalHistTaken()
{
- globalHistory[tid] = (globalHistory[tid] << 1) | 1;
- globalHistory[tid] = globalHistory[tid] & historyRegisterMask;
+ globalHistory = (globalHistory << 1) | 1;
+ globalHistory = globalHistory & historyRegisterMask;
}
inline
void
-TournamentBP::updateGlobalHistNotTaken(ThreadID tid)
+TournamentBP::updateGlobalHistNotTaken()
{
- globalHistory[tid] = (globalHistory[tid] << 1);
- globalHistory[tid] = globalHistory[tid] & historyRegisterMask;
+ globalHistory = (globalHistory << 1);
+ globalHistory = globalHistory & historyRegisterMask;
}
inline
@@ -176,18 +177,18 @@ TournamentBP::updateLocalHistNotTaken(unsigned local_history_idx)
void
-TournamentBP::btbUpdate(ThreadID tid, Addr branch_addr, void * &bp_history)
+TournamentBP::btbUpdate(Addr branch_addr, void * &bp_history)
{
unsigned local_history_idx = calcLocHistIdx(branch_addr);
//Update Global History to Not Taken (clear LSB)
- globalHistory[tid] &= (historyRegisterMask & ~ULL(1));
+ globalHistory &= (historyRegisterMask & ~ULL(1));
//Update Local History to Not Taken
localHistoryTable[local_history_idx] =
localHistoryTable[local_history_idx] & (localPredictorMask & ~ULL(1));
}
bool
-TournamentBP::lookup(ThreadID tid, Addr branch_addr, void * &bp_history)
+TournamentBP::lookup(Addr branch_addr, void * &bp_history)
{
bool local_prediction;
unsigned local_history_idx;
@@ -203,16 +204,16 @@ TournamentBP::lookup(ThreadID tid, Addr branch_addr, void * &bp_history)
local_prediction = localCtrs[local_predictor_idx].read() > localThreshold;
//Lookup in the global predictor to get its branch prediction
- global_prediction = globalThreshold <
- globalCtrs[globalHistory[tid] & globalHistoryMask].read();
+ global_prediction =
+ globalCtrs[globalHistory & globalHistoryMask].read() > globalThreshold;
//Lookup in the choice predictor to see which one to use
- choice_prediction = choiceThreshold <
- choiceCtrs[globalHistory[tid] & choiceHistoryMask].read();
+ choice_prediction =
+ choiceCtrs[globalHistory & choiceHistoryMask].read() > choiceThreshold;
// Create BPHistory and pass it back to be recorded.
BPHistory *history = new BPHistory;
- history->globalHistory = globalHistory[tid];
+ history->globalHistory = globalHistory;
history->localPredTaken = local_prediction;
history->globalPredTaken = global_prediction;
history->globalUsed = choice_prediction;
@@ -226,21 +227,21 @@ TournamentBP::lookup(ThreadID tid, Addr branch_addr, void * &bp_history)
// all histories.
if (choice_prediction) {
if (global_prediction) {
- updateGlobalHistTaken(tid);
+ updateGlobalHistTaken();
updateLocalHistTaken(local_history_idx);
return true;
} else {
- updateGlobalHistNotTaken(tid);
+ updateGlobalHistNotTaken();
updateLocalHistNotTaken(local_history_idx);
return false;
}
} else {
if (local_prediction) {
- updateGlobalHistTaken(tid);
+ updateGlobalHistTaken();
updateLocalHistTaken(local_history_idx);
return true;
} else {
- updateGlobalHistNotTaken(tid);
+ updateGlobalHistNotTaken();
updateLocalHistNotTaken(local_history_idx);
return false;
}
@@ -248,11 +249,11 @@ TournamentBP::lookup(ThreadID tid, Addr branch_addr, void * &bp_history)
}
void
-TournamentBP::uncondBranch(ThreadID tid, Addr pc, void * &bp_history)
+TournamentBP::uncondBranch(Addr pc, void * &bp_history)
{
// Create BPHistory and pass it back to be recorded.
BPHistory *history = new BPHistory;
- history->globalHistory = globalHistory[tid];
+ history->globalHistory = globalHistory;
history->localPredTaken = true;
history->globalPredTaken = true;
history->globalUsed = true;
@@ -260,12 +261,12 @@ TournamentBP::uncondBranch(ThreadID tid, Addr pc, void * &bp_history)
history->localHistory = invalidPredictorIndex;
bp_history = static_cast<void *>(history);
- updateGlobalHistTaken(tid);
+ updateGlobalHistTaken();
}
void
-TournamentBP::update(ThreadID tid, Addr branch_addr, bool taken,
- void *bp_history, bool squashed)
+TournamentBP::update(Addr branch_addr, bool taken, void *bp_history,
+ bool squashed)
{
unsigned local_history_idx;
unsigned local_predictor_idx M5_VAR_USED;
@@ -331,15 +332,15 @@ TournamentBP::update(ThreadID tid, Addr branch_addr, bool taken,
}
if (squashed) {
if (taken) {
- globalHistory[tid] = (history->globalHistory << 1) | 1;
- globalHistory[tid] = globalHistory[tid] & historyRegisterMask;
+ globalHistory = (history->globalHistory << 1) | 1;
+ globalHistory = globalHistory & historyRegisterMask;
if (old_local_pred_valid) {
localHistoryTable[local_history_idx] =
(history->localHistory << 1) | 1;
}
} else {
- globalHistory[tid] = (history->globalHistory << 1);
- globalHistory[tid] = globalHistory[tid] & historyRegisterMask;
+ globalHistory = (history->globalHistory << 1);
+ globalHistory = globalHistory & historyRegisterMask;
if (old_local_pred_valid) {
localHistoryTable[local_history_idx] =
history->localHistory << 1;
@@ -358,19 +359,19 @@ TournamentBP::update(ThreadID tid, Addr branch_addr, bool taken,
}
void
-TournamentBP::retireSquashed(ThreadID tid, void *bp_history)
+TournamentBP::retireSquashed(void *bp_history)
{
BPHistory *history = static_cast<BPHistory *>(bp_history);
delete history;
}
void
-TournamentBP::squash(ThreadID tid, void *bp_history)
+TournamentBP::squash(void *bp_history)
{
BPHistory *history = static_cast<BPHistory *>(bp_history);
// Restore global history to state prior to this branch.
- globalHistory[tid] = history->globalHistory;
+ globalHistory = history->globalHistory;
// Restore local history
if (history->localHistoryIdx != invalidPredictorIndex) {
@@ -387,12 +388,6 @@ TournamentBPParams::create()
return new TournamentBP(this);
}
-unsigned
-TournamentBP::getGHR(ThreadID tid, void *bp_history) const
-{
- return static_cast<BPHistory *>(bp_history)->globalHistory;
-}
-
#ifdef DEBUG
int
TournamentBP::BPHistory::newCount = 0;
generated by cgit v1.2.3 (git 2.25.1) at 2024-07-05 03:56:04 +0000