gem5  v22.0.0.2
tournament.hh
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40 
41 #ifndef __CPU_PRED_TOURNAMENT_PRED_HH__
42 #define __CPU_PRED_TOURNAMENT_PRED_HH__
43 
44 #include <vector>
45 
46 #include "base/sat_counter.hh"
47 #include "base/types.hh"
48 #include "cpu/pred/bpred_unit.hh"
49 #include "params/TournamentBP.hh"
50 
51 namespace gem5
52 {
53 
54 namespace branch_prediction
55 {
56 
65 class TournamentBP : public BPredUnit
66 {
67  public:
71  TournamentBP(const TournamentBPParams &params);
72 
81  bool lookup(ThreadID tid, Addr branch_addr, void * &bp_history);
82 
89  void uncondBranch(ThreadID tid, Addr pc, void * &bp_history);
97  void btbUpdate(ThreadID tid, Addr branch_addr, void * &bp_history);
110  void update(ThreadID tid, Addr branch_addr, bool taken, void *bp_history,
111  bool squashed, const StaticInstPtr & inst, Addr corrTarget);
112 
118  void squash(ThreadID tid, void *bp_history);
119 
120  private:
126  inline bool getPrediction(uint8_t &count);
127 
132  inline unsigned calcLocHistIdx(Addr &branch_addr);
133 
135  inline void updateGlobalHistTaken(ThreadID tid);
136 
138  inline void updateGlobalHistNotTaken(ThreadID tid);
139 
145  inline void updateLocalHistTaken(unsigned local_history_idx);
146 
152  inline void updateLocalHistNotTaken(unsigned local_history_idx);
153 
160  struct BPHistory
161  {
162 #ifdef DEBUG
163  BPHistory()
164  { newCount++; }
165  ~BPHistory()
166  { newCount--; }
167 
168  static int newCount;
169 #endif
170  unsigned globalHistory;
171  unsigned localHistoryIdx;
172  unsigned localHistory;
176  };
177 
179  static const int invalidPredictorIndex = -1;
182 
185 
187  unsigned localCtrBits;
188 
191 
194 
197 
200 
203 
205  unsigned globalCtrBits;
206 
209 
214 
218 
222 
226 
230 
233 
235  unsigned choiceCtrBits;
236 
239 
243  unsigned localThreshold;
244  unsigned globalThreshold;
245  unsigned choiceThreshold;
246 };
247 
248 } // namespace branch_prediction
249 } // namespace gem5
250 
251 #endif // __CPU_PRED_TOURNAMENT_PRED_HH__
gem5::branch_prediction::TournamentBP::squash
void squash(ThreadID tid, void *bp_history)
Restores the global branch history on a squash.
Definition: tournament.cc:336
gem5::branch_prediction::TournamentBP::BPHistory
The branch history information that is created upon predicting a branch.
Definition: tournament.hh:160
gem5::branch_prediction::TournamentBP::BPHistory::globalUsed
bool globalUsed
Definition: tournament.hh:175
gem5::branch_prediction::TournamentBP::invalidPredictorIndex
static const int invalidPredictorIndex
Flag for invalid predictor index.
Definition: tournament.hh:179
gem5::branch_prediction::TournamentBP::globalThreshold
unsigned globalThreshold
Definition: tournament.hh:244
gem5::branch_prediction::TournamentBP::updateLocalHistTaken
void updateLocalHistTaken(unsigned local_history_idx)
Updates local histories as taken.
Definition: tournament.cc:153
gem5::branch_prediction::TournamentBP::choiceThreshold
unsigned choiceThreshold
Definition: tournament.hh:245
gem5::branch_prediction::TournamentBP::localPredictorMask
unsigned localPredictorMask
Mask to truncate values stored in the local history table.
Definition: tournament.hh:184
gem5::branch_prediction::TournamentBP::uncondBranch
void uncondBranch(ThreadID tid, Addr pc, void *&bp_history)
Records that there was an unconditional branch, and modifies the bp history to point to an object tha...
Definition: tournament.cc:241
gem5::branch_prediction::TournamentBP::localPredictorSize
unsigned localPredictorSize
Number of counters in the local predictor.
Definition: tournament.hh:181
gem5::branch_prediction::TournamentBP::choiceCtrs
std::vector< SatCounter8 > choiceCtrs
Array of counters that make up the choice predictor.
Definition: tournament.hh:238
gem5::branch_prediction::TournamentBP::btbUpdate
void btbUpdate(ThreadID tid, Addr branch_addr, void *&bp_history)
Updates the branch predictor to Not Taken if a BTB entry is invalid or not found.
Definition: tournament.cc:169
std::vector
STL vector class.
Definition: stl.hh:37
sat_counter.hh
gem5::branch_prediction::TournamentBP::calcLocHistIdx
unsigned calcLocHistIdx(Addr &branch_addr)
Returns the local history index, given a branch address.
Definition: tournament.cc:129
gem5::RefCountingPtr< StaticInst >
gem5::branch_prediction::TournamentBP::choiceHistoryMask
unsigned choiceHistoryMask
Mask to apply to globalHistory to access choice history table.
Definition: tournament.hh:225
gem5::branch_prediction::TournamentBP::updateGlobalHistNotTaken
void updateGlobalHistNotTaken(ThreadID tid)
Updates global history as not taken.
Definition: tournament.cc:145
gem5::branch_prediction::TournamentBP::update
void update(ThreadID tid, Addr branch_addr, bool taken, void *bp_history, bool squashed, const StaticInstPtr &inst, Addr corrTarget)
Updates the branch predictor with the actual result of a branch.
Definition: tournament.cc:257
gem5::SimObject::params
const Params & params() const
Definition: sim_object.hh:176
gem5::X86ISA::count
count
Definition: misc.hh:703
gem5::branch_prediction::TournamentBP::globalCtrs
std::vector< SatCounter8 > globalCtrs
Array of counters that make up the global predictor.
Definition: tournament.hh:208
gem5::branch_prediction::TournamentBP::localThreshold
unsigned localThreshold
Thresholds for the counter value; above the threshold is taken, equal to or below the threshold is no...
Definition: tournament.hh:243
gem5::branch_prediction::TournamentBP::BPHistory::globalHistory
unsigned globalHistory
Definition: tournament.hh:170
gem5::branch_prediction::TournamentBP::TournamentBP
TournamentBP(const TournamentBPParams &params)
Default branch predictor constructor.
Definition: tournament.cc:52
gem5::branch_prediction::TournamentBP::historyRegisterMask
unsigned historyRegisterMask
Mask to control how much history is stored.
Definition: tournament.hh:229
gem5::branch_prediction::TournamentBP::BPHistory::localPredTaken
bool localPredTaken
Definition: tournament.hh:173
gem5::branch_prediction::TournamentBP::updateGlobalHistTaken
void updateGlobalHistTaken(ThreadID tid)
Updates global history as taken.
Definition: tournament.cc:137
gem5::Addr
uint64_t Addr
Address type This will probably be moved somewhere else in the near future.
Definition: types.hh:147
gem5::branch_prediction::TournamentBP::localCtrs
std::vector< SatCounter8 > localCtrs
Local counters.
Definition: tournament.hh:190
gem5::branch_prediction::TournamentBP::globalHistoryMask
unsigned globalHistoryMask
Mask to apply to globalHistory to access global history table.
Definition: tournament.hh:221
gem5::branch_prediction::TournamentBP::localHistoryBits
unsigned localHistoryBits
Number of bits for each entry of the local history table.
Definition: tournament.hh:199
gem5::branch_prediction::TournamentBP::updateLocalHistNotTaken
void updateLocalHistNotTaken(unsigned local_history_idx)
Updates local histories as not taken.
Definition: tournament.cc:161
gem5::branch_prediction::TournamentBP::choiceCtrBits
unsigned choiceCtrBits
Number of bits in the choice predictor's counters.
Definition: tournament.hh:235
gem5::branch_prediction::TournamentBP::lookup
bool lookup(ThreadID tid, Addr branch_addr, void *&bp_history)
Looks up the given address in the branch predictor and returns a true/false value as to whether it is...
Definition: tournament.cc:180
gem5::branch_prediction::TournamentBP::choicePredictorSize
unsigned choicePredictorSize
Number of entries in the choice predictor.
Definition: tournament.hh:232
gem5::branch_prediction::TournamentBP::globalCtrBits
unsigned globalCtrBits
Number of bits of the global predictor's counters.
Definition: tournament.hh:205
gem5::branch_prediction::TournamentBP::localHistoryTableSize
unsigned localHistoryTableSize
Number of entries in the local history table.
Definition: tournament.hh:196
types.hh
gem5::branch_prediction::TournamentBP::BPHistory::localHistoryIdx
unsigned localHistoryIdx
Definition: tournament.hh:171
bpred_unit.hh
gem5::MipsISA::pc
Bitfield< 4 > pc
Definition: pra_constants.hh:243
gem5::branch_prediction::TournamentBP::globalHistoryBits
unsigned globalHistoryBits
Number of bits for the global history.
Definition: tournament.hh:217
gem5::branch_prediction::TournamentBP::getPrediction
bool getPrediction(uint8_t &count)
Returns if the branch should be taken or not, given a counter value.
gem5::branch_prediction::BPredUnit
Basically a wrapper class to hold both the branch predictor and the BTB.
Definition: bpred_unit.hh:68
gem5::branch_prediction::TournamentBP::localHistoryTable
std::vector< unsigned > localHistoryTable
Array of local history table entries.
Definition: tournament.hh:193
gem5::branch_prediction::TournamentBP::globalPredictorSize
unsigned globalPredictorSize
Number of entries in the global predictor.
Definition: tournament.hh:202
gem5::branch_prediction::TournamentBP::globalHistory
std::vector< unsigned > globalHistory
Global history register.
Definition: tournament.hh:213
gem5::branch_prediction::TournamentBP
Implements a tournament branch predictor, hopefully identical to the one used in the 21264.
Definition: tournament.hh:65
gem5
Reference material can be found at the JEDEC website: UFS standard http://www.jedec....
Definition: gpu_translation_state.hh:37
gem5::branch_prediction::TournamentBP::BPHistory::globalPredTaken
bool globalPredTaken
Definition: tournament.hh:174
gem5::branch_prediction::TournamentBP::BPHistory::localHistory
unsigned localHistory
Definition: tournament.hh:172
gem5::branch_prediction::TournamentBP::localCtrBits
unsigned localCtrBits
Number of bits of the local predictor's counters.
Definition: tournament.hh:187
gem5::ThreadID
int16_t ThreadID
Thread index/ID type.
Definition: types.hh:235

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