gem5  v21.2.0.0
2bit_local.hh
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40 
41 #ifndef __CPU_PRED_2BIT_LOCAL_PRED_HH__
42 #define __CPU_PRED_2BIT_LOCAL_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/LocalBP.hh"
50 
51 namespace gem5
52 {
53 
54 namespace branch_prediction
55 {
56 
64 class LocalBP : public BPredUnit
65 {
66  public:
70  LocalBP(const LocalBPParams &params);
71 
72  virtual void uncondBranch(ThreadID tid, Addr pc, void * &bp_history);
73 
81  bool lookup(ThreadID tid, Addr branch_addr, void * &bp_history);
82 
90  void btbUpdate(ThreadID tid, Addr branch_addr, void * &bp_history);
91 
97  void update(ThreadID tid, Addr branch_addr, bool taken, void *bp_history,
98  bool squashed, const StaticInstPtr & inst, Addr corrTarget);
99 
100  void squash(ThreadID tid, void *bp_history)
101  { assert(bp_history == NULL); }
102 
103  private:
110  inline bool getPrediction(uint8_t &count);
111 
113  inline unsigned getLocalIndex(Addr &PC);
114 
116  const unsigned localPredictorSize;
117 
119  const unsigned localCtrBits;
120 
122  const unsigned localPredictorSets;
123 
126 
128  const unsigned indexMask;
129 };
130 
131 } // namespace branch_prediction
132 } // namespace gem5
133 
134 #endif // __CPU_PRED_2BIT_LOCAL_PRED_HH__
gem5::branch_prediction::LocalBP::localCtrs
std::vector< SatCounter8 > localCtrs
Array of counters that make up the local predictor.
Definition: 2bit_local.hh:125
gem5::branch_prediction::LocalBP::LocalBP
LocalBP(const LocalBPParams &params)
Default branch predictor constructor.
Definition: 2bit_local.cc:42
std::vector
STL vector class.
Definition: stl.hh:37
sat_counter.hh
gem5::RefCountingPtr< StaticInst >
gem5::branch_prediction::LocalBP::squash
void squash(ThreadID tid, void *bp_history)
Definition: 2bit_local.hh:100
gem5::SimObject::params
const Params & params() const
Definition: sim_object.hh:176
gem5::X86ISA::count
count
Definition: misc.hh:709
gem5::branch_prediction::LocalBP::localPredictorSize
const unsigned localPredictorSize
Size of the local predictor.
Definition: 2bit_local.hh:116
gem5::branch_prediction::LocalBP::indexMask
const unsigned indexMask
Mask to get index bits.
Definition: 2bit_local.hh:128
gem5::branch_prediction::LocalBP::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: 2bit_local.cc:97
gem5::branch_prediction::LocalBP::localCtrBits
const unsigned localCtrBits
Number of bits of the local predictor's counters.
Definition: 2bit_local.hh:119
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::LocalBP::getLocalIndex
unsigned getLocalIndex(Addr &PC)
Calculates the local index based on the PC.
Definition: 2bit_local.cc:133
gem5::branch_prediction::LocalBP::localPredictorSets
const unsigned localPredictorSets
Number of sets.
Definition: 2bit_local.hh:122
gem5::branch_prediction::LocalBP::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: 2bit_local.cc:78
types.hh
bpred_unit.hh
gem5::branch_prediction::LocalBP::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: 2bit_local.cc:70
gem5::MipsISA::pc
Bitfield< 4 > pc
Definition: pra_constants.hh:243
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::LocalBP::uncondBranch
virtual void uncondBranch(ThreadID tid, Addr pc, void *&bp_history)
Definition: 2bit_local.cc:139
gem5::branch_prediction::LocalBP
Implements a local predictor that uses the PC to index into a table of counters.
Definition: 2bit_local.hh:64
gem5
Reference material can be found at the JEDEC website: UFS standard http://www.jedec....
Definition: tlb.cc:60
gem5::branch_prediction::LocalBP::getPrediction
bool getPrediction(uint8_t &count)
Returns the taken/not taken prediction given the value of the counter.
Definition: 2bit_local.cc:125
gem5::ThreadID
int16_t ThreadID
Thread index/ID type.
Definition: types.hh:242

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