* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
- *
- * Authors: Kevin Lim
- * Korey Sewell
- * Timothy M. Jones
- * Nilay Vaish
*/
#ifndef __CPU_PRED_BPRED_UNIT_HH__
#include "base/statistics.hh"
#include "base/types.hh"
#include "cpu/pred/btb.hh"
+#include "cpu/pred/indirect.hh"
#include "cpu/pred/ras.hh"
#include "cpu/inst_seq.hh"
#include "cpu/static_inst.hh"
*/
BPredUnit(const Params *p);
- /**
- * Registers statistics.
- */
- void regStats();
-
- void regProbePoints() M5_ATTR_OVERRIDE;
+ void regProbePoints() override;
/** Perform sanity checks after a drain. */
void drainSanityCheck() const;
*/
bool predict(const StaticInstPtr &inst, const InstSeqNum &seqNum,
TheISA::PCState &pc, ThreadID tid);
- bool predictInOrder(const StaticInstPtr &inst, const InstSeqNum &seqNum,
- int asid, TheISA::PCState &instPC,
- TheISA::PCState &predPC, ThreadID tid);
// @todo: Rename this function.
- virtual void uncondBranch(void * &bp_history) = 0;
+ virtual void uncondBranch(ThreadID tid, Addr pc, void * &bp_history) = 0;
/**
* Tells the branch predictor to commit any updates until the given
* @param bp_history Pointer to the history object. The predictor
* will need to update any state and delete the object.
*/
- virtual void squash(void *bp_history) = 0;
+ virtual void squash(ThreadID tid, void *bp_history) = 0;
/**
* Looks up a given PC in the BP to see if it is taken or not taken.
* has the branch predictor state associated with the lookup.
* @return Whether the branch is taken or not taken.
*/
- virtual bool lookup(Addr instPC, void * &bp_history) = 0;
+ virtual bool lookup(ThreadID tid, Addr instPC, void * &bp_history) = 0;
/**
* If a branch is not taken, because the BTB address is invalid or missing,
* @param bp_history Pointer that will be set to an object that
* has the branch predictor state associated with the lookup.
*/
- virtual void btbUpdate(Addr instPC, void * &bp_history) = 0;
+ virtual void btbUpdate(ThreadID tid, Addr instPC, void * &bp_history) = 0;
/**
* Looks up a given PC in the BTB to see if a matching entry exists.
* associated with the branch lookup that is being updated.
* @param squashed Set to true when this function is called during a
* squash operation.
+ * @param inst Static instruction information
+ * @param corrTarget The resolved target of the branch (only needed
+ * for squashed branches)
* @todo Make this update flexible enough to handle a global predictor.
*/
- virtual void update(Addr instPC, bool taken, void *bp_history,
- bool squashed) = 0;
- /**
- * Deletes the associated history with a branch, performs no predictor
- * updates. Used for branches that mispredict and update tables but
- * are still speculative and later retire.
- * @param bp_history History to delete associated with this predictor
- */
- virtual void retireSquashed(void *bp_history) = 0;
-
+ virtual void update(ThreadID tid, Addr instPC, bool taken,
+ void *bp_history, bool squashed,
+ const StaticInstPtr &inst, Addr corrTarget) = 0;
/**
* Updates the BTB with the target of a branch.
* @param inst_PC The branch's PC that will be updated.
void BTBUpdate(Addr instPC, const TheISA::PCState &target)
{ BTB.update(instPC, target, 0); }
+
void dump();
private:
*/
PredictorHistory(const InstSeqNum &seq_num, Addr instPC,
bool pred_taken, void *bp_history,
- ThreadID _tid)
- : seqNum(seq_num), pc(instPC), bpHistory(bp_history), RASTarget(0),
- RASIndex(0), tid(_tid), predTaken(pred_taken), usedRAS(0), pushedRAS(0),
- wasCall(0), wasReturn(0), wasSquashed(0)
+ void *indirect_history, ThreadID _tid,
+ const StaticInstPtr & inst)
+ : seqNum(seq_num), pc(instPC), bpHistory(bp_history),
+ indirectHistory(indirect_history), RASTarget(0), RASIndex(0),
+ tid(_tid), predTaken(pred_taken), usedRAS(0), pushedRAS(0),
+ wasCall(0), wasReturn(0), wasIndirect(0), target(MaxAddr),
+ inst(inst)
{}
bool operator==(const PredictorHistory &entry) const {
*/
void *bpHistory;
+ void *indirectHistory;
+
/** The RAS target (only valid if a return). */
TheISA::PCState RASTarget;
/** Whether or not the instruction was a return. */
bool wasReturn;
- /** Whether this instruction has already mispredicted/updated bp */
- bool wasSquashed;
+ /** Wether this instruction was an indirect branch */
+ bool wasIndirect;
+
+ /** Target of the branch. First it is predicted, and fixed later
+ * if necessary
+ */
+ Addr target;
+
+ /** The branch instrction */
+ const StaticInstPtr inst;
};
typedef std::deque<PredictorHistory> History;
/** Number of the threads for which the branch history is maintained. */
- uint32_t numThreads;
+ const unsigned numThreads;
+
/**
* The per-thread predictor history. This is used to update the predictor
/** The per-thread return address stack. */
std::vector<ReturnAddrStack> RAS;
- /** Stat for number of BP lookups. */
- Stats::Scalar lookups;
- /** Stat for number of conditional branches predicted. */
- Stats::Scalar condPredicted;
- /** Stat for number of conditional branches predicted incorrectly. */
- Stats::Scalar condIncorrect;
- /** Stat for number of BTB lookups. */
- Stats::Scalar BTBLookups;
- /** Stat for number of BTB hits. */
- Stats::Scalar BTBHits;
- /** Stat for number of times the BTB is correct. */
- Stats::Scalar BTBCorrect;
- /** Stat for percent times an entry in BTB found. */
- Stats::Formula BTBHitPct;
- /** Stat for number of times the RAS is used to get a target. */
- Stats::Scalar usedRAS;
- /** Stat for number of times the RAS is incorrect. */
- Stats::Scalar RASIncorrect;
+ /** The indirect target predictor. */
+ IndirectPredictor * iPred;
+
+ struct BPredUnitStats : public Stats::Group {
+ BPredUnitStats(Stats::Group *parent);
+
+ /** Stat for number of BP lookups. */
+ Stats::Scalar lookups;
+ /** Stat for number of conditional branches predicted. */
+ Stats::Scalar condPredicted;
+ /** Stat for number of conditional branches predicted incorrectly. */
+ Stats::Scalar condIncorrect;
+ /** Stat for number of BTB lookups. */
+ Stats::Scalar BTBLookups;
+ /** Stat for number of BTB hits. */
+ Stats::Scalar BTBHits;
+ /** Stat for percent times an entry in BTB found. */
+ Stats::Formula BTBHitPct;
+ /** Stat for number of times the RAS is used to get a target. */
+ Stats::Scalar RASUsed;
+ /** Stat for number of times the RAS is incorrect. */
+ Stats::Scalar RASIncorrect;
+
+ /** Stat for the number of indirect target lookups.*/
+ Stats::Scalar indirectLookups;
+ /** Stat for the number of indirect target hits.*/
+ Stats::Scalar indirectHits;
+ /** Stat for the number of indirect target misses.*/
+ Stats::Scalar indirectMisses;
+ /** Stat for the number of indirect target mispredictions.*/
+ Stats::Scalar indirectMispredicted;
+ } stats;
protected:
+ /** Number of bits to shift instructions by for predictor addresses. */
+ const unsigned instShiftAmt;
+
/**
* @{
* @name PMU Probe points.
projects / gem5.git / blobdiff