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Diffstat (limited to 'src/cpu/o3/bpred_unit.hh')
| -rw-r--r-- | src/cpu/o3/bpred_unit.hh | 299 |
1 files changed, 0 insertions, 299 deletions
diff --git a/src/cpu/o3/bpred_unit.hh b/src/cpu/o3/bpred_unit.hh deleted file mode 100644 index 3f83f9bef..000000000 --- a/src/cpu/o3/bpred_unit.hh +++ /dev/null @@ -1,299 +0,0 @@ -/* - * Copyright (c) 2011-2012 ARM Limited - * All rights reserved - * - * The license below extends only to copyright in the software and shall - * not be construed as granting a license to any other intellectual - * property including but not limited to intellectual property relating - * to a hardware implementation of the functionality of the software - * licensed hereunder. You may use the software subject to the license - * terms below provided that you ensure that this notice is replicated - * unmodified and in its entirety in all distributions of the software, - * modified or unmodified, in source code or in binary form. - * - * Copyright (c) 2004-2005 The Regents of The University of Michigan - * All rights reserved. - * - * Redistribution and use in source and binary forms, with or without - * modification, are permitted provided that the following conditions are - * met: redistributions of source code must retain the above copyright - * notice, this list of conditions and the following disclaimer; - * redistributions in binary form must reproduce the above copyright - * notice, this list of conditions and the following disclaimer in the - * documentation and/or other materials provided with the distribution; - * neither the name of the copyright holders nor the names of its - * contributors may be used to endorse or promote products derived from - * this software without specific prior written permission. - * - * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS - * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT - * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR - * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT - * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, - * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT - * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, - * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY - * 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 - */ - -#ifndef __CPU_O3_BPRED_UNIT_HH__ -#define __CPU_O3_BPRED_UNIT_HH__ - -#include <list> - -#include "base/statistics.hh" -#include "base/types.hh" -#include "cpu/pred/2bit_local.hh" -#include "cpu/pred/btb.hh" -#include "cpu/pred/ras.hh" -#include "cpu/pred/tournament.hh" -#include "cpu/inst_seq.hh" - -struct DerivO3CPUParams; - -/** - * Basically a wrapper class to hold both the branch predictor - * and the BTB. - */ -template<class Impl> -class BPredUnit -{ - private: - typedef typename Impl::DynInstPtr DynInstPtr; - - enum PredType { - Local, - Tournament - }; - - PredType predictor; - - const std::string _name; - - public: - - /** - * @param params The params object, that has the size of the BP and BTB. - */ - BPredUnit(DerivO3CPUParams *params); - - const std::string &name() const { return _name; } - - /** - * Registers statistics. - */ - void regStats(); - - /** Perform sanity checks after a drain. */ - void drainSanityCheck() const; - - /** Take over execution from another CPU's thread. */ - void takeOverFrom(); - - /** - * Predicts whether or not the instruction is a taken branch, and the - * target of the branch if it is taken. - * @param inst The branch instruction. - * @param PC The predicted PC is passed back through this parameter. - * @param tid The thread id. - * @return Returns if the branch is taken or not. - */ - bool predict(DynInstPtr &inst, TheISA::PCState &pc, ThreadID tid); - - // @todo: Rename this function. - void BPUncond(void * &bp_history); - - /** - * Tells the branch predictor to commit any updates until the given - * sequence number. - * @param done_sn The sequence number to commit any older updates up until. - * @param tid The thread id. - */ - void update(const InstSeqNum &done_sn, ThreadID tid); - - /** - * Squashes all outstanding updates until a given sequence number. - * @param squashed_sn The sequence number to squash any younger updates up - * until. - * @param tid The thread id. - */ - void squash(const InstSeqNum &squashed_sn, ThreadID tid); - - /** - * Squashes all outstanding updates until a given sequence number, and - * corrects that sn's update with the proper address and taken/not taken. - * @param squashed_sn The sequence number to squash any younger updates up - * until. - * @param corr_target The correct branch target. - * @param actually_taken The correct branch direction. - * @param tid The thread id. - */ - void squash(const InstSeqNum &squashed_sn, - const TheISA::PCState &corr_target, - bool actually_taken, ThreadID tid); - - /** - * @param bp_history Pointer to the history object. The predictor - * will need to update any state and delete the object. - */ - void BPSquash(void *bp_history); - - /** - * Looks up a given PC in the BP to see if it is taken or not taken. - * @param inst_PC The PC to look up. - * @param bp_history Pointer that will be set to an object that - * has the branch predictor state associated with the lookup. - * @return Whether the branch is taken or not taken. - */ - bool BPLookup(Addr instPC, void * &bp_history); - - /** - * If a branch is not taken, because the BTB address is invalid or missing, - * this function sets the appropriate counter in the global and local - * predictors to not taken. - * @param inst_PC The PC to look up the local predictor. - * @param bp_history Pointer that will be set to an object that - * has the branch predictor state associated with the lookup. - */ - void BPBTBUpdate(Addr instPC, void * &bp_history); - - /** - * Looks up a given PC in the BTB to see if a matching entry exists. - * @param inst_PC The PC to look up. - * @return Whether the BTB contains the given PC. - */ - bool BTBValid(Addr instPC) - { return BTB.valid(instPC, 0); } - - /** - * Looks up a given PC in the BTB to get the predicted target. - * @param inst_PC The PC to look up. - * @return The address of the target of the branch. - */ - TheISA::PCState BTBLookup(Addr instPC) - { return BTB.lookup(instPC, 0); } - - /** - * Updates the BP with taken/not taken information. - * @param inst_PC The branch's PC that will be updated. - * @param taken Whether the branch was taken or not taken. - * @param bp_history Pointer to the branch predictor state that is - * associated with the branch lookup that is being updated. - * @param squashed Set to true when this function is called during a - * squash operation. - * @todo Make this update flexible enough to handle a global predictor. - */ - void BPUpdate(Addr instPC, bool taken, void *bp_history, bool squashed); - - /** - * Updates the BTB with the target of a branch. - * @param inst_PC The branch's PC that will be updated. - * @param target_PC The branch's target that will be added to the BTB. - */ - void BTBUpdate(Addr instPC, const TheISA::PCState &target) - { BTB.update(instPC, target, 0); } - - void dump(); - - private: - struct PredictorHistory { - /** - * Makes a predictor history struct that contains any - * information needed to update the predictor, BTB, and RAS. - */ - 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), validBTB(0) - {} - - bool operator==(const PredictorHistory &entry) const { - return this->seqNum == entry.seqNum; - } - - /** The sequence number for the predictor history entry. */ - InstSeqNum seqNum; - - /** The PC associated with the sequence number. */ - Addr pc; - - /** Pointer to the history object passed back from the branch - * predictor. It is used to update or restore state of the - * branch predictor. - */ - void *bpHistory; - - /** The RAS target (only valid if a return). */ - TheISA::PCState RASTarget; - - /** The RAS index of the instruction (only valid if a call). */ - unsigned RASIndex; - - /** The thread id. */ - ThreadID tid; - - /** Whether or not it was predicted taken. */ - bool predTaken; - - /** Whether or not the RAS was used. */ - bool usedRAS; - - /* Wether or not the RAS was pushed */ - bool pushedRAS; - - /** Whether or not the instruction was a call. */ - bool wasCall; - - /** Whether or not the instruction was a return. */ - bool wasReturn; - /** Whether or not the instruction had a valid BTB entry. */ - bool validBTB; - }; - - typedef std::list<PredictorHistory> History; - typedef typename History::iterator HistoryIt; - - /** - * The per-thread predictor history. This is used to update the predictor - * as instructions are committed, or restore it to the proper state after - * a squash. - */ - History predHist[Impl::MaxThreads]; - - /** The local branch predictor. */ - LocalBP *localBP; - - /** The tournament branch predictor. */ - TournamentBP *tournamentBP; - - /** The BTB. */ - DefaultBTB BTB; - - /** The per-thread return address stack. */ - ReturnAddrStack RAS[Impl::MaxThreads]; - - /** 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 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; -}; - -#endif // __CPU_O3_BPRED_UNIT_HH__ |