From 047caf24ba9a640247b63584c2291e760f1f4d54 Mon Sep 17 00:00:00 2001 From: Jason Lowe-Power Date: Wed, 30 Nov 2016 17:10:27 -0500 Subject: cpu: Remove branch predictor function predictInOrder This function was used by the now-defunct InOrderCPU model. Since this model is no longer in gem5, this function was not called from anywhere in the code. --- src/cpu/pred/bpred_unit.cc | 122 --------------------------------------------- 1 file changed, 122 deletions(-) (limited to 'src/cpu/pred/bpred_unit.cc') diff --git a/src/cpu/pred/bpred_unit.cc b/src/cpu/pred/bpred_unit.cc index 523697ff6..660475017 100644 --- a/src/cpu/pred/bpred_unit.cc +++ b/src/cpu/pred/bpred_unit.cc @@ -320,128 +320,6 @@ BPredUnit::predict(const StaticInstPtr &inst, const InstSeqNum &seqNum, return pred_taken; } -bool -BPredUnit::predictInOrder(const StaticInstPtr &inst, const InstSeqNum &seqNum, - int asid, TheISA::PCState &instPC, - TheISA::PCState &predPC, ThreadID tid) -{ - // See if branch predictor predicts taken. - // If so, get its target addr either from the BTB or the RAS. - // Save off record of branch stuff so the RAS can be fixed - // up once it's done. - - using TheISA::MachInst; - - bool pred_taken = false; - TheISA::PCState target; - - ++lookups; - ppBranches->notify(1); - - DPRINTF(Branch, "[tid:%i] [sn:%i] %s ... PC %s doing branch " - "prediction\n", tid, seqNum, - inst->disassemble(instPC.instAddr()), instPC); - - void *bp_history = NULL; - - if (inst->isUncondCtrl()) { - DPRINTF(Branch, "[tid:%i] Unconditional control.\n", tid); - pred_taken = true; - // Tell the BP there was an unconditional branch. - uncondBranch(tid, instPC.instAddr(), bp_history); - - if (inst->isReturn() && RAS[tid].empty()) { - DPRINTF(Branch, "[tid:%i] RAS is empty, predicting " - "false.\n", tid); - pred_taken = false; - } - } else { - ++condPredicted; - - pred_taken = lookup(tid, predPC.instAddr(), bp_history); - } - - PredictorHistory predict_record(seqNum, predPC.instAddr(), pred_taken, - bp_history, tid); - - // Now lookup in the BTB or RAS. - if (pred_taken) { - if (inst->isReturn()) { - ++usedRAS; - - // If it's a function return call, then look up the address - // in the RAS. - TheISA::PCState rasTop = RAS[tid].top(); - target = TheISA::buildRetPC(instPC, rasTop); - - // Record the top entry of the RAS, and its index. - predict_record.usedRAS = true; - predict_record.RASIndex = RAS[tid].topIdx(); - predict_record.RASTarget = rasTop; - - assert(predict_record.RASIndex < 16); - - RAS[tid].pop(); - - DPRINTF(Branch, "[tid:%i]: Instruction %s is a return, " - "RAS predicted target: %s, RAS index: %i.\n", - tid, instPC, target, - predict_record.RASIndex); - } else { - ++BTBLookups; - - if (inst->isCall()) { - - RAS[tid].push(instPC); - predict_record.pushedRAS = true; - - // Record that it was a call so that the top RAS entry can - // be popped off if the speculation is incorrect. - predict_record.wasCall = true; - - DPRINTF(Branch, "[tid:%i]: Instruction %s was a call" - ", adding %s to the RAS index: %i.\n", - tid, instPC, predPC, - RAS[tid].topIdx()); - } - - if (inst->isCall() && - inst->isUncondCtrl() && - inst->isDirectCtrl()) { - target = inst->branchTarget(instPC); - } else if (BTB.valid(predPC.instAddr(), asid)) { - ++BTBHits; - - // If it's not a return, use the BTB to get the target addr. - target = BTB.lookup(predPC.instAddr(), asid); - - DPRINTF(Branch, "[tid:%i]: [asid:%i] Instruction %s " - "predicted target is %s.\n", - tid, asid, instPC, target); - } else { - DPRINTF(Branch, "[tid:%i]: BTB doesn't have a " - "valid entry, predicting false.\n",tid); - pred_taken = false; - } - } - } - - if (pred_taken) { - // Set the PC and the instruction's predicted target. - predPC = target; - } - DPRINTF(Branch, "[tid:%i]: [sn:%i]: Setting Predicted PC to %s.\n", - tid, seqNum, predPC); - - predHist[tid].push_front(predict_record); - - DPRINTF(Branch, "[tid:%i] [sn:%i] pushed onto front of predHist " - "...predHist.size(): %i\n", - tid, seqNum, predHist[tid].size()); - - return pred_taken; -} - void BPredUnit::update(const InstSeqNum &done_sn, ThreadID tid) { -- cgit v1.2.3