bpred_unit.cc (13733:e0829ba19545) bpred_unit.cc (13810:f50e3b82df73)
1/*
2 * Copyright (c) 2011-2012, 2014 ARM Limited
3 * Copyright (c) 2010 The University of Edinburgh
4 * Copyright (c) 2012 Mark D. Hill and David A. Wood
5 * All rights reserved
6 *
7 * The license below extends only to copyright in the software and shall
8 * not be construed as granting a license to any other intellectual

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65 useIndirect(params->useIndirect),
66 iPred(params->indirectHashGHR,
67 params->indirectHashTargets,
68 params->indirectSets,
69 params->indirectWays,
70 params->indirectTagSize,
71 params->indirectPathLength,
72 params->instShiftAmt,
1/*
2 * Copyright (c) 2011-2012, 2014 ARM Limited
3 * Copyright (c) 2010 The University of Edinburgh
4 * Copyright (c) 2012 Mark D. Hill and David A. Wood
5 * All rights reserved
6 *
7 * The license below extends only to copyright in the software and shall
8 * not be construed as granting a license to any other intellectual

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65 useIndirect(params->useIndirect),
66 iPred(params->indirectHashGHR,
67 params->indirectHashTargets,
68 params->indirectSets,
69 params->indirectWays,
70 params->indirectTagSize,
71 params->indirectPathLength,
72 params->instShiftAmt,
73 params->numThreads),
73 params->numThreads,
74 params->indirectGHRBits),
74 instShiftAmt(params->instShiftAmt)
75{
76 for (auto& r : RAS)
77 r.init(params->RASSize);
78}
79
80void
81BPredUnit::regStats()

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202 } else {
203 ++condPredicted;
204 pred_taken = lookup(tid, pc.instAddr(), bp_history);
205
206 DPRINTF(Branch, "[tid:%i]: [sn:%i] Branch predictor"
207 " predicted %i for PC %s\n", tid, seqNum, pred_taken, pc);
208 }
209
75 instShiftAmt(params->instShiftAmt)
76{
77 for (auto& r : RAS)
78 r.init(params->RASSize);
79}
80
81void
82BPredUnit::regStats()

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203 } else {
204 ++condPredicted;
205 pred_taken = lookup(tid, pc.instAddr(), bp_history);
206
207 DPRINTF(Branch, "[tid:%i]: [sn:%i] Branch predictor"
208 " predicted %i for PC %s\n", tid, seqNum, pred_taken, pc);
209 }
210
211 const bool orig_pred_taken = pred_taken;
210 if (useIndirect) {
212 if (useIndirect) {
211 iPred.updateDirectionInfo(tid, pred_taken, indirect_history);
213 iPred.genIndirectInfo(tid, indirect_history);
212 }
213
214 DPRINTF(Branch, "[tid:%i]: [sn:%i] Creating prediction history "
215 "for PC %s\n", tid, seqNum, pc);
216
217 PredictorHistory predict_record(seqNum, pc.instAddr(), pred_taken,
218 bp_history, indirect_history, tid, inst);
219

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312 predict_record.wasReturn = true;
313 }
314 TheISA::advancePC(target, inst);
315 }
316 predict_record.target = target.instAddr();
317
318 pc = target;
319
214 }
215
216 DPRINTF(Branch, "[tid:%i]: [sn:%i] Creating prediction history "
217 "for PC %s\n", tid, seqNum, pc);
218
219 PredictorHistory predict_record(seqNum, pc.instAddr(), pred_taken,
220 bp_history, indirect_history, tid, inst);
221

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314 predict_record.wasReturn = true;
315 }
316 TheISA::advancePC(target, inst);
317 }
318 predict_record.target = target.instAddr();
319
320 pc = target;
321
322 if (useIndirect) {
323 // Update the indirect predictor with the direction prediction
324 // Note that this happens after indirect lookup, so it does not use
325 // the new information
326 // Note also that we use orig_pred_taken instead of pred_taken in
327 // as this is the actual outcome of the direction prediction
328 iPred.updateDirectionInfo(tid, orig_pred_taken);
329 }
330
320 predHist[tid].push_front(predict_record);
321
322 DPRINTF(Branch, "[tid:%i]: [sn:%i]: History entry added."
323 "predHist.size(): %i\n", tid, seqNum, predHist[tid].size());
324
325 return pred_taken;
326}
327

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335 predHist[tid].back().seqNum <= done_sn) {
336 // Update the branch predictor with the correct results.
337 update(tid, predHist[tid].back().pc,
338 predHist[tid].back().predTaken,
339 predHist[tid].back().bpHistory, false,
340 predHist[tid].back().inst,
341 predHist[tid].back().target);
342
331 predHist[tid].push_front(predict_record);
332
333 DPRINTF(Branch, "[tid:%i]: [sn:%i]: History entry added."
334 "predHist.size(): %i\n", tid, seqNum, predHist[tid].size());
335
336 return pred_taken;
337}
338

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346 predHist[tid].back().seqNum <= done_sn) {
347 // Update the branch predictor with the correct results.
348 update(tid, predHist[tid].back().pc,
349 predHist[tid].back().predTaken,
350 predHist[tid].back().bpHistory, false,
351 predHist[tid].back().inst,
352 predHist[tid].back().target);
353
343 iPred.commit(done_sn, tid, predHist[tid].back().indirectHistory);
354 if (useIndirect) {
355 iPred.commit(done_sn, tid, predHist[tid].back().indirectHistory);
356 }
344
345 predHist[tid].pop_back();
346 }
347}
348
349void
350BPredUnit::squash(const InstSeqNum &squashed_sn, ThreadID tid)
351{
352 History &pred_hist = predHist[tid];
353
357
358 predHist[tid].pop_back();
359 }
360}
361
362void
363BPredUnit::squash(const InstSeqNum &squashed_sn, ThreadID tid)
364{
365 History &pred_hist = predHist[tid];
366
354 iPred.squash(squashed_sn, tid);
367 if (useIndirect) {
368 iPred.squash(squashed_sn, tid);
369 }
370
355 while (!pred_hist.empty() &&
356 pred_hist.front().seqNum > squashed_sn) {
357 if (pred_hist.front().usedRAS) {
358 DPRINTF(Branch, "[tid:%i]: Restoring top of RAS to: %i,"
359 " target: %s.\n", tid,
360 pred_hist.front().RASIndex, pred_hist.front().RASTarget);
361
362 RAS[tid].restore(pred_hist.front().RASIndex,

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367 " Call [sn:%i] PC: %s Popping RAS\n", tid,
368 pred_hist.front().seqNum, pred_hist.front().pc);
369 RAS[tid].pop();
370 }
371
372 // This call should delete the bpHistory.
373 squash(tid, pred_hist.front().bpHistory);
374 if (useIndirect) {
371 while (!pred_hist.empty() &&
372 pred_hist.front().seqNum > squashed_sn) {
373 if (pred_hist.front().usedRAS) {
374 DPRINTF(Branch, "[tid:%i]: Restoring top of RAS to: %i,"
375 " target: %s.\n", tid,
376 pred_hist.front().RASIndex, pred_hist.front().RASTarget);
377
378 RAS[tid].restore(pred_hist.front().RASIndex,

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383 " Call [sn:%i] PC: %s Popping RAS\n", tid,
384 pred_hist.front().seqNum, pred_hist.front().pc);
385 RAS[tid].pop();
386 }
387
388 // This call should delete the bpHistory.
389 squash(tid, pred_hist.front().bpHistory);
390 if (useIndirect) {
375 iPred.deleteDirectionInfo(tid, pred_hist.front().indirectHistory);
391 iPred.deleteIndirectInfo(tid, pred_hist.front().indirectHistory);
376 }
377
378 DPRINTF(Branch, "[tid:%i]: Removing history for [sn:%i] "
379 "PC %s.\n", tid, pred_hist.front().seqNum,
380 pred_hist.front().pc);
381
382 pred_hist.pop_front();
383

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464 DPRINTF(Branch, "[tid: %i] Incorrectly predicted"
465 " return [sn:%i] PC: %s\n", tid, hist_it->seqNum,
466 hist_it->pc);
467 RAS[tid].pop();
468 hist_it->usedRAS = true;
469 }
470 if (hist_it->wasIndirect) {
471 ++indirectMispredicted;
392 }
393
394 DPRINTF(Branch, "[tid:%i]: Removing history for [sn:%i] "
395 "PC %s.\n", tid, pred_hist.front().seqNum,
396 pred_hist.front().pc);
397
398 pred_hist.pop_front();
399

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480 DPRINTF(Branch, "[tid: %i] Incorrectly predicted"
481 " return [sn:%i] PC: %s\n", tid, hist_it->seqNum,
482 hist_it->pc);
483 RAS[tid].pop();
484 hist_it->usedRAS = true;
485 }
486 if (hist_it->wasIndirect) {
487 ++indirectMispredicted;
472 iPred.recordTarget(hist_it->seqNum, corrTarget, tid);
488 iPred.recordTarget(
489 hist_it->seqNum, pred_hist.front().indirectHistory,
490 corrTarget, tid);
473 } else {
474 DPRINTF(Branch,"[tid: %i] BTB Update called for [sn:%i]"
475 " PC: %s\n", tid,hist_it->seqNum, hist_it->pc);
476
477 BTB.update((*hist_it).pc, corrTarget, tid);
478 }
479 } else {
480 //Actually not Taken

--- 48 unchanged lines hidden --- 		491 } else {
492 DPRINTF(Branch,"[tid: %i] BTB Update called for [sn:%i]"
493 " PC: %s\n", tid,hist_it->seqNum, hist_it->pc);
494
495 BTB.update((*hist_it).pc, corrTarget, tid);
496 }
497 } else {
498 //Actually not Taken

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