1/*
2 * Copyright (c) 2004-2006 The Regents of The University of Michigan
3 * All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions are
7 * met: redistributions of source code must retain the above copyright
8 * notice, this list of conditions and the following disclaimer;
9 * redistributions in binary form must reproduce the above copyright
10 * notice, this list of conditions and the following disclaimer in the
11 * documentation and/or other materials provided with the distribution;
12 * neither the name of the copyright holders nor the names of its
13 * contributors may be used to endorse or promote products derived from
14 * this software without specific prior written permission.
15 *
16 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
17 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
18 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
19 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
20 * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
21 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
22 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
23 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
24 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
25 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
26 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
27 *
28 * Authors: Kevin Lim
29 */
30
31#include <list>
32
33#include "config/full_system.hh"
34#include "cpu/o3/rename.hh"
35
36using namespace std;
37
38template <class Impl>
39DefaultRename<Impl>::DefaultRename(Params *params)
40 : iewToRenameDelay(params->iewToRenameDelay),
41 decodeToRenameDelay(params->decodeToRenameDelay),
42 commitToRenameDelay(params->commitToRenameDelay),
43 renameWidth(params->renameWidth),
44 commitWidth(params->commitWidth),
45 numThreads(params->numberOfThreads)
46{
47 _status = Inactive;
48
49 for (int i=0; i< numThreads; i++) {
50 renameStatus[i] = Idle;
51
52 freeEntries[i].iqEntries = 0;
53 freeEntries[i].lsqEntries = 0;
54 freeEntries[i].robEntries = 0;
55
56 stalls[i].iew = false;
57 stalls[i].commit = false;
58 serializeInst[i] = NULL;
59
60 instsInProgress[i] = 0;
61
62 emptyROB[i] = true;
63
64 serializeOnNextInst[i] = false;
65 }
66
67 // @todo: Make into a parameter.
68 skidBufferMax = (2 * (iewToRenameDelay * params->decodeWidth)) + renameWidth;
69}
70
71template <class Impl>
72std::string
73DefaultRename<Impl>::name() const
74{
75 return cpu->name() + ".rename";
76}
77
78template <class Impl>
79void
80DefaultRename<Impl>::regStats()
81{
82 renameSquashCycles
83 .name(name() + ".RENAME:SquashCycles")
84 .desc("Number of cycles rename is squashing")
85 .prereq(renameSquashCycles);
86 renameIdleCycles
87 .name(name() + ".RENAME:IdleCycles")
88 .desc("Number of cycles rename is idle")
89 .prereq(renameIdleCycles);
90 renameBlockCycles
91 .name(name() + ".RENAME:BlockCycles")
92 .desc("Number of cycles rename is blocking")
93 .prereq(renameBlockCycles);
94 renameSerializeStallCycles
95 .name(name() + ".RENAME:serializeStallCycles")
96 .desc("count of cycles rename stalled for serializing inst")
97 .flags(Stats::total);
98 renameRunCycles
99 .name(name() + ".RENAME:RunCycles")
100 .desc("Number of cycles rename is running")
101 .prereq(renameIdleCycles);
102 renameUnblockCycles
103 .name(name() + ".RENAME:UnblockCycles")
104 .desc("Number of cycles rename is unblocking")
105 .prereq(renameUnblockCycles);
106 renameRenamedInsts
107 .name(name() + ".RENAME:RenamedInsts")
108 .desc("Number of instructions processed by rename")
109 .prereq(renameRenamedInsts);
110 renameSquashedInsts
111 .name(name() + ".RENAME:SquashedInsts")
112 .desc("Number of squashed instructions processed by rename")
113 .prereq(renameSquashedInsts);
114 renameROBFullEvents
115 .name(name() + ".RENAME:ROBFullEvents")
116 .desc("Number of times rename has blocked due to ROB full")
117 .prereq(renameROBFullEvents);
118 renameIQFullEvents
119 .name(name() + ".RENAME:IQFullEvents")
120 .desc("Number of times rename has blocked due to IQ full")
121 .prereq(renameIQFullEvents);
122 renameLSQFullEvents
123 .name(name() + ".RENAME:LSQFullEvents")
124 .desc("Number of times rename has blocked due to LSQ full")
125 .prereq(renameLSQFullEvents);
126 renameFullRegistersEvents
127 .name(name() + ".RENAME:FullRegisterEvents")
128 .desc("Number of times there has been no free registers")
129 .prereq(renameFullRegistersEvents);
130 renameRenamedOperands
131 .name(name() + ".RENAME:RenamedOperands")
132 .desc("Number of destination operands rename has renamed")
133 .prereq(renameRenamedOperands);
134 renameRenameLookups
135 .name(name() + ".RENAME:RenameLookups")
136 .desc("Number of register rename lookups that rename has made")
137 .prereq(renameRenameLookups);
138 renameCommittedMaps
139 .name(name() + ".RENAME:CommittedMaps")
140 .desc("Number of HB maps that are committed")
141 .prereq(renameCommittedMaps);
142 renameUndoneMaps
143 .name(name() + ".RENAME:UndoneMaps")
144 .desc("Number of HB maps that are undone due to squashing")
145 .prereq(renameUndoneMaps);
146 renamedSerializing
147 .name(name() + ".RENAME:serializingInsts")
148 .desc("count of serializing insts renamed")
149 .flags(Stats::total)
150 ;
151 renamedTempSerializing
152 .name(name() + ".RENAME:tempSerializingInsts")
153 .desc("count of temporary serializing insts renamed")
154 .flags(Stats::total)
155 ;
156 renameSkidInsts
157 .name(name() + ".RENAME:skidInsts")
158 .desc("count of insts added to the skid buffer")
159 .flags(Stats::total)
160 ;
161}
162
163template <class Impl>
164void
165DefaultRename<Impl>::setCPU(O3CPU *cpu_ptr)
166{
167 DPRINTF(Rename, "Setting CPU pointer.\n");
168 cpu = cpu_ptr;
169}
170
171template <class Impl>
172void
173DefaultRename<Impl>::setTimeBuffer(TimeBuffer<TimeStruct> *tb_ptr)
174{
175 DPRINTF(Rename, "Setting time buffer pointer.\n");
176 timeBuffer = tb_ptr;
177
178 // Setup wire to read information from time buffer, from IEW stage.
179 fromIEW = timeBuffer->getWire(-iewToRenameDelay);
180
181 // Setup wire to read infromation from time buffer, from commit stage.
182 fromCommit = timeBuffer->getWire(-commitToRenameDelay);
183
184 // Setup wire to write information to previous stages.
185 toDecode = timeBuffer->getWire(0);
186}
187
188template <class Impl>
189void
190DefaultRename<Impl>::setRenameQueue(TimeBuffer<RenameStruct> *rq_ptr)
191{
192 DPRINTF(Rename, "Setting rename queue pointer.\n");
193 renameQueue = rq_ptr;
194
195 // Setup wire to write information to future stages.
196 toIEW = renameQueue->getWire(0);
197}
198
199template <class Impl>
200void
201DefaultRename<Impl>::setDecodeQueue(TimeBuffer<DecodeStruct> *dq_ptr)
202{
203 DPRINTF(Rename, "Setting decode queue pointer.\n");
204 decodeQueue = dq_ptr;
205
206 // Setup wire to get information from decode.
207 fromDecode = decodeQueue->getWire(-decodeToRenameDelay);
208}
209
210template <class Impl>
211void
212DefaultRename<Impl>::initStage()
213{
214 // Grab the number of free entries directly from the stages.
215 for (int tid=0; tid < numThreads; tid++) {
216 freeEntries[tid].iqEntries = iew_ptr->instQueue.numFreeEntries(tid);
217 freeEntries[tid].lsqEntries = iew_ptr->ldstQueue.numFreeEntries(tid);
218 freeEntries[tid].robEntries = commit_ptr->numROBFreeEntries(tid);
219 emptyROB[tid] = true;
220 }
221}
222
223template<class Impl>
224void
225DefaultRename<Impl>::setActiveThreads(list<unsigned> *at_ptr)
226{
227 DPRINTF(Rename, "Setting active threads list pointer.\n");
228 activeThreads = at_ptr;
229}
230
231
232template <class Impl>
233void
234DefaultRename<Impl>::setRenameMap(RenameMap rm_ptr[])
235{
236 DPRINTF(Rename, "Setting rename map pointers.\n");
237
238 for (int i=0; i<numThreads; i++) {
239 renameMap[i] = &rm_ptr[i];
240 }
241}
242
243template <class Impl>
244void
245DefaultRename<Impl>::setFreeList(FreeList *fl_ptr)
246{
247 DPRINTF(Rename, "Setting free list pointer.\n");
248 freeList = fl_ptr;
249}
250
251template<class Impl>
252void
253DefaultRename<Impl>::setScoreboard(Scoreboard *_scoreboard)
254{
255 DPRINTF(Rename, "Setting scoreboard pointer.\n");
256 scoreboard = _scoreboard;
257}
258
259template <class Impl>
260void
|
270{
271 // Clear any state, fix up the rename map.
272 for (int i = 0; i < numThreads; i++) {
273 typename list<RenameHistory>::iterator hb_it = historyBuffer[i].begin();
274
275 while (!historyBuffer[i].empty()) {
276 assert(hb_it != historyBuffer[i].end());
277
278 DPRINTF(Rename, "[tid:%u]: Removing history entry with sequence "
279 "number %i.\n", i, (*hb_it).instSeqNum);
280
281 // Tell the rename map to set the architected register to the
282 // previous physical register that it was renamed to.
283 renameMap[i]->setEntry(hb_it->archReg, hb_it->prevPhysReg);
284
285 // Put the renamed physical register back on the free list.
286 freeList->addReg(hb_it->newPhysReg);
287
288 historyBuffer[i].erase(hb_it++);
289 }
290 insts[i].clear();
291 skidBuffer[i].clear();
292 }
293}
294
295template <class Impl>
296void
297DefaultRename<Impl>::takeOverFrom()
298{
299 _status = Inactive;
300 initStage();
301
302 // Reset all state prior to taking over from the other CPU.
303 for (int i=0; i< numThreads; i++) {
304 renameStatus[i] = Idle;
305
306 stalls[i].iew = false;
307 stalls[i].commit = false;
308 serializeInst[i] = NULL;
309
310 instsInProgress[i] = 0;
311
312 emptyROB[i] = true;
313
314 serializeOnNextInst[i] = false;
315 }
316}
317
318template <class Impl>
319void
320DefaultRename<Impl>::squash(unsigned tid)
321{
322 DPRINTF(Rename, "[tid:%u]: Squashing instructions.\n",tid);
323
324 // Clear the stall signal if rename was blocked or unblocking before.
325 // If it still needs to block, the blocking should happen the next
326 // cycle and there should be space to hold everything due to the squash.
327 if (renameStatus[tid] == Blocked ||
328 renameStatus[tid] == Unblocking ||
329 renameStatus[tid] == SerializeStall) {
330
331 toDecode->renameUnblock[tid] = 1;
332
333 serializeInst[tid] = NULL;
334 }
335
336 // Set the status to Squashing.
337 renameStatus[tid] = Squashing;
338
339 // Squash any instructions from decode.
340 unsigned squashCount = 0;
341
342 for (int i=0; i<fromDecode->size; i++) {
343 if (fromDecode->insts[i]->threadNumber == tid) {
344 fromDecode->insts[i]->setSquashed();
345 wroteToTimeBuffer = true;
346 squashCount++;
347 }
348 }
349
350 insts[tid].clear();
351
352 // Clear the skid buffer in case it has any data in it.
353 skidBuffer[tid].clear();
354
355 doSquash(tid);
356}
357
358template <class Impl>
359void
360DefaultRename<Impl>::tick()
361{
362 wroteToTimeBuffer = false;
363
364 blockThisCycle = false;
365
366 bool status_change = false;
367
368 toIEWIndex = 0;
369
370 sortInsts();
371
372 list<unsigned>::iterator threads = (*activeThreads).begin();
373
374 // Check stall and squash signals.
375 while (threads != (*activeThreads).end()) {
376 unsigned tid = *threads++;
377
378 DPRINTF(Rename, "Processing [tid:%i]\n", tid);
379
380 status_change = checkSignalsAndUpdate(tid) || status_change;
381
382 rename(status_change, tid);
383 }
384
385 if (status_change) {
386 updateStatus();
387 }
388
389 if (wroteToTimeBuffer) {
390 DPRINTF(Activity, "Activity this cycle.\n");
391 cpu->activityThisCycle();
392 }
393
394 threads = (*activeThreads).begin();
395
396 while (threads != (*activeThreads).end()) {
397 unsigned tid = *threads++;
398
399 // If we committed this cycle then doneSeqNum will be > 0
400 if (fromCommit->commitInfo[tid].doneSeqNum != 0 &&
401 !fromCommit->commitInfo[tid].squash &&
402 renameStatus[tid] != Squashing) {
403
404 removeFromHistory(fromCommit->commitInfo[tid].doneSeqNum,
405 tid);
406 }
407 }
408
409 // @todo: make into updateProgress function
410 for (int tid=0; tid < numThreads; tid++) {
411 instsInProgress[tid] -= fromIEW->iewInfo[tid].dispatched;
412
413 assert(instsInProgress[tid] >=0);
414 }
415
416}
417
418template<class Impl>
419void
420DefaultRename<Impl>::rename(bool &status_change, unsigned tid)
421{
422 // If status is Running or idle,
423 // call renameInsts()
424 // If status is Unblocking,
425 // buffer any instructions coming from decode
426 // continue trying to empty skid buffer
427 // check if stall conditions have passed
428
429 if (renameStatus[tid] == Blocked) {
430 ++renameBlockCycles;
431 } else if (renameStatus[tid] == Squashing) {
432 ++renameSquashCycles;
433 } else if (renameStatus[tid] == SerializeStall) {
434 ++renameSerializeStallCycles;
435 }
436
437 if (renameStatus[tid] == Running ||
438 renameStatus[tid] == Idle) {
439 DPRINTF(Rename, "[tid:%u]: Not blocked, so attempting to run "
440 "stage.\n", tid);
441
442 renameInsts(tid);
443 } else if (renameStatus[tid] == Unblocking) {
444 renameInsts(tid);
445
446 if (validInsts()) {
447 // Add the current inputs to the skid buffer so they can be
448 // reprocessed when this stage unblocks.
449 skidInsert(tid);
450 }
451
452 // If we switched over to blocking, then there's a potential for
453 // an overall status change.
454 status_change = unblock(tid) || status_change || blockThisCycle;
455 }
456}
457
458template <class Impl>
459void
460DefaultRename<Impl>::renameInsts(unsigned tid)
461{
462 // Instructions can be either in the skid buffer or the queue of
463 // instructions coming from decode, depending on the status.
464 int insts_available = renameStatus[tid] == Unblocking ?
465 skidBuffer[tid].size() : insts[tid].size();
466
467 // Check the decode queue to see if instructions are available.
468 // If there are no available instructions to rename, then do nothing.
469 if (insts_available == 0) {
470 DPRINTF(Rename, "[tid:%u]: Nothing to do, breaking out early.\n",
471 tid);
472 // Should I change status to idle?
473 ++renameIdleCycles;
474 return;
475 } else if (renameStatus[tid] == Unblocking) {
476 ++renameUnblockCycles;
477 } else if (renameStatus[tid] == Running) {
478 ++renameRunCycles;
479 }
480
481 DynInstPtr inst;
482
483 // Will have to do a different calculation for the number of free
484 // entries.
485 int free_rob_entries = calcFreeROBEntries(tid);
486 int free_iq_entries = calcFreeIQEntries(tid);
487 int free_lsq_entries = calcFreeLSQEntries(tid);
488 int min_free_entries = free_rob_entries;
489
490 FullSource source = ROB;
491
492 if (free_iq_entries < min_free_entries) {
493 min_free_entries = free_iq_entries;
494 source = IQ;
495 }
496
497 if (free_lsq_entries < min_free_entries) {
498 min_free_entries = free_lsq_entries;
499 source = LSQ;
500 }
501
502 // Check if there's any space left.
503 if (min_free_entries <= 0) {
504 DPRINTF(Rename, "[tid:%u]: Blocking due to no free ROB/IQ/LSQ "
505 "entries.\n"
506 "ROB has %i free entries.\n"
507 "IQ has %i free entries.\n"
508 "LSQ has %i free entries.\n",
509 tid,
510 free_rob_entries,
511 free_iq_entries,
512 free_lsq_entries);
513
514 blockThisCycle = true;
515
516 block(tid);
517
518 incrFullStat(source);
519
520 return;
521 } else if (min_free_entries < insts_available) {
522 DPRINTF(Rename, "[tid:%u]: Will have to block this cycle."
523 "%i insts available, but only %i insts can be "
524 "renamed due to ROB/IQ/LSQ limits.\n",
525 tid, insts_available, min_free_entries);
526
527 insts_available = min_free_entries;
528
529 blockThisCycle = true;
530
531 incrFullStat(source);
532 }
533
534 InstQueue &insts_to_rename = renameStatus[tid] == Unblocking ?
535 skidBuffer[tid] : insts[tid];
536
537 DPRINTF(Rename, "[tid:%u]: %i available instructions to "
538 "send iew.\n", tid, insts_available);
539
540 DPRINTF(Rename, "[tid:%u]: %i insts pipelining from Rename | %i insts "
541 "dispatched to IQ last cycle.\n",
542 tid, instsInProgress[tid], fromIEW->iewInfo[tid].dispatched);
543
544 // Handle serializing the next instruction if necessary.
545 if (serializeOnNextInst[tid]) {
546 if (emptyROB[tid] && instsInProgress[tid] == 0) {
547 // ROB already empty; no need to serialize.
548 serializeOnNextInst[tid] = false;
549 } else if (!insts_to_rename.empty()) {
550 insts_to_rename.front()->setSerializeBefore();
551 }
552 }
553
554 int renamed_insts = 0;
555
556 while (insts_available > 0 && toIEWIndex < renameWidth) {
557 DPRINTF(Rename, "[tid:%u]: Sending instructions to IEW.\n", tid);
558
559 assert(!insts_to_rename.empty());
560
561 inst = insts_to_rename.front();
562
563 insts_to_rename.pop_front();
564
565 if (renameStatus[tid] == Unblocking) {
566 DPRINTF(Rename,"[tid:%u]: Removing [sn:%lli] PC:%#x from rename "
567 "skidBuffer\n",
568 tid, inst->seqNum, inst->readPC());
569 }
570
571 if (inst->isSquashed()) {
572 DPRINTF(Rename, "[tid:%u]: instruction %i with PC %#x is "
573 "squashed, skipping.\n",
574 tid, inst->seqNum, inst->threadNumber,inst->readPC());
575
576 ++renameSquashedInsts;
577
578 // Decrement how many instructions are available.
579 --insts_available;
580
581 continue;
582 }
583
584 DPRINTF(Rename, "[tid:%u]: Processing instruction [sn:%lli] with "
585 "PC %#x.\n",
586 tid, inst->seqNum, inst->readPC());
587
588 // Handle serializeAfter/serializeBefore instructions.
589 // serializeAfter marks the next instruction as serializeBefore.
590 // serializeBefore makes the instruction wait in rename until the ROB
591 // is empty.
592
593 // In this model, IPR accesses are serialize before
594 // instructions, and store conditionals are serialize after
595 // instructions. This is mainly due to lack of support for
596 // out-of-order operations of either of those classes of
597 // instructions.
598 if ((inst->isIprAccess() || inst->isSerializeBefore()) &&
599 !inst->isSerializeHandled()) {
600 DPRINTF(Rename, "Serialize before instruction encountered.\n");
601
602 if (!inst->isTempSerializeBefore()) {
603 renamedSerializing++;
604 inst->setSerializeHandled();
605 } else {
606 renamedTempSerializing++;
607 }
608
609 // Change status over to SerializeStall so that other stages know
610 // what this is blocked on.
611 renameStatus[tid] = SerializeStall;
612
613 serializeInst[tid] = inst;
614
615 blockThisCycle = true;
616
617 break;
618 } else if ((inst->isStoreConditional() || inst->isSerializeAfter()) &&
619 !inst->isSerializeHandled()) {
620 DPRINTF(Rename, "Serialize after instruction encountered.\n");
621
622 renamedSerializing++;
623
624 inst->setSerializeHandled();
625
626 serializeAfter(insts_to_rename, tid);
627 }
628
629 // Check here to make sure there are enough destination registers
630 // to rename to. Otherwise block.
631 if (renameMap[tid]->numFreeEntries() < inst->numDestRegs()) {
632 DPRINTF(Rename, "Blocking due to lack of free "
633 "physical registers to rename to.\n");
634 blockThisCycle = true;
635
636 ++renameFullRegistersEvents;
637
638 break;
639 }
640
641 renameSrcRegs(inst, inst->threadNumber);
642
643 renameDestRegs(inst, inst->threadNumber);
644
645 ++renamed_insts;
646
647 // Put instruction in rename queue.
648 toIEW->insts[toIEWIndex] = inst;
649 ++(toIEW->size);
650
651 // Increment which instruction we're on.
652 ++toIEWIndex;
653
654 // Decrement how many instructions are available.
655 --insts_available;
656 }
657
658 instsInProgress[tid] += renamed_insts;
659 renameRenamedInsts += renamed_insts;
660
661 // If we wrote to the time buffer, record this.
662 if (toIEWIndex) {
663 wroteToTimeBuffer = true;
664 }
665
666 // Check if there's any instructions left that haven't yet been renamed.
667 // If so then block.
668 if (insts_available) {
669 blockThisCycle = true;
670 }
671
672 if (blockThisCycle) {
673 block(tid);
674 toDecode->renameUnblock[tid] = false;
675 }
676}
677
678template<class Impl>
679void
680DefaultRename<Impl>::skidInsert(unsigned tid)
681{
682 DynInstPtr inst = NULL;
683
684 while (!insts[tid].empty()) {
685 inst = insts[tid].front();
686
687 insts[tid].pop_front();
688
689 assert(tid == inst->threadNumber);
690
691 DPRINTF(Rename, "[tid:%u]: Inserting [sn:%lli] PC:%#x into Rename "
692 "skidBuffer\n", tid, inst->seqNum, inst->readPC());
693
694 ++renameSkidInsts;
695
696 skidBuffer[tid].push_back(inst);
697 }
698
699 if (skidBuffer[tid].size() > skidBufferMax)
700 panic("Skidbuffer Exceeded Max Size");
701}
702
703template <class Impl>
704void
705DefaultRename<Impl>::sortInsts()
706{
707 int insts_from_decode = fromDecode->size;
708#ifdef DEBUG
709 for (int i=0; i < numThreads; i++)
710 assert(insts[i].empty());
711#endif
712 for (int i = 0; i < insts_from_decode; ++i) {
713 DynInstPtr inst = fromDecode->insts[i];
714 insts[inst->threadNumber].push_back(inst);
715 }
716}
717
718template<class Impl>
719bool
720DefaultRename<Impl>::skidsEmpty()
721{
722 list<unsigned>::iterator threads = (*activeThreads).begin();
723
724 while (threads != (*activeThreads).end()) {
725 if (!skidBuffer[*threads++].empty())
726 return false;
727 }
728
729 return true;
730}
731
732template<class Impl>
733void
734DefaultRename<Impl>::updateStatus()
735{
736 bool any_unblocking = false;
737
738 list<unsigned>::iterator threads = (*activeThreads).begin();
739
740 threads = (*activeThreads).begin();
741
742 while (threads != (*activeThreads).end()) {
743 unsigned tid = *threads++;
744
745 if (renameStatus[tid] == Unblocking) {
746 any_unblocking = true;
747 break;
748 }
749 }
750
751 // Rename will have activity if it's unblocking.
752 if (any_unblocking) {
753 if (_status == Inactive) {
754 _status = Active;
755
756 DPRINTF(Activity, "Activating stage.\n");
757
758 cpu->activateStage(O3CPU::RenameIdx);
759 }
760 } else {
761 // If it's not unblocking, then rename will not have any internal
762 // activity. Switch it to inactive.
763 if (_status == Active) {
764 _status = Inactive;
765 DPRINTF(Activity, "Deactivating stage.\n");
766
767 cpu->deactivateStage(O3CPU::RenameIdx);
768 }
769 }
770}
771
772template <class Impl>
773bool
774DefaultRename<Impl>::block(unsigned tid)
775{
776 DPRINTF(Rename, "[tid:%u]: Blocking.\n", tid);
777
778 // Add the current inputs onto the skid buffer, so they can be
779 // reprocessed when this stage unblocks.
780 skidInsert(tid);
781
782 // Only signal backwards to block if the previous stages do not think
783 // rename is already blocked.
784 if (renameStatus[tid] != Blocked) {
785 if (renameStatus[tid] != Unblocking) {
786 toDecode->renameBlock[tid] = true;
787 toDecode->renameUnblock[tid] = false;
788 wroteToTimeBuffer = true;
789 }
790
791 // Rename can not go from SerializeStall to Blocked, otherwise
792 // it would not know to complete the serialize stall.
793 if (renameStatus[tid] != SerializeStall) {
794 // Set status to Blocked.
795 renameStatus[tid] = Blocked;
796 return true;
797 }
798 }
799
800 return false;
801}
802
803template <class Impl>
804bool
805DefaultRename<Impl>::unblock(unsigned tid)
806{
807 DPRINTF(Rename, "[tid:%u]: Trying to unblock.\n", tid);
808
809 // Rename is done unblocking if the skid buffer is empty.
810 if (skidBuffer[tid].empty() && renameStatus[tid] != SerializeStall) {
811
812 DPRINTF(Rename, "[tid:%u]: Done unblocking.\n", tid);
813
814 toDecode->renameUnblock[tid] = true;
815 wroteToTimeBuffer = true;
816
817 renameStatus[tid] = Running;
818 return true;
819 }
820
821 return false;
822}
823
824template <class Impl>
825void
826DefaultRename<Impl>::doSquash(unsigned tid)
827{
828 typename list<RenameHistory>::iterator hb_it = historyBuffer[tid].begin();
829
830 InstSeqNum squashed_seq_num = fromCommit->commitInfo[tid].doneSeqNum;
831
832 // After a syscall squashes everything, the history buffer may be empty
833 // but the ROB may still be squashing instructions.
834 if (historyBuffer[tid].empty()) {
835 return;
836 }
837
838 // Go through the most recent instructions, undoing the mappings
839 // they did and freeing up the registers.
840 while (!historyBuffer[tid].empty() &&
841 (*hb_it).instSeqNum > squashed_seq_num) {
842 assert(hb_it != historyBuffer[tid].end());
843
844 DPRINTF(Rename, "[tid:%u]: Removing history entry with sequence "
845 "number %i.\n", tid, (*hb_it).instSeqNum);
846
847 // Tell the rename map to set the architected register to the
848 // previous physical register that it was renamed to.
849 renameMap[tid]->setEntry(hb_it->archReg, hb_it->prevPhysReg);
850
851 // Put the renamed physical register back on the free list.
852 freeList->addReg(hb_it->newPhysReg);
853
854 historyBuffer[tid].erase(hb_it++);
855
856 ++renameUndoneMaps;
857 }
858}
859
860template<class Impl>
861void
862DefaultRename<Impl>::removeFromHistory(InstSeqNum inst_seq_num, unsigned tid)
863{
864 DPRINTF(Rename, "[tid:%u]: Removing a committed instruction from the "
865 "history buffer %u (size=%i), until [sn:%lli].\n",
866 tid, tid, historyBuffer[tid].size(), inst_seq_num);
867
868 typename list<RenameHistory>::iterator hb_it = historyBuffer[tid].end();
869
870 --hb_it;
871
872 if (historyBuffer[tid].empty()) {
873 DPRINTF(Rename, "[tid:%u]: History buffer is empty.\n", tid);
874 return;
875 } else if (hb_it->instSeqNum > inst_seq_num) {
876 DPRINTF(Rename, "[tid:%u]: Old sequence number encountered. Ensure "
877 "that a syscall happened recently.\n", tid);
878 return;
879 }
880
881 // Commit all the renames up until (and including) the committed sequence
882 // number. Some or even all of the committed instructions may not have
883 // rename histories if they did not have destination registers that were
884 // renamed.
885 while (!historyBuffer[tid].empty() &&
886 hb_it != historyBuffer[tid].end() &&
887 (*hb_it).instSeqNum <= inst_seq_num) {
888
889 DPRINTF(Rename, "[tid:%u]: Freeing up older rename of reg %i, "
890 "[sn:%lli].\n",
891 tid, (*hb_it).prevPhysReg, (*hb_it).instSeqNum);
892
893 freeList->addReg((*hb_it).prevPhysReg);
894 ++renameCommittedMaps;
895
896 historyBuffer[tid].erase(hb_it--);
897 }
898}
899
900template <class Impl>
901inline void
902DefaultRename<Impl>::renameSrcRegs(DynInstPtr &inst,unsigned tid)
903{
904 assert(renameMap[tid] != 0);
905
906 unsigned num_src_regs = inst->numSrcRegs();
907
908 // Get the architectual register numbers from the source and
909 // destination operands, and redirect them to the right register.
910 // Will need to mark dependencies though.
911 for (int src_idx = 0; src_idx < num_src_regs; src_idx++) {
912 RegIndex src_reg = inst->srcRegIdx(src_idx);
913
914 // Look up the source registers to get the phys. register they've
915 // been renamed to, and set the sources to those registers.
916 PhysRegIndex renamed_reg = renameMap[tid]->lookup(src_reg);
917
918 DPRINTF(Rename, "[tid:%u]: Looking up arch reg %i, got "
919 "physical reg %i.\n", tid, (int)src_reg,
920 (int)renamed_reg);
921
922 inst->renameSrcReg(src_idx, renamed_reg);
923
924 // See if the register is ready or not.
925 if (scoreboard->getReg(renamed_reg) == true) {
926 DPRINTF(Rename, "[tid:%u]: Register is ready.\n", tid);
927
928 inst->markSrcRegReady(src_idx);
929 }
930
931 ++renameRenameLookups;
932 }
933}
934
935template <class Impl>
936inline void
937DefaultRename<Impl>::renameDestRegs(DynInstPtr &inst,unsigned tid)
938{
939 typename RenameMap::RenameInfo rename_result;
940
941 unsigned num_dest_regs = inst->numDestRegs();
942
943 // Rename the destination registers.
944 for (int dest_idx = 0; dest_idx < num_dest_regs; dest_idx++) {
945 RegIndex dest_reg = inst->destRegIdx(dest_idx);
946
947 // Get the physical register that the destination will be
948 // renamed to.
949 rename_result = renameMap[tid]->rename(dest_reg);
950
951 //Mark Scoreboard entry as not ready
952 scoreboard->unsetReg(rename_result.first);
953
954 DPRINTF(Rename, "[tid:%u]: Renaming arch reg %i to physical "
955 "reg %i.\n", tid, (int)dest_reg,
956 (int)rename_result.first);
957
958 // Record the rename information so that a history can be kept.
959 RenameHistory hb_entry(inst->seqNum, dest_reg,
960 rename_result.first,
961 rename_result.second);
962
963 historyBuffer[tid].push_front(hb_entry);
964
965 DPRINTF(Rename, "[tid:%u]: Adding instruction to history buffer, "
966 "[sn:%lli].\n",tid,
967 (*historyBuffer[tid].begin()).instSeqNum);
968
969 // Tell the instruction to rename the appropriate destination
970 // register (dest_idx) to the new physical register
971 // (rename_result.first), and record the previous physical
972 // register that the same logical register was renamed to
973 // (rename_result.second).
974 inst->renameDestReg(dest_idx,
975 rename_result.first,
976 rename_result.second);
977
978 ++renameRenamedOperands;
979 }
980}
981
982template <class Impl>
983inline int
984DefaultRename<Impl>::calcFreeROBEntries(unsigned tid)
985{
986 int num_free = freeEntries[tid].robEntries -
987 (instsInProgress[tid] - fromIEW->iewInfo[tid].dispatched);
988
989 //DPRINTF(Rename,"[tid:%i]: %i rob free\n",tid,num_free);
990
991 return num_free;
992}
993
994template <class Impl>
995inline int
996DefaultRename<Impl>::calcFreeIQEntries(unsigned tid)
997{
998 int num_free = freeEntries[tid].iqEntries -
999 (instsInProgress[tid] - fromIEW->iewInfo[tid].dispatched);
1000
1001 //DPRINTF(Rename,"[tid:%i]: %i iq free\n",tid,num_free);
1002
1003 return num_free;
1004}
1005
1006template <class Impl>
1007inline int
1008DefaultRename<Impl>::calcFreeLSQEntries(unsigned tid)
1009{
1010 int num_free = freeEntries[tid].lsqEntries -
1011 (instsInProgress[tid] - fromIEW->iewInfo[tid].dispatchedToLSQ);
1012
1013 //DPRINTF(Rename,"[tid:%i]: %i lsq free\n",tid,num_free);
1014
1015 return num_free;
1016}
1017
1018template <class Impl>
1019unsigned
1020DefaultRename<Impl>::validInsts()
1021{
1022 unsigned inst_count = 0;
1023
1024 for (int i=0; i<fromDecode->size; i++) {
1025 if (!fromDecode->insts[i]->isSquashed())
1026 inst_count++;
1027 }
1028
1029 return inst_count;
1030}
1031
1032template <class Impl>
1033void
1034DefaultRename<Impl>::readStallSignals(unsigned tid)
1035{
1036 if (fromIEW->iewBlock[tid]) {
1037 stalls[tid].iew = true;
1038 }
1039
1040 if (fromIEW->iewUnblock[tid]) {
1041 assert(stalls[tid].iew);
1042 stalls[tid].iew = false;
1043 }
1044
1045 if (fromCommit->commitBlock[tid]) {
1046 stalls[tid].commit = true;
1047 }
1048
1049 if (fromCommit->commitUnblock[tid]) {
1050 assert(stalls[tid].commit);
1051 stalls[tid].commit = false;
1052 }
1053}
1054
1055template <class Impl>
1056bool
1057DefaultRename<Impl>::checkStall(unsigned tid)
1058{
1059 bool ret_val = false;
1060
1061 if (stalls[tid].iew) {
1062 DPRINTF(Rename,"[tid:%i]: Stall from IEW stage detected.\n", tid);
1063 ret_val = true;
1064 } else if (stalls[tid].commit) {
1065 DPRINTF(Rename,"[tid:%i]: Stall from Commit stage detected.\n", tid);
1066 ret_val = true;
1067 } else if (calcFreeROBEntries(tid) <= 0) {
1068 DPRINTF(Rename,"[tid:%i]: Stall: ROB has 0 free entries.\n", tid);
1069 ret_val = true;
1070 } else if (calcFreeIQEntries(tid) <= 0) {
1071 DPRINTF(Rename,"[tid:%i]: Stall: IQ has 0 free entries.\n", tid);
1072 ret_val = true;
1073 } else if (calcFreeLSQEntries(tid) <= 0) {
1074 DPRINTF(Rename,"[tid:%i]: Stall: LSQ has 0 free entries.\n", tid);
1075 ret_val = true;
1076 } else if (renameMap[tid]->numFreeEntries() <= 0) {
1077 DPRINTF(Rename,"[tid:%i]: Stall: RenameMap has 0 free entries.\n", tid);
1078 ret_val = true;
1079 } else if (renameStatus[tid] == SerializeStall &&
1080 (!emptyROB[tid] || instsInProgress[tid])) {
1081 DPRINTF(Rename,"[tid:%i]: Stall: Serialize stall and ROB is not "
1082 "empty.\n",
1083 tid);
1084 ret_val = true;
1085 }
1086
1087 return ret_val;
1088}
1089
1090template <class Impl>
1091void
1092DefaultRename<Impl>::readFreeEntries(unsigned tid)
1093{
1094 bool updated = false;
1095 if (fromIEW->iewInfo[tid].usedIQ) {
1096 freeEntries[tid].iqEntries =
1097 fromIEW->iewInfo[tid].freeIQEntries;
1098 updated = true;
1099 }
1100
1101 if (fromIEW->iewInfo[tid].usedLSQ) {
1102 freeEntries[tid].lsqEntries =
1103 fromIEW->iewInfo[tid].freeLSQEntries;
1104 updated = true;
1105 }
1106
1107 if (fromCommit->commitInfo[tid].usedROB) {
1108 freeEntries[tid].robEntries =
1109 fromCommit->commitInfo[tid].freeROBEntries;
1110 emptyROB[tid] = fromCommit->commitInfo[tid].emptyROB;
1111 updated = true;
1112 }
1113
1114 DPRINTF(Rename, "[tid:%i]: Free IQ: %i, Free ROB: %i, Free LSQ: %i\n",
1115 tid,
1116 freeEntries[tid].iqEntries,
1117 freeEntries[tid].robEntries,
1118 freeEntries[tid].lsqEntries);
1119
1120 DPRINTF(Rename, "[tid:%i]: %i instructions not yet in ROB\n",
1121 tid, instsInProgress[tid]);
1122}
1123
1124template <class Impl>
1125bool
1126DefaultRename<Impl>::checkSignalsAndUpdate(unsigned tid)
1127{
1128 // Check if there's a squash signal, squash if there is
1129 // Check stall signals, block if necessary.
1130 // If status was blocked
1131 // check if stall conditions have passed
1132 // if so then go to unblocking
1133 // If status was Squashing
1134 // check if squashing is not high. Switch to running this cycle.
1135 // If status was serialize stall
1136 // check if ROB is empty and no insts are in flight to the ROB
1137
1138 readFreeEntries(tid);
1139 readStallSignals(tid);
1140
1141 if (fromCommit->commitInfo[tid].squash) {
1142 DPRINTF(Rename, "[tid:%u]: Squashing instructions due to squash from "
1143 "commit.\n", tid);
1144
1145 squash(tid);
1146
1147 return true;
1148 }
1149
1150 if (fromCommit->commitInfo[tid].robSquashing) {
1151 DPRINTF(Rename, "[tid:%u]: ROB is still squashing.\n", tid);
1152
1153 renameStatus[tid] = Squashing;
1154
1155 return true;
1156 }
1157
1158 if (checkStall(tid)) {
1159 return block(tid);
1160 }
1161
1162 if (renameStatus[tid] == Blocked) {
1163 DPRINTF(Rename, "[tid:%u]: Done blocking, switching to unblocking.\n",
1164 tid);
1165
1166 renameStatus[tid] = Unblocking;
1167
1168 unblock(tid);
1169
1170 return true;
1171 }
1172
1173 if (renameStatus[tid] == Squashing) {
1174 // Switch status to running if rename isn't being told to block or
1175 // squash this cycle.
1176 DPRINTF(Rename, "[tid:%u]: Done squashing, switching to running.\n",
1177 tid);
1178
1179 renameStatus[tid] = Running;
1180
1181 return false;
1182 }
1183
1184 if (renameStatus[tid] == SerializeStall) {
1185 // Stall ends once the ROB is free.
1186 DPRINTF(Rename, "[tid:%u]: Done with serialize stall, switching to "
1187 "unblocking.\n", tid);
1188
1189 DynInstPtr serial_inst = serializeInst[tid];
1190
1191 renameStatus[tid] = Unblocking;
1192
1193 unblock(tid);
1194
1195 DPRINTF(Rename, "[tid:%u]: Processing instruction [%lli] with "
1196 "PC %#x.\n",
1197 tid, serial_inst->seqNum, serial_inst->readPC());
1198
1199 // Put instruction into queue here.
1200 serial_inst->clearSerializeBefore();
1201
1202 if (!skidBuffer[tid].empty()) {
1203 skidBuffer[tid].push_front(serial_inst);
1204 } else {
1205 insts[tid].push_front(serial_inst);
1206 }
1207
1208 DPRINTF(Rename, "[tid:%u]: Instruction must be processed by rename."
1209 " Adding to front of list.\n", tid);
1210
1211 serializeInst[tid] = NULL;
1212
1213 return true;
1214 }
1215
1216 // If we've reached this point, we have not gotten any signals that
1217 // cause rename to change its status. Rename remains the same as before.
1218 return false;
1219}
1220
1221template<class Impl>
1222void
1223DefaultRename<Impl>::serializeAfter(InstQueue &inst_list,
1224 unsigned tid)
1225{
1226 if (inst_list.empty()) {
1227 // Mark a bit to say that I must serialize on the next instruction.
1228 serializeOnNextInst[tid] = true;
1229 return;
1230 }
1231
1232 // Set the next instruction as serializing.
1233 inst_list.front()->setSerializeBefore();
1234}
1235
1236template <class Impl>
1237inline void
1238DefaultRename<Impl>::incrFullStat(const FullSource &source)
1239{
1240 switch (source) {
1241 case ROB:
1242 ++renameROBFullEvents;
1243 break;
1244 case IQ:
1245 ++renameIQFullEvents;
1246 break;
1247 case LSQ:
1248 ++renameLSQFullEvents;
1249 break;
1250 default:
1251 panic("Rename full stall stat should be incremented for a reason!");
1252 break;
1253 }
1254}
1255
1256template <class Impl>
1257void
1258DefaultRename<Impl>::dumpHistory()
1259{
1260 typename list<RenameHistory>::iterator buf_it;
1261
1262 for (int i = 0; i < numThreads; i++) {
1263
1264 buf_it = historyBuffer[i].begin();
1265
1266 while (buf_it != historyBuffer[i].end()) {
1267 cprintf("Seq num: %i\nArch reg: %i New phys reg: %i Old phys "
1268 "reg: %i\n", (*buf_it).instSeqNum, (int)(*buf_it).archReg,
1269 (int)(*buf_it).newPhysReg, (int)(*buf_it).prevPhysReg);
1270
1271 buf_it++;
1272 }
1273 }
1274}
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