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 * Korey Sewell
30 */
31
32#include <list>
33
34#include "arch/isa_traits.hh"
35#include "arch/regfile.hh"
36#include "config/full_system.hh"
37#include "cpu/o3/rename.hh"
38
39template <class Impl>
40DefaultRename<Impl>::DefaultRename(O3CPU *_cpu, Params *params)
41 : cpu(_cpu),
42 iewToRenameDelay(params->iewToRenameDelay),
43 decodeToRenameDelay(params->decodeToRenameDelay),
44 commitToRenameDelay(params->commitToRenameDelay),
45 renameWidth(params->renameWidth),
46 commitWidth(params->commitWidth),
47 resumeSerialize(false),
48 resumeUnblocking(false),
49 numThreads(params->numberOfThreads),
50 maxPhysicalRegs(params->numPhysIntRegs + params->numPhysFloatRegs)
51{
52 _status = Inactive;
53
54 for (int i=0; i< numThreads; i++) {
55 renameStatus[i] = Idle;
56
57 freeEntries[i].iqEntries = 0;
58 freeEntries[i].lsqEntries = 0;
59 freeEntries[i].robEntries = 0;
60
61 stalls[i].iew = false;
62 stalls[i].commit = false;
63 serializeInst[i] = NULL;
64
65 instsInProgress[i] = 0;
66
67 emptyROB[i] = true;
68
69 serializeOnNextInst[i] = false;
70 }
71
72 // @todo: Make into a parameter.
73 skidBufferMax = (2 * (iewToRenameDelay * params->decodeWidth)) + renameWidth;
74}
75
76template <class Impl>
77std::string
78DefaultRename<Impl>::name() const
79{
80 return cpu->name() + ".rename";
81}
82
83template <class Impl>
84void
85DefaultRename<Impl>::regStats()
86{
87 renameSquashCycles
88 .name(name() + ".RENAME:SquashCycles")
89 .desc("Number of cycles rename is squashing")
90 .prereq(renameSquashCycles);
91 renameIdleCycles
92 .name(name() + ".RENAME:IdleCycles")
93 .desc("Number of cycles rename is idle")
94 .prereq(renameIdleCycles);
95 renameBlockCycles
96 .name(name() + ".RENAME:BlockCycles")
97 .desc("Number of cycles rename is blocking")
98 .prereq(renameBlockCycles);
99 renameSerializeStallCycles
100 .name(name() + ".RENAME:serializeStallCycles")
101 .desc("count of cycles rename stalled for serializing inst")
102 .flags(Stats::total);
103 renameRunCycles
104 .name(name() + ".RENAME:RunCycles")
105 .desc("Number of cycles rename is running")
106 .prereq(renameIdleCycles);
107 renameUnblockCycles
108 .name(name() + ".RENAME:UnblockCycles")
109 .desc("Number of cycles rename is unblocking")
110 .prereq(renameUnblockCycles);
111 renameRenamedInsts
112 .name(name() + ".RENAME:RenamedInsts")
113 .desc("Number of instructions processed by rename")
114 .prereq(renameRenamedInsts);
115 renameSquashedInsts
116 .name(name() + ".RENAME:SquashedInsts")
117 .desc("Number of squashed instructions processed by rename")
118 .prereq(renameSquashedInsts);
119 renameROBFullEvents
120 .name(name() + ".RENAME:ROBFullEvents")
121 .desc("Number of times rename has blocked due to ROB full")
122 .prereq(renameROBFullEvents);
123 renameIQFullEvents
124 .name(name() + ".RENAME:IQFullEvents")
125 .desc("Number of times rename has blocked due to IQ full")
126 .prereq(renameIQFullEvents);
127 renameLSQFullEvents
128 .name(name() + ".RENAME:LSQFullEvents")
129 .desc("Number of times rename has blocked due to LSQ full")
130 .prereq(renameLSQFullEvents);
131 renameFullRegistersEvents
132 .name(name() + ".RENAME:FullRegisterEvents")
133 .desc("Number of times there has been no free registers")
134 .prereq(renameFullRegistersEvents);
135 renameRenamedOperands
136 .name(name() + ".RENAME:RenamedOperands")
137 .desc("Number of destination operands rename has renamed")
138 .prereq(renameRenamedOperands);
139 renameRenameLookups
140 .name(name() + ".RENAME:RenameLookups")
141 .desc("Number of register rename lookups that rename has made")
142 .prereq(renameRenameLookups);
143 renameCommittedMaps
144 .name(name() + ".RENAME:CommittedMaps")
145 .desc("Number of HB maps that are committed")
146 .prereq(renameCommittedMaps);
147 renameUndoneMaps
148 .name(name() + ".RENAME:UndoneMaps")
149 .desc("Number of HB maps that are undone due to squashing")
150 .prereq(renameUndoneMaps);
151 renamedSerializing
152 .name(name() + ".RENAME:serializingInsts")
153 .desc("count of serializing insts renamed")
154 .flags(Stats::total)
155 ;
156 renamedTempSerializing
157 .name(name() + ".RENAME:tempSerializingInsts")
158 .desc("count of temporary serializing insts renamed")
159 .flags(Stats::total)
160 ;
161 renameSkidInsts
162 .name(name() + ".RENAME:skidInsts")
163 .desc("count of insts added to the skid buffer")
164 .flags(Stats::total)
165 ;
166}
167
168template <class Impl>
169void
170DefaultRename<Impl>::setTimeBuffer(TimeBuffer<TimeStruct> *tb_ptr)
171{
172 timeBuffer = tb_ptr;
173
174 // Setup wire to read information from time buffer, from IEW stage.
175 fromIEW = timeBuffer->getWire(-iewToRenameDelay);
176
177 // Setup wire to read infromation from time buffer, from commit stage.
178 fromCommit = timeBuffer->getWire(-commitToRenameDelay);
179
180 // Setup wire to write information to previous stages.
181 toDecode = timeBuffer->getWire(0);
182}
183
184template <class Impl>
185void
186DefaultRename<Impl>::setRenameQueue(TimeBuffer<RenameStruct> *rq_ptr)
187{
188 renameQueue = rq_ptr;
189
190 // Setup wire to write information to future stages.
191 toIEW = renameQueue->getWire(0);
192}
193
194template <class Impl>
195void
196DefaultRename<Impl>::setDecodeQueue(TimeBuffer<DecodeStruct> *dq_ptr)
197{
198 decodeQueue = dq_ptr;
199
200 // Setup wire to get information from decode.
201 fromDecode = decodeQueue->getWire(-decodeToRenameDelay);
202}
203
204template <class Impl>
205void
206DefaultRename<Impl>::initStage()
207{
208 // Grab the number of free entries directly from the stages.
209 for (int tid=0; tid < numThreads; tid++) {
210 freeEntries[tid].iqEntries = iew_ptr->instQueue.numFreeEntries(tid);
211 freeEntries[tid].lsqEntries = iew_ptr->ldstQueue.numFreeEntries(tid);
212 freeEntries[tid].robEntries = commit_ptr->numROBFreeEntries(tid);
213 emptyROB[tid] = true;
214 }
215}
216
217template<class Impl>
218void
219DefaultRename<Impl>::setActiveThreads(std::list<unsigned> *at_ptr)
220{
221 activeThreads = at_ptr;
222}
223
224
225template <class Impl>
226void
227DefaultRename<Impl>::setRenameMap(RenameMap rm_ptr[])
228{
229 for (int i=0; i<numThreads; i++) {
230 renameMap[i] = &rm_ptr[i];
231 }
232}
233
234template <class Impl>
235void
236DefaultRename<Impl>::setFreeList(FreeList *fl_ptr)
237{
238 freeList = fl_ptr;
239}
240
241template<class Impl>
242void
243DefaultRename<Impl>::setScoreboard(Scoreboard *_scoreboard)
244{
245 scoreboard = _scoreboard;
246}
247
248template <class Impl>
249bool
250DefaultRename<Impl>::drain()
251{
252 // Rename is ready to switch out at any time.
253 cpu->signalDrained();
254 return true;
255}
256
257template <class Impl>
258void
259DefaultRename<Impl>::switchOut()
260{
261 // Clear any state, fix up the rename map.
262 for (int i = 0; i < numThreads; i++) {
263 typename std::list<RenameHistory>::iterator hb_it =
264 historyBuffer[i].begin();
265
266 while (!historyBuffer[i].empty()) {
267 assert(hb_it != historyBuffer[i].end());
268
269 DPRINTF(Rename, "[tid:%u]: Removing history entry with sequence "
270 "number %i.\n", i, (*hb_it).instSeqNum);
271
272 // Tell the rename map to set the architected register to the
273 // previous physical register that it was renamed to.
274 renameMap[i]->setEntry(hb_it->archReg, hb_it->prevPhysReg);
275
276 // Put the renamed physical register back on the free list.
277 freeList->addReg(hb_it->newPhysReg);
278
279 // Be sure to mark its register as ready if it's a misc register.
280 if (hb_it->newPhysReg >= maxPhysicalRegs) {
281 scoreboard->setReg(hb_it->newPhysReg);
282 }
283
284 historyBuffer[i].erase(hb_it++);
285 }
286 insts[i].clear();
287 skidBuffer[i].clear();
288 }
289}
290
291template <class Impl>
292void
293DefaultRename<Impl>::takeOverFrom()
294{
295 _status = Inactive;
296 initStage();
297
298 // Reset all state prior to taking over from the other CPU.
299 for (int i=0; i< numThreads; i++) {
300 renameStatus[i] = Idle;
301
302 stalls[i].iew = false;
303 stalls[i].commit = false;
304 serializeInst[i] = NULL;
305
306 instsInProgress[i] = 0;
307
308 emptyROB[i] = true;
309
310 serializeOnNextInst[i] = false;
311 }
312}
313
314template <class Impl>
315void
316DefaultRename<Impl>::squash(const InstSeqNum &squash_seq_num, unsigned tid)
317{
318 DPRINTF(Rename, "[tid:%u]: Squashing instructions.\n",tid);
319
320 // Clear the stall signal if rename was blocked or unblocking before.
321 // If it still needs to block, the blocking should happen the next
322 // cycle and there should be space to hold everything due to the squash.
323 if (renameStatus[tid] == Blocked ||
324 renameStatus[tid] == Unblocking) {
325 toDecode->renameUnblock[tid] = 1;
326
327 resumeSerialize = false;
328 serializeInst[tid] = NULL;
329 } else if (renameStatus[tid] == SerializeStall) {
330 if (serializeInst[tid]->seqNum <= squash_seq_num) {
331 DPRINTF(Rename, "Rename will resume serializing after squash\n");
332 resumeSerialize = true;
333 assert(serializeInst[tid]);
334 } else {
335 resumeSerialize = false;
336 toDecode->renameUnblock[tid] = 1;
337
338 serializeInst[tid] = NULL;
339 }
340 }
341
342 // Set the status to Squashing.
343 renameStatus[tid] = Squashing;
344
345 // Squash any instructions from decode.
346 unsigned squashCount = 0;
347
348 for (int i=0; i<fromDecode->size; i++) {
349 if (fromDecode->insts[i]->threadNumber == tid &&
350 fromDecode->insts[i]->seqNum > squash_seq_num) {
351 fromDecode->insts[i]->setSquashed();
352 wroteToTimeBuffer = true;
353 squashCount++;
354 }
355
356 }
357
358 // Clear the instruction list and skid buffer in case they have any
359 // insts in them.
360 insts[tid].clear();
361
362 // Clear the skid buffer in case it has any data in it.
363 skidBuffer[tid].clear();
364
365 doSquash(squash_seq_num, tid);
366}
367
368template <class Impl>
369void
370DefaultRename<Impl>::tick()
371{
372 wroteToTimeBuffer = false;
373
374 blockThisCycle = false;
375
376 bool status_change = false;
377
378 toIEWIndex = 0;
379
380 sortInsts();
381
382 std::list<unsigned>::iterator threads = activeThreads->begin();
383 std::list<unsigned>::iterator end = activeThreads->end();
384
385 // Check stall and squash signals.
386 while (threads != end) {
387 unsigned tid = *threads++;
388
389 DPRINTF(Rename, "Processing [tid:%i]\n", tid);
390
391 status_change = checkSignalsAndUpdate(tid) || status_change;
392
393 rename(status_change, tid);
394 }
395
396 if (status_change) {
397 updateStatus();
398 }
399
400 if (wroteToTimeBuffer) {
401 DPRINTF(Activity, "Activity this cycle.\n");
402 cpu->activityThisCycle();
403 }
404
405 threads = activeThreads->begin();
406
407 while (threads != end) {
408 unsigned tid = *threads++;
409
410 // If we committed this cycle then doneSeqNum will be > 0
411 if (fromCommit->commitInfo[tid].doneSeqNum != 0 &&
412 !fromCommit->commitInfo[tid].squash &&
413 renameStatus[tid] != Squashing) {
414
415 removeFromHistory(fromCommit->commitInfo[tid].doneSeqNum,
416 tid);
417 }
418 }
419
420 // @todo: make into updateProgress function
421 for (int tid=0; tid < numThreads; tid++) {
422 instsInProgress[tid] -= fromIEW->iewInfo[tid].dispatched;
423
424 assert(instsInProgress[tid] >=0);
425 }
426
427}
428
429template<class Impl>
430void
431DefaultRename<Impl>::rename(bool &status_change, unsigned tid)
432{
433 // If status is Running or idle,
434 // call renameInsts()
435 // If status is Unblocking,
436 // buffer any instructions coming from decode
437 // continue trying to empty skid buffer
438 // check if stall conditions have passed
439
440 if (renameStatus[tid] == Blocked) {
441 ++renameBlockCycles;
442 } else if (renameStatus[tid] == Squashing) {
443 ++renameSquashCycles;
444 } else if (renameStatus[tid] == SerializeStall) {
445 ++renameSerializeStallCycles;
446 // If we are currently in SerializeStall and resumeSerialize
447 // was set, then that means that we are resuming serializing
448 // this cycle. Tell the previous stages to block.
449 if (resumeSerialize) {
450 resumeSerialize = false;
451 block(tid);
452 toDecode->renameUnblock[tid] = false;
453 }
454 } else if (renameStatus[tid] == Unblocking) {
455 if (resumeUnblocking) {
456 block(tid);
457 resumeUnblocking = false;
458 toDecode->renameUnblock[tid] = false;
459 }
460 }
461
462 if (renameStatus[tid] == Running ||
463 renameStatus[tid] == Idle) {
464 DPRINTF(Rename, "[tid:%u]: Not blocked, so attempting to run "
465 "stage.\n", tid);
466
467 renameInsts(tid);
468 } else if (renameStatus[tid] == Unblocking) {
469 renameInsts(tid);
470
471 if (validInsts()) {
472 // Add the current inputs to the skid buffer so they can be
473 // reprocessed when this stage unblocks.
474 skidInsert(tid);
475 }
476
477 // If we switched over to blocking, then there's a potential for
478 // an overall status change.
479 status_change = unblock(tid) || status_change || blockThisCycle;
480 }
481}
482
483template <class Impl>
484void
485DefaultRename<Impl>::renameInsts(unsigned tid)
486{
487 // Instructions can be either in the skid buffer or the queue of
488 // instructions coming from decode, depending on the status.
489 int insts_available = renameStatus[tid] == Unblocking ?
490 skidBuffer[tid].size() : insts[tid].size();
491
492 // Check the decode queue to see if instructions are available.
493 // If there are no available instructions to rename, then do nothing.
494 if (insts_available == 0) {
495 DPRINTF(Rename, "[tid:%u]: Nothing to do, breaking out early.\n",
496 tid);
497 // Should I change status to idle?
498 ++renameIdleCycles;
499 return;
500 } else if (renameStatus[tid] == Unblocking) {
501 ++renameUnblockCycles;
502 } else if (renameStatus[tid] == Running) {
503 ++renameRunCycles;
504 }
505
506 DynInstPtr inst;
507
508 // Will have to do a different calculation for the number of free
509 // entries.
510 int free_rob_entries = calcFreeROBEntries(tid);
511 int free_iq_entries = calcFreeIQEntries(tid);
512 int free_lsq_entries = calcFreeLSQEntries(tid);
513 int min_free_entries = free_rob_entries;
514
515 FullSource source = ROB;
516
517 if (free_iq_entries < min_free_entries) {
518 min_free_entries = free_iq_entries;
519 source = IQ;
520 }
521
522 if (free_lsq_entries < min_free_entries) {
523 min_free_entries = free_lsq_entries;
524 source = LSQ;
525 }
526
527 // Check if there's any space left.
528 if (min_free_entries <= 0) {
529 DPRINTF(Rename, "[tid:%u]: Blocking due to no free ROB/IQ/LSQ "
530 "entries.\n"
531 "ROB has %i free entries.\n"
532 "IQ has %i free entries.\n"
533 "LSQ has %i free entries.\n",
534 tid,
535 free_rob_entries,
536 free_iq_entries,
537 free_lsq_entries);
538
539 blockThisCycle = true;
540
541 block(tid);
542
543 incrFullStat(source);
544
545 return;
546 } else if (min_free_entries < insts_available) {
547 DPRINTF(Rename, "[tid:%u]: Will have to block this cycle."
548 "%i insts available, but only %i insts can be "
549 "renamed due to ROB/IQ/LSQ limits.\n",
550 tid, insts_available, min_free_entries);
551
552 insts_available = min_free_entries;
553
554 blockThisCycle = true;
555
556 incrFullStat(source);
557 }
558
559 InstQueue &insts_to_rename = renameStatus[tid] == Unblocking ?
560 skidBuffer[tid] : insts[tid];
561
562 DPRINTF(Rename, "[tid:%u]: %i available instructions to "
563 "send iew.\n", tid, insts_available);
564
565 DPRINTF(Rename, "[tid:%u]: %i insts pipelining from Rename | %i insts "
566 "dispatched to IQ last cycle.\n",
567 tid, instsInProgress[tid], fromIEW->iewInfo[tid].dispatched);
568
569 // Handle serializing the next instruction if necessary.
570 if (serializeOnNextInst[tid]) {
571 if (emptyROB[tid] && instsInProgress[tid] == 0) {
572 // ROB already empty; no need to serialize.
573 serializeOnNextInst[tid] = false;
574 } else if (!insts_to_rename.empty()) {
575 insts_to_rename.front()->setSerializeBefore();
576 }
577 }
578
579 int renamed_insts = 0;
580
581 while (insts_available > 0 && toIEWIndex < renameWidth) {
582 DPRINTF(Rename, "[tid:%u]: Sending instructions to IEW.\n", tid);
583
584 assert(!insts_to_rename.empty());
585
586 inst = insts_to_rename.front();
587
588 insts_to_rename.pop_front();
589
590 if (renameStatus[tid] == Unblocking) {
591 DPRINTF(Rename,"[tid:%u]: Removing [sn:%lli] PC:%#x from rename "
592 "skidBuffer\n",
593 tid, inst->seqNum, inst->readPC());
594 }
595
596 if (inst->isSquashed()) {
597 DPRINTF(Rename, "[tid:%u]: instruction %i with PC %#x is "
598 "squashed, skipping.\n",
599 tid, inst->seqNum, inst->readPC());
600
601 ++renameSquashedInsts;
602
603 // Decrement how many instructions are available.
604 --insts_available;
605
606 continue;
607 }
608
609 DPRINTF(Rename, "[tid:%u]: Processing instruction [sn:%lli] with "
610 "PC %#x.\n",
611 tid, inst->seqNum, inst->readPC());
612
613 // Handle serializeAfter/serializeBefore instructions.
614 // serializeAfter marks the next instruction as serializeBefore.
615 // serializeBefore makes the instruction wait in rename until the ROB
616 // is empty.
617
618 // In this model, IPR accesses are serialize before
619 // instructions, and store conditionals are serialize after
620 // instructions. This is mainly due to lack of support for
621 // out-of-order operations of either of those classes of
622 // instructions.
623 if ((inst->isIprAccess() || inst->isSerializeBefore()) &&
624 !inst->isSerializeHandled()) {
625 DPRINTF(Rename, "Serialize before instruction encountered.\n");
626
627 if (!inst->isTempSerializeBefore()) {
628 renamedSerializing++;
629 inst->setSerializeHandled();
630 } else {
631 renamedTempSerializing++;
632 }
633
634 // Change status over to SerializeStall so that other stages know
635 // what this is blocked on.
636 renameStatus[tid] = SerializeStall;
637
638 serializeInst[tid] = inst;
639
640 blockThisCycle = true;
641
642 break;
643 } else if ((inst->isStoreConditional() || inst->isSerializeAfter()) &&
644 !inst->isSerializeHandled()) {
645 DPRINTF(Rename, "Serialize after instruction encountered.\n");
646
647 renamedSerializing++;
648
649 inst->setSerializeHandled();
650
651 serializeAfter(insts_to_rename, tid);
652 }
653
654 // Check here to make sure there are enough destination registers
655 // to rename to. Otherwise block.
656 if (renameMap[tid]->numFreeEntries() < inst->numDestRegs()) {
657 DPRINTF(Rename, "Blocking due to lack of free "
658 "physical registers to rename to.\n");
659 blockThisCycle = true;
660 insts_to_rename.push_front(inst);
661 ++renameFullRegistersEvents;
662
663 break;
664 }
665
666 renameSrcRegs(inst, inst->threadNumber);
667
668 renameDestRegs(inst, inst->threadNumber);
669
670 ++renamed_insts;
671
672 // Put instruction in rename queue.
673 toIEW->insts[toIEWIndex] = inst;
674 ++(toIEW->size);
675
676 // Increment which instruction we're on.
677 ++toIEWIndex;
678
679 // Decrement how many instructions are available.
680 --insts_available;
681 }
682
683 instsInProgress[tid] += renamed_insts;
684 renameRenamedInsts += renamed_insts;
685
686 // If we wrote to the time buffer, record this.
687 if (toIEWIndex) {
688 wroteToTimeBuffer = true;
689 }
690
691 // Check if there's any instructions left that haven't yet been renamed.
692 // If so then block.
693 if (insts_available) {
694 blockThisCycle = true;
695 }
696
697 if (blockThisCycle) {
698 block(tid);
699 toDecode->renameUnblock[tid] = false;
700 }
701}
702
703template<class Impl>
704void
705DefaultRename<Impl>::skidInsert(unsigned tid)
706{
707 DynInstPtr inst = NULL;
708
709 while (!insts[tid].empty()) {
710 inst = insts[tid].front();
711
712 insts[tid].pop_front();
713
714 assert(tid == inst->threadNumber);
715
716 DPRINTF(Rename, "[tid:%u]: Inserting [sn:%lli] PC:%#x into Rename "
717 "skidBuffer\n", tid, inst->seqNum, inst->readPC());
718
719 ++renameSkidInsts;
720
721 skidBuffer[tid].push_back(inst);
722 }
723
724 if (skidBuffer[tid].size() > skidBufferMax)
725 {
726 typename InstQueue::iterator it;
727 warn("Skidbuffer contents:\n");
728 for(it = skidBuffer[tid].begin(); it != skidBuffer[tid].end(); it++)
729 {
730 warn("[tid:%u]: %s [sn:%i].\n", tid,
731 (*it)->staticInst->disassemble(inst->readPC()),
732 (*it)->seqNum);
733 }
734 panic("Skidbuffer Exceeded Max Size");
735 }
736}
737
738template <class Impl>
739void
740DefaultRename<Impl>::sortInsts()
741{
742 int insts_from_decode = fromDecode->size;
743#ifdef DEBUG
744 for (int i=0; i < numThreads; i++)
745 assert(insts[i].empty());
746#endif
747 for (int i = 0; i < insts_from_decode; ++i) {
748 DynInstPtr inst = fromDecode->insts[i];
749 insts[inst->threadNumber].push_back(inst);
750 }
751}
752
753template<class Impl>
754bool
755DefaultRename<Impl>::skidsEmpty()
756{
757 std::list<unsigned>::iterator threads = activeThreads->begin();
758 std::list<unsigned>::iterator end = activeThreads->end();
759
760 while (threads != end) {
761 unsigned tid = *threads++;
762
763 if (!skidBuffer[tid].empty())
764 return false;
765 }
766
767 return true;
768}
769
770template<class Impl>
771void
772DefaultRename<Impl>::updateStatus()
773{
774 bool any_unblocking = false;
775
776 std::list<unsigned>::iterator threads = activeThreads->begin();
777 std::list<unsigned>::iterator end = activeThreads->end();
778
779 while (threads != end) {
780 unsigned tid = *threads++;
781
782 if (renameStatus[tid] == Unblocking) {
783 any_unblocking = true;
784 break;
785 }
786 }
787
788 // Rename will have activity if it's unblocking.
789 if (any_unblocking) {
790 if (_status == Inactive) {
791 _status = Active;
792
793 DPRINTF(Activity, "Activating stage.\n");
794
795 cpu->activateStage(O3CPU::RenameIdx);
796 }
797 } else {
798 // If it's not unblocking, then rename will not have any internal
799 // activity. Switch it to inactive.
800 if (_status == Active) {
801 _status = Inactive;
802 DPRINTF(Activity, "Deactivating stage.\n");
803
804 cpu->deactivateStage(O3CPU::RenameIdx);
805 }
806 }
807}
808
809template <class Impl>
810bool
811DefaultRename<Impl>::block(unsigned tid)
812{
813 DPRINTF(Rename, "[tid:%u]: Blocking.\n", tid);
814
815 // Add the current inputs onto the skid buffer, so they can be
816 // reprocessed when this stage unblocks.
817 skidInsert(tid);
818
819 // Only signal backwards to block if the previous stages do not think
820 // rename is already blocked.
821 if (renameStatus[tid] != Blocked) {
822 // If resumeUnblocking is set, we unblocked during the squash,
823 // but now we're have unblocking status. We need to tell earlier
824 // stages to block.
825 if (resumeUnblocking || renameStatus[tid] != Unblocking) {
826 toDecode->renameBlock[tid] = true;
827 toDecode->renameUnblock[tid] = false;
828 wroteToTimeBuffer = true;
829 }
830
831 // Rename can not go from SerializeStall to Blocked, otherwise
832 // it would not know to complete the serialize stall.
833 if (renameStatus[tid] != SerializeStall) {
834 // Set status to Blocked.
835 renameStatus[tid] = Blocked;
836 return true;
837 }
838 }
839
840 return false;
841}
842
843template <class Impl>
844bool
845DefaultRename<Impl>::unblock(unsigned tid)
846{
847 DPRINTF(Rename, "[tid:%u]: Trying to unblock.\n", tid);
848
849 // Rename is done unblocking if the skid buffer is empty.
850 if (skidBuffer[tid].empty() && renameStatus[tid] != SerializeStall) {
851
852 DPRINTF(Rename, "[tid:%u]: Done unblocking.\n", tid);
853
854 toDecode->renameUnblock[tid] = true;
855 wroteToTimeBuffer = true;
856
857 renameStatus[tid] = Running;
858 return true;
859 }
860
861 return false;
862}
863
864template <class Impl>
865void
866DefaultRename<Impl>::doSquash(const InstSeqNum &squashed_seq_num, unsigned tid)
867{
868 typename std::list<RenameHistory>::iterator hb_it =
869 historyBuffer[tid].begin();
870
871 // After a syscall squashes everything, the history buffer may be empty
872 // but the ROB may still be squashing instructions.
873 if (historyBuffer[tid].empty()) {
874 return;
875 }
876
877 // Go through the most recent instructions, undoing the mappings
878 // they did and freeing up the registers.
879 while (!historyBuffer[tid].empty() &&
880 (*hb_it).instSeqNum > squashed_seq_num) {
881 assert(hb_it != historyBuffer[tid].end());
882
883 DPRINTF(Rename, "[tid:%u]: Removing history entry with sequence "
884 "number %i.\n", tid, (*hb_it).instSeqNum);
885
886 // Tell the rename map to set the architected register to the
887 // previous physical register that it was renamed to.
888 renameMap[tid]->setEntry(hb_it->archReg, hb_it->prevPhysReg);
889
890 // Put the renamed physical register back on the free list.
891 freeList->addReg(hb_it->newPhysReg);
892
893 // Be sure to mark its register as ready if it's a misc register.
894 if (hb_it->newPhysReg >= maxPhysicalRegs) {
895 scoreboard->setReg(hb_it->newPhysReg);
896 }
897
898 historyBuffer[tid].erase(hb_it++);
899
900 ++renameUndoneMaps;
901 }
902}
903
904template<class Impl>
905void
906DefaultRename<Impl>::removeFromHistory(InstSeqNum inst_seq_num, unsigned tid)
907{
908 DPRINTF(Rename, "[tid:%u]: Removing a committed instruction from the "
909 "history buffer %u (size=%i), until [sn:%lli].\n",
910 tid, tid, historyBuffer[tid].size(), inst_seq_num);
911
912 typename std::list<RenameHistory>::iterator hb_it =
913 historyBuffer[tid].end();
914
915 --hb_it;
916
917 if (historyBuffer[tid].empty()) {
918 DPRINTF(Rename, "[tid:%u]: History buffer is empty.\n", tid);
919 return;
920 } else if (hb_it->instSeqNum > inst_seq_num) {
921 DPRINTF(Rename, "[tid:%u]: Old sequence number encountered. Ensure "
922 "that a syscall happened recently.\n", tid);
923 return;
924 }
925
926 // Commit all the renames up until (and including) the committed sequence
927 // number. Some or even all of the committed instructions may not have
928 // rename histories if they did not have destination registers that were
929 // renamed.
930 while (!historyBuffer[tid].empty() &&
931 hb_it != historyBuffer[tid].end() &&
932 (*hb_it).instSeqNum <= inst_seq_num) {
933
934 DPRINTF(Rename, "[tid:%u]: Freeing up older rename of reg %i, "
935 "[sn:%lli].\n",
936 tid, (*hb_it).prevPhysReg, (*hb_it).instSeqNum);
937
938 freeList->addReg((*hb_it).prevPhysReg);
939 ++renameCommittedMaps;
940
941 historyBuffer[tid].erase(hb_it--);
942 }
943}
944
945template <class Impl>
946inline void
947DefaultRename<Impl>::renameSrcRegs(DynInstPtr &inst,unsigned tid)
948{
949 assert(renameMap[tid] != 0);
950
951 unsigned num_src_regs = inst->numSrcRegs();
952
953 // Get the architectual register numbers from the source and
954 // destination operands, and redirect them to the right register.
955 // Will need to mark dependencies though.
956 for (int src_idx = 0; src_idx < num_src_regs; src_idx++) {
957 RegIndex src_reg = inst->srcRegIdx(src_idx);
958 RegIndex flat_src_reg = src_reg;
959 if (src_reg < TheISA::FP_Base_DepTag) {
960 flat_src_reg = TheISA::flattenIntIndex(inst->tcBase(), src_reg);
961 DPRINTF(Rename, "Flattening index %d to %d.\n", (int)src_reg, (int)flat_src_reg);
962 } else {
963 // Floating point and Miscellaneous registers need their indexes
964 // adjusted to account for the expanded number of flattened int regs.
965 flat_src_reg = src_reg - TheISA::FP_Base_DepTag + TheISA::NumIntRegs;
966 }
967
968 inst->flattenSrcReg(src_idx, flat_src_reg);
969
970 // Look up the source registers to get the phys. register they've
971 // been renamed to, and set the sources to those registers.
972 PhysRegIndex renamed_reg = renameMap[tid]->lookup(flat_src_reg);
973
974 DPRINTF(Rename, "[tid:%u]: Looking up arch reg %i, got "
975 "physical reg %i.\n", tid, (int)flat_src_reg,
976 (int)renamed_reg);
977
978 inst->renameSrcReg(src_idx, renamed_reg);
979
980 // See if the register is ready or not.
981 if (scoreboard->getReg(renamed_reg) == true) {
982 DPRINTF(Rename, "[tid:%u]: Register is ready.\n", tid);
983
984 inst->markSrcRegReady(src_idx);
985 }
986
987 ++renameRenameLookups;
988 }
989}
990
991template <class Impl>
992inline void
993DefaultRename<Impl>::renameDestRegs(DynInstPtr &inst,unsigned tid)
994{
995 typename RenameMap::RenameInfo rename_result;
996
997 unsigned num_dest_regs = inst->numDestRegs();
998
999 // Rename the destination registers.
1000 for (int dest_idx = 0; dest_idx < num_dest_regs; dest_idx++) {
1001 RegIndex dest_reg = inst->destRegIdx(dest_idx);
1002 RegIndex flat_dest_reg = dest_reg;
1003 if (dest_reg < TheISA::FP_Base_DepTag) {
1004 // Integer registers are flattened.
1005 flat_dest_reg = TheISA::flattenIntIndex(inst->tcBase(), dest_reg);
1006 DPRINTF(Rename, "Flattening index %d to %d.\n", (int)dest_reg, (int)flat_dest_reg);
1007 } else {
1008 // Floating point and Miscellaneous registers need their indexes
1009 // adjusted to account for the expanded number of flattened int regs.
1010 flat_dest_reg = dest_reg - TheISA::FP_Base_DepTag + TheISA::NumIntRegs;
1011 }
1012
1013 inst->flattenDestReg(dest_idx, flat_dest_reg);
1014
1015 // Get the physical register that the destination will be
1016 // renamed to.
1017 rename_result = renameMap[tid]->rename(flat_dest_reg);
1018
1019 //Mark Scoreboard entry as not ready
1020 scoreboard->unsetReg(rename_result.first);
1021
1022 DPRINTF(Rename, "[tid:%u]: Renaming arch reg %i to physical "
1023 "reg %i.\n", tid, (int)flat_dest_reg,
1024 (int)rename_result.first);
1025
1026 // Record the rename information so that a history can be kept.
1027 RenameHistory hb_entry(inst->seqNum, flat_dest_reg,
1028 rename_result.first,
1029 rename_result.second);
1030
1031 historyBuffer[tid].push_front(hb_entry);
1032
1033 DPRINTF(Rename, "[tid:%u]: Adding instruction to history buffer "
1034 "(size=%i), [sn:%lli].\n",tid,
1035 historyBuffer[tid].size(),
1036 (*historyBuffer[tid].begin()).instSeqNum);
1037
1038 // Tell the instruction to rename the appropriate destination
1039 // register (dest_idx) to the new physical register
1040 // (rename_result.first), and record the previous physical
1041 // register that the same logical register was renamed to
1042 // (rename_result.second).
1043 inst->renameDestReg(dest_idx,
1044 rename_result.first,
1045 rename_result.second);
1046
1047 ++renameRenamedOperands;
1048 }
1049}
1050
1051template <class Impl>
1052inline int
1053DefaultRename<Impl>::calcFreeROBEntries(unsigned tid)
1054{
1055 int num_free = freeEntries[tid].robEntries -
1056 (instsInProgress[tid] - fromIEW->iewInfo[tid].dispatched);
1057
1058 //DPRINTF(Rename,"[tid:%i]: %i rob free\n",tid,num_free);
1059
1060 return num_free;
1061}
1062
1063template <class Impl>
1064inline int
1065DefaultRename<Impl>::calcFreeIQEntries(unsigned tid)
1066{
1067 int num_free = freeEntries[tid].iqEntries -
1068 (instsInProgress[tid] - fromIEW->iewInfo[tid].dispatched);
1069
1070 //DPRINTF(Rename,"[tid:%i]: %i iq free\n",tid,num_free);
1071
1072 return num_free;
1073}
1074
1075template <class Impl>
1076inline int
1077DefaultRename<Impl>::calcFreeLSQEntries(unsigned tid)
1078{
1079 int num_free = freeEntries[tid].lsqEntries -
1080 (instsInProgress[tid] - fromIEW->iewInfo[tid].dispatchedToLSQ);
1081
1082 //DPRINTF(Rename,"[tid:%i]: %i lsq free\n",tid,num_free);
1083
1084 return num_free;
1085}
1086
1087template <class Impl>
1088unsigned
1089DefaultRename<Impl>::validInsts()
1090{
1091 unsigned inst_count = 0;
1092
1093 for (int i=0; i<fromDecode->size; i++) {
1094 if (!fromDecode->insts[i]->isSquashed())
1095 inst_count++;
1096 }
1097
1098 return inst_count;
1099}
1100
1101template <class Impl>
1102void
1103DefaultRename<Impl>::readStallSignals(unsigned tid)
1104{
1105 if (fromIEW->iewBlock[tid]) {
1106 stalls[tid].iew = true;
1107 }
1108
1109 if (fromIEW->iewUnblock[tid]) {
1110 assert(stalls[tid].iew);
1111 stalls[tid].iew = false;
1112 }
1113
1114 if (fromCommit->commitBlock[tid]) {
1115 stalls[tid].commit = true;
1116 }
1117
1118 if (fromCommit->commitUnblock[tid]) {
1119 assert(stalls[tid].commit);
1120 stalls[tid].commit = false;
1121 }
1122}
1123
1124template <class Impl>
1125bool
1126DefaultRename<Impl>::checkStall(unsigned tid)
1127{
1128 bool ret_val = false;
1129
1130 if (stalls[tid].iew) {
1131 DPRINTF(Rename,"[tid:%i]: Stall from IEW stage detected.\n", tid);
1132 ret_val = true;
1133 } else if (stalls[tid].commit) {
1134 DPRINTF(Rename,"[tid:%i]: Stall from Commit stage detected.\n", tid);
1135 ret_val = true;
1136 } else if (calcFreeROBEntries(tid) <= 0) {
1137 DPRINTF(Rename,"[tid:%i]: Stall: ROB has 0 free entries.\n", tid);
1138 ret_val = true;
1139 } else if (calcFreeIQEntries(tid) <= 0) {
1140 DPRINTF(Rename,"[tid:%i]: Stall: IQ has 0 free entries.\n", tid);
1141 ret_val = true;
1142 } else if (calcFreeLSQEntries(tid) <= 0) {
1143 DPRINTF(Rename,"[tid:%i]: Stall: LSQ has 0 free entries.\n", tid);
1144 ret_val = true;
1145 } else if (renameMap[tid]->numFreeEntries() <= 0) {
1146 DPRINTF(Rename,"[tid:%i]: Stall: RenameMap has 0 free entries.\n", tid);
1147 ret_val = true;
1148 } else if (renameStatus[tid] == SerializeStall &&
1149 (!emptyROB[tid] || instsInProgress[tid])) {
1150 DPRINTF(Rename,"[tid:%i]: Stall: Serialize stall and ROB is not "
1151 "empty.\n",
1152 tid);
1153 ret_val = true;
1154 }
1155
1156 return ret_val;
1157}
1158
1159template <class Impl>
1160void
1161DefaultRename<Impl>::readFreeEntries(unsigned tid)
1162{
1163 bool updated = false;
1164 if (fromIEW->iewInfo[tid].usedIQ) {
1165 freeEntries[tid].iqEntries =
1166 fromIEW->iewInfo[tid].freeIQEntries;
1167 updated = true;
1168 }
1169
1170 if (fromIEW->iewInfo[tid].usedLSQ) {
1171 freeEntries[tid].lsqEntries =
1172 fromIEW->iewInfo[tid].freeLSQEntries;
1173 updated = true;
1174 }
1175
1176 if (fromCommit->commitInfo[tid].usedROB) {
1177 freeEntries[tid].robEntries =
1178 fromCommit->commitInfo[tid].freeROBEntries;
1179 emptyROB[tid] = fromCommit->commitInfo[tid].emptyROB;
1180 updated = true;
1181 }
1182
1183 DPRINTF(Rename, "[tid:%i]: Free IQ: %i, Free ROB: %i, Free LSQ: %i\n",
1184 tid,
1185 freeEntries[tid].iqEntries,
1186 freeEntries[tid].robEntries,
1187 freeEntries[tid].lsqEntries);
1188
1189 DPRINTF(Rename, "[tid:%i]: %i instructions not yet in ROB\n",
1190 tid, instsInProgress[tid]);
1191}
1192
1193template <class Impl>
1194bool
1195DefaultRename<Impl>::checkSignalsAndUpdate(unsigned tid)
1196{
1197 // Check if there's a squash signal, squash if there is
1198 // Check stall signals, block if necessary.
1199 // If status was blocked
1200 // check if stall conditions have passed
1201 // if so then go to unblocking
1202 // If status was Squashing
1203 // check if squashing is not high. Switch to running this cycle.
1204 // If status was serialize stall
1205 // check if ROB is empty and no insts are in flight to the ROB
1206
1207 readFreeEntries(tid);
1208 readStallSignals(tid);
1209
1210 if (fromCommit->commitInfo[tid].squash) {
1211 DPRINTF(Rename, "[tid:%u]: Squashing instructions due to squash from "
1212 "commit.\n", tid);
1213
1214 squash(fromCommit->commitInfo[tid].doneSeqNum, tid);
1215
1216 return true;
1217 }
1218
1219 if (fromCommit->commitInfo[tid].robSquashing) {
1220 DPRINTF(Rename, "[tid:%u]: ROB is still squashing.\n", tid);
1221
1222 renameStatus[tid] = Squashing;
1223
1224 return true;
1225 }
1226
1227 if (checkStall(tid)) {
1228 return block(tid);
1229 }
1230
1231 if (renameStatus[tid] == Blocked) {
1232 DPRINTF(Rename, "[tid:%u]: Done blocking, switching to unblocking.\n",
1233 tid);
1234
1235 renameStatus[tid] = Unblocking;
1236
1237 unblock(tid);
1238
1239 return true;
1240 }
1241
1242 if (renameStatus[tid] == Squashing) {
1243 // Switch status to running if rename isn't being told to block or
1244 // squash this cycle.
1245 if (resumeSerialize) {
1246 DPRINTF(Rename, "[tid:%u]: Done squashing, switching to serialize.\n",
1247 tid);
1248
1249 renameStatus[tid] = SerializeStall;
1250 return true;
1251 } else if (resumeUnblocking) {
1252 DPRINTF(Rename, "[tid:%u]: Done squashing, switching to unblocking.\n",
1253 tid);
1254 renameStatus[tid] = Unblocking;
1255 return true;
1256 } else {
1257 DPRINTF(Rename, "[tid:%u]: Done squashing, switching to running.\n",
1258 tid);
1259
1260 renameStatus[tid] = Running;
1261 return false;
1262 }
1263 }
1264
1265 if (renameStatus[tid] == SerializeStall) {
1266 // Stall ends once the ROB is free.
1267 DPRINTF(Rename, "[tid:%u]: Done with serialize stall, switching to "
1268 "unblocking.\n", tid);
1269
1270 DynInstPtr serial_inst = serializeInst[tid];
1271
1272 renameStatus[tid] = Unblocking;
1273
1274 unblock(tid);
1275
1276 DPRINTF(Rename, "[tid:%u]: Processing instruction [%lli] with "
1277 "PC %#x.\n",
1278 tid, serial_inst->seqNum, serial_inst->readPC());
1279
1280 // Put instruction into queue here.
1281 serial_inst->clearSerializeBefore();
1282
1283 if (!skidBuffer[tid].empty()) {
1284 skidBuffer[tid].push_front(serial_inst);
1285 } else {
1286 insts[tid].push_front(serial_inst);
1287 }
1288
1289 DPRINTF(Rename, "[tid:%u]: Instruction must be processed by rename."
1290 " Adding to front of list.\n", tid);
1291
1292 serializeInst[tid] = NULL;
1293
1294 return true;
1295 }
1296
1297 // If we've reached this point, we have not gotten any signals that
1298 // cause rename to change its status. Rename remains the same as before.
1299 return false;
1300}
1301
1302template<class Impl>
1303void
1304DefaultRename<Impl>::serializeAfter(InstQueue &inst_list,
1305 unsigned tid)
1306{
1307 if (inst_list.empty()) {
1308 // Mark a bit to say that I must serialize on the next instruction.
1309 serializeOnNextInst[tid] = true;
1310 return;
1311 }
1312
1313 // Set the next instruction as serializing.
1314 inst_list.front()->setSerializeBefore();
1315}
1316
1317template <class Impl>
1318inline void
1319DefaultRename<Impl>::incrFullStat(const FullSource &source)
1320{
1321 switch (source) {
1322 case ROB:
1323 ++renameROBFullEvents;
1324 break;
1325 case IQ:
1326 ++renameIQFullEvents;
1327 break;
1328 case LSQ:
1329 ++renameLSQFullEvents;
1330 break;
1331 default:
1332 panic("Rename full stall stat should be incremented for a reason!");
1333 break;
1334 }
1335}
1336
1337template <class Impl>
1338void
1339DefaultRename<Impl>::dumpHistory()
1340{
1341 typename std::list<RenameHistory>::iterator buf_it;
1342
1343 for (int i = 0; i < numThreads; i++) {
1344
1345 buf_it = historyBuffer[i].begin();
1346
1347 while (buf_it != historyBuffer[i].end()) {
1348 cprintf("Seq num: %i\nArch reg: %i New phys reg: %i Old phys "
1349 "reg: %i\n", (*buf_it).instSeqNum, (int)(*buf_it).archReg,
1350 (int)(*buf_it).newPhysReg, (int)(*buf_it).prevPhysReg);
1351
1352 buf_it++;
1353 }
1354 }
1355}