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(Params *params)
41 : iewToRenameDelay(params->iewToRenameDelay),
42 decodeToRenameDelay(params->decodeToRenameDelay),
43 commitToRenameDelay(params->commitToRenameDelay),
44 renameWidth(params->renameWidth),
45 commitWidth(params->commitWidth),
46 resumeSerialize(false),
47 resumeUnblocking(false),
48 numThreads(params->numberOfThreads),
49 maxPhysicalRegs(params->numPhysIntRegs + params->numPhysFloatRegs)
50{
51 _status = Inactive;
52
53 for (int i=0; i< numThreads; i++) {
54 renameStatus[i] = Idle;
55
56 freeEntries[i].iqEntries = 0;
57 freeEntries[i].lsqEntries = 0;
58 freeEntries[i].robEntries = 0;
59
60 stalls[i].iew = false;
61 stalls[i].commit = false;
62 serializeInst[i] = NULL;
63
64 instsInProgress[i] = 0;
65
66 emptyROB[i] = true;
67
68 serializeOnNextInst[i] = false;
69 }
70
71 // @todo: Make into a parameter.
72 skidBufferMax = (2 * (iewToRenameDelay * params->decodeWidth)) + renameWidth;
73}
74
75template <class Impl>
76std::string
77DefaultRename<Impl>::name() const
78{
79 return cpu->name() + ".rename";
80}
81
82template <class Impl>
83void
84DefaultRename<Impl>::regStats()
85{
86 renameSquashCycles
87 .name(name() + ".RENAME:SquashCycles")
88 .desc("Number of cycles rename is squashing")
89 .prereq(renameSquashCycles);
90 renameIdleCycles
91 .name(name() + ".RENAME:IdleCycles")
92 .desc("Number of cycles rename is idle")
93 .prereq(renameIdleCycles);
94 renameBlockCycles
95 .name(name() + ".RENAME:BlockCycles")
96 .desc("Number of cycles rename is blocking")
97 .prereq(renameBlockCycles);
98 renameSerializeStallCycles
99 .name(name() + ".RENAME:serializeStallCycles")
100 .desc("count of cycles rename stalled for serializing inst")
101 .flags(Stats::total);
102 renameRunCycles
103 .name(name() + ".RENAME:RunCycles")
104 .desc("Number of cycles rename is running")
105 .prereq(renameIdleCycles);
106 renameUnblockCycles
107 .name(name() + ".RENAME:UnblockCycles")
108 .desc("Number of cycles rename is unblocking")
109 .prereq(renameUnblockCycles);
110 renameRenamedInsts
111 .name(name() + ".RENAME:RenamedInsts")
112 .desc("Number of instructions processed by rename")
113 .prereq(renameRenamedInsts);
114 renameSquashedInsts
115 .name(name() + ".RENAME:SquashedInsts")
116 .desc("Number of squashed instructions processed by rename")
117 .prereq(renameSquashedInsts);
118 renameROBFullEvents
119 .name(name() + ".RENAME:ROBFullEvents")
120 .desc("Number of times rename has blocked due to ROB full")
121 .prereq(renameROBFullEvents);
122 renameIQFullEvents
123 .name(name() + ".RENAME:IQFullEvents")
124 .desc("Number of times rename has blocked due to IQ full")
125 .prereq(renameIQFullEvents);
126 renameLSQFullEvents
127 .name(name() + ".RENAME:LSQFullEvents")
128 .desc("Number of times rename has blocked due to LSQ full")
129 .prereq(renameLSQFullEvents);
130 renameFullRegistersEvents
131 .name(name() + ".RENAME:FullRegisterEvents")
132 .desc("Number of times there has been no free registers")
133 .prereq(renameFullRegistersEvents);
134 renameRenamedOperands
135 .name(name() + ".RENAME:RenamedOperands")
136 .desc("Number of destination operands rename has renamed")
137 .prereq(renameRenamedOperands);
138 renameRenameLookups
139 .name(name() + ".RENAME:RenameLookups")
140 .desc("Number of register rename lookups that rename has made")
141 .prereq(renameRenameLookups);
142 renameCommittedMaps
143 .name(name() + ".RENAME:CommittedMaps")
144 .desc("Number of HB maps that are committed")
145 .prereq(renameCommittedMaps);
146 renameUndoneMaps
147 .name(name() + ".RENAME:UndoneMaps")
148 .desc("Number of HB maps that are undone due to squashing")
149 .prereq(renameUndoneMaps);
150 renamedSerializing
151 .name(name() + ".RENAME:serializingInsts")
152 .desc("count of serializing insts renamed")
153 .flags(Stats::total)
154 ;
155 renamedTempSerializing
156 .name(name() + ".RENAME:tempSerializingInsts")
157 .desc("count of temporary serializing insts renamed")
158 .flags(Stats::total)
159 ;
160 renameSkidInsts
161 .name(name() + ".RENAME:skidInsts")
162 .desc("count of insts added to the skid buffer")
163 .flags(Stats::total)
164 ;
165}
166
167template <class Impl>
168void
169DefaultRename<Impl>::setCPU(O3CPU *cpu_ptr)
170{
171 DPRINTF(Rename, "Setting CPU pointer.\n");
172 cpu = cpu_ptr;
173}
174
175template <class Impl>
176void
177DefaultRename<Impl>::setTimeBuffer(TimeBuffer<TimeStruct> *tb_ptr)
178{
179 DPRINTF(Rename, "Setting time buffer pointer.\n");
180 timeBuffer = tb_ptr;
181
182 // Setup wire to read information from time buffer, from IEW stage.
183 fromIEW = timeBuffer->getWire(-iewToRenameDelay);
184
185 // Setup wire to read infromation from time buffer, from commit stage.
186 fromCommit = timeBuffer->getWire(-commitToRenameDelay);
187
188 // Setup wire to write information to previous stages.
189 toDecode = timeBuffer->getWire(0);
190}
191
192template <class Impl>
193void
194DefaultRename<Impl>::setRenameQueue(TimeBuffer<RenameStruct> *rq_ptr)
195{
196 DPRINTF(Rename, "Setting rename queue pointer.\n");
197 renameQueue = rq_ptr;
198
199 // Setup wire to write information to future stages.
200 toIEW = renameQueue->getWire(0);
201}
202
203template <class Impl>
204void
205DefaultRename<Impl>::setDecodeQueue(TimeBuffer<DecodeStruct> *dq_ptr)
206{
207 DPRINTF(Rename, "Setting decode queue pointer.\n");
208 decodeQueue = dq_ptr;
209
210 // Setup wire to get information from decode.
211 fromDecode = decodeQueue->getWire(-decodeToRenameDelay);
212}
213
214template <class Impl>
215void
216DefaultRename<Impl>::initStage()
217{
218 // Grab the number of free entries directly from the stages.
219 for (int tid=0; tid < numThreads; tid++) {
220 freeEntries[tid].iqEntries = iew_ptr->instQueue.numFreeEntries(tid);
221 freeEntries[tid].lsqEntries = iew_ptr->ldstQueue.numFreeEntries(tid);
222 freeEntries[tid].robEntries = commit_ptr->numROBFreeEntries(tid);
223 emptyROB[tid] = true;
224 }
225}
226
227template<class Impl>
228void
229DefaultRename<Impl>::setActiveThreads(std::list<unsigned> *at_ptr)
230{
231 DPRINTF(Rename, "Setting active threads list pointer.\n");
232 activeThreads = at_ptr;
233}
234
235
236template <class Impl>
237void
238DefaultRename<Impl>::setRenameMap(RenameMap rm_ptr[])
239{
240 DPRINTF(Rename, "Setting rename map pointers.\n");
241
242 for (int i=0; i<numThreads; i++) {
243 renameMap[i] = &rm_ptr[i];
244 }
245}
246
247template <class Impl>
248void
249DefaultRename<Impl>::setFreeList(FreeList *fl_ptr)
250{
251 DPRINTF(Rename, "Setting free list pointer.\n");
252 freeList = fl_ptr;
253}
254
255template<class Impl>
256void
257DefaultRename<Impl>::setScoreboard(Scoreboard *_scoreboard)
258{
259 DPRINTF(Rename, "Setting scoreboard pointer.\n");
260 scoreboard = _scoreboard;
261}
262
263template <class Impl>
264bool
265DefaultRename<Impl>::drain()
266{
267 // Rename is ready to switch out at any time.
268 cpu->signalDrained();
269 return true;
270}
271
272template <class Impl>
273void
274DefaultRename<Impl>::switchOut()
275{
276 // Clear any state, fix up the rename map.
277 for (int i = 0; i < numThreads; i++) {
278 typename std::list<RenameHistory>::iterator hb_it =
279 historyBuffer[i].begin();
280
281 while (!historyBuffer[i].empty()) {
282 assert(hb_it != historyBuffer[i].end());
283
284 DPRINTF(Rename, "[tid:%u]: Removing history entry with sequence "
285 "number %i.\n", i, (*hb_it).instSeqNum);
286
287 // Tell the rename map to set the architected register to the
288 // previous physical register that it was renamed to.
289 renameMap[i]->setEntry(hb_it->archReg, hb_it->prevPhysReg);
290
291 // Put the renamed physical register back on the free list.
292 freeList->addReg(hb_it->newPhysReg);
293
294 // Be sure to mark its register as ready if it's a misc register.
295 if (hb_it->newPhysReg >= maxPhysicalRegs) {
296 scoreboard->setReg(hb_it->newPhysReg);
297 }
298
299 historyBuffer[i].erase(hb_it++);
300 }
301 insts[i].clear();
302 skidBuffer[i].clear();
303 }
304}
305
306template <class Impl>
307void
308DefaultRename<Impl>::takeOverFrom()
309{
310 _status = Inactive;
311 initStage();
312
313 // Reset all state prior to taking over from the other CPU.
314 for (int i=0; i< numThreads; i++) {
315 renameStatus[i] = Idle;
316
317 stalls[i].iew = false;
318 stalls[i].commit = false;
319 serializeInst[i] = NULL;
320
321 instsInProgress[i] = 0;
322
323 emptyROB[i] = true;
324
325 serializeOnNextInst[i] = false;
326 }
327}
328
329template <class Impl>
330void
331DefaultRename<Impl>::squash(const InstSeqNum &squash_seq_num, unsigned tid)
332{
333 DPRINTF(Rename, "[tid:%u]: Squashing instructions.\n",tid);
334
335 // Clear the stall signal if rename was blocked or unblocking before.
336 // If it still needs to block, the blocking should happen the next
337 // cycle and there should be space to hold everything due to the squash.
338 if (renameStatus[tid] == Blocked ||
339 renameStatus[tid] == Unblocking) {
340 toDecode->renameUnblock[tid] = 1;
341
342 resumeSerialize = false;
343 serializeInst[tid] = NULL;
344 } else if (renameStatus[tid] == SerializeStall) {
345 if (serializeInst[tid]->seqNum <= squash_seq_num) {
346 DPRINTF(Rename, "Rename will resume serializing after squash\n");
347 resumeSerialize = true;
348 assert(serializeInst[tid]);
349 } else {
350 resumeSerialize = false;
351 toDecode->renameUnblock[tid] = 1;
352
353 serializeInst[tid] = NULL;
354 }
355 }
356
357 // Set the status to Squashing.
358 renameStatus[tid] = Squashing;
359
360 // Squash any instructions from decode.
361 unsigned squashCount = 0;
362
363 for (int i=0; i<fromDecode->size; i++) {
364 if (fromDecode->insts[i]->threadNumber == tid &&
365 fromDecode->insts[i]->seqNum > squash_seq_num) {
366 fromDecode->insts[i]->setSquashed();
367 wroteToTimeBuffer = true;
368 squashCount++;
369 }
370
371 }
372
373 // Clear the instruction list and skid buffer in case they have any
374 // insts in them. Since we support multiple ISAs, we cant just:
375 // "insts[tid].clear();" or "skidBuffer[tid].clear()" since there is
376 // a possible delay slot inst for different architectures
377 // insts[tid].clear();
378#if ISA_HAS_DELAY_SLOT
379 DPRINTF(Rename, "[tid:%i] Squashing incoming decode instructions until "
380 "[sn:%i].\n",tid, squash_seq_num);
381 ListIt ilist_it = insts[tid].begin();
382 while (ilist_it != insts[tid].end()) {
383 if ((*ilist_it)->seqNum > squash_seq_num) {
384 (*ilist_it)->setSquashed();
385 DPRINTF(Rename, "Squashing incoming decode instruction, "
386 "[tid:%i] [sn:%i] PC %08p.\n", tid, (*ilist_it)->seqNum, (*ilist_it)->PC);
387 }
388 ilist_it++;
389 }
390#else
391 insts[tid].clear();
392#endif
393
394 // Clear the skid buffer in case it has any data in it.
395 // See comments above.
396 // skidBuffer[tid].clear();
397#if ISA_HAS_DELAY_SLOT
398 DPRINTF(Rename, "[tid:%i] Squashing incoming skidbuffer instructions "
399 "until [sn:%i].\n", tid, squash_seq_num);
400 ListIt slist_it = skidBuffer[tid].begin();
401 while (slist_it != skidBuffer[tid].end()) {
402 if ((*slist_it)->seqNum > squash_seq_num) {
403 (*slist_it)->setSquashed();
404 DPRINTF(Rename, "Squashing skidbuffer instruction, [tid:%i] [sn:%i]"
405 "PC %08p.\n", tid, (*slist_it)->seqNum, (*slist_it)->PC);
406 }
407 slist_it++;
408 }
409 resumeUnblocking = (skidBuffer[tid].size() != 0);
410 DPRINTF(Rename, "Resume unblocking set to %s\n",
411 resumeUnblocking ? "true" : "false");
412#else
413 skidBuffer[tid].clear();
414#endif
415 doSquash(squash_seq_num, tid);
416}
417
418template <class Impl>
419void
420DefaultRename<Impl>::tick()
421{
422 wroteToTimeBuffer = false;
423
424 blockThisCycle = false;
425
426 bool status_change = false;
427
428 toIEWIndex = 0;
429
430 sortInsts();
431
432 std::list<unsigned>::iterator threads = activeThreads->begin();
433 std::list<unsigned>::iterator end = activeThreads->end();
434
435 // Check stall and squash signals.
436 while (threads != end) {
437 unsigned tid = *threads++;
438
439 DPRINTF(Rename, "Processing [tid:%i]\n", tid);
440
441 status_change = checkSignalsAndUpdate(tid) || status_change;
442
443 rename(status_change, tid);
444 }
445
446 if (status_change) {
447 updateStatus();
448 }
449
450 if (wroteToTimeBuffer) {
451 DPRINTF(Activity, "Activity this cycle.\n");
452 cpu->activityThisCycle();
453 }
454
455 threads = activeThreads->begin();
456
457 while (threads != end) {
458 unsigned tid = *threads++;
459
460 // If we committed this cycle then doneSeqNum will be > 0
461 if (fromCommit->commitInfo[tid].doneSeqNum != 0 &&
462 !fromCommit->commitInfo[tid].squash &&
463 renameStatus[tid] != Squashing) {
464
465 removeFromHistory(fromCommit->commitInfo[tid].doneSeqNum,
466 tid);
467 }
468 }
469
470 // @todo: make into updateProgress function
471 for (int tid=0; tid < numThreads; tid++) {
472 instsInProgress[tid] -= fromIEW->iewInfo[tid].dispatched;
473
474 assert(instsInProgress[tid] >=0);
475 }
476
477}
478
479template<class Impl>
480void
481DefaultRename<Impl>::rename(bool &status_change, unsigned tid)
482{
483 // If status is Running or idle,
484 // call renameInsts()
485 // If status is Unblocking,
486 // buffer any instructions coming from decode
487 // continue trying to empty skid buffer
488 // check if stall conditions have passed
489
490 if (renameStatus[tid] == Blocked) {
491 ++renameBlockCycles;
492 } else if (renameStatus[tid] == Squashing) {
493 ++renameSquashCycles;
494 } else if (renameStatus[tid] == SerializeStall) {
495 ++renameSerializeStallCycles;
496 // If we are currently in SerializeStall and resumeSerialize
497 // was set, then that means that we are resuming serializing
498 // this cycle. Tell the previous stages to block.
499 if (resumeSerialize) {
500 resumeSerialize = false;
501 block(tid);
502 toDecode->renameUnblock[tid] = false;
503 }
504 } else if (renameStatus[tid] == Unblocking) {
505 if (resumeUnblocking) {
506 block(tid);
507 resumeUnblocking = false;
508 toDecode->renameUnblock[tid] = false;
509 }
510 }
511
512 if (renameStatus[tid] == Running ||
513 renameStatus[tid] == Idle) {
514 DPRINTF(Rename, "[tid:%u]: Not blocked, so attempting to run "
515 "stage.\n", tid);
516
517 renameInsts(tid);
518 } else if (renameStatus[tid] == Unblocking) {
519 renameInsts(tid);
520
521 if (validInsts()) {
522 // Add the current inputs to the skid buffer so they can be
523 // reprocessed when this stage unblocks.
524 skidInsert(tid);
525 }
526
527 // If we switched over to blocking, then there's a potential for
528 // an overall status change.
529 status_change = unblock(tid) || status_change || blockThisCycle;
530 }
531}
532
533template <class Impl>
534void
535DefaultRename<Impl>::renameInsts(unsigned tid)
536{
537 // Instructions can be either in the skid buffer or the queue of
538 // instructions coming from decode, depending on the status.
539 int insts_available = renameStatus[tid] == Unblocking ?
540 skidBuffer[tid].size() : insts[tid].size();
541
542 // Check the decode queue to see if instructions are available.
543 // If there are no available instructions to rename, then do nothing.
544 if (insts_available == 0) {
545 DPRINTF(Rename, "[tid:%u]: Nothing to do, breaking out early.\n",
546 tid);
547 // Should I change status to idle?
548 ++renameIdleCycles;
549 return;
550 } else if (renameStatus[tid] == Unblocking) {
551 ++renameUnblockCycles;
552 } else if (renameStatus[tid] == Running) {
553 ++renameRunCycles;
554 }
555
556 DynInstPtr inst;
557
558 // Will have to do a different calculation for the number of free
559 // entries.
560 int free_rob_entries = calcFreeROBEntries(tid);
561 int free_iq_entries = calcFreeIQEntries(tid);
562 int free_lsq_entries = calcFreeLSQEntries(tid);
563 int min_free_entries = free_rob_entries;
564
565 FullSource source = ROB;
566
567 if (free_iq_entries < min_free_entries) {
568 min_free_entries = free_iq_entries;
569 source = IQ;
570 }
571
572 if (free_lsq_entries < min_free_entries) {
573 min_free_entries = free_lsq_entries;
574 source = LSQ;
575 }
576
577 // Check if there's any space left.
578 if (min_free_entries <= 0) {
579 DPRINTF(Rename, "[tid:%u]: Blocking due to no free ROB/IQ/LSQ "
580 "entries.\n"
581 "ROB has %i free entries.\n"
582 "IQ has %i free entries.\n"
583 "LSQ has %i free entries.\n",
584 tid,
585 free_rob_entries,
586 free_iq_entries,
587 free_lsq_entries);
588
589 blockThisCycle = true;
590
591 block(tid);
592
593 incrFullStat(source);
594
595 return;
596 } else if (min_free_entries < insts_available) {
597 DPRINTF(Rename, "[tid:%u]: Will have to block this cycle."
598 "%i insts available, but only %i insts can be "
599 "renamed due to ROB/IQ/LSQ limits.\n",
600 tid, insts_available, min_free_entries);
601
602 insts_available = min_free_entries;
603
604 blockThisCycle = true;
605
606 incrFullStat(source);
607 }
608
609 InstQueue &insts_to_rename = renameStatus[tid] == Unblocking ?
610 skidBuffer[tid] : insts[tid];
611
612 DPRINTF(Rename, "[tid:%u]: %i available instructions to "
613 "send iew.\n", tid, insts_available);
614
615 DPRINTF(Rename, "[tid:%u]: %i insts pipelining from Rename | %i insts "
616 "dispatched to IQ last cycle.\n",
617 tid, instsInProgress[tid], fromIEW->iewInfo[tid].dispatched);
618
619 // Handle serializing the next instruction if necessary.
620 if (serializeOnNextInst[tid]) {
621 if (emptyROB[tid] && instsInProgress[tid] == 0) {
622 // ROB already empty; no need to serialize.
623 serializeOnNextInst[tid] = false;
624 } else if (!insts_to_rename.empty()) {
625 insts_to_rename.front()->setSerializeBefore();
626 }
627 }
628
629 int renamed_insts = 0;
630
631 while (insts_available > 0 && toIEWIndex < renameWidth) {
632 DPRINTF(Rename, "[tid:%u]: Sending instructions to IEW.\n", tid);
633
634 assert(!insts_to_rename.empty());
635
636 inst = insts_to_rename.front();
637
638 insts_to_rename.pop_front();
639
640 if (renameStatus[tid] == Unblocking) {
641 DPRINTF(Rename,"[tid:%u]: Removing [sn:%lli] PC:%#x from rename "
642 "skidBuffer\n",
643 tid, inst->seqNum, inst->readPC());
644 }
645
646 if (inst->isSquashed()) {
647 DPRINTF(Rename, "[tid:%u]: instruction %i with PC %#x is "
648 "squashed, skipping.\n",
649 tid, inst->seqNum, inst->readPC());
650
651 ++renameSquashedInsts;
652
653 // Decrement how many instructions are available.
654 --insts_available;
655
656 continue;
657 }
658
659 DPRINTF(Rename, "[tid:%u]: Processing instruction [sn:%lli] with "
660 "PC %#x.\n",
661 tid, inst->seqNum, inst->readPC());
662
663 // Handle serializeAfter/serializeBefore instructions.
664 // serializeAfter marks the next instruction as serializeBefore.
665 // serializeBefore makes the instruction wait in rename until the ROB
666 // is empty.
667
668 // In this model, IPR accesses are serialize before
669 // instructions, and store conditionals are serialize after
670 // instructions. This is mainly due to lack of support for
671 // out-of-order operations of either of those classes of
672 // instructions.
673 if ((inst->isIprAccess() || inst->isSerializeBefore()) &&
674 !inst->isSerializeHandled()) {
675 DPRINTF(Rename, "Serialize before instruction encountered.\n");
676
677 if (!inst->isTempSerializeBefore()) {
678 renamedSerializing++;
679 inst->setSerializeHandled();
680 } else {
681 renamedTempSerializing++;
682 }
683
684 // Change status over to SerializeStall so that other stages know
685 // what this is blocked on.
686 renameStatus[tid] = SerializeStall;
687
688 serializeInst[tid] = inst;
689
690 blockThisCycle = true;
691
692 break;
693 } else if ((inst->isStoreConditional() || inst->isSerializeAfter()) &&
694 !inst->isSerializeHandled()) {
695 DPRINTF(Rename, "Serialize after instruction encountered.\n");
696
697 renamedSerializing++;
698
699 inst->setSerializeHandled();
700
701 serializeAfter(insts_to_rename, tid);
702 }
703
704 // Check here to make sure there are enough destination registers
705 // to rename to. Otherwise block.
706 if (renameMap[tid]->numFreeEntries() < inst->numDestRegs()) {
707 DPRINTF(Rename, "Blocking due to lack of free "
708 "physical registers to rename to.\n");
709 blockThisCycle = true;
710
711 ++renameFullRegistersEvents;
712
713 break;
714 }
715
716 renameSrcRegs(inst, inst->threadNumber);
717
718 renameDestRegs(inst, inst->threadNumber);
719
720 ++renamed_insts;
721
722 // Put instruction in rename queue.
723 toIEW->insts[toIEWIndex] = inst;
724 ++(toIEW->size);
725
726 // Increment which instruction we're on.
727 ++toIEWIndex;
728
729 // Decrement how many instructions are available.
730 --insts_available;
731 }
732
733 instsInProgress[tid] += renamed_insts;
734 renameRenamedInsts += renamed_insts;
735
736 // If we wrote to the time buffer, record this.
737 if (toIEWIndex) {
738 wroteToTimeBuffer = true;
739 }
740
741 // Check if there's any instructions left that haven't yet been renamed.
742 // If so then block.
743 if (insts_available) {
744 blockThisCycle = true;
745 }
746
747 if (blockThisCycle) {
748 block(tid);
749 toDecode->renameUnblock[tid] = false;
750 }
751}
752
753template<class Impl>
754void
755DefaultRename<Impl>::skidInsert(unsigned tid)
756{
757 DynInstPtr inst = NULL;
758
759 while (!insts[tid].empty()) {
760 inst = insts[tid].front();
761
762 insts[tid].pop_front();
763
764 assert(tid == inst->threadNumber);
765
766 DPRINTF(Rename, "[tid:%u]: Inserting [sn:%lli] PC:%#x into Rename "
767 "skidBuffer\n", tid, inst->seqNum, inst->readPC());
768
769 ++renameSkidInsts;
770
771 skidBuffer[tid].push_back(inst);
772 }
773
774 if (skidBuffer[tid].size() > skidBufferMax)
775 {
776 typename InstQueue::iterator it;
777 warn("Skidbuffer contents:\n");
778 for(it = skidBuffer[tid].begin(); it != skidBuffer[tid].end(); it++)
779 {
780 warn("[tid:%u]: %s [sn:%i].\n", tid,
781 (*it)->staticInst->disassemble(inst->readPC()),
782 (*it)->seqNum);
783 }
784 panic("Skidbuffer Exceeded Max Size");
785 }
786}
787
788template <class Impl>
789void
790DefaultRename<Impl>::sortInsts()
791{
792 int insts_from_decode = fromDecode->size;
793#ifdef DEBUG
794#if !ISA_HAS_DELAY_SLOT
795 for (int i=0; i < numThreads; i++)
796 assert(insts[i].empty());
797#endif
798#endif
799 for (int i = 0; i < insts_from_decode; ++i) {
800 DynInstPtr inst = fromDecode->insts[i];
801 insts[inst->threadNumber].push_back(inst);
802 }
803}
804
805template<class Impl>
806bool
807DefaultRename<Impl>::skidsEmpty()
808{
809 std::list<unsigned>::iterator threads = activeThreads->begin();
810 std::list<unsigned>::iterator end = activeThreads->end();
811
812 while (threads != end) {
813 unsigned tid = *threads++;
814
815 if (!skidBuffer[tid].empty())
816 return false;
817 }
818
819 return true;
820}
821
822template<class Impl>
823void
824DefaultRename<Impl>::updateStatus()
825{
826 bool any_unblocking = false;
827
828 std::list<unsigned>::iterator threads = activeThreads->begin();
829 std::list<unsigned>::iterator end = activeThreads->end();
830
831 while (threads != end) {
832 unsigned tid = *threads++;
833
834 if (renameStatus[tid] == Unblocking) {
835 any_unblocking = true;
836 break;
837 }
838 }
839
840 // Rename will have activity if it's unblocking.
841 if (any_unblocking) {
842 if (_status == Inactive) {
843 _status = Active;
844
845 DPRINTF(Activity, "Activating stage.\n");
846
847 cpu->activateStage(O3CPU::RenameIdx);
848 }
849 } else {
850 // If it's not unblocking, then rename will not have any internal
851 // activity. Switch it to inactive.
852 if (_status == Active) {
853 _status = Inactive;
854 DPRINTF(Activity, "Deactivating stage.\n");
855
856 cpu->deactivateStage(O3CPU::RenameIdx);
857 }
858 }
859}
860
861template <class Impl>
862bool
863DefaultRename<Impl>::block(unsigned tid)
864{
865 DPRINTF(Rename, "[tid:%u]: Blocking.\n", tid);
866
867 // Add the current inputs onto the skid buffer, so they can be
868 // reprocessed when this stage unblocks.
869 skidInsert(tid);
870
871 // Only signal backwards to block if the previous stages do not think
872 // rename is already blocked.
873 if (renameStatus[tid] != Blocked) {
874 // If resumeUnblocking is set, we unblocked during the squash,
875 // but now we're have unblocking status. We need to tell earlier
876 // stages to block.
877 if (resumeUnblocking || renameStatus[tid] != Unblocking) {
878 toDecode->renameBlock[tid] = true;
879 toDecode->renameUnblock[tid] = false;
880 wroteToTimeBuffer = true;
881 }
882
883 // Rename can not go from SerializeStall to Blocked, otherwise
884 // it would not know to complete the serialize stall.
885 if (renameStatus[tid] != SerializeStall) {
886 // Set status to Blocked.
887 renameStatus[tid] = Blocked;
888 return true;
889 }
890 }
891
892 return false;
893}
894
895template <class Impl>
896bool
897DefaultRename<Impl>::unblock(unsigned tid)
898{
899 DPRINTF(Rename, "[tid:%u]: Trying to unblock.\n", tid);
900
901 // Rename is done unblocking if the skid buffer is empty.
902 if (skidBuffer[tid].empty() && renameStatus[tid] != SerializeStall) {
903
904 DPRINTF(Rename, "[tid:%u]: Done unblocking.\n", tid);
905
906 toDecode->renameUnblock[tid] = true;
907 wroteToTimeBuffer = true;
908
909 renameStatus[tid] = Running;
910 return true;
911 }
912
913 return false;
914}
915
916template <class Impl>
917void
918DefaultRename<Impl>::doSquash(const InstSeqNum &squashed_seq_num, unsigned tid)
919{
920 typename std::list<RenameHistory>::iterator hb_it =
921 historyBuffer[tid].begin();
922
923 // After a syscall squashes everything, the history buffer may be empty
924 // but the ROB may still be squashing instructions.
925 if (historyBuffer[tid].empty()) {
926 return;
927 }
928
929 // Go through the most recent instructions, undoing the mappings
930 // they did and freeing up the registers.
931 while (!historyBuffer[tid].empty() &&
932 (*hb_it).instSeqNum > squashed_seq_num) {
933 assert(hb_it != historyBuffer[tid].end());
934
935 DPRINTF(Rename, "[tid:%u]: Removing history entry with sequence "
936 "number %i.\n", tid, (*hb_it).instSeqNum);
937
938 // Tell the rename map to set the architected register to the
939 // previous physical register that it was renamed to.
940 renameMap[tid]->setEntry(hb_it->archReg, hb_it->prevPhysReg);
941
942 // Put the renamed physical register back on the free list.
943 freeList->addReg(hb_it->newPhysReg);
944
945 // Be sure to mark its register as ready if it's a misc register.
946 if (hb_it->newPhysReg >= maxPhysicalRegs) {
947 scoreboard->setReg(hb_it->newPhysReg);
948 }
949
950 historyBuffer[tid].erase(hb_it++);
951
952 ++renameUndoneMaps;
953 }
954}
955
956template<class Impl>
957void
958DefaultRename<Impl>::removeFromHistory(InstSeqNum inst_seq_num, unsigned tid)
959{
960 DPRINTF(Rename, "[tid:%u]: Removing a committed instruction from the "
961 "history buffer %u (size=%i), until [sn:%lli].\n",
962 tid, tid, historyBuffer[tid].size(), inst_seq_num);
963
964 typename std::list<RenameHistory>::iterator hb_it =
965 historyBuffer[tid].end();
966
967 --hb_it;
968
969 if (historyBuffer[tid].empty()) {
970 DPRINTF(Rename, "[tid:%u]: History buffer is empty.\n", tid);
971 return;
972 } else if (hb_it->instSeqNum > inst_seq_num) {
973 DPRINTF(Rename, "[tid:%u]: Old sequence number encountered. Ensure "
974 "that a syscall happened recently.\n", tid);
975 return;
976 }
977
978 // Commit all the renames up until (and including) the committed sequence
979 // number. Some or even all of the committed instructions may not have
980 // rename histories if they did not have destination registers that were
981 // renamed.
982 while (!historyBuffer[tid].empty() &&
983 hb_it != historyBuffer[tid].end() &&
984 (*hb_it).instSeqNum <= inst_seq_num) {
985
986 DPRINTF(Rename, "[tid:%u]: Freeing up older rename of reg %i, "
987 "[sn:%lli].\n",
988 tid, (*hb_it).prevPhysReg, (*hb_it).instSeqNum);
989
990 freeList->addReg((*hb_it).prevPhysReg);
991 ++renameCommittedMaps;
992
993 historyBuffer[tid].erase(hb_it--);
994 }
995}
996
997template <class Impl>
998inline void
999DefaultRename<Impl>::renameSrcRegs(DynInstPtr &inst,unsigned tid)
1000{
1001 assert(renameMap[tid] != 0);
1002
1003 unsigned num_src_regs = inst->numSrcRegs();
1004
1005 // Get the architectual register numbers from the source and
1006 // destination operands, and redirect them to the right register.
1007 // Will need to mark dependencies though.
1008 for (int src_idx = 0; src_idx < num_src_regs; src_idx++) {
1009 RegIndex src_reg = inst->srcRegIdx(src_idx);
1010 RegIndex flat_src_reg = src_reg;
1011 if (src_reg < TheISA::FP_Base_DepTag) {
1012 flat_src_reg = TheISA::flattenIntIndex(inst->tcBase(), src_reg);
1013 DPRINTF(Rename, "Flattening index %d to %d.\n", (int)src_reg, (int)flat_src_reg);
1014 }
1015 inst->flattenSrcReg(src_idx, flat_src_reg);
1016
1017 // Look up the source registers to get the phys. register they've
1018 // been renamed to, and set the sources to those registers.
1019 PhysRegIndex renamed_reg = renameMap[tid]->lookup(flat_src_reg);
1020
1021 DPRINTF(Rename, "[tid:%u]: Looking up arch reg %i, got "
1022 "physical reg %i.\n", tid, (int)flat_src_reg,
1023 (int)renamed_reg);
1024
1025 inst->renameSrcReg(src_idx, renamed_reg);
1026
1027 // See if the register is ready or not.
1028 if (scoreboard->getReg(renamed_reg) == true) {
1029 DPRINTF(Rename, "[tid:%u]: Register is ready.\n", tid);
1030
1031 inst->markSrcRegReady(src_idx);
1032 }
1033
1034 ++renameRenameLookups;
1035 }
1036}
1037
1038template <class Impl>
1039inline void
1040DefaultRename<Impl>::renameDestRegs(DynInstPtr &inst,unsigned tid)
1041{
1042 typename RenameMap::RenameInfo rename_result;
1043
1044 unsigned num_dest_regs = inst->numDestRegs();
1045
1046 // Rename the destination registers.
1047 for (int dest_idx = 0; dest_idx < num_dest_regs; dest_idx++) {
1048 RegIndex dest_reg = inst->destRegIdx(dest_idx);
1049 RegIndex flat_dest_reg = dest_reg;
1050 if (dest_reg < TheISA::FP_Base_DepTag) {
1051 flat_dest_reg = TheISA::flattenIntIndex(inst->tcBase(), dest_reg);
1052 DPRINTF(Rename, "Flattening index %d to %d.\n", (int)dest_reg, (int)flat_dest_reg);
1053 }
1054
1055 inst->flattenDestReg(dest_idx, flat_dest_reg);
1056
1057 // Get the physical register that the destination will be
1058 // renamed to.
1059 rename_result = renameMap[tid]->rename(flat_dest_reg);
1060
1061 //Mark Scoreboard entry as not ready
1062 scoreboard->unsetReg(rename_result.first);
1063
1064 DPRINTF(Rename, "[tid:%u]: Renaming arch reg %i to physical "
1065 "reg %i.\n", tid, (int)flat_dest_reg,
1066 (int)rename_result.first);
1067
1068 // Record the rename information so that a history can be kept.
1069 RenameHistory hb_entry(inst->seqNum, flat_dest_reg,
1070 rename_result.first,
1071 rename_result.second);
1072
1073 historyBuffer[tid].push_front(hb_entry);
1074
1075 DPRINTF(Rename, "[tid:%u]: Adding instruction to history buffer "
1076 "(size=%i), [sn:%lli].\n",tid,
1077 historyBuffer[tid].size(),
1078 (*historyBuffer[tid].begin()).instSeqNum);
1079
1080 // Tell the instruction to rename the appropriate destination
1081 // register (dest_idx) to the new physical register
1082 // (rename_result.first), and record the previous physical
1083 // register that the same logical register was renamed to
1084 // (rename_result.second).
1085 inst->renameDestReg(dest_idx,
1086 rename_result.first,
1087 rename_result.second);
1088
1089 ++renameRenamedOperands;
1090 }
1091}
1092
1093template <class Impl>
1094inline int
1095DefaultRename<Impl>::calcFreeROBEntries(unsigned tid)
1096{
1097 int num_free = freeEntries[tid].robEntries -
1098 (instsInProgress[tid] - fromIEW->iewInfo[tid].dispatched);
1099
1100 //DPRINTF(Rename,"[tid:%i]: %i rob free\n",tid,num_free);
1101
1102 return num_free;
1103}
1104
1105template <class Impl>
1106inline int
1107DefaultRename<Impl>::calcFreeIQEntries(unsigned tid)
1108{
1109 int num_free = freeEntries[tid].iqEntries -
1110 (instsInProgress[tid] - fromIEW->iewInfo[tid].dispatched);
1111
1112 //DPRINTF(Rename,"[tid:%i]: %i iq free\n",tid,num_free);
1113
1114 return num_free;
1115}
1116
1117template <class Impl>
1118inline int
1119DefaultRename<Impl>::calcFreeLSQEntries(unsigned tid)
1120{
1121 int num_free = freeEntries[tid].lsqEntries -
1122 (instsInProgress[tid] - fromIEW->iewInfo[tid].dispatchedToLSQ);
1123
1124 //DPRINTF(Rename,"[tid:%i]: %i lsq free\n",tid,num_free);
1125
1126 return num_free;
1127}
1128
1129template <class Impl>
1130unsigned
1131DefaultRename<Impl>::validInsts()
1132{
1133 unsigned inst_count = 0;
1134
1135 for (int i=0; i<fromDecode->size; i++) {
1136 if (!fromDecode->insts[i]->isSquashed())
1137 inst_count++;
1138 }
1139
1140 return inst_count;
1141}
1142
1143template <class Impl>
1144void
1145DefaultRename<Impl>::readStallSignals(unsigned tid)
1146{
1147 if (fromIEW->iewBlock[tid]) {
1148 stalls[tid].iew = true;
1149 }
1150
1151 if (fromIEW->iewUnblock[tid]) {
1152 assert(stalls[tid].iew);
1153 stalls[tid].iew = false;
1154 }
1155
1156 if (fromCommit->commitBlock[tid]) {
1157 stalls[tid].commit = true;
1158 }
1159
1160 if (fromCommit->commitUnblock[tid]) {
1161 assert(stalls[tid].commit);
1162 stalls[tid].commit = false;
1163 }
1164}
1165
1166template <class Impl>
1167bool
1168DefaultRename<Impl>::checkStall(unsigned tid)
1169{
1170 bool ret_val = false;
1171
1172 if (stalls[tid].iew) {
1173 DPRINTF(Rename,"[tid:%i]: Stall from IEW stage detected.\n", tid);
1174 ret_val = true;
1175 } else if (stalls[tid].commit) {
1176 DPRINTF(Rename,"[tid:%i]: Stall from Commit stage detected.\n", tid);
1177 ret_val = true;
1178 } else if (calcFreeROBEntries(tid) <= 0) {
1179 DPRINTF(Rename,"[tid:%i]: Stall: ROB has 0 free entries.\n", tid);
1180 ret_val = true;
1181 } else if (calcFreeIQEntries(tid) <= 0) {
1182 DPRINTF(Rename,"[tid:%i]: Stall: IQ has 0 free entries.\n", tid);
1183 ret_val = true;
1184 } else if (calcFreeLSQEntries(tid) <= 0) {
1185 DPRINTF(Rename,"[tid:%i]: Stall: LSQ has 0 free entries.\n", tid);
1186 ret_val = true;
1187 } else if (renameMap[tid]->numFreeEntries() <= 0) {
1188 DPRINTF(Rename,"[tid:%i]: Stall: RenameMap has 0 free entries.\n", tid);
1189 ret_val = true;
1190 } else if (renameStatus[tid] == SerializeStall &&
1191 (!emptyROB[tid] || instsInProgress[tid])) {
1192 DPRINTF(Rename,"[tid:%i]: Stall: Serialize stall and ROB is not "
1193 "empty.\n",
1194 tid);
1195 ret_val = true;
1196 }
1197
1198 return ret_val;
1199}
1200
1201template <class Impl>
1202void
1203DefaultRename<Impl>::readFreeEntries(unsigned tid)
1204{
1205 bool updated = false;
1206 if (fromIEW->iewInfo[tid].usedIQ) {
1207 freeEntries[tid].iqEntries =
1208 fromIEW->iewInfo[tid].freeIQEntries;
1209 updated = true;
1210 }
1211
1212 if (fromIEW->iewInfo[tid].usedLSQ) {
1213 freeEntries[tid].lsqEntries =
1214 fromIEW->iewInfo[tid].freeLSQEntries;
1215 updated = true;
1216 }
1217
1218 if (fromCommit->commitInfo[tid].usedROB) {
1219 freeEntries[tid].robEntries =
1220 fromCommit->commitInfo[tid].freeROBEntries;
1221 emptyROB[tid] = fromCommit->commitInfo[tid].emptyROB;
1222 updated = true;
1223 }
1224
1225 DPRINTF(Rename, "[tid:%i]: Free IQ: %i, Free ROB: %i, Free LSQ: %i\n",
1226 tid,
1227 freeEntries[tid].iqEntries,
1228 freeEntries[tid].robEntries,
1229 freeEntries[tid].lsqEntries);
1230
1231 DPRINTF(Rename, "[tid:%i]: %i instructions not yet in ROB\n",
1232 tid, instsInProgress[tid]);
1233}
1234
1235template <class Impl>
1236bool
1237DefaultRename<Impl>::checkSignalsAndUpdate(unsigned tid)
1238{
1239 // Check if there's a squash signal, squash if there is
1240 // Check stall signals, block if necessary.
1241 // If status was blocked
1242 // check if stall conditions have passed
1243 // if so then go to unblocking
1244 // If status was Squashing
1245 // check if squashing is not high. Switch to running this cycle.
1246 // If status was serialize stall
1247 // check if ROB is empty and no insts are in flight to the ROB
1248
1249 readFreeEntries(tid);
1250 readStallSignals(tid);
1251
1252 if (fromCommit->commitInfo[tid].squash) {
1253 DPRINTF(Rename, "[tid:%u]: Squashing instructions due to squash from "
1254 "commit.\n", tid);
1255
1256#if ISA_HAS_DELAY_SLOT
1257 InstSeqNum squashed_seq_num = fromCommit->commitInfo[tid].bdelayDoneSeqNum;
1258#else
1259 InstSeqNum squashed_seq_num = fromCommit->commitInfo[tid].doneSeqNum;
1260#endif
1261
1262 squash(squashed_seq_num, tid);
1263
1264 return true;
1265 }
1266
1267 if (fromCommit->commitInfo[tid].robSquashing) {
1268 DPRINTF(Rename, "[tid:%u]: ROB is still squashing.\n", tid);
1269
1270 renameStatus[tid] = Squashing;
1271
1272 return true;
1273 }
1274
1275 if (checkStall(tid)) {
1276 return block(tid);
1277 }
1278
1279 if (renameStatus[tid] == Blocked) {
1280 DPRINTF(Rename, "[tid:%u]: Done blocking, switching to unblocking.\n",
1281 tid);
1282
1283 renameStatus[tid] = Unblocking;
1284
1285 unblock(tid);
1286
1287 return true;
1288 }
1289
1290 if (renameStatus[tid] == Squashing) {
1291 // Switch status to running if rename isn't being told to block or
1292 // squash this cycle.
1293 if (resumeSerialize) {
1294 DPRINTF(Rename, "[tid:%u]: Done squashing, switching to serialize.\n",
1295 tid);
1296
1297 renameStatus[tid] = SerializeStall;
1298 return true;
1299 } else if (resumeUnblocking) {
1300 DPRINTF(Rename, "[tid:%u]: Done squashing, switching to unblocking.\n",
1301 tid);
1302 renameStatus[tid] = Unblocking;
1303 return true;
1304 } else {
1305 DPRINTF(Rename, "[tid:%u]: Done squashing, switching to running.\n",
1306 tid);
1307
1308 renameStatus[tid] = Running;
1309 return false;
1310 }
1311 }
1312
1313 if (renameStatus[tid] == SerializeStall) {
1314 // Stall ends once the ROB is free.
1315 DPRINTF(Rename, "[tid:%u]: Done with serialize stall, switching to "
1316 "unblocking.\n", tid);
1317
1318 DynInstPtr serial_inst = serializeInst[tid];
1319
1320 renameStatus[tid] = Unblocking;
1321
1322 unblock(tid);
1323
1324 DPRINTF(Rename, "[tid:%u]: Processing instruction [%lli] with "
1325 "PC %#x.\n",
1326 tid, serial_inst->seqNum, serial_inst->readPC());
1327
1328 // Put instruction into queue here.
1329 serial_inst->clearSerializeBefore();
1330
1331 if (!skidBuffer[tid].empty()) {
1332 skidBuffer[tid].push_front(serial_inst);
1333 } else {
1334 insts[tid].push_front(serial_inst);
1335 }
1336
1337 DPRINTF(Rename, "[tid:%u]: Instruction must be processed by rename."
1338 " Adding to front of list.\n", tid);
1339
1340 serializeInst[tid] = NULL;
1341
1342 return true;
1343 }
1344
1345 // If we've reached this point, we have not gotten any signals that
1346 // cause rename to change its status. Rename remains the same as before.
1347 return false;
1348}
1349
1350template<class Impl>
1351void
1352DefaultRename<Impl>::serializeAfter(InstQueue &inst_list,
1353 unsigned tid)
1354{
1355 if (inst_list.empty()) {
1356 // Mark a bit to say that I must serialize on the next instruction.
1357 serializeOnNextInst[tid] = true;
1358 return;
1359 }
1360
1361 // Set the next instruction as serializing.
1362 inst_list.front()->setSerializeBefore();
1363}
1364
1365template <class Impl>
1366inline void
1367DefaultRename<Impl>::incrFullStat(const FullSource &source)
1368{
1369 switch (source) {
1370 case ROB:
1371 ++renameROBFullEvents;
1372 break;
1373 case IQ:
1374 ++renameIQFullEvents;
1375 break;
1376 case LSQ:
1377 ++renameLSQFullEvents;
1378 break;
1379 default:
1380 panic("Rename full stall stat should be incremented for a reason!");
1381 break;
1382 }
1383}
1384
1385template <class Impl>
1386void
1387DefaultRename<Impl>::dumpHistory()
1388{
1389 typename std::list<RenameHistory>::iterator buf_it;
1390
1391 for (int i = 0; i < numThreads; i++) {
1392
1393 buf_it = historyBuffer[i].begin();
1394
1395 while (buf_it != historyBuffer[i].end()) {
1396 cprintf("Seq num: %i\nArch reg: %i New phys reg: %i Old phys "
1397 "reg: %i\n", (*buf_it).instSeqNum, (int)(*buf_it).archReg,
1398 (int)(*buf_it).newPhysReg, (int)(*buf_it).prevPhysReg);
1399
1400 buf_it++;
1401 }
1402 }
1403}
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(Params *params)
41 : iewToRenameDelay(params->iewToRenameDelay),
42 decodeToRenameDelay(params->decodeToRenameDelay),
43 commitToRenameDelay(params->commitToRenameDelay),
44 renameWidth(params->renameWidth),
45 commitWidth(params->commitWidth),
46 resumeSerialize(false),
47 resumeUnblocking(false),
48 numThreads(params->numberOfThreads),
49 maxPhysicalRegs(params->numPhysIntRegs + params->numPhysFloatRegs)
50{
51 _status = Inactive;
52
53 for (int i=0; i< numThreads; i++) {
54 renameStatus[i] = Idle;
55
56 freeEntries[i].iqEntries = 0;
57 freeEntries[i].lsqEntries = 0;
58 freeEntries[i].robEntries = 0;
59
60 stalls[i].iew = false;
61 stalls[i].commit = false;
62 serializeInst[i] = NULL;
63
64 instsInProgress[i] = 0;
65
66 emptyROB[i] = true;
67
68 serializeOnNextInst[i] = false;
69 }
70
71 // @todo: Make into a parameter.
72 skidBufferMax = (2 * (iewToRenameDelay * params->decodeWidth)) + renameWidth;
73}
74
75template <class Impl>
76std::string
77DefaultRename<Impl>::name() const
78{
79 return cpu->name() + ".rename";
80}
81
82template <class Impl>
83void
84DefaultRename<Impl>::regStats()
85{
86 renameSquashCycles
87 .name(name() + ".RENAME:SquashCycles")
88 .desc("Number of cycles rename is squashing")
89 .prereq(renameSquashCycles);
90 renameIdleCycles
91 .name(name() + ".RENAME:IdleCycles")
92 .desc("Number of cycles rename is idle")
93 .prereq(renameIdleCycles);
94 renameBlockCycles
95 .name(name() + ".RENAME:BlockCycles")
96 .desc("Number of cycles rename is blocking")
97 .prereq(renameBlockCycles);
98 renameSerializeStallCycles
99 .name(name() + ".RENAME:serializeStallCycles")
100 .desc("count of cycles rename stalled for serializing inst")
101 .flags(Stats::total);
102 renameRunCycles
103 .name(name() + ".RENAME:RunCycles")
104 .desc("Number of cycles rename is running")
105 .prereq(renameIdleCycles);
106 renameUnblockCycles
107 .name(name() + ".RENAME:UnblockCycles")
108 .desc("Number of cycles rename is unblocking")
109 .prereq(renameUnblockCycles);
110 renameRenamedInsts
111 .name(name() + ".RENAME:RenamedInsts")
112 .desc("Number of instructions processed by rename")
113 .prereq(renameRenamedInsts);
114 renameSquashedInsts
115 .name(name() + ".RENAME:SquashedInsts")
116 .desc("Number of squashed instructions processed by rename")
117 .prereq(renameSquashedInsts);
118 renameROBFullEvents
119 .name(name() + ".RENAME:ROBFullEvents")
120 .desc("Number of times rename has blocked due to ROB full")
121 .prereq(renameROBFullEvents);
122 renameIQFullEvents
123 .name(name() + ".RENAME:IQFullEvents")
124 .desc("Number of times rename has blocked due to IQ full")
125 .prereq(renameIQFullEvents);
126 renameLSQFullEvents
127 .name(name() + ".RENAME:LSQFullEvents")
128 .desc("Number of times rename has blocked due to LSQ full")
129 .prereq(renameLSQFullEvents);
130 renameFullRegistersEvents
131 .name(name() + ".RENAME:FullRegisterEvents")
132 .desc("Number of times there has been no free registers")
133 .prereq(renameFullRegistersEvents);
134 renameRenamedOperands
135 .name(name() + ".RENAME:RenamedOperands")
136 .desc("Number of destination operands rename has renamed")
137 .prereq(renameRenamedOperands);
138 renameRenameLookups
139 .name(name() + ".RENAME:RenameLookups")
140 .desc("Number of register rename lookups that rename has made")
141 .prereq(renameRenameLookups);
142 renameCommittedMaps
143 .name(name() + ".RENAME:CommittedMaps")
144 .desc("Number of HB maps that are committed")
145 .prereq(renameCommittedMaps);
146 renameUndoneMaps
147 .name(name() + ".RENAME:UndoneMaps")
148 .desc("Number of HB maps that are undone due to squashing")
149 .prereq(renameUndoneMaps);
150 renamedSerializing
151 .name(name() + ".RENAME:serializingInsts")
152 .desc("count of serializing insts renamed")
153 .flags(Stats::total)
154 ;
155 renamedTempSerializing
156 .name(name() + ".RENAME:tempSerializingInsts")
157 .desc("count of temporary serializing insts renamed")
158 .flags(Stats::total)
159 ;
160 renameSkidInsts
161 .name(name() + ".RENAME:skidInsts")
162 .desc("count of insts added to the skid buffer")
163 .flags(Stats::total)
164 ;
165}
166
167template <class Impl>
168void
169DefaultRename<Impl>::setCPU(O3CPU *cpu_ptr)
170{
171 DPRINTF(Rename, "Setting CPU pointer.\n");
172 cpu = cpu_ptr;
173}
174
175template <class Impl>
176void
177DefaultRename<Impl>::setTimeBuffer(TimeBuffer<TimeStruct> *tb_ptr)
178{
179 DPRINTF(Rename, "Setting time buffer pointer.\n");
180 timeBuffer = tb_ptr;
181
182 // Setup wire to read information from time buffer, from IEW stage.
183 fromIEW = timeBuffer->getWire(-iewToRenameDelay);
184
185 // Setup wire to read infromation from time buffer, from commit stage.
186 fromCommit = timeBuffer->getWire(-commitToRenameDelay);
187
188 // Setup wire to write information to previous stages.
189 toDecode = timeBuffer->getWire(0);
190}
191
192template <class Impl>
193void
194DefaultRename<Impl>::setRenameQueue(TimeBuffer<RenameStruct> *rq_ptr)
195{
196 DPRINTF(Rename, "Setting rename queue pointer.\n");
197 renameQueue = rq_ptr;
198
199 // Setup wire to write information to future stages.
200 toIEW = renameQueue->getWire(0);
201}
202
203template <class Impl>
204void
205DefaultRename<Impl>::setDecodeQueue(TimeBuffer<DecodeStruct> *dq_ptr)
206{
207 DPRINTF(Rename, "Setting decode queue pointer.\n");
208 decodeQueue = dq_ptr;
209
210 // Setup wire to get information from decode.
211 fromDecode = decodeQueue->getWire(-decodeToRenameDelay);
212}
213
214template <class Impl>
215void
216DefaultRename<Impl>::initStage()
217{
218 // Grab the number of free entries directly from the stages.
219 for (int tid=0; tid < numThreads; tid++) {
220 freeEntries[tid].iqEntries = iew_ptr->instQueue.numFreeEntries(tid);
221 freeEntries[tid].lsqEntries = iew_ptr->ldstQueue.numFreeEntries(tid);
222 freeEntries[tid].robEntries = commit_ptr->numROBFreeEntries(tid);
223 emptyROB[tid] = true;
224 }
225}
226
227template<class Impl>
228void
229DefaultRename<Impl>::setActiveThreads(std::list<unsigned> *at_ptr)
230{
231 DPRINTF(Rename, "Setting active threads list pointer.\n");
232 activeThreads = at_ptr;
233}
234
235
236template <class Impl>
237void
238DefaultRename<Impl>::setRenameMap(RenameMap rm_ptr[])
239{
240 DPRINTF(Rename, "Setting rename map pointers.\n");
241
242 for (int i=0; i<numThreads; i++) {
243 renameMap[i] = &rm_ptr[i];
244 }
245}
246
247template <class Impl>
248void
249DefaultRename<Impl>::setFreeList(FreeList *fl_ptr)
250{
251 DPRINTF(Rename, "Setting free list pointer.\n");
252 freeList = fl_ptr;
253}
254
255template<class Impl>
256void
257DefaultRename<Impl>::setScoreboard(Scoreboard *_scoreboard)
258{
259 DPRINTF(Rename, "Setting scoreboard pointer.\n");
260 scoreboard = _scoreboard;
261}
262
263template <class Impl>
264bool
265DefaultRename<Impl>::drain()
266{
267 // Rename is ready to switch out at any time.
268 cpu->signalDrained();
269 return true;
270}
271
272template <class Impl>
273void
274DefaultRename<Impl>::switchOut()
275{
276 // Clear any state, fix up the rename map.
277 for (int i = 0; i < numThreads; i++) {
278 typename std::list<RenameHistory>::iterator hb_it =
279 historyBuffer[i].begin();
280
281 while (!historyBuffer[i].empty()) {
282 assert(hb_it != historyBuffer[i].end());
283
284 DPRINTF(Rename, "[tid:%u]: Removing history entry with sequence "
285 "number %i.\n", i, (*hb_it).instSeqNum);
286
287 // Tell the rename map to set the architected register to the
288 // previous physical register that it was renamed to.
289 renameMap[i]->setEntry(hb_it->archReg, hb_it->prevPhysReg);
290
291 // Put the renamed physical register back on the free list.
292 freeList->addReg(hb_it->newPhysReg);
293
294 // Be sure to mark its register as ready if it's a misc register.
295 if (hb_it->newPhysReg >= maxPhysicalRegs) {
296 scoreboard->setReg(hb_it->newPhysReg);
297 }
298
299 historyBuffer[i].erase(hb_it++);
300 }
301 insts[i].clear();
302 skidBuffer[i].clear();
303 }
304}
305
306template <class Impl>
307void
308DefaultRename<Impl>::takeOverFrom()
309{
310 _status = Inactive;
311 initStage();
312
313 // Reset all state prior to taking over from the other CPU.
314 for (int i=0; i< numThreads; i++) {
315 renameStatus[i] = Idle;
316
317 stalls[i].iew = false;
318 stalls[i].commit = false;
319 serializeInst[i] = NULL;
320
321 instsInProgress[i] = 0;
322
323 emptyROB[i] = true;
324
325 serializeOnNextInst[i] = false;
326 }
327}
328
329template <class Impl>
330void
331DefaultRename<Impl>::squash(const InstSeqNum &squash_seq_num, unsigned tid)
332{
333 DPRINTF(Rename, "[tid:%u]: Squashing instructions.\n",tid);
334
335 // Clear the stall signal if rename was blocked or unblocking before.
336 // If it still needs to block, the blocking should happen the next
337 // cycle and there should be space to hold everything due to the squash.
338 if (renameStatus[tid] == Blocked ||
339 renameStatus[tid] == Unblocking) {
340 toDecode->renameUnblock[tid] = 1;
341
342 resumeSerialize = false;
343 serializeInst[tid] = NULL;
344 } else if (renameStatus[tid] == SerializeStall) {
345 if (serializeInst[tid]->seqNum <= squash_seq_num) {
346 DPRINTF(Rename, "Rename will resume serializing after squash\n");
347 resumeSerialize = true;
348 assert(serializeInst[tid]);
349 } else {
350 resumeSerialize = false;
351 toDecode->renameUnblock[tid] = 1;
352
353 serializeInst[tid] = NULL;
354 }
355 }
356
357 // Set the status to Squashing.
358 renameStatus[tid] = Squashing;
359
360 // Squash any instructions from decode.
361 unsigned squashCount = 0;
362
363 for (int i=0; i<fromDecode->size; i++) {
364 if (fromDecode->insts[i]->threadNumber == tid &&
365 fromDecode->insts[i]->seqNum > squash_seq_num) {
366 fromDecode->insts[i]->setSquashed();
367 wroteToTimeBuffer = true;
368 squashCount++;
369 }
370
371 }
372
373 // Clear the instruction list and skid buffer in case they have any
374 // insts in them. Since we support multiple ISAs, we cant just:
375 // "insts[tid].clear();" or "skidBuffer[tid].clear()" since there is
376 // a possible delay slot inst for different architectures
377 // insts[tid].clear();
378#if ISA_HAS_DELAY_SLOT
379 DPRINTF(Rename, "[tid:%i] Squashing incoming decode instructions until "
380 "[sn:%i].\n",tid, squash_seq_num);
381 ListIt ilist_it = insts[tid].begin();
382 while (ilist_it != insts[tid].end()) {
383 if ((*ilist_it)->seqNum > squash_seq_num) {
384 (*ilist_it)->setSquashed();
385 DPRINTF(Rename, "Squashing incoming decode instruction, "
386 "[tid:%i] [sn:%i] PC %08p.\n", tid, (*ilist_it)->seqNum, (*ilist_it)->PC);
387 }
388 ilist_it++;
389 }
390#else
391 insts[tid].clear();
392#endif
393
394 // Clear the skid buffer in case it has any data in it.
395 // See comments above.
396 // skidBuffer[tid].clear();
397#if ISA_HAS_DELAY_SLOT
398 DPRINTF(Rename, "[tid:%i] Squashing incoming skidbuffer instructions "
399 "until [sn:%i].\n", tid, squash_seq_num);
400 ListIt slist_it = skidBuffer[tid].begin();
401 while (slist_it != skidBuffer[tid].end()) {
402 if ((*slist_it)->seqNum > squash_seq_num) {
403 (*slist_it)->setSquashed();
404 DPRINTF(Rename, "Squashing skidbuffer instruction, [tid:%i] [sn:%i]"
405 "PC %08p.\n", tid, (*slist_it)->seqNum, (*slist_it)->PC);
406 }
407 slist_it++;
408 }
409 resumeUnblocking = (skidBuffer[tid].size() != 0);
410 DPRINTF(Rename, "Resume unblocking set to %s\n",
411 resumeUnblocking ? "true" : "false");
412#else
413 skidBuffer[tid].clear();
414#endif
415 doSquash(squash_seq_num, tid);
416}
417
418template <class Impl>
419void
420DefaultRename<Impl>::tick()
421{
422 wroteToTimeBuffer = false;
423
424 blockThisCycle = false;
425
426 bool status_change = false;
427
428 toIEWIndex = 0;
429
430 sortInsts();
431
432 std::list<unsigned>::iterator threads = activeThreads->begin();
433 std::list<unsigned>::iterator end = activeThreads->end();
434
435 // Check stall and squash signals.
436 while (threads != end) {
437 unsigned tid = *threads++;
438
439 DPRINTF(Rename, "Processing [tid:%i]\n", tid);
440
441 status_change = checkSignalsAndUpdate(tid) || status_change;
442
443 rename(status_change, tid);
444 }
445
446 if (status_change) {
447 updateStatus();
448 }
449
450 if (wroteToTimeBuffer) {
451 DPRINTF(Activity, "Activity this cycle.\n");
452 cpu->activityThisCycle();
453 }
454
455 threads = activeThreads->begin();
456
457 while (threads != end) {
458 unsigned tid = *threads++;
459
460 // If we committed this cycle then doneSeqNum will be > 0
461 if (fromCommit->commitInfo[tid].doneSeqNum != 0 &&
462 !fromCommit->commitInfo[tid].squash &&
463 renameStatus[tid] != Squashing) {
464
465 removeFromHistory(fromCommit->commitInfo[tid].doneSeqNum,
466 tid);
467 }
468 }
469
470 // @todo: make into updateProgress function
471 for (int tid=0; tid < numThreads; tid++) {
472 instsInProgress[tid] -= fromIEW->iewInfo[tid].dispatched;
473
474 assert(instsInProgress[tid] >=0);
475 }
476
477}
478
479template<class Impl>
480void
481DefaultRename<Impl>::rename(bool &status_change, unsigned tid)
482{
483 // If status is Running or idle,
484 // call renameInsts()
485 // If status is Unblocking,
486 // buffer any instructions coming from decode
487 // continue trying to empty skid buffer
488 // check if stall conditions have passed
489
490 if (renameStatus[tid] == Blocked) {
491 ++renameBlockCycles;
492 } else if (renameStatus[tid] == Squashing) {
493 ++renameSquashCycles;
494 } else if (renameStatus[tid] == SerializeStall) {
495 ++renameSerializeStallCycles;
496 // If we are currently in SerializeStall and resumeSerialize
497 // was set, then that means that we are resuming serializing
498 // this cycle. Tell the previous stages to block.
499 if (resumeSerialize) {
500 resumeSerialize = false;
501 block(tid);
502 toDecode->renameUnblock[tid] = false;
503 }
504 } else if (renameStatus[tid] == Unblocking) {
505 if (resumeUnblocking) {
506 block(tid);
507 resumeUnblocking = false;
508 toDecode->renameUnblock[tid] = false;
509 }
510 }
511
512 if (renameStatus[tid] == Running ||
513 renameStatus[tid] == Idle) {
514 DPRINTF(Rename, "[tid:%u]: Not blocked, so attempting to run "
515 "stage.\n", tid);
516
517 renameInsts(tid);
518 } else if (renameStatus[tid] == Unblocking) {
519 renameInsts(tid);
520
521 if (validInsts()) {
522 // Add the current inputs to the skid buffer so they can be
523 // reprocessed when this stage unblocks.
524 skidInsert(tid);
525 }
526
527 // If we switched over to blocking, then there's a potential for
528 // an overall status change.
529 status_change = unblock(tid) || status_change || blockThisCycle;
530 }
531}
532
533template <class Impl>
534void
535DefaultRename<Impl>::renameInsts(unsigned tid)
536{
537 // Instructions can be either in the skid buffer or the queue of
538 // instructions coming from decode, depending on the status.
539 int insts_available = renameStatus[tid] == Unblocking ?
540 skidBuffer[tid].size() : insts[tid].size();
541
542 // Check the decode queue to see if instructions are available.
543 // If there are no available instructions to rename, then do nothing.
544 if (insts_available == 0) {
545 DPRINTF(Rename, "[tid:%u]: Nothing to do, breaking out early.\n",
546 tid);
547 // Should I change status to idle?
548 ++renameIdleCycles;
549 return;
550 } else if (renameStatus[tid] == Unblocking) {
551 ++renameUnblockCycles;
552 } else if (renameStatus[tid] == Running) {
553 ++renameRunCycles;
554 }
555
556 DynInstPtr inst;
557
558 // Will have to do a different calculation for the number of free
559 // entries.
560 int free_rob_entries = calcFreeROBEntries(tid);
561 int free_iq_entries = calcFreeIQEntries(tid);
562 int free_lsq_entries = calcFreeLSQEntries(tid);
563 int min_free_entries = free_rob_entries;
564
565 FullSource source = ROB;
566
567 if (free_iq_entries < min_free_entries) {
568 min_free_entries = free_iq_entries;
569 source = IQ;
570 }
571
572 if (free_lsq_entries < min_free_entries) {
573 min_free_entries = free_lsq_entries;
574 source = LSQ;
575 }
576
577 // Check if there's any space left.
578 if (min_free_entries <= 0) {
579 DPRINTF(Rename, "[tid:%u]: Blocking due to no free ROB/IQ/LSQ "
580 "entries.\n"
581 "ROB has %i free entries.\n"
582 "IQ has %i free entries.\n"
583 "LSQ has %i free entries.\n",
584 tid,
585 free_rob_entries,
586 free_iq_entries,
587 free_lsq_entries);
588
589 blockThisCycle = true;
590
591 block(tid);
592
593 incrFullStat(source);
594
595 return;
596 } else if (min_free_entries < insts_available) {
597 DPRINTF(Rename, "[tid:%u]: Will have to block this cycle."
598 "%i insts available, but only %i insts can be "
599 "renamed due to ROB/IQ/LSQ limits.\n",
600 tid, insts_available, min_free_entries);
601
602 insts_available = min_free_entries;
603
604 blockThisCycle = true;
605
606 incrFullStat(source);
607 }
608
609 InstQueue &insts_to_rename = renameStatus[tid] == Unblocking ?
610 skidBuffer[tid] : insts[tid];
611
612 DPRINTF(Rename, "[tid:%u]: %i available instructions to "
613 "send iew.\n", tid, insts_available);
614
615 DPRINTF(Rename, "[tid:%u]: %i insts pipelining from Rename | %i insts "
616 "dispatched to IQ last cycle.\n",
617 tid, instsInProgress[tid], fromIEW->iewInfo[tid].dispatched);
618
619 // Handle serializing the next instruction if necessary.
620 if (serializeOnNextInst[tid]) {
621 if (emptyROB[tid] && instsInProgress[tid] == 0) {
622 // ROB already empty; no need to serialize.
623 serializeOnNextInst[tid] = false;
624 } else if (!insts_to_rename.empty()) {
625 insts_to_rename.front()->setSerializeBefore();
626 }
627 }
628
629 int renamed_insts = 0;
630
631 while (insts_available > 0 && toIEWIndex < renameWidth) {
632 DPRINTF(Rename, "[tid:%u]: Sending instructions to IEW.\n", tid);
633
634 assert(!insts_to_rename.empty());
635
636 inst = insts_to_rename.front();
637
638 insts_to_rename.pop_front();
639
640 if (renameStatus[tid] == Unblocking) {
641 DPRINTF(Rename,"[tid:%u]: Removing [sn:%lli] PC:%#x from rename "
642 "skidBuffer\n",
643 tid, inst->seqNum, inst->readPC());
644 }
645
646 if (inst->isSquashed()) {
647 DPRINTF(Rename, "[tid:%u]: instruction %i with PC %#x is "
648 "squashed, skipping.\n",
649 tid, inst->seqNum, inst->readPC());
650
651 ++renameSquashedInsts;
652
653 // Decrement how many instructions are available.
654 --insts_available;
655
656 continue;
657 }
658
659 DPRINTF(Rename, "[tid:%u]: Processing instruction [sn:%lli] with "
660 "PC %#x.\n",
661 tid, inst->seqNum, inst->readPC());
662
663 // Handle serializeAfter/serializeBefore instructions.
664 // serializeAfter marks the next instruction as serializeBefore.
665 // serializeBefore makes the instruction wait in rename until the ROB
666 // is empty.
667
668 // In this model, IPR accesses are serialize before
669 // instructions, and store conditionals are serialize after
670 // instructions. This is mainly due to lack of support for
671 // out-of-order operations of either of those classes of
672 // instructions.
673 if ((inst->isIprAccess() || inst->isSerializeBefore()) &&
674 !inst->isSerializeHandled()) {
675 DPRINTF(Rename, "Serialize before instruction encountered.\n");
676
677 if (!inst->isTempSerializeBefore()) {
678 renamedSerializing++;
679 inst->setSerializeHandled();
680 } else {
681 renamedTempSerializing++;
682 }
683
684 // Change status over to SerializeStall so that other stages know
685 // what this is blocked on.
686 renameStatus[tid] = SerializeStall;
687
688 serializeInst[tid] = inst;
689
690 blockThisCycle = true;
691
692 break;
693 } else if ((inst->isStoreConditional() || inst->isSerializeAfter()) &&
694 !inst->isSerializeHandled()) {
695 DPRINTF(Rename, "Serialize after instruction encountered.\n");
696
697 renamedSerializing++;
698
699 inst->setSerializeHandled();
700
701 serializeAfter(insts_to_rename, tid);
702 }
703
704 // Check here to make sure there are enough destination registers
705 // to rename to. Otherwise block.
706 if (renameMap[tid]->numFreeEntries() < inst->numDestRegs()) {
707 DPRINTF(Rename, "Blocking due to lack of free "
708 "physical registers to rename to.\n");
709 blockThisCycle = true;
710
711 ++renameFullRegistersEvents;
712
713 break;
714 }
715
716 renameSrcRegs(inst, inst->threadNumber);
717
718 renameDestRegs(inst, inst->threadNumber);
719
720 ++renamed_insts;
721
722 // Put instruction in rename queue.
723 toIEW->insts[toIEWIndex] = inst;
724 ++(toIEW->size);
725
726 // Increment which instruction we're on.
727 ++toIEWIndex;
728
729 // Decrement how many instructions are available.
730 --insts_available;
731 }
732
733 instsInProgress[tid] += renamed_insts;
734 renameRenamedInsts += renamed_insts;
735
736 // If we wrote to the time buffer, record this.
737 if (toIEWIndex) {
738 wroteToTimeBuffer = true;
739 }
740
741 // Check if there's any instructions left that haven't yet been renamed.
742 // If so then block.
743 if (insts_available) {
744 blockThisCycle = true;
745 }
746
747 if (blockThisCycle) {
748 block(tid);
749 toDecode->renameUnblock[tid] = false;
750 }
751}
752
753template<class Impl>
754void
755DefaultRename<Impl>::skidInsert(unsigned tid)
756{
757 DynInstPtr inst = NULL;
758
759 while (!insts[tid].empty()) {
760 inst = insts[tid].front();
761
762 insts[tid].pop_front();
763
764 assert(tid == inst->threadNumber);
765
766 DPRINTF(Rename, "[tid:%u]: Inserting [sn:%lli] PC:%#x into Rename "
767 "skidBuffer\n", tid, inst->seqNum, inst->readPC());
768
769 ++renameSkidInsts;
770
771 skidBuffer[tid].push_back(inst);
772 }
773
774 if (skidBuffer[tid].size() > skidBufferMax)
775 {
776 typename InstQueue::iterator it;
777 warn("Skidbuffer contents:\n");
778 for(it = skidBuffer[tid].begin(); it != skidBuffer[tid].end(); it++)
779 {
780 warn("[tid:%u]: %s [sn:%i].\n", tid,
781 (*it)->staticInst->disassemble(inst->readPC()),
782 (*it)->seqNum);
783 }
784 panic("Skidbuffer Exceeded Max Size");
785 }
786}
787
788template <class Impl>
789void
790DefaultRename<Impl>::sortInsts()
791{
792 int insts_from_decode = fromDecode->size;
793#ifdef DEBUG
794#if !ISA_HAS_DELAY_SLOT
795 for (int i=0; i < numThreads; i++)
796 assert(insts[i].empty());
797#endif
798#endif
799 for (int i = 0; i < insts_from_decode; ++i) {
800 DynInstPtr inst = fromDecode->insts[i];
801 insts[inst->threadNumber].push_back(inst);
802 }
803}
804
805template<class Impl>
806bool
807DefaultRename<Impl>::skidsEmpty()
808{
809 std::list<unsigned>::iterator threads = activeThreads->begin();
810 std::list<unsigned>::iterator end = activeThreads->end();
811
812 while (threads != end) {
813 unsigned tid = *threads++;
814
815 if (!skidBuffer[tid].empty())
816 return false;
817 }
818
819 return true;
820}
821
822template<class Impl>
823void
824DefaultRename<Impl>::updateStatus()
825{
826 bool any_unblocking = false;
827
828 std::list<unsigned>::iterator threads = activeThreads->begin();
829 std::list<unsigned>::iterator end = activeThreads->end();
830
831 while (threads != end) {
832 unsigned tid = *threads++;
833
834 if (renameStatus[tid] == Unblocking) {
835 any_unblocking = true;
836 break;
837 }
838 }
839
840 // Rename will have activity if it's unblocking.
841 if (any_unblocking) {
842 if (_status == Inactive) {
843 _status = Active;
844
845 DPRINTF(Activity, "Activating stage.\n");
846
847 cpu->activateStage(O3CPU::RenameIdx);
848 }
849 } else {
850 // If it's not unblocking, then rename will not have any internal
851 // activity. Switch it to inactive.
852 if (_status == Active) {
853 _status = Inactive;
854 DPRINTF(Activity, "Deactivating stage.\n");
855
856 cpu->deactivateStage(O3CPU::RenameIdx);
857 }
858 }
859}
860
861template <class Impl>
862bool
863DefaultRename<Impl>::block(unsigned tid)
864{
865 DPRINTF(Rename, "[tid:%u]: Blocking.\n", tid);
866
867 // Add the current inputs onto the skid buffer, so they can be
868 // reprocessed when this stage unblocks.
869 skidInsert(tid);
870
871 // Only signal backwards to block if the previous stages do not think
872 // rename is already blocked.
873 if (renameStatus[tid] != Blocked) {
874 // If resumeUnblocking is set, we unblocked during the squash,
875 // but now we're have unblocking status. We need to tell earlier
876 // stages to block.
877 if (resumeUnblocking || renameStatus[tid] != Unblocking) {
878 toDecode->renameBlock[tid] = true;
879 toDecode->renameUnblock[tid] = false;
880 wroteToTimeBuffer = true;
881 }
882
883 // Rename can not go from SerializeStall to Blocked, otherwise
884 // it would not know to complete the serialize stall.
885 if (renameStatus[tid] != SerializeStall) {
886 // Set status to Blocked.
887 renameStatus[tid] = Blocked;
888 return true;
889 }
890 }
891
892 return false;
893}
894
895template <class Impl>
896bool
897DefaultRename<Impl>::unblock(unsigned tid)
898{
899 DPRINTF(Rename, "[tid:%u]: Trying to unblock.\n", tid);
900
901 // Rename is done unblocking if the skid buffer is empty.
902 if (skidBuffer[tid].empty() && renameStatus[tid] != SerializeStall) {
903
904 DPRINTF(Rename, "[tid:%u]: Done unblocking.\n", tid);
905
906 toDecode->renameUnblock[tid] = true;
907 wroteToTimeBuffer = true;
908
909 renameStatus[tid] = Running;
910 return true;
911 }
912
913 return false;
914}
915
916template <class Impl>
917void
918DefaultRename<Impl>::doSquash(const InstSeqNum &squashed_seq_num, unsigned tid)
919{
920 typename std::list<RenameHistory>::iterator hb_it =
921 historyBuffer[tid].begin();
922
923 // After a syscall squashes everything, the history buffer may be empty
924 // but the ROB may still be squashing instructions.
925 if (historyBuffer[tid].empty()) {
926 return;
927 }
928
929 // Go through the most recent instructions, undoing the mappings
930 // they did and freeing up the registers.
931 while (!historyBuffer[tid].empty() &&
932 (*hb_it).instSeqNum > squashed_seq_num) {
933 assert(hb_it != historyBuffer[tid].end());
934
935 DPRINTF(Rename, "[tid:%u]: Removing history entry with sequence "
936 "number %i.\n", tid, (*hb_it).instSeqNum);
937
938 // Tell the rename map to set the architected register to the
939 // previous physical register that it was renamed to.
940 renameMap[tid]->setEntry(hb_it->archReg, hb_it->prevPhysReg);
941
942 // Put the renamed physical register back on the free list.
943 freeList->addReg(hb_it->newPhysReg);
944
945 // Be sure to mark its register as ready if it's a misc register.
946 if (hb_it->newPhysReg >= maxPhysicalRegs) {
947 scoreboard->setReg(hb_it->newPhysReg);
948 }
949
950 historyBuffer[tid].erase(hb_it++);
951
952 ++renameUndoneMaps;
953 }
954}
955
956template<class Impl>
957void
958DefaultRename<Impl>::removeFromHistory(InstSeqNum inst_seq_num, unsigned tid)
959{
960 DPRINTF(Rename, "[tid:%u]: Removing a committed instruction from the "
961 "history buffer %u (size=%i), until [sn:%lli].\n",
962 tid, tid, historyBuffer[tid].size(), inst_seq_num);
963
964 typename std::list<RenameHistory>::iterator hb_it =
965 historyBuffer[tid].end();
966
967 --hb_it;
968
969 if (historyBuffer[tid].empty()) {
970 DPRINTF(Rename, "[tid:%u]: History buffer is empty.\n", tid);
971 return;
972 } else if (hb_it->instSeqNum > inst_seq_num) {
973 DPRINTF(Rename, "[tid:%u]: Old sequence number encountered. Ensure "
974 "that a syscall happened recently.\n", tid);
975 return;
976 }
977
978 // Commit all the renames up until (and including) the committed sequence
979 // number. Some or even all of the committed instructions may not have
980 // rename histories if they did not have destination registers that were
981 // renamed.
982 while (!historyBuffer[tid].empty() &&
983 hb_it != historyBuffer[tid].end() &&
984 (*hb_it).instSeqNum <= inst_seq_num) {
985
986 DPRINTF(Rename, "[tid:%u]: Freeing up older rename of reg %i, "
987 "[sn:%lli].\n",
988 tid, (*hb_it).prevPhysReg, (*hb_it).instSeqNum);
989
990 freeList->addReg((*hb_it).prevPhysReg);
991 ++renameCommittedMaps;
992
993 historyBuffer[tid].erase(hb_it--);
994 }
995}
996
997template <class Impl>
998inline void
999DefaultRename<Impl>::renameSrcRegs(DynInstPtr &inst,unsigned tid)
1000{
1001 assert(renameMap[tid] != 0);
1002
1003 unsigned num_src_regs = inst->numSrcRegs();
1004
1005 // Get the architectual register numbers from the source and
1006 // destination operands, and redirect them to the right register.
1007 // Will need to mark dependencies though.
1008 for (int src_idx = 0; src_idx < num_src_regs; src_idx++) {
1009 RegIndex src_reg = inst->srcRegIdx(src_idx);
1010 RegIndex flat_src_reg = src_reg;
1011 if (src_reg < TheISA::FP_Base_DepTag) {
1012 flat_src_reg = TheISA::flattenIntIndex(inst->tcBase(), src_reg);
1013 DPRINTF(Rename, "Flattening index %d to %d.\n", (int)src_reg, (int)flat_src_reg);
1014 }
1015 inst->flattenSrcReg(src_idx, flat_src_reg);
1016
1017 // Look up the source registers to get the phys. register they've
1018 // been renamed to, and set the sources to those registers.
1019 PhysRegIndex renamed_reg = renameMap[tid]->lookup(flat_src_reg);
1020
1021 DPRINTF(Rename, "[tid:%u]: Looking up arch reg %i, got "
1022 "physical reg %i.\n", tid, (int)flat_src_reg,
1023 (int)renamed_reg);
1024
1025 inst->renameSrcReg(src_idx, renamed_reg);
1026
1027 // See if the register is ready or not.
1028 if (scoreboard->getReg(renamed_reg) == true) {
1029 DPRINTF(Rename, "[tid:%u]: Register is ready.\n", tid);
1030
1031 inst->markSrcRegReady(src_idx);
1032 }
1033
1034 ++renameRenameLookups;
1035 }
1036}
1037
1038template <class Impl>
1039inline void
1040DefaultRename<Impl>::renameDestRegs(DynInstPtr &inst,unsigned tid)
1041{
1042 typename RenameMap::RenameInfo rename_result;
1043
1044 unsigned num_dest_regs = inst->numDestRegs();
1045
1046 // Rename the destination registers.
1047 for (int dest_idx = 0; dest_idx < num_dest_regs; dest_idx++) {
1048 RegIndex dest_reg = inst->destRegIdx(dest_idx);
1049 RegIndex flat_dest_reg = dest_reg;
1050 if (dest_reg < TheISA::FP_Base_DepTag) {
1051 flat_dest_reg = TheISA::flattenIntIndex(inst->tcBase(), dest_reg);
1052 DPRINTF(Rename, "Flattening index %d to %d.\n", (int)dest_reg, (int)flat_dest_reg);
1053 }
1054
1055 inst->flattenDestReg(dest_idx, flat_dest_reg);
1056
1057 // Get the physical register that the destination will be
1058 // renamed to.
1059 rename_result = renameMap[tid]->rename(flat_dest_reg);
1060
1061 //Mark Scoreboard entry as not ready
1062 scoreboard->unsetReg(rename_result.first);
1063
1064 DPRINTF(Rename, "[tid:%u]: Renaming arch reg %i to physical "
1065 "reg %i.\n", tid, (int)flat_dest_reg,
1066 (int)rename_result.first);
1067
1068 // Record the rename information so that a history can be kept.
1069 RenameHistory hb_entry(inst->seqNum, flat_dest_reg,
1070 rename_result.first,
1071 rename_result.second);
1072
1073 historyBuffer[tid].push_front(hb_entry);
1074
1075 DPRINTF(Rename, "[tid:%u]: Adding instruction to history buffer "
1076 "(size=%i), [sn:%lli].\n",tid,
1077 historyBuffer[tid].size(),
1078 (*historyBuffer[tid].begin()).instSeqNum);
1079
1080 // Tell the instruction to rename the appropriate destination
1081 // register (dest_idx) to the new physical register
1082 // (rename_result.first), and record the previous physical
1083 // register that the same logical register was renamed to
1084 // (rename_result.second).
1085 inst->renameDestReg(dest_idx,
1086 rename_result.first,
1087 rename_result.second);
1088
1089 ++renameRenamedOperands;
1090 }
1091}
1092
1093template <class Impl>
1094inline int
1095DefaultRename<Impl>::calcFreeROBEntries(unsigned tid)
1096{
1097 int num_free = freeEntries[tid].robEntries -
1098 (instsInProgress[tid] - fromIEW->iewInfo[tid].dispatched);
1099
1100 //DPRINTF(Rename,"[tid:%i]: %i rob free\n",tid,num_free);
1101
1102 return num_free;
1103}
1104
1105template <class Impl>
1106inline int
1107DefaultRename<Impl>::calcFreeIQEntries(unsigned tid)
1108{
1109 int num_free = freeEntries[tid].iqEntries -
1110 (instsInProgress[tid] - fromIEW->iewInfo[tid].dispatched);
1111
1112 //DPRINTF(Rename,"[tid:%i]: %i iq free\n",tid,num_free);
1113
1114 return num_free;
1115}
1116
1117template <class Impl>
1118inline int
1119DefaultRename<Impl>::calcFreeLSQEntries(unsigned tid)
1120{
1121 int num_free = freeEntries[tid].lsqEntries -
1122 (instsInProgress[tid] - fromIEW->iewInfo[tid].dispatchedToLSQ);
1123
1124 //DPRINTF(Rename,"[tid:%i]: %i lsq free\n",tid,num_free);
1125
1126 return num_free;
1127}
1128
1129template <class Impl>
1130unsigned
1131DefaultRename<Impl>::validInsts()
1132{
1133 unsigned inst_count = 0;
1134
1135 for (int i=0; i<fromDecode->size; i++) {
1136 if (!fromDecode->insts[i]->isSquashed())
1137 inst_count++;
1138 }
1139
1140 return inst_count;
1141}
1142
1143template <class Impl>
1144void
1145DefaultRename<Impl>::readStallSignals(unsigned tid)
1146{
1147 if (fromIEW->iewBlock[tid]) {
1148 stalls[tid].iew = true;
1149 }
1150
1151 if (fromIEW->iewUnblock[tid]) {
1152 assert(stalls[tid].iew);
1153 stalls[tid].iew = false;
1154 }
1155
1156 if (fromCommit->commitBlock[tid]) {
1157 stalls[tid].commit = true;
1158 }
1159
1160 if (fromCommit->commitUnblock[tid]) {
1161 assert(stalls[tid].commit);
1162 stalls[tid].commit = false;
1163 }
1164}
1165
1166template <class Impl>
1167bool
1168DefaultRename<Impl>::checkStall(unsigned tid)
1169{
1170 bool ret_val = false;
1171
1172 if (stalls[tid].iew) {
1173 DPRINTF(Rename,"[tid:%i]: Stall from IEW stage detected.\n", tid);
1174 ret_val = true;
1175 } else if (stalls[tid].commit) {
1176 DPRINTF(Rename,"[tid:%i]: Stall from Commit stage detected.\n", tid);
1177 ret_val = true;
1178 } else if (calcFreeROBEntries(tid) <= 0) {
1179 DPRINTF(Rename,"[tid:%i]: Stall: ROB has 0 free entries.\n", tid);
1180 ret_val = true;
1181 } else if (calcFreeIQEntries(tid) <= 0) {
1182 DPRINTF(Rename,"[tid:%i]: Stall: IQ has 0 free entries.\n", tid);
1183 ret_val = true;
1184 } else if (calcFreeLSQEntries(tid) <= 0) {
1185 DPRINTF(Rename,"[tid:%i]: Stall: LSQ has 0 free entries.\n", tid);
1186 ret_val = true;
1187 } else if (renameMap[tid]->numFreeEntries() <= 0) {
1188 DPRINTF(Rename,"[tid:%i]: Stall: RenameMap has 0 free entries.\n", tid);
1189 ret_val = true;
1190 } else if (renameStatus[tid] == SerializeStall &&
1191 (!emptyROB[tid] || instsInProgress[tid])) {
1192 DPRINTF(Rename,"[tid:%i]: Stall: Serialize stall and ROB is not "
1193 "empty.\n",
1194 tid);
1195 ret_val = true;
1196 }
1197
1198 return ret_val;
1199}
1200
1201template <class Impl>
1202void
1203DefaultRename<Impl>::readFreeEntries(unsigned tid)
1204{
1205 bool updated = false;
1206 if (fromIEW->iewInfo[tid].usedIQ) {
1207 freeEntries[tid].iqEntries =
1208 fromIEW->iewInfo[tid].freeIQEntries;
1209 updated = true;
1210 }
1211
1212 if (fromIEW->iewInfo[tid].usedLSQ) {
1213 freeEntries[tid].lsqEntries =
1214 fromIEW->iewInfo[tid].freeLSQEntries;
1215 updated = true;
1216 }
1217
1218 if (fromCommit->commitInfo[tid].usedROB) {
1219 freeEntries[tid].robEntries =
1220 fromCommit->commitInfo[tid].freeROBEntries;
1221 emptyROB[tid] = fromCommit->commitInfo[tid].emptyROB;
1222 updated = true;
1223 }
1224
1225 DPRINTF(Rename, "[tid:%i]: Free IQ: %i, Free ROB: %i, Free LSQ: %i\n",
1226 tid,
1227 freeEntries[tid].iqEntries,
1228 freeEntries[tid].robEntries,
1229 freeEntries[tid].lsqEntries);
1230
1231 DPRINTF(Rename, "[tid:%i]: %i instructions not yet in ROB\n",
1232 tid, instsInProgress[tid]);
1233}
1234
1235template <class Impl>
1236bool
1237DefaultRename<Impl>::checkSignalsAndUpdate(unsigned tid)
1238{
1239 // Check if there's a squash signal, squash if there is
1240 // Check stall signals, block if necessary.
1241 // If status was blocked
1242 // check if stall conditions have passed
1243 // if so then go to unblocking
1244 // If status was Squashing
1245 // check if squashing is not high. Switch to running this cycle.
1246 // If status was serialize stall
1247 // check if ROB is empty and no insts are in flight to the ROB
1248
1249 readFreeEntries(tid);
1250 readStallSignals(tid);
1251
1252 if (fromCommit->commitInfo[tid].squash) {
1253 DPRINTF(Rename, "[tid:%u]: Squashing instructions due to squash from "
1254 "commit.\n", tid);
1255
1256#if ISA_HAS_DELAY_SLOT
1257 InstSeqNum squashed_seq_num = fromCommit->commitInfo[tid].bdelayDoneSeqNum;
1258#else
1259 InstSeqNum squashed_seq_num = fromCommit->commitInfo[tid].doneSeqNum;
1260#endif
1261
1262 squash(squashed_seq_num, tid);
1263
1264 return true;
1265 }
1266
1267 if (fromCommit->commitInfo[tid].robSquashing) {
1268 DPRINTF(Rename, "[tid:%u]: ROB is still squashing.\n", tid);
1269
1270 renameStatus[tid] = Squashing;
1271
1272 return true;
1273 }
1274
1275 if (checkStall(tid)) {
1276 return block(tid);
1277 }
1278
1279 if (renameStatus[tid] == Blocked) {
1280 DPRINTF(Rename, "[tid:%u]: Done blocking, switching to unblocking.\n",
1281 tid);
1282
1283 renameStatus[tid] = Unblocking;
1284
1285 unblock(tid);
1286
1287 return true;
1288 }
1289
1290 if (renameStatus[tid] == Squashing) {
1291 // Switch status to running if rename isn't being told to block or
1292 // squash this cycle.
1293 if (resumeSerialize) {
1294 DPRINTF(Rename, "[tid:%u]: Done squashing, switching to serialize.\n",
1295 tid);
1296
1297 renameStatus[tid] = SerializeStall;
1298 return true;
1299 } else if (resumeUnblocking) {
1300 DPRINTF(Rename, "[tid:%u]: Done squashing, switching to unblocking.\n",
1301 tid);
1302 renameStatus[tid] = Unblocking;
1303 return true;
1304 } else {
1305 DPRINTF(Rename, "[tid:%u]: Done squashing, switching to running.\n",
1306 tid);
1307
1308 renameStatus[tid] = Running;
1309 return false;
1310 }
1311 }
1312
1313 if (renameStatus[tid] == SerializeStall) {
1314 // Stall ends once the ROB is free.
1315 DPRINTF(Rename, "[tid:%u]: Done with serialize stall, switching to "
1316 "unblocking.\n", tid);
1317
1318 DynInstPtr serial_inst = serializeInst[tid];
1319
1320 renameStatus[tid] = Unblocking;
1321
1322 unblock(tid);
1323
1324 DPRINTF(Rename, "[tid:%u]: Processing instruction [%lli] with "
1325 "PC %#x.\n",
1326 tid, serial_inst->seqNum, serial_inst->readPC());
1327
1328 // Put instruction into queue here.
1329 serial_inst->clearSerializeBefore();
1330
1331 if (!skidBuffer[tid].empty()) {
1332 skidBuffer[tid].push_front(serial_inst);
1333 } else {
1334 insts[tid].push_front(serial_inst);
1335 }
1336
1337 DPRINTF(Rename, "[tid:%u]: Instruction must be processed by rename."
1338 " Adding to front of list.\n", tid);
1339
1340 serializeInst[tid] = NULL;
1341
1342 return true;
1343 }
1344
1345 // If we've reached this point, we have not gotten any signals that
1346 // cause rename to change its status. Rename remains the same as before.
1347 return false;
1348}
1349
1350template<class Impl>
1351void
1352DefaultRename<Impl>::serializeAfter(InstQueue &inst_list,
1353 unsigned tid)
1354{
1355 if (inst_list.empty()) {
1356 // Mark a bit to say that I must serialize on the next instruction.
1357 serializeOnNextInst[tid] = true;
1358 return;
1359 }
1360
1361 // Set the next instruction as serializing.
1362 inst_list.front()->setSerializeBefore();
1363}
1364
1365template <class Impl>
1366inline void
1367DefaultRename<Impl>::incrFullStat(const FullSource &source)
1368{
1369 switch (source) {
1370 case ROB:
1371 ++renameROBFullEvents;
1372 break;
1373 case IQ:
1374 ++renameIQFullEvents;
1375 break;
1376 case LSQ:
1377 ++renameLSQFullEvents;
1378 break;
1379 default:
1380 panic("Rename full stall stat should be incremented for a reason!");
1381 break;
1382 }
1383}
1384
1385template <class Impl>
1386void
1387DefaultRename<Impl>::dumpHistory()
1388{
1389 typename std::list<RenameHistory>::iterator buf_it;
1390
1391 for (int i = 0; i < numThreads; i++) {
1392
1393 buf_it = historyBuffer[i].begin();
1394
1395 while (buf_it != historyBuffer[i].end()) {
1396 cprintf("Seq num: %i\nArch reg: %i New phys reg: %i Old phys "
1397 "reg: %i\n", (*buf_it).instSeqNum, (int)(*buf_it).archReg,
1398 (int)(*buf_it).newPhysReg, (int)(*buf_it).prevPhysReg);
1399
1400 buf_it++;
1401 }
1402 }
1403}