1/*
2 * Copyright (c) 2010-2014 ARM Limited
3 * Copyright (c) 2012-2013 AMD
4 * All rights reserved.
5 *
6 * The license below extends only to copyright in the software and shall
7 * not be construed as granting a license to any other intellectual
8 * property including but not limited to intellectual property relating
9 * to a hardware implementation of the functionality of the software
10 * licensed hereunder. You may use the software subject to the license
11 * terms below provided that you ensure that this notice is replicated
12 * unmodified and in its entirety in all distributions of the software,
13 * modified or unmodified, in source code or in binary form.
14 *
15 * Copyright (c) 2004-2006 The Regents of The University of Michigan
16 * All rights reserved.
17 *
18 * Redistribution and use in source and binary forms, with or without
19 * modification, are permitted provided that the following conditions are
20 * met: redistributions of source code must retain the above copyright
21 * notice, this list of conditions and the following disclaimer;
22 * redistributions in binary form must reproduce the above copyright
23 * notice, this list of conditions and the following disclaimer in the
24 * documentation and/or other materials provided with the distribution;
25 * neither the name of the copyright holders nor the names of its
26 * contributors may be used to endorse or promote products derived from
27 * this software without specific prior written permission.
28 *
29 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
30 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
31 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
32 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
33 * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
34 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
35 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
36 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
37 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
38 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
39 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
40 *
41 * Authors: Kevin Lim
42 * Korey Sewell
43 */
44
45#ifndef __CPU_O3_FETCH_IMPL_HH__
46#define __CPU_O3_FETCH_IMPL_HH__
47
48#include <algorithm>
49#include <cstring>
50#include <list>
51#include <map>
52#include <queue>
53
54#include "arch/generic/tlb.hh"
55#include "arch/isa_traits.hh"
56#include "arch/utility.hh"
57#include "arch/vtophys.hh"
58#include "base/random.hh"
59#include "base/types.hh"
60#include "config/the_isa.hh"
61#include "cpu/base.hh"
62//#include "cpu/checker/cpu.hh"
63#include "cpu/o3/fetch.hh"
64#include "cpu/exetrace.hh"
65#include "debug/Activity.hh"
66#include "debug/Drain.hh"
67#include "debug/Fetch.hh"
68#include "debug/O3PipeView.hh"
69#include "mem/packet.hh"
70#include "params/DerivO3CPU.hh"
71#include "sim/byteswap.hh"
72#include "sim/core.hh"
73#include "sim/eventq.hh"
74#include "sim/full_system.hh"
75#include "sim/system.hh"
76#include "cpu/o3/isa_specific.hh"
77
78using namespace std;
79
80template<class Impl>
81DefaultFetch<Impl>::DefaultFetch(O3CPU *_cpu, DerivO3CPUParams *params)
82 : cpu(_cpu),
83 decodeToFetchDelay(params->decodeToFetchDelay),
84 renameToFetchDelay(params->renameToFetchDelay),
85 iewToFetchDelay(params->iewToFetchDelay),
86 commitToFetchDelay(params->commitToFetchDelay),
87 fetchWidth(params->fetchWidth),
88 decodeWidth(params->decodeWidth),
89 retryPkt(NULL),
90 retryTid(InvalidThreadID),
91 cacheBlkSize(cpu->cacheLineSize()),
92 fetchBufferSize(params->fetchBufferSize),
93 fetchBufferMask(fetchBufferSize - 1),
94 fetchQueueSize(params->fetchQueueSize),
95 numThreads(params->numThreads),
96 numFetchingThreads(params->smtNumFetchingThreads),
97 finishTranslationEvent(this)
98{
99 if (numThreads > Impl::MaxThreads)
100 fatal("numThreads (%d) is larger than compiled limit (%d),\n"
101 "\tincrease MaxThreads in src/cpu/o3/impl.hh\n",
102 numThreads, static_cast<int>(Impl::MaxThreads));
103 if (fetchWidth > Impl::MaxWidth)
104 fatal("fetchWidth (%d) is larger than compiled limit (%d),\n"
105 "\tincrease MaxWidth in src/cpu/o3/impl.hh\n",
106 fetchWidth, static_cast<int>(Impl::MaxWidth));
107 if (fetchBufferSize > cacheBlkSize)
108 fatal("fetch buffer size (%u bytes) is greater than the cache "
109 "block size (%u bytes)\n", fetchBufferSize, cacheBlkSize);
110 if (cacheBlkSize % fetchBufferSize)
111 fatal("cache block (%u bytes) is not a multiple of the "
112 "fetch buffer (%u bytes)\n", cacheBlkSize, fetchBufferSize);
113
114 std::string policy = params->smtFetchPolicy;
115
116 // Convert string to lowercase
117 std::transform(policy.begin(), policy.end(), policy.begin(),
118 (int(*)(int)) tolower);
119
120 // Figure out fetch policy
121 if (policy == "singlethread") {
122 fetchPolicy = SingleThread;
123 if (numThreads > 1)
124 panic("Invalid Fetch Policy for a SMT workload.");
125 } else if (policy == "roundrobin") {
126 fetchPolicy = RoundRobin;
127 DPRINTF(Fetch, "Fetch policy set to Round Robin\n");
128 } else if (policy == "branch") {
129 fetchPolicy = Branch;
130 DPRINTF(Fetch, "Fetch policy set to Branch Count\n");
131 } else if (policy == "iqcount") {
132 fetchPolicy = IQ;
133 DPRINTF(Fetch, "Fetch policy set to IQ count\n");
134 } else if (policy == "lsqcount") {
135 fetchPolicy = LSQ;
136 DPRINTF(Fetch, "Fetch policy set to LSQ count\n");
137 } else {
138 fatal("Invalid Fetch Policy. Options Are: {SingleThread,"
139 " RoundRobin,LSQcount,IQcount}\n");
140 }
141
142 // Get the size of an instruction.
143 instSize = sizeof(TheISA::MachInst);
144
145 for (int i = 0; i < Impl::MaxThreads; i++) {
146 decoder[i] = NULL;
147 fetchBuffer[i] = NULL;
148 fetchBufferPC[i] = 0;
149 fetchBufferValid[i] = false;
150 }
151
152 branchPred = params->branchPred;
153
154 for (ThreadID tid = 0; tid < numThreads; tid++) {
155 decoder[tid] = new TheISA::Decoder(params->isa[tid]);
156 // Create space to buffer the cache line data,
157 // which may not hold the entire cache line.
158 fetchBuffer[tid] = new uint8_t[fetchBufferSize];
159 }
160}
161
162template <class Impl>
163std::string
164DefaultFetch<Impl>::name() const
165{
166 return cpu->name() + ".fetch";
167}
168
169template <class Impl>
170void
171DefaultFetch<Impl>::regProbePoints()
172{
173 ppFetch = new ProbePointArg<DynInstPtr>(cpu->getProbeManager(), "Fetch");
174 ppFetchRequestSent = new ProbePointArg<RequestPtr>(cpu->getProbeManager(),
175 "FetchRequest");
176
177}
178
179template <class Impl>
180void
181DefaultFetch<Impl>::regStats()
182{
183 icacheStallCycles
184 .name(name() + ".icacheStallCycles")
185 .desc("Number of cycles fetch is stalled on an Icache miss")
186 .prereq(icacheStallCycles);
187
188 fetchedInsts
189 .name(name() + ".Insts")
190 .desc("Number of instructions fetch has processed")
191 .prereq(fetchedInsts);
192
193 fetchedBranches
194 .name(name() + ".Branches")
195 .desc("Number of branches that fetch encountered")
196 .prereq(fetchedBranches);
197
198 predictedBranches
199 .name(name() + ".predictedBranches")
200 .desc("Number of branches that fetch has predicted taken")
201 .prereq(predictedBranches);
202
203 fetchCycles
204 .name(name() + ".Cycles")
205 .desc("Number of cycles fetch has run and was not squashing or"
206 " blocked")
207 .prereq(fetchCycles);
208
209 fetchSquashCycles
210 .name(name() + ".SquashCycles")
211 .desc("Number of cycles fetch has spent squashing")
212 .prereq(fetchSquashCycles);
213
214 fetchTlbCycles
215 .name(name() + ".TlbCycles")
216 .desc("Number of cycles fetch has spent waiting for tlb")
217 .prereq(fetchTlbCycles);
218
219 fetchIdleCycles
220 .name(name() + ".IdleCycles")
221 .desc("Number of cycles fetch was idle")
222 .prereq(fetchIdleCycles);
223
224 fetchBlockedCycles
225 .name(name() + ".BlockedCycles")
226 .desc("Number of cycles fetch has spent blocked")
227 .prereq(fetchBlockedCycles);
228
229 fetchedCacheLines
230 .name(name() + ".CacheLines")
231 .desc("Number of cache lines fetched")
232 .prereq(fetchedCacheLines);
233
234 fetchMiscStallCycles
235 .name(name() + ".MiscStallCycles")
236 .desc("Number of cycles fetch has spent waiting on interrupts, or "
237 "bad addresses, or out of MSHRs")
238 .prereq(fetchMiscStallCycles);
239
240 fetchPendingDrainCycles
241 .name(name() + ".PendingDrainCycles")
242 .desc("Number of cycles fetch has spent waiting on pipes to drain")
243 .prereq(fetchPendingDrainCycles);
244
245 fetchNoActiveThreadStallCycles
246 .name(name() + ".NoActiveThreadStallCycles")
247 .desc("Number of stall cycles due to no active thread to fetch from")
248 .prereq(fetchNoActiveThreadStallCycles);
249
250 fetchPendingTrapStallCycles
251 .name(name() + ".PendingTrapStallCycles")
252 .desc("Number of stall cycles due to pending traps")
253 .prereq(fetchPendingTrapStallCycles);
254
255 fetchPendingQuiesceStallCycles
256 .name(name() + ".PendingQuiesceStallCycles")
257 .desc("Number of stall cycles due to pending quiesce instructions")
258 .prereq(fetchPendingQuiesceStallCycles);
259
260 fetchIcacheWaitRetryStallCycles
261 .name(name() + ".IcacheWaitRetryStallCycles")
262 .desc("Number of stall cycles due to full MSHR")
263 .prereq(fetchIcacheWaitRetryStallCycles);
264
265 fetchIcacheSquashes
266 .name(name() + ".IcacheSquashes")
267 .desc("Number of outstanding Icache misses that were squashed")
268 .prereq(fetchIcacheSquashes);
269
270 fetchTlbSquashes
271 .name(name() + ".ItlbSquashes")
272 .desc("Number of outstanding ITLB misses that were squashed")
273 .prereq(fetchTlbSquashes);
274
275 fetchNisnDist
276 .init(/* base value */ 0,
277 /* last value */ fetchWidth,
278 /* bucket size */ 1)
279 .name(name() + ".rateDist")
280 .desc("Number of instructions fetched each cycle (Total)")
281 .flags(Stats::pdf);
282
283 idleRate
284 .name(name() + ".idleRate")
285 .desc("Percent of cycles fetch was idle")
286 .prereq(idleRate);
287 idleRate = fetchIdleCycles * 100 / cpu->numCycles;
288
289 branchRate
290 .name(name() + ".branchRate")
291 .desc("Number of branch fetches per cycle")
292 .flags(Stats::total);
293 branchRate = fetchedBranches / cpu->numCycles;
294
295 fetchRate
296 .name(name() + ".rate")
297 .desc("Number of inst fetches per cycle")
298 .flags(Stats::total);
299 fetchRate = fetchedInsts / cpu->numCycles;
300}
301
302template<class Impl>
303void
304DefaultFetch<Impl>::setTimeBuffer(TimeBuffer<TimeStruct> *time_buffer)
305{
306 timeBuffer = time_buffer;
307
308 // Create wires to get information from proper places in time buffer.
309 fromDecode = timeBuffer->getWire(-decodeToFetchDelay);
310 fromRename = timeBuffer->getWire(-renameToFetchDelay);
311 fromIEW = timeBuffer->getWire(-iewToFetchDelay);
312 fromCommit = timeBuffer->getWire(-commitToFetchDelay);
313}
314
315template<class Impl>
316void
317DefaultFetch<Impl>::setActiveThreads(std::list<ThreadID> *at_ptr)
318{
319 activeThreads = at_ptr;
320}
321
322template<class Impl>
323void
324DefaultFetch<Impl>::setFetchQueue(TimeBuffer<FetchStruct> *ftb_ptr)
325{
326 // Create wire to write information to proper place in fetch time buf.
327 toDecode = ftb_ptr->getWire(0);
328}
329
330template<class Impl>
331void
332DefaultFetch<Impl>::startupStage()
333{
334 assert(priorityList.empty());
335 resetStage();
336
337 // Fetch needs to start fetching instructions at the very beginning,
338 // so it must start up in active state.
339 switchToActive();
340}
341
342template<class Impl>
343void
344DefaultFetch<Impl>::resetStage()
345{
346 numInst = 0;
347 interruptPending = false;
348 cacheBlocked = false;
349
350 priorityList.clear();
351
352 // Setup PC and nextPC with initial state.
353 for (ThreadID tid = 0; tid < numThreads; ++tid) {
354 fetchStatus[tid] = Running;
355 pc[tid] = cpu->pcState(tid);
356 fetchOffset[tid] = 0;
357 macroop[tid] = NULL;
358
359 delayedCommit[tid] = false;
360 memReq[tid] = NULL;
361
362 stalls[tid].decode = false;
363 stalls[tid].drain = false;
364
365 fetchBufferPC[tid] = 0;
366 fetchBufferValid[tid] = false;
367
368 fetchQueue[tid].clear();
369
370 priorityList.push_back(tid);
371 }
372
373 wroteToTimeBuffer = false;
374 _status = Inactive;
375}
376
377template<class Impl>
378void
379DefaultFetch<Impl>::processCacheCompletion(PacketPtr pkt)
380{
381 ThreadID tid = cpu->contextToThread(pkt->req->contextId());
382
383 DPRINTF(Fetch, "[tid:%u] Waking up from cache miss.\n", tid);
384 assert(!cpu->switchedOut());
385
386 // Only change the status if it's still waiting on the icache access
387 // to return.
388 if (fetchStatus[tid] != IcacheWaitResponse ||
389 pkt->req != memReq[tid]) {
390 ++fetchIcacheSquashes;
391 delete pkt->req;
392 delete pkt;
393 return;
394 }
395
396 memcpy(fetchBuffer[tid], pkt->getConstPtr<uint8_t>(), fetchBufferSize);
397 fetchBufferValid[tid] = true;
398
399 // Wake up the CPU (if it went to sleep and was waiting on
400 // this completion event).
401 cpu->wakeCPU();
402
403 DPRINTF(Activity, "[tid:%u] Activating fetch due to cache completion\n",
404 tid);
405
406 switchToActive();
407
408 // Only switch to IcacheAccessComplete if we're not stalled as well.
409 if (checkStall(tid)) {
410 fetchStatus[tid] = Blocked;
411 } else {
412 fetchStatus[tid] = IcacheAccessComplete;
413 }
414
415 pkt->req->setAccessLatency();
416 cpu->ppInstAccessComplete->notify(pkt);
417 // Reset the mem req to NULL.
418 delete pkt->req;
419 delete pkt;
420 memReq[tid] = NULL;
421}
422
423template <class Impl>
424void
425DefaultFetch<Impl>::drainResume()
426{
427 for (ThreadID i = 0; i < numThreads; ++i) {
428 stalls[i].decode = false;
429 stalls[i].drain = false;
430 }
431}
432
433template <class Impl>
434void
435DefaultFetch<Impl>::drainSanityCheck() const
436{
437 assert(isDrained());
438 assert(retryPkt == NULL);
439 assert(retryTid == InvalidThreadID);
440 assert(!cacheBlocked);
441 assert(!interruptPending);
442
443 for (ThreadID i = 0; i < numThreads; ++i) {
444 assert(!memReq[i]);
445 assert(fetchStatus[i] == Idle || stalls[i].drain);
446 }
447
448 branchPred->drainSanityCheck();
449}
450
451template <class Impl>
452bool
453DefaultFetch<Impl>::isDrained() const
454{
455 /* Make sure that threads are either idle of that the commit stage
456 * has signaled that draining has completed by setting the drain
457 * stall flag. This effectively forces the pipeline to be disabled
458 * until the whole system is drained (simulation may continue to
459 * drain other components).
460 */
461 for (ThreadID i = 0; i < numThreads; ++i) {
462 // Verify fetch queues are drained
463 if (!fetchQueue[i].empty())
464 return false;
465
466 // Return false if not idle or drain stalled
467 if (fetchStatus[i] != Idle) {
468 if (fetchStatus[i] == Blocked && stalls[i].drain)
469 continue;
470 else
471 return false;
472 }
473 }
474
475 /* The pipeline might start up again in the middle of the drain
476 * cycle if the finish translation event is scheduled, so make
477 * sure that's not the case.
478 */
479 return !finishTranslationEvent.scheduled();
480}
481
482template <class Impl>
483void
484DefaultFetch<Impl>::takeOverFrom()
485{
486 assert(cpu->getInstPort().isConnected());
487 resetStage();
488
489}
490
491template <class Impl>
492void
493DefaultFetch<Impl>::drainStall(ThreadID tid)
494{
495 assert(cpu->isDraining());
496 assert(!stalls[tid].drain);
497 DPRINTF(Drain, "%i: Thread drained.\n", tid);
498 stalls[tid].drain = true;
499}
500
501template <class Impl>
502void
503DefaultFetch<Impl>::wakeFromQuiesce()
504{
505 DPRINTF(Fetch, "Waking up from quiesce\n");
506 // Hopefully this is safe
507 // @todo: Allow other threads to wake from quiesce.
508 fetchStatus[0] = Running;
509}
510
511template <class Impl>
512inline void
513DefaultFetch<Impl>::switchToActive()
514{
515 if (_status == Inactive) {
516 DPRINTF(Activity, "Activating stage.\n");
517
518 cpu->activateStage(O3CPU::FetchIdx);
519
520 _status = Active;
521 }
522}
523
524template <class Impl>
525inline void
526DefaultFetch<Impl>::switchToInactive()
527{
528 if (_status == Active) {
529 DPRINTF(Activity, "Deactivating stage.\n");
530
531 cpu->deactivateStage(O3CPU::FetchIdx);
532
533 _status = Inactive;
534 }
535}
536
537template <class Impl>
538void
539DefaultFetch<Impl>::deactivateThread(ThreadID tid)
540{
541 // Update priority list
542 auto thread_it = std::find(priorityList.begin(), priorityList.end(), tid);
543 if (thread_it != priorityList.end()) {
544 priorityList.erase(thread_it);
545 }
546}
547
548template <class Impl>
549bool
550DefaultFetch<Impl>::lookupAndUpdateNextPC(
551 DynInstPtr &inst, TheISA::PCState &nextPC)
552{
553 // Do branch prediction check here.
554 // A bit of a misnomer...next_PC is actually the current PC until
555 // this function updates it.
556 bool predict_taken;
557
558 if (!inst->isControl()) {
559 TheISA::advancePC(nextPC, inst->staticInst);
560 inst->setPredTarg(nextPC);
561 inst->setPredTaken(false);
562 return false;
563 }
564
565 ThreadID tid = inst->threadNumber;
566 predict_taken = branchPred->predict(inst->staticInst, inst->seqNum,
567 nextPC, tid);
568
569 if (predict_taken) {
570 DPRINTF(Fetch, "[tid:%i]: [sn:%i]: Branch predicted to be taken to %s.\n",
571 tid, inst->seqNum, nextPC);
572 } else {
573 DPRINTF(Fetch, "[tid:%i]: [sn:%i]:Branch predicted to be not taken.\n",
574 tid, inst->seqNum);
575 }
576
577 DPRINTF(Fetch, "[tid:%i]: [sn:%i] Branch predicted to go to %s.\n",
578 tid, inst->seqNum, nextPC);
579 inst->setPredTarg(nextPC);
580 inst->setPredTaken(predict_taken);
581
582 ++fetchedBranches;
583
584 if (predict_taken) {
585 ++predictedBranches;
586 }
587
588 return predict_taken;
589}
590
591template <class Impl>
592bool
593DefaultFetch<Impl>::fetchCacheLine(Addr vaddr, ThreadID tid, Addr pc)
594{
595 Fault fault = NoFault;
596
597 assert(!cpu->switchedOut());
598
599 // @todo: not sure if these should block translation.
600 //AlphaDep
601 if (cacheBlocked) {
602 DPRINTF(Fetch, "[tid:%i] Can't fetch cache line, cache blocked\n",
603 tid);
604 return false;
605 } else if (checkInterrupt(pc) && !delayedCommit[tid]) {
606 // Hold off fetch from getting new instructions when:
607 // Cache is blocked, or
608 // while an interrupt is pending and we're not in PAL mode, or
609 // fetch is switched out.
610 DPRINTF(Fetch, "[tid:%i] Can't fetch cache line, interrupt pending\n",
611 tid);
612 return false;
613 }
614
615 // Align the fetch address to the start of a fetch buffer segment.
616 Addr fetchBufferBlockPC = fetchBufferAlignPC(vaddr);
617
618 DPRINTF(Fetch, "[tid:%i] Fetching cache line %#x for addr %#x\n",
619 tid, fetchBufferBlockPC, vaddr);
620
621 // Setup the memReq to do a read of the first instruction's address.
622 // Set the appropriate read size and flags as well.
623 // Build request here.
624 RequestPtr mem_req =
625 new Request(tid, fetchBufferBlockPC, fetchBufferSize,
626 Request::INST_FETCH, cpu->instMasterId(), pc,
627 cpu->thread[tid]->contextId());
628
629 mem_req->taskId(cpu->taskId());
630
631 memReq[tid] = mem_req;
632
633 // Initiate translation of the icache block
634 fetchStatus[tid] = ItlbWait;
635 FetchTranslation *trans = new FetchTranslation(this);
636 cpu->itb->translateTiming(mem_req, cpu->thread[tid]->getTC(),
637 trans, BaseTLB::Execute);
638 return true;
639}
640
641template <class Impl>
642void
643DefaultFetch<Impl>::finishTranslation(const Fault &fault, RequestPtr mem_req)
644{
645 ThreadID tid = cpu->contextToThread(mem_req->contextId());
646 Addr fetchBufferBlockPC = mem_req->getVaddr();
647
648 assert(!cpu->switchedOut());
649
650 // Wake up CPU if it was idle
651 cpu->wakeCPU();
652
653 if (fetchStatus[tid] != ItlbWait || mem_req != memReq[tid] ||
654 mem_req->getVaddr() != memReq[tid]->getVaddr()) {
655 DPRINTF(Fetch, "[tid:%i] Ignoring itlb completed after squash\n",
656 tid);
657 ++fetchTlbSquashes;
658 delete mem_req;
659 return;
660 }
661
662
663 // If translation was successful, attempt to read the icache block.
664 if (fault == NoFault) {
665 // Check that we're not going off into random memory
666 // If we have, just wait around for commit to squash something and put
667 // us on the right track
668 if (!cpu->system->isMemAddr(mem_req->getPaddr())) {
669 warn("Address %#x is outside of physical memory, stopping fetch\n",
670 mem_req->getPaddr());
671 fetchStatus[tid] = NoGoodAddr;
672 delete mem_req;
673 memReq[tid] = NULL;
674 return;
675 }
676
677 // Build packet here.
678 PacketPtr data_pkt = new Packet(mem_req, MemCmd::ReadReq);
679 data_pkt->dataDynamic(new uint8_t[fetchBufferSize]);
680
681 fetchBufferPC[tid] = fetchBufferBlockPC;
682 fetchBufferValid[tid] = false;
683 DPRINTF(Fetch, "Fetch: Doing instruction read.\n");
684
685 fetchedCacheLines++;
686
687 // Access the cache.
688 if (!cpu->getInstPort().sendTimingReq(data_pkt)) {
689 assert(retryPkt == NULL);
690 assert(retryTid == InvalidThreadID);
691 DPRINTF(Fetch, "[tid:%i] Out of MSHRs!\n", tid);
692
693 fetchStatus[tid] = IcacheWaitRetry;
694 retryPkt = data_pkt;
695 retryTid = tid;
696 cacheBlocked = true;
697 } else {
698 DPRINTF(Fetch, "[tid:%i]: Doing Icache access.\n", tid);
699 DPRINTF(Activity, "[tid:%i]: Activity: Waiting on I-cache "
700 "response.\n", tid);
701 lastIcacheStall[tid] = curTick();
702 fetchStatus[tid] = IcacheWaitResponse;
703 // Notify Fetch Request probe when a packet containing a fetch
704 // request is successfully sent
705 ppFetchRequestSent->notify(mem_req);
706 }
707 } else {
708 // Don't send an instruction to decode if we can't handle it.
709 if (!(numInst < fetchWidth) || !(fetchQueue[tid].size() < fetchQueueSize)) {
710 assert(!finishTranslationEvent.scheduled());
711 finishTranslationEvent.setFault(fault);
712 finishTranslationEvent.setReq(mem_req);
713 cpu->schedule(finishTranslationEvent,
714 cpu->clockEdge(Cycles(1)));
715 return;
716 }
717 DPRINTF(Fetch, "[tid:%i] Got back req with addr %#x but expected %#x\n",
718 tid, mem_req->getVaddr(), memReq[tid]->getVaddr());
719 // Translation faulted, icache request won't be sent.
720 delete mem_req;
721 memReq[tid] = NULL;
722
723 // Send the fault to commit. This thread will not do anything
724 // until commit handles the fault. The only other way it can
725 // wake up is if a squash comes along and changes the PC.
726 TheISA::PCState fetchPC = pc[tid];
727
728 DPRINTF(Fetch, "[tid:%i]: Translation faulted, building noop.\n", tid);
729 // We will use a nop in ordier to carry the fault.
730 DynInstPtr instruction = buildInst(tid, StaticInst::nopStaticInstPtr,
731 NULL, fetchPC, fetchPC, false);
| 1/*
2 * Copyright (c) 2010-2014 ARM Limited
3 * Copyright (c) 2012-2013 AMD
4 * All rights reserved.
5 *
6 * The license below extends only to copyright in the software and shall
7 * not be construed as granting a license to any other intellectual
8 * property including but not limited to intellectual property relating
9 * to a hardware implementation of the functionality of the software
10 * licensed hereunder. You may use the software subject to the license
11 * terms below provided that you ensure that this notice is replicated
12 * unmodified and in its entirety in all distributions of the software,
13 * modified or unmodified, in source code or in binary form.
14 *
15 * Copyright (c) 2004-2006 The Regents of The University of Michigan
16 * All rights reserved.
17 *
18 * Redistribution and use in source and binary forms, with or without
19 * modification, are permitted provided that the following conditions are
20 * met: redistributions of source code must retain the above copyright
21 * notice, this list of conditions and the following disclaimer;
22 * redistributions in binary form must reproduce the above copyright
23 * notice, this list of conditions and the following disclaimer in the
24 * documentation and/or other materials provided with the distribution;
25 * neither the name of the copyright holders nor the names of its
26 * contributors may be used to endorse or promote products derived from
27 * this software without specific prior written permission.
28 *
29 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
30 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
31 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
32 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
33 * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
34 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
35 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
36 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
37 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
38 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
39 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
40 *
41 * Authors: Kevin Lim
42 * Korey Sewell
43 */
44
45#ifndef __CPU_O3_FETCH_IMPL_HH__
46#define __CPU_O3_FETCH_IMPL_HH__
47
48#include <algorithm>
49#include <cstring>
50#include <list>
51#include <map>
52#include <queue>
53
54#include "arch/generic/tlb.hh"
55#include "arch/isa_traits.hh"
56#include "arch/utility.hh"
57#include "arch/vtophys.hh"
58#include "base/random.hh"
59#include "base/types.hh"
60#include "config/the_isa.hh"
61#include "cpu/base.hh"
62//#include "cpu/checker/cpu.hh"
63#include "cpu/o3/fetch.hh"
64#include "cpu/exetrace.hh"
65#include "debug/Activity.hh"
66#include "debug/Drain.hh"
67#include "debug/Fetch.hh"
68#include "debug/O3PipeView.hh"
69#include "mem/packet.hh"
70#include "params/DerivO3CPU.hh"
71#include "sim/byteswap.hh"
72#include "sim/core.hh"
73#include "sim/eventq.hh"
74#include "sim/full_system.hh"
75#include "sim/system.hh"
76#include "cpu/o3/isa_specific.hh"
77
78using namespace std;
79
80template<class Impl>
81DefaultFetch<Impl>::DefaultFetch(O3CPU *_cpu, DerivO3CPUParams *params)
82 : cpu(_cpu),
83 decodeToFetchDelay(params->decodeToFetchDelay),
84 renameToFetchDelay(params->renameToFetchDelay),
85 iewToFetchDelay(params->iewToFetchDelay),
86 commitToFetchDelay(params->commitToFetchDelay),
87 fetchWidth(params->fetchWidth),
88 decodeWidth(params->decodeWidth),
89 retryPkt(NULL),
90 retryTid(InvalidThreadID),
91 cacheBlkSize(cpu->cacheLineSize()),
92 fetchBufferSize(params->fetchBufferSize),
93 fetchBufferMask(fetchBufferSize - 1),
94 fetchQueueSize(params->fetchQueueSize),
95 numThreads(params->numThreads),
96 numFetchingThreads(params->smtNumFetchingThreads),
97 finishTranslationEvent(this)
98{
99 if (numThreads > Impl::MaxThreads)
100 fatal("numThreads (%d) is larger than compiled limit (%d),\n"
101 "\tincrease MaxThreads in src/cpu/o3/impl.hh\n",
102 numThreads, static_cast<int>(Impl::MaxThreads));
103 if (fetchWidth > Impl::MaxWidth)
104 fatal("fetchWidth (%d) is larger than compiled limit (%d),\n"
105 "\tincrease MaxWidth in src/cpu/o3/impl.hh\n",
106 fetchWidth, static_cast<int>(Impl::MaxWidth));
107 if (fetchBufferSize > cacheBlkSize)
108 fatal("fetch buffer size (%u bytes) is greater than the cache "
109 "block size (%u bytes)\n", fetchBufferSize, cacheBlkSize);
110 if (cacheBlkSize % fetchBufferSize)
111 fatal("cache block (%u bytes) is not a multiple of the "
112 "fetch buffer (%u bytes)\n", cacheBlkSize, fetchBufferSize);
113
114 std::string policy = params->smtFetchPolicy;
115
116 // Convert string to lowercase
117 std::transform(policy.begin(), policy.end(), policy.begin(),
118 (int(*)(int)) tolower);
119
120 // Figure out fetch policy
121 if (policy == "singlethread") {
122 fetchPolicy = SingleThread;
123 if (numThreads > 1)
124 panic("Invalid Fetch Policy for a SMT workload.");
125 } else if (policy == "roundrobin") {
126 fetchPolicy = RoundRobin;
127 DPRINTF(Fetch, "Fetch policy set to Round Robin\n");
128 } else if (policy == "branch") {
129 fetchPolicy = Branch;
130 DPRINTF(Fetch, "Fetch policy set to Branch Count\n");
131 } else if (policy == "iqcount") {
132 fetchPolicy = IQ;
133 DPRINTF(Fetch, "Fetch policy set to IQ count\n");
134 } else if (policy == "lsqcount") {
135 fetchPolicy = LSQ;
136 DPRINTF(Fetch, "Fetch policy set to LSQ count\n");
137 } else {
138 fatal("Invalid Fetch Policy. Options Are: {SingleThread,"
139 " RoundRobin,LSQcount,IQcount}\n");
140 }
141
142 // Get the size of an instruction.
143 instSize = sizeof(TheISA::MachInst);
144
145 for (int i = 0; i < Impl::MaxThreads; i++) {
146 decoder[i] = NULL;
147 fetchBuffer[i] = NULL;
148 fetchBufferPC[i] = 0;
149 fetchBufferValid[i] = false;
150 }
151
152 branchPred = params->branchPred;
153
154 for (ThreadID tid = 0; tid < numThreads; tid++) {
155 decoder[tid] = new TheISA::Decoder(params->isa[tid]);
156 // Create space to buffer the cache line data,
157 // which may not hold the entire cache line.
158 fetchBuffer[tid] = new uint8_t[fetchBufferSize];
159 }
160}
161
162template <class Impl>
163std::string
164DefaultFetch<Impl>::name() const
165{
166 return cpu->name() + ".fetch";
167}
168
169template <class Impl>
170void
171DefaultFetch<Impl>::regProbePoints()
172{
173 ppFetch = new ProbePointArg<DynInstPtr>(cpu->getProbeManager(), "Fetch");
174 ppFetchRequestSent = new ProbePointArg<RequestPtr>(cpu->getProbeManager(),
175 "FetchRequest");
176
177}
178
179template <class Impl>
180void
181DefaultFetch<Impl>::regStats()
182{
183 icacheStallCycles
184 .name(name() + ".icacheStallCycles")
185 .desc("Number of cycles fetch is stalled on an Icache miss")
186 .prereq(icacheStallCycles);
187
188 fetchedInsts
189 .name(name() + ".Insts")
190 .desc("Number of instructions fetch has processed")
191 .prereq(fetchedInsts);
192
193 fetchedBranches
194 .name(name() + ".Branches")
195 .desc("Number of branches that fetch encountered")
196 .prereq(fetchedBranches);
197
198 predictedBranches
199 .name(name() + ".predictedBranches")
200 .desc("Number of branches that fetch has predicted taken")
201 .prereq(predictedBranches);
202
203 fetchCycles
204 .name(name() + ".Cycles")
205 .desc("Number of cycles fetch has run and was not squashing or"
206 " blocked")
207 .prereq(fetchCycles);
208
209 fetchSquashCycles
210 .name(name() + ".SquashCycles")
211 .desc("Number of cycles fetch has spent squashing")
212 .prereq(fetchSquashCycles);
213
214 fetchTlbCycles
215 .name(name() + ".TlbCycles")
216 .desc("Number of cycles fetch has spent waiting for tlb")
217 .prereq(fetchTlbCycles);
218
219 fetchIdleCycles
220 .name(name() + ".IdleCycles")
221 .desc("Number of cycles fetch was idle")
222 .prereq(fetchIdleCycles);
223
224 fetchBlockedCycles
225 .name(name() + ".BlockedCycles")
226 .desc("Number of cycles fetch has spent blocked")
227 .prereq(fetchBlockedCycles);
228
229 fetchedCacheLines
230 .name(name() + ".CacheLines")
231 .desc("Number of cache lines fetched")
232 .prereq(fetchedCacheLines);
233
234 fetchMiscStallCycles
235 .name(name() + ".MiscStallCycles")
236 .desc("Number of cycles fetch has spent waiting on interrupts, or "
237 "bad addresses, or out of MSHRs")
238 .prereq(fetchMiscStallCycles);
239
240 fetchPendingDrainCycles
241 .name(name() + ".PendingDrainCycles")
242 .desc("Number of cycles fetch has spent waiting on pipes to drain")
243 .prereq(fetchPendingDrainCycles);
244
245 fetchNoActiveThreadStallCycles
246 .name(name() + ".NoActiveThreadStallCycles")
247 .desc("Number of stall cycles due to no active thread to fetch from")
248 .prereq(fetchNoActiveThreadStallCycles);
249
250 fetchPendingTrapStallCycles
251 .name(name() + ".PendingTrapStallCycles")
252 .desc("Number of stall cycles due to pending traps")
253 .prereq(fetchPendingTrapStallCycles);
254
255 fetchPendingQuiesceStallCycles
256 .name(name() + ".PendingQuiesceStallCycles")
257 .desc("Number of stall cycles due to pending quiesce instructions")
258 .prereq(fetchPendingQuiesceStallCycles);
259
260 fetchIcacheWaitRetryStallCycles
261 .name(name() + ".IcacheWaitRetryStallCycles")
262 .desc("Number of stall cycles due to full MSHR")
263 .prereq(fetchIcacheWaitRetryStallCycles);
264
265 fetchIcacheSquashes
266 .name(name() + ".IcacheSquashes")
267 .desc("Number of outstanding Icache misses that were squashed")
268 .prereq(fetchIcacheSquashes);
269
270 fetchTlbSquashes
271 .name(name() + ".ItlbSquashes")
272 .desc("Number of outstanding ITLB misses that were squashed")
273 .prereq(fetchTlbSquashes);
274
275 fetchNisnDist
276 .init(/* base value */ 0,
277 /* last value */ fetchWidth,
278 /* bucket size */ 1)
279 .name(name() + ".rateDist")
280 .desc("Number of instructions fetched each cycle (Total)")
281 .flags(Stats::pdf);
282
283 idleRate
284 .name(name() + ".idleRate")
285 .desc("Percent of cycles fetch was idle")
286 .prereq(idleRate);
287 idleRate = fetchIdleCycles * 100 / cpu->numCycles;
288
289 branchRate
290 .name(name() + ".branchRate")
291 .desc("Number of branch fetches per cycle")
292 .flags(Stats::total);
293 branchRate = fetchedBranches / cpu->numCycles;
294
295 fetchRate
296 .name(name() + ".rate")
297 .desc("Number of inst fetches per cycle")
298 .flags(Stats::total);
299 fetchRate = fetchedInsts / cpu->numCycles;
300}
301
302template<class Impl>
303void
304DefaultFetch<Impl>::setTimeBuffer(TimeBuffer<TimeStruct> *time_buffer)
305{
306 timeBuffer = time_buffer;
307
308 // Create wires to get information from proper places in time buffer.
309 fromDecode = timeBuffer->getWire(-decodeToFetchDelay);
310 fromRename = timeBuffer->getWire(-renameToFetchDelay);
311 fromIEW = timeBuffer->getWire(-iewToFetchDelay);
312 fromCommit = timeBuffer->getWire(-commitToFetchDelay);
313}
314
315template<class Impl>
316void
317DefaultFetch<Impl>::setActiveThreads(std::list<ThreadID> *at_ptr)
318{
319 activeThreads = at_ptr;
320}
321
322template<class Impl>
323void
324DefaultFetch<Impl>::setFetchQueue(TimeBuffer<FetchStruct> *ftb_ptr)
325{
326 // Create wire to write information to proper place in fetch time buf.
327 toDecode = ftb_ptr->getWire(0);
328}
329
330template<class Impl>
331void
332DefaultFetch<Impl>::startupStage()
333{
334 assert(priorityList.empty());
335 resetStage();
336
337 // Fetch needs to start fetching instructions at the very beginning,
338 // so it must start up in active state.
339 switchToActive();
340}
341
342template<class Impl>
343void
344DefaultFetch<Impl>::resetStage()
345{
346 numInst = 0;
347 interruptPending = false;
348 cacheBlocked = false;
349
350 priorityList.clear();
351
352 // Setup PC and nextPC with initial state.
353 for (ThreadID tid = 0; tid < numThreads; ++tid) {
354 fetchStatus[tid] = Running;
355 pc[tid] = cpu->pcState(tid);
356 fetchOffset[tid] = 0;
357 macroop[tid] = NULL;
358
359 delayedCommit[tid] = false;
360 memReq[tid] = NULL;
361
362 stalls[tid].decode = false;
363 stalls[tid].drain = false;
364
365 fetchBufferPC[tid] = 0;
366 fetchBufferValid[tid] = false;
367
368 fetchQueue[tid].clear();
369
370 priorityList.push_back(tid);
371 }
372
373 wroteToTimeBuffer = false;
374 _status = Inactive;
375}
376
377template<class Impl>
378void
379DefaultFetch<Impl>::processCacheCompletion(PacketPtr pkt)
380{
381 ThreadID tid = cpu->contextToThread(pkt->req->contextId());
382
383 DPRINTF(Fetch, "[tid:%u] Waking up from cache miss.\n", tid);
384 assert(!cpu->switchedOut());
385
386 // Only change the status if it's still waiting on the icache access
387 // to return.
388 if (fetchStatus[tid] != IcacheWaitResponse ||
389 pkt->req != memReq[tid]) {
390 ++fetchIcacheSquashes;
391 delete pkt->req;
392 delete pkt;
393 return;
394 }
395
396 memcpy(fetchBuffer[tid], pkt->getConstPtr<uint8_t>(), fetchBufferSize);
397 fetchBufferValid[tid] = true;
398
399 // Wake up the CPU (if it went to sleep and was waiting on
400 // this completion event).
401 cpu->wakeCPU();
402
403 DPRINTF(Activity, "[tid:%u] Activating fetch due to cache completion\n",
404 tid);
405
406 switchToActive();
407
408 // Only switch to IcacheAccessComplete if we're not stalled as well.
409 if (checkStall(tid)) {
410 fetchStatus[tid] = Blocked;
411 } else {
412 fetchStatus[tid] = IcacheAccessComplete;
413 }
414
415 pkt->req->setAccessLatency();
416 cpu->ppInstAccessComplete->notify(pkt);
417 // Reset the mem req to NULL.
418 delete pkt->req;
419 delete pkt;
420 memReq[tid] = NULL;
421}
422
423template <class Impl>
424void
425DefaultFetch<Impl>::drainResume()
426{
427 for (ThreadID i = 0; i < numThreads; ++i) {
428 stalls[i].decode = false;
429 stalls[i].drain = false;
430 }
431}
432
433template <class Impl>
434void
435DefaultFetch<Impl>::drainSanityCheck() const
436{
437 assert(isDrained());
438 assert(retryPkt == NULL);
439 assert(retryTid == InvalidThreadID);
440 assert(!cacheBlocked);
441 assert(!interruptPending);
442
443 for (ThreadID i = 0; i < numThreads; ++i) {
444 assert(!memReq[i]);
445 assert(fetchStatus[i] == Idle || stalls[i].drain);
446 }
447
448 branchPred->drainSanityCheck();
449}
450
451template <class Impl>
452bool
453DefaultFetch<Impl>::isDrained() const
454{
455 /* Make sure that threads are either idle of that the commit stage
456 * has signaled that draining has completed by setting the drain
457 * stall flag. This effectively forces the pipeline to be disabled
458 * until the whole system is drained (simulation may continue to
459 * drain other components).
460 */
461 for (ThreadID i = 0; i < numThreads; ++i) {
462 // Verify fetch queues are drained
463 if (!fetchQueue[i].empty())
464 return false;
465
466 // Return false if not idle or drain stalled
467 if (fetchStatus[i] != Idle) {
468 if (fetchStatus[i] == Blocked && stalls[i].drain)
469 continue;
470 else
471 return false;
472 }
473 }
474
475 /* The pipeline might start up again in the middle of the drain
476 * cycle if the finish translation event is scheduled, so make
477 * sure that's not the case.
478 */
479 return !finishTranslationEvent.scheduled();
480}
481
482template <class Impl>
483void
484DefaultFetch<Impl>::takeOverFrom()
485{
486 assert(cpu->getInstPort().isConnected());
487 resetStage();
488
489}
490
491template <class Impl>
492void
493DefaultFetch<Impl>::drainStall(ThreadID tid)
494{
495 assert(cpu->isDraining());
496 assert(!stalls[tid].drain);
497 DPRINTF(Drain, "%i: Thread drained.\n", tid);
498 stalls[tid].drain = true;
499}
500
501template <class Impl>
502void
503DefaultFetch<Impl>::wakeFromQuiesce()
504{
505 DPRINTF(Fetch, "Waking up from quiesce\n");
506 // Hopefully this is safe
507 // @todo: Allow other threads to wake from quiesce.
508 fetchStatus[0] = Running;
509}
510
511template <class Impl>
512inline void
513DefaultFetch<Impl>::switchToActive()
514{
515 if (_status == Inactive) {
516 DPRINTF(Activity, "Activating stage.\n");
517
518 cpu->activateStage(O3CPU::FetchIdx);
519
520 _status = Active;
521 }
522}
523
524template <class Impl>
525inline void
526DefaultFetch<Impl>::switchToInactive()
527{
528 if (_status == Active) {
529 DPRINTF(Activity, "Deactivating stage.\n");
530
531 cpu->deactivateStage(O3CPU::FetchIdx);
532
533 _status = Inactive;
534 }
535}
536
537template <class Impl>
538void
539DefaultFetch<Impl>::deactivateThread(ThreadID tid)
540{
541 // Update priority list
542 auto thread_it = std::find(priorityList.begin(), priorityList.end(), tid);
543 if (thread_it != priorityList.end()) {
544 priorityList.erase(thread_it);
545 }
546}
547
548template <class Impl>
549bool
550DefaultFetch<Impl>::lookupAndUpdateNextPC(
551 DynInstPtr &inst, TheISA::PCState &nextPC)
552{
553 // Do branch prediction check here.
554 // A bit of a misnomer...next_PC is actually the current PC until
555 // this function updates it.
556 bool predict_taken;
557
558 if (!inst->isControl()) {
559 TheISA::advancePC(nextPC, inst->staticInst);
560 inst->setPredTarg(nextPC);
561 inst->setPredTaken(false);
562 return false;
563 }
564
565 ThreadID tid = inst->threadNumber;
566 predict_taken = branchPred->predict(inst->staticInst, inst->seqNum,
567 nextPC, tid);
568
569 if (predict_taken) {
570 DPRINTF(Fetch, "[tid:%i]: [sn:%i]: Branch predicted to be taken to %s.\n",
571 tid, inst->seqNum, nextPC);
572 } else {
573 DPRINTF(Fetch, "[tid:%i]: [sn:%i]:Branch predicted to be not taken.\n",
574 tid, inst->seqNum);
575 }
576
577 DPRINTF(Fetch, "[tid:%i]: [sn:%i] Branch predicted to go to %s.\n",
578 tid, inst->seqNum, nextPC);
579 inst->setPredTarg(nextPC);
580 inst->setPredTaken(predict_taken);
581
582 ++fetchedBranches;
583
584 if (predict_taken) {
585 ++predictedBranches;
586 }
587
588 return predict_taken;
589}
590
591template <class Impl>
592bool
593DefaultFetch<Impl>::fetchCacheLine(Addr vaddr, ThreadID tid, Addr pc)
594{
595 Fault fault = NoFault;
596
597 assert(!cpu->switchedOut());
598
599 // @todo: not sure if these should block translation.
600 //AlphaDep
601 if (cacheBlocked) {
602 DPRINTF(Fetch, "[tid:%i] Can't fetch cache line, cache blocked\n",
603 tid);
604 return false;
605 } else if (checkInterrupt(pc) && !delayedCommit[tid]) {
606 // Hold off fetch from getting new instructions when:
607 // Cache is blocked, or
608 // while an interrupt is pending and we're not in PAL mode, or
609 // fetch is switched out.
610 DPRINTF(Fetch, "[tid:%i] Can't fetch cache line, interrupt pending\n",
611 tid);
612 return false;
613 }
614
615 // Align the fetch address to the start of a fetch buffer segment.
616 Addr fetchBufferBlockPC = fetchBufferAlignPC(vaddr);
617
618 DPRINTF(Fetch, "[tid:%i] Fetching cache line %#x for addr %#x\n",
619 tid, fetchBufferBlockPC, vaddr);
620
621 // Setup the memReq to do a read of the first instruction's address.
622 // Set the appropriate read size and flags as well.
623 // Build request here.
624 RequestPtr mem_req =
625 new Request(tid, fetchBufferBlockPC, fetchBufferSize,
626 Request::INST_FETCH, cpu->instMasterId(), pc,
627 cpu->thread[tid]->contextId());
628
629 mem_req->taskId(cpu->taskId());
630
631 memReq[tid] = mem_req;
632
633 // Initiate translation of the icache block
634 fetchStatus[tid] = ItlbWait;
635 FetchTranslation *trans = new FetchTranslation(this);
636 cpu->itb->translateTiming(mem_req, cpu->thread[tid]->getTC(),
637 trans, BaseTLB::Execute);
638 return true;
639}
640
641template <class Impl>
642void
643DefaultFetch<Impl>::finishTranslation(const Fault &fault, RequestPtr mem_req)
644{
645 ThreadID tid = cpu->contextToThread(mem_req->contextId());
646 Addr fetchBufferBlockPC = mem_req->getVaddr();
647
648 assert(!cpu->switchedOut());
649
650 // Wake up CPU if it was idle
651 cpu->wakeCPU();
652
653 if (fetchStatus[tid] != ItlbWait || mem_req != memReq[tid] ||
654 mem_req->getVaddr() != memReq[tid]->getVaddr()) {
655 DPRINTF(Fetch, "[tid:%i] Ignoring itlb completed after squash\n",
656 tid);
657 ++fetchTlbSquashes;
658 delete mem_req;
659 return;
660 }
661
662
663 // If translation was successful, attempt to read the icache block.
664 if (fault == NoFault) {
665 // Check that we're not going off into random memory
666 // If we have, just wait around for commit to squash something and put
667 // us on the right track
668 if (!cpu->system->isMemAddr(mem_req->getPaddr())) {
669 warn("Address %#x is outside of physical memory, stopping fetch\n",
670 mem_req->getPaddr());
671 fetchStatus[tid] = NoGoodAddr;
672 delete mem_req;
673 memReq[tid] = NULL;
674 return;
675 }
676
677 // Build packet here.
678 PacketPtr data_pkt = new Packet(mem_req, MemCmd::ReadReq);
679 data_pkt->dataDynamic(new uint8_t[fetchBufferSize]);
680
681 fetchBufferPC[tid] = fetchBufferBlockPC;
682 fetchBufferValid[tid] = false;
683 DPRINTF(Fetch, "Fetch: Doing instruction read.\n");
684
685 fetchedCacheLines++;
686
687 // Access the cache.
688 if (!cpu->getInstPort().sendTimingReq(data_pkt)) {
689 assert(retryPkt == NULL);
690 assert(retryTid == InvalidThreadID);
691 DPRINTF(Fetch, "[tid:%i] Out of MSHRs!\n", tid);
692
693 fetchStatus[tid] = IcacheWaitRetry;
694 retryPkt = data_pkt;
695 retryTid = tid;
696 cacheBlocked = true;
697 } else {
698 DPRINTF(Fetch, "[tid:%i]: Doing Icache access.\n", tid);
699 DPRINTF(Activity, "[tid:%i]: Activity: Waiting on I-cache "
700 "response.\n", tid);
701 lastIcacheStall[tid] = curTick();
702 fetchStatus[tid] = IcacheWaitResponse;
703 // Notify Fetch Request probe when a packet containing a fetch
704 // request is successfully sent
705 ppFetchRequestSent->notify(mem_req);
706 }
707 } else {
708 // Don't send an instruction to decode if we can't handle it.
709 if (!(numInst < fetchWidth) || !(fetchQueue[tid].size() < fetchQueueSize)) {
710 assert(!finishTranslationEvent.scheduled());
711 finishTranslationEvent.setFault(fault);
712 finishTranslationEvent.setReq(mem_req);
713 cpu->schedule(finishTranslationEvent,
714 cpu->clockEdge(Cycles(1)));
715 return;
716 }
717 DPRINTF(Fetch, "[tid:%i] Got back req with addr %#x but expected %#x\n",
718 tid, mem_req->getVaddr(), memReq[tid]->getVaddr());
719 // Translation faulted, icache request won't be sent.
720 delete mem_req;
721 memReq[tid] = NULL;
722
723 // Send the fault to commit. This thread will not do anything
724 // until commit handles the fault. The only other way it can
725 // wake up is if a squash comes along and changes the PC.
726 TheISA::PCState fetchPC = pc[tid];
727
728 DPRINTF(Fetch, "[tid:%i]: Translation faulted, building noop.\n", tid);
729 // We will use a nop in ordier to carry the fault.
730 DynInstPtr instruction = buildInst(tid, StaticInst::nopStaticInstPtr,
731 NULL, fetchPC, fetchPC, false);
|
732
733 instruction->setPredTarg(fetchPC);
734 instruction->fault = fault;
735 wroteToTimeBuffer = true;
736
737 DPRINTF(Activity, "Activity this cycle.\n");
738 cpu->activityThisCycle();
739
740 fetchStatus[tid] = TrapPending;
741
742 DPRINTF(Fetch, "[tid:%i]: Blocked, need to handle the trap.\n", tid);
743 DPRINTF(Fetch, "[tid:%i]: fault (%s) detected @ PC %s.\n",
744 tid, fault->name(), pc[tid]);
745 }
746 _status = updateFetchStatus();
747}
748
749template <class Impl>
750inline void
751DefaultFetch<Impl>::doSquash(const TheISA::PCState &newPC,
752 const DynInstPtr squashInst, ThreadID tid)
753{
754 DPRINTF(Fetch, "[tid:%i]: Squashing, setting PC to: %s.\n",
755 tid, newPC);
756
757 pc[tid] = newPC;
758 fetchOffset[tid] = 0;
759 if (squashInst && squashInst->pcState().instAddr() == newPC.instAddr())
760 macroop[tid] = squashInst->macroop;
761 else
762 macroop[tid] = NULL;
763 decoder[tid]->reset();
764
765 // Clear the icache miss if it's outstanding.
766 if (fetchStatus[tid] == IcacheWaitResponse) {
767 DPRINTF(Fetch, "[tid:%i]: Squashing outstanding Icache miss.\n",
768 tid);
769 memReq[tid] = NULL;
770 } else if (fetchStatus[tid] == ItlbWait) {
771 DPRINTF(Fetch, "[tid:%i]: Squashing outstanding ITLB miss.\n",
772 tid);
773 memReq[tid] = NULL;
774 }
775
776 // Get rid of the retrying packet if it was from this thread.
777 if (retryTid == tid) {
778 assert(cacheBlocked);
779 if (retryPkt) {
780 delete retryPkt->req;
781 delete retryPkt;
782 }
783 retryPkt = NULL;
784 retryTid = InvalidThreadID;
785 }
786
787 fetchStatus[tid] = Squashing;
788
789 // Empty fetch queue
790 fetchQueue[tid].clear();
791
792 // microops are being squashed, it is not known wheather the
793 // youngest non-squashed microop was marked delayed commit
794 // or not. Setting the flag to true ensures that the
795 // interrupts are not handled when they cannot be, though
796 // some opportunities to handle interrupts may be missed.
797 delayedCommit[tid] = true;
798
799 ++fetchSquashCycles;
800}
801
802template<class Impl>
803void
804DefaultFetch<Impl>::squashFromDecode(const TheISA::PCState &newPC,
805 const DynInstPtr squashInst,
806 const InstSeqNum seq_num, ThreadID tid)
807{
808 DPRINTF(Fetch, "[tid:%i]: Squashing from decode.\n", tid);
809
810 doSquash(newPC, squashInst, tid);
811
812 // Tell the CPU to remove any instructions that are in flight between
813 // fetch and decode.
814 cpu->removeInstsUntil(seq_num, tid);
815}
816
817template<class Impl>
818bool
819DefaultFetch<Impl>::checkStall(ThreadID tid) const
820{
821 bool ret_val = false;
822
823 if (stalls[tid].drain) {
824 assert(cpu->isDraining());
825 DPRINTF(Fetch,"[tid:%i]: Drain stall detected.\n",tid);
826 ret_val = true;
827 }
828
829 return ret_val;
830}
831
832template<class Impl>
833typename DefaultFetch<Impl>::FetchStatus
834DefaultFetch<Impl>::updateFetchStatus()
835{
836 //Check Running
837 list<ThreadID>::iterator threads = activeThreads->begin();
838 list<ThreadID>::iterator end = activeThreads->end();
839
840 while (threads != end) {
841 ThreadID tid = *threads++;
842
843 if (fetchStatus[tid] == Running ||
844 fetchStatus[tid] == Squashing ||
845 fetchStatus[tid] == IcacheAccessComplete) {
846
847 if (_status == Inactive) {
848 DPRINTF(Activity, "[tid:%i]: Activating stage.\n",tid);
849
850 if (fetchStatus[tid] == IcacheAccessComplete) {
851 DPRINTF(Activity, "[tid:%i]: Activating fetch due to cache"
852 "completion\n",tid);
853 }
854
855 cpu->activateStage(O3CPU::FetchIdx);
856 }
857
858 return Active;
859 }
860 }
861
862 // Stage is switching from active to inactive, notify CPU of it.
863 if (_status == Active) {
864 DPRINTF(Activity, "Deactivating stage.\n");
865
866 cpu->deactivateStage(O3CPU::FetchIdx);
867 }
868
869 return Inactive;
870}
871
872template <class Impl>
873void
874DefaultFetch<Impl>::squash(const TheISA::PCState &newPC,
875 const InstSeqNum seq_num, DynInstPtr squashInst,
876 ThreadID tid)
877{
878 DPRINTF(Fetch, "[tid:%u]: Squash from commit.\n", tid);
879
880 doSquash(newPC, squashInst, tid);
881
882 // Tell the CPU to remove any instructions that are not in the ROB.
883 cpu->removeInstsNotInROB(tid);
884}
885
886template <class Impl>
887void
888DefaultFetch<Impl>::tick()
889{
890 list<ThreadID>::iterator threads = activeThreads->begin();
891 list<ThreadID>::iterator end = activeThreads->end();
892 bool status_change = false;
893
894 wroteToTimeBuffer = false;
895
896 for (ThreadID i = 0; i < numThreads; ++i) {
897 issuePipelinedIfetch[i] = false;
898 }
899
900 while (threads != end) {
901 ThreadID tid = *threads++;
902
903 // Check the signals for each thread to determine the proper status
904 // for each thread.
905 bool updated_status = checkSignalsAndUpdate(tid);
906 status_change = status_change || updated_status;
907 }
908
909 DPRINTF(Fetch, "Running stage.\n");
910
911 if (FullSystem) {
912 if (fromCommit->commitInfo[0].interruptPending) {
913 interruptPending = true;
914 }
915
916 if (fromCommit->commitInfo[0].clearInterrupt) {
917 interruptPending = false;
918 }
919 }
920
921 for (threadFetched = 0; threadFetched < numFetchingThreads;
922 threadFetched++) {
923 // Fetch each of the actively fetching threads.
924 fetch(status_change);
925 }
926
927 // Record number of instructions fetched this cycle for distribution.
928 fetchNisnDist.sample(numInst);
929
930 if (status_change) {
931 // Change the fetch stage status if there was a status change.
932 _status = updateFetchStatus();
933 }
934
935 // Issue the next I-cache request if possible.
936 for (ThreadID i = 0; i < numThreads; ++i) {
937 if (issuePipelinedIfetch[i]) {
938 pipelineIcacheAccesses(i);
939 }
940 }
941
942 // Send instructions enqueued into the fetch queue to decode.
943 // Limit rate by fetchWidth. Stall if decode is stalled.
944 unsigned insts_to_decode = 0;
945 unsigned available_insts = 0;
946
947 for (auto tid : *activeThreads) {
948 if (!stalls[tid].decode) {
949 available_insts += fetchQueue[tid].size();
950 }
951 }
952
953 // Pick a random thread to start trying to grab instructions from
954 auto tid_itr = activeThreads->begin();
955 std::advance(tid_itr, random_mt.random<uint8_t>(0, activeThreads->size() - 1));
956
957 while (available_insts != 0 && insts_to_decode < decodeWidth) {
958 ThreadID tid = *tid_itr;
959 if (!stalls[tid].decode && !fetchQueue[tid].empty()) {
960 auto inst = fetchQueue[tid].front();
961 toDecode->insts[toDecode->size++] = inst;
962 DPRINTF(Fetch, "[tid:%i][sn:%i]: Sending instruction to decode from "
963 "fetch queue. Fetch queue size: %i.\n",
964 tid, inst->seqNum, fetchQueue[tid].size());
965
966 wroteToTimeBuffer = true;
967 fetchQueue[tid].pop_front();
968 insts_to_decode++;
969 available_insts--;
970 }
971
972 tid_itr++;
973 // Wrap around if at end of active threads list
974 if (tid_itr == activeThreads->end())
975 tid_itr = activeThreads->begin();
976 }
977
978 // If there was activity this cycle, inform the CPU of it.
979 if (wroteToTimeBuffer) {
980 DPRINTF(Activity, "Activity this cycle.\n");
981 cpu->activityThisCycle();
982 }
983
984 // Reset the number of the instruction we've fetched.
985 numInst = 0;
986}
987
988template <class Impl>
989bool
990DefaultFetch<Impl>::checkSignalsAndUpdate(ThreadID tid)
991{
992 // Update the per thread stall statuses.
993 if (fromDecode->decodeBlock[tid]) {
994 stalls[tid].decode = true;
995 }
996
997 if (fromDecode->decodeUnblock[tid]) {
998 assert(stalls[tid].decode);
999 assert(!fromDecode->decodeBlock[tid]);
1000 stalls[tid].decode = false;
1001 }
1002
1003 // Check squash signals from commit.
1004 if (fromCommit->commitInfo[tid].squash) {
1005
1006 DPRINTF(Fetch, "[tid:%u]: Squashing instructions due to squash "
1007 "from commit.\n",tid);
1008 // In any case, squash.
1009 squash(fromCommit->commitInfo[tid].pc,
1010 fromCommit->commitInfo[tid].doneSeqNum,
1011 fromCommit->commitInfo[tid].squashInst, tid);
1012
1013 // If it was a branch mispredict on a control instruction, update the
1014 // branch predictor with that instruction, otherwise just kill the
1015 // invalid state we generated in after sequence number
1016 if (fromCommit->commitInfo[tid].mispredictInst &&
1017 fromCommit->commitInfo[tid].mispredictInst->isControl()) {
1018 branchPred->squash(fromCommit->commitInfo[tid].doneSeqNum,
1019 fromCommit->commitInfo[tid].pc,
1020 fromCommit->commitInfo[tid].branchTaken,
1021 tid);
1022 } else {
1023 branchPred->squash(fromCommit->commitInfo[tid].doneSeqNum,
1024 tid);
1025 }
1026
1027 return true;
1028 } else if (fromCommit->commitInfo[tid].doneSeqNum) {
1029 // Update the branch predictor if it wasn't a squashed instruction
1030 // that was broadcasted.
1031 branchPred->update(fromCommit->commitInfo[tid].doneSeqNum, tid);
1032 }
1033
1034 // Check squash signals from decode.
1035 if (fromDecode->decodeInfo[tid].squash) {
1036 DPRINTF(Fetch, "[tid:%u]: Squashing instructions due to squash "
1037 "from decode.\n",tid);
1038
1039 // Update the branch predictor.
1040 if (fromDecode->decodeInfo[tid].branchMispredict) {
1041 branchPred->squash(fromDecode->decodeInfo[tid].doneSeqNum,
1042 fromDecode->decodeInfo[tid].nextPC,
1043 fromDecode->decodeInfo[tid].branchTaken,
1044 tid);
1045 } else {
1046 branchPred->squash(fromDecode->decodeInfo[tid].doneSeqNum,
1047 tid);
1048 }
1049
1050 if (fetchStatus[tid] != Squashing) {
1051
1052 DPRINTF(Fetch, "Squashing from decode with PC = %s\n",
1053 fromDecode->decodeInfo[tid].nextPC);
1054 // Squash unless we're already squashing
1055 squashFromDecode(fromDecode->decodeInfo[tid].nextPC,
1056 fromDecode->decodeInfo[tid].squashInst,
1057 fromDecode->decodeInfo[tid].doneSeqNum,
1058 tid);
1059
1060 return true;
1061 }
1062 }
1063
1064 if (checkStall(tid) &&
1065 fetchStatus[tid] != IcacheWaitResponse &&
1066 fetchStatus[tid] != IcacheWaitRetry &&
1067 fetchStatus[tid] != ItlbWait &&
1068 fetchStatus[tid] != QuiescePending) {
1069 DPRINTF(Fetch, "[tid:%i]: Setting to blocked\n",tid);
1070
1071 fetchStatus[tid] = Blocked;
1072
1073 return true;
1074 }
1075
1076 if (fetchStatus[tid] == Blocked ||
1077 fetchStatus[tid] == Squashing) {
1078 // Switch status to running if fetch isn't being told to block or
1079 // squash this cycle.
1080 DPRINTF(Fetch, "[tid:%i]: Done squashing, switching to running.\n",
1081 tid);
1082
1083 fetchStatus[tid] = Running;
1084
1085 return true;
1086 }
1087
1088 // If we've reached this point, we have not gotten any signals that
1089 // cause fetch to change its status. Fetch remains the same as before.
1090 return false;
1091}
1092
1093template<class Impl>
1094typename Impl::DynInstPtr
1095DefaultFetch<Impl>::buildInst(ThreadID tid, StaticInstPtr staticInst,
1096 StaticInstPtr curMacroop, TheISA::PCState thisPC,
1097 TheISA::PCState nextPC, bool trace)
1098{
1099 // Get a sequence number.
1100 InstSeqNum seq = cpu->getAndIncrementInstSeq();
1101
1102 // Create a new DynInst from the instruction fetched.
1103 DynInstPtr instruction =
1104 new DynInst(staticInst, curMacroop, thisPC, nextPC, seq, cpu);
1105 instruction->setTid(tid);
1106
1107 instruction->setASID(tid);
1108
1109 instruction->setThreadState(cpu->thread[tid]);
1110
1111 DPRINTF(Fetch, "[tid:%i]: Instruction PC %#x (%d) created "
1112 "[sn:%lli].\n", tid, thisPC.instAddr(),
1113 thisPC.microPC(), seq);
1114
1115 DPRINTF(Fetch, "[tid:%i]: Instruction is: %s\n", tid,
1116 instruction->staticInst->
1117 disassemble(thisPC.instAddr()));
1118
1119#if TRACING_ON
1120 if (trace) {
1121 instruction->traceData =
1122 cpu->getTracer()->getInstRecord(curTick(), cpu->tcBase(tid),
1123 instruction->staticInst, thisPC, curMacroop);
1124 }
1125#else
1126 instruction->traceData = NULL;
1127#endif
1128
1129 // Add instruction to the CPU's list of instructions.
1130 instruction->setInstListIt(cpu->addInst(instruction));
1131
1132 // Write the instruction to the first slot in the queue
1133 // that heads to decode.
1134 assert(numInst < fetchWidth);
1135 fetchQueue[tid].push_back(instruction);
1136 assert(fetchQueue[tid].size() <= fetchQueueSize);
1137 DPRINTF(Fetch, "[tid:%i]: Fetch queue entry created (%i/%i).\n",
1138 tid, fetchQueue[tid].size(), fetchQueueSize);
1139 //toDecode->insts[toDecode->size++] = instruction;
1140
1141 // Keep track of if we can take an interrupt at this boundary
1142 delayedCommit[tid] = instruction->isDelayedCommit();
1143
1144 return instruction;
1145}
1146
1147template<class Impl>
1148void
1149DefaultFetch<Impl>::fetch(bool &status_change)
1150{
1151 //////////////////////////////////////////
1152 // Start actual fetch
1153 //////////////////////////////////////////
1154 ThreadID tid = getFetchingThread(fetchPolicy);
1155
1156 assert(!cpu->switchedOut());
1157
1158 if (tid == InvalidThreadID) {
1159 // Breaks looping condition in tick()
1160 threadFetched = numFetchingThreads;
1161
1162 if (numThreads == 1) { // @todo Per-thread stats
1163 profileStall(0);
1164 }
1165
1166 return;
1167 }
1168
1169 DPRINTF(Fetch, "Attempting to fetch from [tid:%i]\n", tid);
1170
1171 // The current PC.
1172 TheISA::PCState thisPC = pc[tid];
1173
1174 Addr pcOffset = fetchOffset[tid];
1175 Addr fetchAddr = (thisPC.instAddr() + pcOffset) & BaseCPU::PCMask;
1176
1177 bool inRom = isRomMicroPC(thisPC.microPC());
1178
1179 // If returning from the delay of a cache miss, then update the status
1180 // to running, otherwise do the cache access. Possibly move this up
1181 // to tick() function.
1182 if (fetchStatus[tid] == IcacheAccessComplete) {
1183 DPRINTF(Fetch, "[tid:%i]: Icache miss is complete.\n", tid);
1184
1185 fetchStatus[tid] = Running;
1186 status_change = true;
1187 } else if (fetchStatus[tid] == Running) {
1188 // Align the fetch PC so its at the start of a fetch buffer segment.
1189 Addr fetchBufferBlockPC = fetchBufferAlignPC(fetchAddr);
1190
1191 // If buffer is no longer valid or fetchAddr has moved to point
1192 // to the next cache block, AND we have no remaining ucode
1193 // from a macro-op, then start fetch from icache.
1194 if (!(fetchBufferValid[tid] && fetchBufferBlockPC == fetchBufferPC[tid])
1195 && !inRom && !macroop[tid]) {
1196 DPRINTF(Fetch, "[tid:%i]: Attempting to translate and read "
1197 "instruction, starting at PC %s.\n", tid, thisPC);
1198
1199 fetchCacheLine(fetchAddr, tid, thisPC.instAddr());
1200
1201 if (fetchStatus[tid] == IcacheWaitResponse)
1202 ++icacheStallCycles;
1203 else if (fetchStatus[tid] == ItlbWait)
1204 ++fetchTlbCycles;
1205 else
1206 ++fetchMiscStallCycles;
1207 return;
1208 } else if ((checkInterrupt(thisPC.instAddr()) && !delayedCommit[tid])) {
1209 // Stall CPU if an interrupt is posted and we're not issuing
1210 // an delayed commit micro-op currently (delayed commit instructions
1211 // are not interruptable by interrupts, only faults)
1212 ++fetchMiscStallCycles;
1213 DPRINTF(Fetch, "[tid:%i]: Fetch is stalled!\n", tid);
1214 return;
1215 }
1216 } else {
1217 if (fetchStatus[tid] == Idle) {
1218 ++fetchIdleCycles;
1219 DPRINTF(Fetch, "[tid:%i]: Fetch is idle!\n", tid);
1220 }
1221
1222 // Status is Idle, so fetch should do nothing.
1223 return;
1224 }
1225
1226 ++fetchCycles;
1227
1228 TheISA::PCState nextPC = thisPC;
1229
1230 StaticInstPtr staticInst = NULL;
1231 StaticInstPtr curMacroop = macroop[tid];
1232
1233 // If the read of the first instruction was successful, then grab the
1234 // instructions from the rest of the cache line and put them into the
1235 // queue heading to decode.
1236
1237 DPRINTF(Fetch, "[tid:%i]: Adding instructions to queue to "
1238 "decode.\n", tid);
1239
1240 // Need to keep track of whether or not a predicted branch
1241 // ended this fetch block.
1242 bool predictedBranch = false;
1243
1244 // Need to halt fetch if quiesce instruction detected
1245 bool quiesce = false;
1246
1247 TheISA::MachInst *cacheInsts =
1248 reinterpret_cast<TheISA::MachInst *>(fetchBuffer[tid]);
1249
1250 const unsigned numInsts = fetchBufferSize / instSize;
1251 unsigned blkOffset = (fetchAddr - fetchBufferPC[tid]) / instSize;
1252
1253 // Loop through instruction memory from the cache.
1254 // Keep issuing while fetchWidth is available and branch is not
1255 // predicted taken
1256 while (numInst < fetchWidth && fetchQueue[tid].size() < fetchQueueSize
1257 && !predictedBranch && !quiesce) {
1258 // We need to process more memory if we aren't going to get a
1259 // StaticInst from the rom, the current macroop, or what's already
1260 // in the decoder.
1261 bool needMem = !inRom && !curMacroop &&
1262 !decoder[tid]->instReady();
1263 fetchAddr = (thisPC.instAddr() + pcOffset) & BaseCPU::PCMask;
1264 Addr fetchBufferBlockPC = fetchBufferAlignPC(fetchAddr);
1265
1266 if (needMem) {
1267 // If buffer is no longer valid or fetchAddr has moved to point
1268 // to the next cache block then start fetch from icache.
1269 if (!fetchBufferValid[tid] ||
1270 fetchBufferBlockPC != fetchBufferPC[tid])
1271 break;
1272
1273 if (blkOffset >= numInsts) {
1274 // We need to process more memory, but we've run out of the
1275 // current block.
1276 break;
1277 }
1278
1279 if (ISA_HAS_DELAY_SLOT && pcOffset == 0) {
1280 // Walk past any annulled delay slot instructions.
1281 Addr pcAddr = thisPC.instAddr() & BaseCPU::PCMask;
1282 while (fetchAddr != pcAddr && blkOffset < numInsts) {
1283 blkOffset++;
1284 fetchAddr += instSize;
1285 }
1286 if (blkOffset >= numInsts)
1287 break;
1288 }
1289
1290 MachInst inst = TheISA::gtoh(cacheInsts[blkOffset]);
1291 decoder[tid]->moreBytes(thisPC, fetchAddr, inst);
1292
1293 if (decoder[tid]->needMoreBytes()) {
1294 blkOffset++;
1295 fetchAddr += instSize;
1296 pcOffset += instSize;
1297 }
1298 }
1299
1300 // Extract as many instructions and/or microops as we can from
1301 // the memory we've processed so far.
1302 do {
1303 if (!(curMacroop || inRom)) {
1304 if (decoder[tid]->instReady()) {
1305 staticInst = decoder[tid]->decode(thisPC);
1306
1307 // Increment stat of fetched instructions.
1308 ++fetchedInsts;
1309
1310 if (staticInst->isMacroop()) {
1311 curMacroop = staticInst;
1312 } else {
1313 pcOffset = 0;
1314 }
1315 } else {
1316 // We need more bytes for this instruction so blkOffset and
1317 // pcOffset will be updated
1318 break;
1319 }
1320 }
1321 // Whether we're moving to a new macroop because we're at the
1322 // end of the current one, or the branch predictor incorrectly
1323 // thinks we are...
1324 bool newMacro = false;
1325 if (curMacroop || inRom) {
1326 if (inRom) {
1327 staticInst = cpu->microcodeRom.fetchMicroop(
1328 thisPC.microPC(), curMacroop);
1329 } else {
1330 staticInst = curMacroop->fetchMicroop(thisPC.microPC());
1331 }
1332 newMacro |= staticInst->isLastMicroop();
1333 }
1334
1335 DynInstPtr instruction =
1336 buildInst(tid, staticInst, curMacroop,
1337 thisPC, nextPC, true);
1338
1339 ppFetch->notify(instruction);
1340 numInst++;
1341
1342#if TRACING_ON
1343 if (DTRACE(O3PipeView)) {
1344 instruction->fetchTick = curTick();
1345 }
1346#endif
1347
1348 nextPC = thisPC;
1349
1350 // If we're branching after this instruction, quit fetching
1351 // from the same block.
1352 predictedBranch |= thisPC.branching();
1353 predictedBranch |=
1354 lookupAndUpdateNextPC(instruction, nextPC);
1355 if (predictedBranch) {
1356 DPRINTF(Fetch, "Branch detected with PC = %s\n", thisPC);
1357 }
1358
1359 newMacro |= thisPC.instAddr() != nextPC.instAddr();
1360
1361 // Move to the next instruction, unless we have a branch.
1362 thisPC = nextPC;
1363 inRom = isRomMicroPC(thisPC.microPC());
1364
1365 if (newMacro) {
1366 fetchAddr = thisPC.instAddr() & BaseCPU::PCMask;
1367 blkOffset = (fetchAddr - fetchBufferPC[tid]) / instSize;
1368 pcOffset = 0;
1369 curMacroop = NULL;
1370 }
1371
1372 if (instruction->isQuiesce()) {
1373 DPRINTF(Fetch,
1374 "Quiesce instruction encountered, halting fetch!\n");
1375 fetchStatus[tid] = QuiescePending;
1376 status_change = true;
1377 quiesce = true;
1378 break;
1379 }
1380 } while ((curMacroop || decoder[tid]->instReady()) &&
1381 numInst < fetchWidth &&
1382 fetchQueue[tid].size() < fetchQueueSize);
1383
1384 // Re-evaluate whether the next instruction to fetch is in micro-op ROM
1385 // or not.
1386 inRom = isRomMicroPC(thisPC.microPC());
1387 }
1388
1389 if (predictedBranch) {
1390 DPRINTF(Fetch, "[tid:%i]: Done fetching, predicted branch "
1391 "instruction encountered.\n", tid);
1392 } else if (numInst >= fetchWidth) {
1393 DPRINTF(Fetch, "[tid:%i]: Done fetching, reached fetch bandwidth "
1394 "for this cycle.\n", tid);
1395 } else if (blkOffset >= fetchBufferSize) {
1396 DPRINTF(Fetch, "[tid:%i]: Done fetching, reached the end of the"
1397 "fetch buffer.\n", tid);
1398 }
1399
1400 macroop[tid] = curMacroop;
1401 fetchOffset[tid] = pcOffset;
1402
1403 if (numInst > 0) {
1404 wroteToTimeBuffer = true;
1405 }
1406
1407 pc[tid] = thisPC;
1408
1409 // pipeline a fetch if we're crossing a fetch buffer boundary and not in
1410 // a state that would preclude fetching
1411 fetchAddr = (thisPC.instAddr() + pcOffset) & BaseCPU::PCMask;
1412 Addr fetchBufferBlockPC = fetchBufferAlignPC(fetchAddr);
1413 issuePipelinedIfetch[tid] = fetchBufferBlockPC != fetchBufferPC[tid] &&
1414 fetchStatus[tid] != IcacheWaitResponse &&
1415 fetchStatus[tid] != ItlbWait &&
1416 fetchStatus[tid] != IcacheWaitRetry &&
1417 fetchStatus[tid] != QuiescePending &&
1418 !curMacroop;
1419}
1420
1421template<class Impl>
1422void
1423DefaultFetch<Impl>::recvReqRetry()
1424{
1425 if (retryPkt != NULL) {
1426 assert(cacheBlocked);
1427 assert(retryTid != InvalidThreadID);
1428 assert(fetchStatus[retryTid] == IcacheWaitRetry);
1429
1430 if (cpu->getInstPort().sendTimingReq(retryPkt)) {
1431 fetchStatus[retryTid] = IcacheWaitResponse;
1432 // Notify Fetch Request probe when a retryPkt is successfully sent.
1433 // Note that notify must be called before retryPkt is set to NULL.
1434 ppFetchRequestSent->notify(retryPkt->req);
1435 retryPkt = NULL;
1436 retryTid = InvalidThreadID;
1437 cacheBlocked = false;
1438 }
1439 } else {
1440 assert(retryTid == InvalidThreadID);
1441 // Access has been squashed since it was sent out. Just clear
1442 // the cache being blocked.
1443 cacheBlocked = false;
1444 }
1445}
1446
1447///////////////////////////////////////
1448// //
1449// SMT FETCH POLICY MAINTAINED HERE //
1450// //
1451///////////////////////////////////////
1452template<class Impl>
1453ThreadID
1454DefaultFetch<Impl>::getFetchingThread(FetchPriority &fetch_priority)
1455{
1456 if (numThreads > 1) {
1457 switch (fetch_priority) {
1458
1459 case SingleThread:
1460 return 0;
1461
1462 case RoundRobin:
1463 return roundRobin();
1464
1465 case IQ:
1466 return iqCount();
1467
1468 case LSQ:
1469 return lsqCount();
1470
1471 case Branch:
1472 return branchCount();
1473
1474 default:
1475 return InvalidThreadID;
1476 }
1477 } else {
1478 list<ThreadID>::iterator thread = activeThreads->begin();
1479 if (thread == activeThreads->end()) {
1480 return InvalidThreadID;
1481 }
1482
1483 ThreadID tid = *thread;
1484
1485 if (fetchStatus[tid] == Running ||
1486 fetchStatus[tid] == IcacheAccessComplete ||
1487 fetchStatus[tid] == Idle) {
1488 return tid;
1489 } else {
1490 return InvalidThreadID;
1491 }
1492 }
1493}
1494
1495
1496template<class Impl>
1497ThreadID
1498DefaultFetch<Impl>::roundRobin()
1499{
1500 list<ThreadID>::iterator pri_iter = priorityList.begin();
1501 list<ThreadID>::iterator end = priorityList.end();
1502
1503 ThreadID high_pri;
1504
1505 while (pri_iter != end) {
1506 high_pri = *pri_iter;
1507
1508 assert(high_pri <= numThreads);
1509
1510 if (fetchStatus[high_pri] == Running ||
1511 fetchStatus[high_pri] == IcacheAccessComplete ||
1512 fetchStatus[high_pri] == Idle) {
1513
1514 priorityList.erase(pri_iter);
1515 priorityList.push_back(high_pri);
1516
1517 return high_pri;
1518 }
1519
1520 pri_iter++;
1521 }
1522
1523 return InvalidThreadID;
1524}
1525
1526template<class Impl>
1527ThreadID
1528DefaultFetch<Impl>::iqCount()
1529{
1530 //sorted from lowest->highest
1531 std::priority_queue<unsigned,vector<unsigned>,
1532 std::greater<unsigned> > PQ;
1533 std::map<unsigned, ThreadID> threadMap;
1534
1535 list<ThreadID>::iterator threads = activeThreads->begin();
1536 list<ThreadID>::iterator end = activeThreads->end();
1537
1538 while (threads != end) {
1539 ThreadID tid = *threads++;
1540 unsigned iqCount = fromIEW->iewInfo[tid].iqCount;
1541
1542 //we can potentially get tid collisions if two threads
1543 //have the same iqCount, but this should be rare.
1544 PQ.push(iqCount);
1545 threadMap[iqCount] = tid;
1546 }
1547
1548 while (!PQ.empty()) {
1549 ThreadID high_pri = threadMap[PQ.top()];
1550
1551 if (fetchStatus[high_pri] == Running ||
1552 fetchStatus[high_pri] == IcacheAccessComplete ||
1553 fetchStatus[high_pri] == Idle)
1554 return high_pri;
1555 else
1556 PQ.pop();
1557
1558 }
1559
1560 return InvalidThreadID;
1561}
1562
1563template<class Impl>
1564ThreadID
1565DefaultFetch<Impl>::lsqCount()
1566{
1567 //sorted from lowest->highest
1568 std::priority_queue<unsigned,vector<unsigned>,
1569 std::greater<unsigned> > PQ;
1570 std::map<unsigned, ThreadID> threadMap;
1571
1572 list<ThreadID>::iterator threads = activeThreads->begin();
1573 list<ThreadID>::iterator end = activeThreads->end();
1574
1575 while (threads != end) {
1576 ThreadID tid = *threads++;
1577 unsigned ldstqCount = fromIEW->iewInfo[tid].ldstqCount;
1578
1579 //we can potentially get tid collisions if two threads
1580 //have the same iqCount, but this should be rare.
1581 PQ.push(ldstqCount);
1582 threadMap[ldstqCount] = tid;
1583 }
1584
1585 while (!PQ.empty()) {
1586 ThreadID high_pri = threadMap[PQ.top()];
1587
1588 if (fetchStatus[high_pri] == Running ||
1589 fetchStatus[high_pri] == IcacheAccessComplete ||
1590 fetchStatus[high_pri] == Idle)
1591 return high_pri;
1592 else
1593 PQ.pop();
1594 }
1595
1596 return InvalidThreadID;
1597}
1598
1599template<class Impl>
1600ThreadID
1601DefaultFetch<Impl>::branchCount()
1602{
1603#if 0
1604 list<ThreadID>::iterator thread = activeThreads->begin();
1605 assert(thread != activeThreads->end());
1606 ThreadID tid = *thread;
1607#endif
1608
1609 panic("Branch Count Fetch policy unimplemented\n");
1610 return InvalidThreadID;
1611}
1612
1613template<class Impl>
1614void
1615DefaultFetch<Impl>::pipelineIcacheAccesses(ThreadID tid)
1616{
1617 if (!issuePipelinedIfetch[tid]) {
1618 return;
1619 }
1620
1621 // The next PC to access.
1622 TheISA::PCState thisPC = pc[tid];
1623
1624 if (isRomMicroPC(thisPC.microPC())) {
1625 return;
1626 }
1627
1628 Addr pcOffset = fetchOffset[tid];
1629 Addr fetchAddr = (thisPC.instAddr() + pcOffset) & BaseCPU::PCMask;
1630
1631 // Align the fetch PC so its at the start of a fetch buffer segment.
1632 Addr fetchBufferBlockPC = fetchBufferAlignPC(fetchAddr);
1633
1634 // Unless buffer already got the block, fetch it from icache.
1635 if (!(fetchBufferValid[tid] && fetchBufferBlockPC == fetchBufferPC[tid])) {
1636 DPRINTF(Fetch, "[tid:%i]: Issuing a pipelined I-cache access, "
1637 "starting at PC %s.\n", tid, thisPC);
1638
1639 fetchCacheLine(fetchAddr, tid, thisPC.instAddr());
1640 }
1641}
1642
1643template<class Impl>
1644void
1645DefaultFetch<Impl>::profileStall(ThreadID tid) {
1646 DPRINTF(Fetch,"There are no more threads available to fetch from.\n");
1647
1648 // @todo Per-thread stats
1649
1650 if (stalls[tid].drain) {
1651 ++fetchPendingDrainCycles;
1652 DPRINTF(Fetch, "Fetch is waiting for a drain!\n");
1653 } else if (activeThreads->empty()) {
1654 ++fetchNoActiveThreadStallCycles;
1655 DPRINTF(Fetch, "Fetch has no active thread!\n");
1656 } else if (fetchStatus[tid] == Blocked) {
1657 ++fetchBlockedCycles;
1658 DPRINTF(Fetch, "[tid:%i]: Fetch is blocked!\n", tid);
1659 } else if (fetchStatus[tid] == Squashing) {
1660 ++fetchSquashCycles;
1661 DPRINTF(Fetch, "[tid:%i]: Fetch is squashing!\n", tid);
1662 } else if (fetchStatus[tid] == IcacheWaitResponse) {
1663 ++icacheStallCycles;
1664 DPRINTF(Fetch, "[tid:%i]: Fetch is waiting cache response!\n",
1665 tid);
1666 } else if (fetchStatus[tid] == ItlbWait) {
1667 ++fetchTlbCycles;
1668 DPRINTF(Fetch, "[tid:%i]: Fetch is waiting ITLB walk to "
1669 "finish!\n", tid);
1670 } else if (fetchStatus[tid] == TrapPending) {
1671 ++fetchPendingTrapStallCycles;
1672 DPRINTF(Fetch, "[tid:%i]: Fetch is waiting for a pending trap!\n",
1673 tid);
1674 } else if (fetchStatus[tid] == QuiescePending) {
1675 ++fetchPendingQuiesceStallCycles;
1676 DPRINTF(Fetch, "[tid:%i]: Fetch is waiting for a pending quiesce "
1677 "instruction!\n", tid);
1678 } else if (fetchStatus[tid] == IcacheWaitRetry) {
1679 ++fetchIcacheWaitRetryStallCycles;
1680 DPRINTF(Fetch, "[tid:%i]: Fetch is waiting for an I-cache retry!\n",
1681 tid);
1682 } else if (fetchStatus[tid] == NoGoodAddr) {
1683 DPRINTF(Fetch, "[tid:%i]: Fetch predicted non-executable address\n",
1684 tid);
1685 } else {
1686 DPRINTF(Fetch, "[tid:%i]: Unexpected fetch stall reason (Status: %i).\n",
1687 tid, fetchStatus[tid]);
1688 }
1689}
1690
1691#endif//__CPU_O3_FETCH_IMPL_HH__
| 733
734 instruction->setPredTarg(fetchPC);
735 instruction->fault = fault;
736 wroteToTimeBuffer = true;
737
738 DPRINTF(Activity, "Activity this cycle.\n");
739 cpu->activityThisCycle();
740
741 fetchStatus[tid] = TrapPending;
742
743 DPRINTF(Fetch, "[tid:%i]: Blocked, need to handle the trap.\n", tid);
744 DPRINTF(Fetch, "[tid:%i]: fault (%s) detected @ PC %s.\n",
745 tid, fault->name(), pc[tid]);
746 }
747 _status = updateFetchStatus();
748}
749
750template <class Impl>
751inline void
752DefaultFetch<Impl>::doSquash(const TheISA::PCState &newPC,
753 const DynInstPtr squashInst, ThreadID tid)
754{
755 DPRINTF(Fetch, "[tid:%i]: Squashing, setting PC to: %s.\n",
756 tid, newPC);
757
758 pc[tid] = newPC;
759 fetchOffset[tid] = 0;
760 if (squashInst && squashInst->pcState().instAddr() == newPC.instAddr())
761 macroop[tid] = squashInst->macroop;
762 else
763 macroop[tid] = NULL;
764 decoder[tid]->reset();
765
766 // Clear the icache miss if it's outstanding.
767 if (fetchStatus[tid] == IcacheWaitResponse) {
768 DPRINTF(Fetch, "[tid:%i]: Squashing outstanding Icache miss.\n",
769 tid);
770 memReq[tid] = NULL;
771 } else if (fetchStatus[tid] == ItlbWait) {
772 DPRINTF(Fetch, "[tid:%i]: Squashing outstanding ITLB miss.\n",
773 tid);
774 memReq[tid] = NULL;
775 }
776
777 // Get rid of the retrying packet if it was from this thread.
778 if (retryTid == tid) {
779 assert(cacheBlocked);
780 if (retryPkt) {
781 delete retryPkt->req;
782 delete retryPkt;
783 }
784 retryPkt = NULL;
785 retryTid = InvalidThreadID;
786 }
787
788 fetchStatus[tid] = Squashing;
789
790 // Empty fetch queue
791 fetchQueue[tid].clear();
792
793 // microops are being squashed, it is not known wheather the
794 // youngest non-squashed microop was marked delayed commit
795 // or not. Setting the flag to true ensures that the
796 // interrupts are not handled when they cannot be, though
797 // some opportunities to handle interrupts may be missed.
798 delayedCommit[tid] = true;
799
800 ++fetchSquashCycles;
801}
802
803template<class Impl>
804void
805DefaultFetch<Impl>::squashFromDecode(const TheISA::PCState &newPC,
806 const DynInstPtr squashInst,
807 const InstSeqNum seq_num, ThreadID tid)
808{
809 DPRINTF(Fetch, "[tid:%i]: Squashing from decode.\n", tid);
810
811 doSquash(newPC, squashInst, tid);
812
813 // Tell the CPU to remove any instructions that are in flight between
814 // fetch and decode.
815 cpu->removeInstsUntil(seq_num, tid);
816}
817
818template<class Impl>
819bool
820DefaultFetch<Impl>::checkStall(ThreadID tid) const
821{
822 bool ret_val = false;
823
824 if (stalls[tid].drain) {
825 assert(cpu->isDraining());
826 DPRINTF(Fetch,"[tid:%i]: Drain stall detected.\n",tid);
827 ret_val = true;
828 }
829
830 return ret_val;
831}
832
833template<class Impl>
834typename DefaultFetch<Impl>::FetchStatus
835DefaultFetch<Impl>::updateFetchStatus()
836{
837 //Check Running
838 list<ThreadID>::iterator threads = activeThreads->begin();
839 list<ThreadID>::iterator end = activeThreads->end();
840
841 while (threads != end) {
842 ThreadID tid = *threads++;
843
844 if (fetchStatus[tid] == Running ||
845 fetchStatus[tid] == Squashing ||
846 fetchStatus[tid] == IcacheAccessComplete) {
847
848 if (_status == Inactive) {
849 DPRINTF(Activity, "[tid:%i]: Activating stage.\n",tid);
850
851 if (fetchStatus[tid] == IcacheAccessComplete) {
852 DPRINTF(Activity, "[tid:%i]: Activating fetch due to cache"
853 "completion\n",tid);
854 }
855
856 cpu->activateStage(O3CPU::FetchIdx);
857 }
858
859 return Active;
860 }
861 }
862
863 // Stage is switching from active to inactive, notify CPU of it.
864 if (_status == Active) {
865 DPRINTF(Activity, "Deactivating stage.\n");
866
867 cpu->deactivateStage(O3CPU::FetchIdx);
868 }
869
870 return Inactive;
871}
872
873template <class Impl>
874void
875DefaultFetch<Impl>::squash(const TheISA::PCState &newPC,
876 const InstSeqNum seq_num, DynInstPtr squashInst,
877 ThreadID tid)
878{
879 DPRINTF(Fetch, "[tid:%u]: Squash from commit.\n", tid);
880
881 doSquash(newPC, squashInst, tid);
882
883 // Tell the CPU to remove any instructions that are not in the ROB.
884 cpu->removeInstsNotInROB(tid);
885}
886
887template <class Impl>
888void
889DefaultFetch<Impl>::tick()
890{
891 list<ThreadID>::iterator threads = activeThreads->begin();
892 list<ThreadID>::iterator end = activeThreads->end();
893 bool status_change = false;
894
895 wroteToTimeBuffer = false;
896
897 for (ThreadID i = 0; i < numThreads; ++i) {
898 issuePipelinedIfetch[i] = false;
899 }
900
901 while (threads != end) {
902 ThreadID tid = *threads++;
903
904 // Check the signals for each thread to determine the proper status
905 // for each thread.
906 bool updated_status = checkSignalsAndUpdate(tid);
907 status_change = status_change || updated_status;
908 }
909
910 DPRINTF(Fetch, "Running stage.\n");
911
912 if (FullSystem) {
913 if (fromCommit->commitInfo[0].interruptPending) {
914 interruptPending = true;
915 }
916
917 if (fromCommit->commitInfo[0].clearInterrupt) {
918 interruptPending = false;
919 }
920 }
921
922 for (threadFetched = 0; threadFetched < numFetchingThreads;
923 threadFetched++) {
924 // Fetch each of the actively fetching threads.
925 fetch(status_change);
926 }
927
928 // Record number of instructions fetched this cycle for distribution.
929 fetchNisnDist.sample(numInst);
930
931 if (status_change) {
932 // Change the fetch stage status if there was a status change.
933 _status = updateFetchStatus();
934 }
935
936 // Issue the next I-cache request if possible.
937 for (ThreadID i = 0; i < numThreads; ++i) {
938 if (issuePipelinedIfetch[i]) {
939 pipelineIcacheAccesses(i);
940 }
941 }
942
943 // Send instructions enqueued into the fetch queue to decode.
944 // Limit rate by fetchWidth. Stall if decode is stalled.
945 unsigned insts_to_decode = 0;
946 unsigned available_insts = 0;
947
948 for (auto tid : *activeThreads) {
949 if (!stalls[tid].decode) {
950 available_insts += fetchQueue[tid].size();
951 }
952 }
953
954 // Pick a random thread to start trying to grab instructions from
955 auto tid_itr = activeThreads->begin();
956 std::advance(tid_itr, random_mt.random<uint8_t>(0, activeThreads->size() - 1));
957
958 while (available_insts != 0 && insts_to_decode < decodeWidth) {
959 ThreadID tid = *tid_itr;
960 if (!stalls[tid].decode && !fetchQueue[tid].empty()) {
961 auto inst = fetchQueue[tid].front();
962 toDecode->insts[toDecode->size++] = inst;
963 DPRINTF(Fetch, "[tid:%i][sn:%i]: Sending instruction to decode from "
964 "fetch queue. Fetch queue size: %i.\n",
965 tid, inst->seqNum, fetchQueue[tid].size());
966
967 wroteToTimeBuffer = true;
968 fetchQueue[tid].pop_front();
969 insts_to_decode++;
970 available_insts--;
971 }
972
973 tid_itr++;
974 // Wrap around if at end of active threads list
975 if (tid_itr == activeThreads->end())
976 tid_itr = activeThreads->begin();
977 }
978
979 // If there was activity this cycle, inform the CPU of it.
980 if (wroteToTimeBuffer) {
981 DPRINTF(Activity, "Activity this cycle.\n");
982 cpu->activityThisCycle();
983 }
984
985 // Reset the number of the instruction we've fetched.
986 numInst = 0;
987}
988
989template <class Impl>
990bool
991DefaultFetch<Impl>::checkSignalsAndUpdate(ThreadID tid)
992{
993 // Update the per thread stall statuses.
994 if (fromDecode->decodeBlock[tid]) {
995 stalls[tid].decode = true;
996 }
997
998 if (fromDecode->decodeUnblock[tid]) {
999 assert(stalls[tid].decode);
1000 assert(!fromDecode->decodeBlock[tid]);
1001 stalls[tid].decode = false;
1002 }
1003
1004 // Check squash signals from commit.
1005 if (fromCommit->commitInfo[tid].squash) {
1006
1007 DPRINTF(Fetch, "[tid:%u]: Squashing instructions due to squash "
1008 "from commit.\n",tid);
1009 // In any case, squash.
1010 squash(fromCommit->commitInfo[tid].pc,
1011 fromCommit->commitInfo[tid].doneSeqNum,
1012 fromCommit->commitInfo[tid].squashInst, tid);
1013
1014 // If it was a branch mispredict on a control instruction, update the
1015 // branch predictor with that instruction, otherwise just kill the
1016 // invalid state we generated in after sequence number
1017 if (fromCommit->commitInfo[tid].mispredictInst &&
1018 fromCommit->commitInfo[tid].mispredictInst->isControl()) {
1019 branchPred->squash(fromCommit->commitInfo[tid].doneSeqNum,
1020 fromCommit->commitInfo[tid].pc,
1021 fromCommit->commitInfo[tid].branchTaken,
1022 tid);
1023 } else {
1024 branchPred->squash(fromCommit->commitInfo[tid].doneSeqNum,
1025 tid);
1026 }
1027
1028 return true;
1029 } else if (fromCommit->commitInfo[tid].doneSeqNum) {
1030 // Update the branch predictor if it wasn't a squashed instruction
1031 // that was broadcasted.
1032 branchPred->update(fromCommit->commitInfo[tid].doneSeqNum, tid);
1033 }
1034
1035 // Check squash signals from decode.
1036 if (fromDecode->decodeInfo[tid].squash) {
1037 DPRINTF(Fetch, "[tid:%u]: Squashing instructions due to squash "
1038 "from decode.\n",tid);
1039
1040 // Update the branch predictor.
1041 if (fromDecode->decodeInfo[tid].branchMispredict) {
1042 branchPred->squash(fromDecode->decodeInfo[tid].doneSeqNum,
1043 fromDecode->decodeInfo[tid].nextPC,
1044 fromDecode->decodeInfo[tid].branchTaken,
1045 tid);
1046 } else {
1047 branchPred->squash(fromDecode->decodeInfo[tid].doneSeqNum,
1048 tid);
1049 }
1050
1051 if (fetchStatus[tid] != Squashing) {
1052
1053 DPRINTF(Fetch, "Squashing from decode with PC = %s\n",
1054 fromDecode->decodeInfo[tid].nextPC);
1055 // Squash unless we're already squashing
1056 squashFromDecode(fromDecode->decodeInfo[tid].nextPC,
1057 fromDecode->decodeInfo[tid].squashInst,
1058 fromDecode->decodeInfo[tid].doneSeqNum,
1059 tid);
1060
1061 return true;
1062 }
1063 }
1064
1065 if (checkStall(tid) &&
1066 fetchStatus[tid] != IcacheWaitResponse &&
1067 fetchStatus[tid] != IcacheWaitRetry &&
1068 fetchStatus[tid] != ItlbWait &&
1069 fetchStatus[tid] != QuiescePending) {
1070 DPRINTF(Fetch, "[tid:%i]: Setting to blocked\n",tid);
1071
1072 fetchStatus[tid] = Blocked;
1073
1074 return true;
1075 }
1076
1077 if (fetchStatus[tid] == Blocked ||
1078 fetchStatus[tid] == Squashing) {
1079 // Switch status to running if fetch isn't being told to block or
1080 // squash this cycle.
1081 DPRINTF(Fetch, "[tid:%i]: Done squashing, switching to running.\n",
1082 tid);
1083
1084 fetchStatus[tid] = Running;
1085
1086 return true;
1087 }
1088
1089 // If we've reached this point, we have not gotten any signals that
1090 // cause fetch to change its status. Fetch remains the same as before.
1091 return false;
1092}
1093
1094template<class Impl>
1095typename Impl::DynInstPtr
1096DefaultFetch<Impl>::buildInst(ThreadID tid, StaticInstPtr staticInst,
1097 StaticInstPtr curMacroop, TheISA::PCState thisPC,
1098 TheISA::PCState nextPC, bool trace)
1099{
1100 // Get a sequence number.
1101 InstSeqNum seq = cpu->getAndIncrementInstSeq();
1102
1103 // Create a new DynInst from the instruction fetched.
1104 DynInstPtr instruction =
1105 new DynInst(staticInst, curMacroop, thisPC, nextPC, seq, cpu);
1106 instruction->setTid(tid);
1107
1108 instruction->setASID(tid);
1109
1110 instruction->setThreadState(cpu->thread[tid]);
1111
1112 DPRINTF(Fetch, "[tid:%i]: Instruction PC %#x (%d) created "
1113 "[sn:%lli].\n", tid, thisPC.instAddr(),
1114 thisPC.microPC(), seq);
1115
1116 DPRINTF(Fetch, "[tid:%i]: Instruction is: %s\n", tid,
1117 instruction->staticInst->
1118 disassemble(thisPC.instAddr()));
1119
1120#if TRACING_ON
1121 if (trace) {
1122 instruction->traceData =
1123 cpu->getTracer()->getInstRecord(curTick(), cpu->tcBase(tid),
1124 instruction->staticInst, thisPC, curMacroop);
1125 }
1126#else
1127 instruction->traceData = NULL;
1128#endif
1129
1130 // Add instruction to the CPU's list of instructions.
1131 instruction->setInstListIt(cpu->addInst(instruction));
1132
1133 // Write the instruction to the first slot in the queue
1134 // that heads to decode.
1135 assert(numInst < fetchWidth);
1136 fetchQueue[tid].push_back(instruction);
1137 assert(fetchQueue[tid].size() <= fetchQueueSize);
1138 DPRINTF(Fetch, "[tid:%i]: Fetch queue entry created (%i/%i).\n",
1139 tid, fetchQueue[tid].size(), fetchQueueSize);
1140 //toDecode->insts[toDecode->size++] = instruction;
1141
1142 // Keep track of if we can take an interrupt at this boundary
1143 delayedCommit[tid] = instruction->isDelayedCommit();
1144
1145 return instruction;
1146}
1147
1148template<class Impl>
1149void
1150DefaultFetch<Impl>::fetch(bool &status_change)
1151{
1152 //////////////////////////////////////////
1153 // Start actual fetch
1154 //////////////////////////////////////////
1155 ThreadID tid = getFetchingThread(fetchPolicy);
1156
1157 assert(!cpu->switchedOut());
1158
1159 if (tid == InvalidThreadID) {
1160 // Breaks looping condition in tick()
1161 threadFetched = numFetchingThreads;
1162
1163 if (numThreads == 1) { // @todo Per-thread stats
1164 profileStall(0);
1165 }
1166
1167 return;
1168 }
1169
1170 DPRINTF(Fetch, "Attempting to fetch from [tid:%i]\n", tid);
1171
1172 // The current PC.
1173 TheISA::PCState thisPC = pc[tid];
1174
1175 Addr pcOffset = fetchOffset[tid];
1176 Addr fetchAddr = (thisPC.instAddr() + pcOffset) & BaseCPU::PCMask;
1177
1178 bool inRom = isRomMicroPC(thisPC.microPC());
1179
1180 // If returning from the delay of a cache miss, then update the status
1181 // to running, otherwise do the cache access. Possibly move this up
1182 // to tick() function.
1183 if (fetchStatus[tid] == IcacheAccessComplete) {
1184 DPRINTF(Fetch, "[tid:%i]: Icache miss is complete.\n", tid);
1185
1186 fetchStatus[tid] = Running;
1187 status_change = true;
1188 } else if (fetchStatus[tid] == Running) {
1189 // Align the fetch PC so its at the start of a fetch buffer segment.
1190 Addr fetchBufferBlockPC = fetchBufferAlignPC(fetchAddr);
1191
1192 // If buffer is no longer valid or fetchAddr has moved to point
1193 // to the next cache block, AND we have no remaining ucode
1194 // from a macro-op, then start fetch from icache.
1195 if (!(fetchBufferValid[tid] && fetchBufferBlockPC == fetchBufferPC[tid])
1196 && !inRom && !macroop[tid]) {
1197 DPRINTF(Fetch, "[tid:%i]: Attempting to translate and read "
1198 "instruction, starting at PC %s.\n", tid, thisPC);
1199
1200 fetchCacheLine(fetchAddr, tid, thisPC.instAddr());
1201
1202 if (fetchStatus[tid] == IcacheWaitResponse)
1203 ++icacheStallCycles;
1204 else if (fetchStatus[tid] == ItlbWait)
1205 ++fetchTlbCycles;
1206 else
1207 ++fetchMiscStallCycles;
1208 return;
1209 } else if ((checkInterrupt(thisPC.instAddr()) && !delayedCommit[tid])) {
1210 // Stall CPU if an interrupt is posted and we're not issuing
1211 // an delayed commit micro-op currently (delayed commit instructions
1212 // are not interruptable by interrupts, only faults)
1213 ++fetchMiscStallCycles;
1214 DPRINTF(Fetch, "[tid:%i]: Fetch is stalled!\n", tid);
1215 return;
1216 }
1217 } else {
1218 if (fetchStatus[tid] == Idle) {
1219 ++fetchIdleCycles;
1220 DPRINTF(Fetch, "[tid:%i]: Fetch is idle!\n", tid);
1221 }
1222
1223 // Status is Idle, so fetch should do nothing.
1224 return;
1225 }
1226
1227 ++fetchCycles;
1228
1229 TheISA::PCState nextPC = thisPC;
1230
1231 StaticInstPtr staticInst = NULL;
1232 StaticInstPtr curMacroop = macroop[tid];
1233
1234 // If the read of the first instruction was successful, then grab the
1235 // instructions from the rest of the cache line and put them into the
1236 // queue heading to decode.
1237
1238 DPRINTF(Fetch, "[tid:%i]: Adding instructions to queue to "
1239 "decode.\n", tid);
1240
1241 // Need to keep track of whether or not a predicted branch
1242 // ended this fetch block.
1243 bool predictedBranch = false;
1244
1245 // Need to halt fetch if quiesce instruction detected
1246 bool quiesce = false;
1247
1248 TheISA::MachInst *cacheInsts =
1249 reinterpret_cast<TheISA::MachInst *>(fetchBuffer[tid]);
1250
1251 const unsigned numInsts = fetchBufferSize / instSize;
1252 unsigned blkOffset = (fetchAddr - fetchBufferPC[tid]) / instSize;
1253
1254 // Loop through instruction memory from the cache.
1255 // Keep issuing while fetchWidth is available and branch is not
1256 // predicted taken
1257 while (numInst < fetchWidth && fetchQueue[tid].size() < fetchQueueSize
1258 && !predictedBranch && !quiesce) {
1259 // We need to process more memory if we aren't going to get a
1260 // StaticInst from the rom, the current macroop, or what's already
1261 // in the decoder.
1262 bool needMem = !inRom && !curMacroop &&
1263 !decoder[tid]->instReady();
1264 fetchAddr = (thisPC.instAddr() + pcOffset) & BaseCPU::PCMask;
1265 Addr fetchBufferBlockPC = fetchBufferAlignPC(fetchAddr);
1266
1267 if (needMem) {
1268 // If buffer is no longer valid or fetchAddr has moved to point
1269 // to the next cache block then start fetch from icache.
1270 if (!fetchBufferValid[tid] ||
1271 fetchBufferBlockPC != fetchBufferPC[tid])
1272 break;
1273
1274 if (blkOffset >= numInsts) {
1275 // We need to process more memory, but we've run out of the
1276 // current block.
1277 break;
1278 }
1279
1280 if (ISA_HAS_DELAY_SLOT && pcOffset == 0) {
1281 // Walk past any annulled delay slot instructions.
1282 Addr pcAddr = thisPC.instAddr() & BaseCPU::PCMask;
1283 while (fetchAddr != pcAddr && blkOffset < numInsts) {
1284 blkOffset++;
1285 fetchAddr += instSize;
1286 }
1287 if (blkOffset >= numInsts)
1288 break;
1289 }
1290
1291 MachInst inst = TheISA::gtoh(cacheInsts[blkOffset]);
1292 decoder[tid]->moreBytes(thisPC, fetchAddr, inst);
1293
1294 if (decoder[tid]->needMoreBytes()) {
1295 blkOffset++;
1296 fetchAddr += instSize;
1297 pcOffset += instSize;
1298 }
1299 }
1300
1301 // Extract as many instructions and/or microops as we can from
1302 // the memory we've processed so far.
1303 do {
1304 if (!(curMacroop || inRom)) {
1305 if (decoder[tid]->instReady()) {
1306 staticInst = decoder[tid]->decode(thisPC);
1307
1308 // Increment stat of fetched instructions.
1309 ++fetchedInsts;
1310
1311 if (staticInst->isMacroop()) {
1312 curMacroop = staticInst;
1313 } else {
1314 pcOffset = 0;
1315 }
1316 } else {
1317 // We need more bytes for this instruction so blkOffset and
1318 // pcOffset will be updated
1319 break;
1320 }
1321 }
1322 // Whether we're moving to a new macroop because we're at the
1323 // end of the current one, or the branch predictor incorrectly
1324 // thinks we are...
1325 bool newMacro = false;
1326 if (curMacroop || inRom) {
1327 if (inRom) {
1328 staticInst = cpu->microcodeRom.fetchMicroop(
1329 thisPC.microPC(), curMacroop);
1330 } else {
1331 staticInst = curMacroop->fetchMicroop(thisPC.microPC());
1332 }
1333 newMacro |= staticInst->isLastMicroop();
1334 }
1335
1336 DynInstPtr instruction =
1337 buildInst(tid, staticInst, curMacroop,
1338 thisPC, nextPC, true);
1339
1340 ppFetch->notify(instruction);
1341 numInst++;
1342
1343#if TRACING_ON
1344 if (DTRACE(O3PipeView)) {
1345 instruction->fetchTick = curTick();
1346 }
1347#endif
1348
1349 nextPC = thisPC;
1350
1351 // If we're branching after this instruction, quit fetching
1352 // from the same block.
1353 predictedBranch |= thisPC.branching();
1354 predictedBranch |=
1355 lookupAndUpdateNextPC(instruction, nextPC);
1356 if (predictedBranch) {
1357 DPRINTF(Fetch, "Branch detected with PC = %s\n", thisPC);
1358 }
1359
1360 newMacro |= thisPC.instAddr() != nextPC.instAddr();
1361
1362 // Move to the next instruction, unless we have a branch.
1363 thisPC = nextPC;
1364 inRom = isRomMicroPC(thisPC.microPC());
1365
1366 if (newMacro) {
1367 fetchAddr = thisPC.instAddr() & BaseCPU::PCMask;
1368 blkOffset = (fetchAddr - fetchBufferPC[tid]) / instSize;
1369 pcOffset = 0;
1370 curMacroop = NULL;
1371 }
1372
1373 if (instruction->isQuiesce()) {
1374 DPRINTF(Fetch,
1375 "Quiesce instruction encountered, halting fetch!\n");
1376 fetchStatus[tid] = QuiescePending;
1377 status_change = true;
1378 quiesce = true;
1379 break;
1380 }
1381 } while ((curMacroop || decoder[tid]->instReady()) &&
1382 numInst < fetchWidth &&
1383 fetchQueue[tid].size() < fetchQueueSize);
1384
1385 // Re-evaluate whether the next instruction to fetch is in micro-op ROM
1386 // or not.
1387 inRom = isRomMicroPC(thisPC.microPC());
1388 }
1389
1390 if (predictedBranch) {
1391 DPRINTF(Fetch, "[tid:%i]: Done fetching, predicted branch "
1392 "instruction encountered.\n", tid);
1393 } else if (numInst >= fetchWidth) {
1394 DPRINTF(Fetch, "[tid:%i]: Done fetching, reached fetch bandwidth "
1395 "for this cycle.\n", tid);
1396 } else if (blkOffset >= fetchBufferSize) {
1397 DPRINTF(Fetch, "[tid:%i]: Done fetching, reached the end of the"
1398 "fetch buffer.\n", tid);
1399 }
1400
1401 macroop[tid] = curMacroop;
1402 fetchOffset[tid] = pcOffset;
1403
1404 if (numInst > 0) {
1405 wroteToTimeBuffer = true;
1406 }
1407
1408 pc[tid] = thisPC;
1409
1410 // pipeline a fetch if we're crossing a fetch buffer boundary and not in
1411 // a state that would preclude fetching
1412 fetchAddr = (thisPC.instAddr() + pcOffset) & BaseCPU::PCMask;
1413 Addr fetchBufferBlockPC = fetchBufferAlignPC(fetchAddr);
1414 issuePipelinedIfetch[tid] = fetchBufferBlockPC != fetchBufferPC[tid] &&
1415 fetchStatus[tid] != IcacheWaitResponse &&
1416 fetchStatus[tid] != ItlbWait &&
1417 fetchStatus[tid] != IcacheWaitRetry &&
1418 fetchStatus[tid] != QuiescePending &&
1419 !curMacroop;
1420}
1421
1422template<class Impl>
1423void
1424DefaultFetch<Impl>::recvReqRetry()
1425{
1426 if (retryPkt != NULL) {
1427 assert(cacheBlocked);
1428 assert(retryTid != InvalidThreadID);
1429 assert(fetchStatus[retryTid] == IcacheWaitRetry);
1430
1431 if (cpu->getInstPort().sendTimingReq(retryPkt)) {
1432 fetchStatus[retryTid] = IcacheWaitResponse;
1433 // Notify Fetch Request probe when a retryPkt is successfully sent.
1434 // Note that notify must be called before retryPkt is set to NULL.
1435 ppFetchRequestSent->notify(retryPkt->req);
1436 retryPkt = NULL;
1437 retryTid = InvalidThreadID;
1438 cacheBlocked = false;
1439 }
1440 } else {
1441 assert(retryTid == InvalidThreadID);
1442 // Access has been squashed since it was sent out. Just clear
1443 // the cache being blocked.
1444 cacheBlocked = false;
1445 }
1446}
1447
1448///////////////////////////////////////
1449// //
1450// SMT FETCH POLICY MAINTAINED HERE //
1451// //
1452///////////////////////////////////////
1453template<class Impl>
1454ThreadID
1455DefaultFetch<Impl>::getFetchingThread(FetchPriority &fetch_priority)
1456{
1457 if (numThreads > 1) {
1458 switch (fetch_priority) {
1459
1460 case SingleThread:
1461 return 0;
1462
1463 case RoundRobin:
1464 return roundRobin();
1465
1466 case IQ:
1467 return iqCount();
1468
1469 case LSQ:
1470 return lsqCount();
1471
1472 case Branch:
1473 return branchCount();
1474
1475 default:
1476 return InvalidThreadID;
1477 }
1478 } else {
1479 list<ThreadID>::iterator thread = activeThreads->begin();
1480 if (thread == activeThreads->end()) {
1481 return InvalidThreadID;
1482 }
1483
1484 ThreadID tid = *thread;
1485
1486 if (fetchStatus[tid] == Running ||
1487 fetchStatus[tid] == IcacheAccessComplete ||
1488 fetchStatus[tid] == Idle) {
1489 return tid;
1490 } else {
1491 return InvalidThreadID;
1492 }
1493 }
1494}
1495
1496
1497template<class Impl>
1498ThreadID
1499DefaultFetch<Impl>::roundRobin()
1500{
1501 list<ThreadID>::iterator pri_iter = priorityList.begin();
1502 list<ThreadID>::iterator end = priorityList.end();
1503
1504 ThreadID high_pri;
1505
1506 while (pri_iter != end) {
1507 high_pri = *pri_iter;
1508
1509 assert(high_pri <= numThreads);
1510
1511 if (fetchStatus[high_pri] == Running ||
1512 fetchStatus[high_pri] == IcacheAccessComplete ||
1513 fetchStatus[high_pri] == Idle) {
1514
1515 priorityList.erase(pri_iter);
1516 priorityList.push_back(high_pri);
1517
1518 return high_pri;
1519 }
1520
1521 pri_iter++;
1522 }
1523
1524 return InvalidThreadID;
1525}
1526
1527template<class Impl>
1528ThreadID
1529DefaultFetch<Impl>::iqCount()
1530{
1531 //sorted from lowest->highest
1532 std::priority_queue<unsigned,vector<unsigned>,
1533 std::greater<unsigned> > PQ;
1534 std::map<unsigned, ThreadID> threadMap;
1535
1536 list<ThreadID>::iterator threads = activeThreads->begin();
1537 list<ThreadID>::iterator end = activeThreads->end();
1538
1539 while (threads != end) {
1540 ThreadID tid = *threads++;
1541 unsigned iqCount = fromIEW->iewInfo[tid].iqCount;
1542
1543 //we can potentially get tid collisions if two threads
1544 //have the same iqCount, but this should be rare.
1545 PQ.push(iqCount);
1546 threadMap[iqCount] = tid;
1547 }
1548
1549 while (!PQ.empty()) {
1550 ThreadID high_pri = threadMap[PQ.top()];
1551
1552 if (fetchStatus[high_pri] == Running ||
1553 fetchStatus[high_pri] == IcacheAccessComplete ||
1554 fetchStatus[high_pri] == Idle)
1555 return high_pri;
1556 else
1557 PQ.pop();
1558
1559 }
1560
1561 return InvalidThreadID;
1562}
1563
1564template<class Impl>
1565ThreadID
1566DefaultFetch<Impl>::lsqCount()
1567{
1568 //sorted from lowest->highest
1569 std::priority_queue<unsigned,vector<unsigned>,
1570 std::greater<unsigned> > PQ;
1571 std::map<unsigned, ThreadID> threadMap;
1572
1573 list<ThreadID>::iterator threads = activeThreads->begin();
1574 list<ThreadID>::iterator end = activeThreads->end();
1575
1576 while (threads != end) {
1577 ThreadID tid = *threads++;
1578 unsigned ldstqCount = fromIEW->iewInfo[tid].ldstqCount;
1579
1580 //we can potentially get tid collisions if two threads
1581 //have the same iqCount, but this should be rare.
1582 PQ.push(ldstqCount);
1583 threadMap[ldstqCount] = tid;
1584 }
1585
1586 while (!PQ.empty()) {
1587 ThreadID high_pri = threadMap[PQ.top()];
1588
1589 if (fetchStatus[high_pri] == Running ||
1590 fetchStatus[high_pri] == IcacheAccessComplete ||
1591 fetchStatus[high_pri] == Idle)
1592 return high_pri;
1593 else
1594 PQ.pop();
1595 }
1596
1597 return InvalidThreadID;
1598}
1599
1600template<class Impl>
1601ThreadID
1602DefaultFetch<Impl>::branchCount()
1603{
1604#if 0
1605 list<ThreadID>::iterator thread = activeThreads->begin();
1606 assert(thread != activeThreads->end());
1607 ThreadID tid = *thread;
1608#endif
1609
1610 panic("Branch Count Fetch policy unimplemented\n");
1611 return InvalidThreadID;
1612}
1613
1614template<class Impl>
1615void
1616DefaultFetch<Impl>::pipelineIcacheAccesses(ThreadID tid)
1617{
1618 if (!issuePipelinedIfetch[tid]) {
1619 return;
1620 }
1621
1622 // The next PC to access.
1623 TheISA::PCState thisPC = pc[tid];
1624
1625 if (isRomMicroPC(thisPC.microPC())) {
1626 return;
1627 }
1628
1629 Addr pcOffset = fetchOffset[tid];
1630 Addr fetchAddr = (thisPC.instAddr() + pcOffset) & BaseCPU::PCMask;
1631
1632 // Align the fetch PC so its at the start of a fetch buffer segment.
1633 Addr fetchBufferBlockPC = fetchBufferAlignPC(fetchAddr);
1634
1635 // Unless buffer already got the block, fetch it from icache.
1636 if (!(fetchBufferValid[tid] && fetchBufferBlockPC == fetchBufferPC[tid])) {
1637 DPRINTF(Fetch, "[tid:%i]: Issuing a pipelined I-cache access, "
1638 "starting at PC %s.\n", tid, thisPC);
1639
1640 fetchCacheLine(fetchAddr, tid, thisPC.instAddr());
1641 }
1642}
1643
1644template<class Impl>
1645void
1646DefaultFetch<Impl>::profileStall(ThreadID tid) {
1647 DPRINTF(Fetch,"There are no more threads available to fetch from.\n");
1648
1649 // @todo Per-thread stats
1650
1651 if (stalls[tid].drain) {
1652 ++fetchPendingDrainCycles;
1653 DPRINTF(Fetch, "Fetch is waiting for a drain!\n");
1654 } else if (activeThreads->empty()) {
1655 ++fetchNoActiveThreadStallCycles;
1656 DPRINTF(Fetch, "Fetch has no active thread!\n");
1657 } else if (fetchStatus[tid] == Blocked) {
1658 ++fetchBlockedCycles;
1659 DPRINTF(Fetch, "[tid:%i]: Fetch is blocked!\n", tid);
1660 } else if (fetchStatus[tid] == Squashing) {
1661 ++fetchSquashCycles;
1662 DPRINTF(Fetch, "[tid:%i]: Fetch is squashing!\n", tid);
1663 } else if (fetchStatus[tid] == IcacheWaitResponse) {
1664 ++icacheStallCycles;
1665 DPRINTF(Fetch, "[tid:%i]: Fetch is waiting cache response!\n",
1666 tid);
1667 } else if (fetchStatus[tid] == ItlbWait) {
1668 ++fetchTlbCycles;
1669 DPRINTF(Fetch, "[tid:%i]: Fetch is waiting ITLB walk to "
1670 "finish!\n", tid);
1671 } else if (fetchStatus[tid] == TrapPending) {
1672 ++fetchPendingTrapStallCycles;
1673 DPRINTF(Fetch, "[tid:%i]: Fetch is waiting for a pending trap!\n",
1674 tid);
1675 } else if (fetchStatus[tid] == QuiescePending) {
1676 ++fetchPendingQuiesceStallCycles;
1677 DPRINTF(Fetch, "[tid:%i]: Fetch is waiting for a pending quiesce "
1678 "instruction!\n", tid);
1679 } else if (fetchStatus[tid] == IcacheWaitRetry) {
1680 ++fetchIcacheWaitRetryStallCycles;
1681 DPRINTF(Fetch, "[tid:%i]: Fetch is waiting for an I-cache retry!\n",
1682 tid);
1683 } else if (fetchStatus[tid] == NoGoodAddr) {
1684 DPRINTF(Fetch, "[tid:%i]: Fetch predicted non-executable address\n",
1685 tid);
1686 } else {
1687 DPRINTF(Fetch, "[tid:%i]: Unexpected fetch stall reason (Status: %i).\n",
1688 tid, fetchStatus[tid]);
1689 }
1690}
1691
1692#endif//__CPU_O3_FETCH_IMPL_HH__
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