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;
392 return;
393 }
394
395 memcpy(fetchBuffer[tid], pkt->getConstPtr<uint8_t>(), fetchBufferSize);
396 fetchBufferValid[tid] = true;
397
398 // Wake up the CPU (if it went to sleep and was waiting on
399 // this completion event).
400 cpu->wakeCPU();
401
402 DPRINTF(Activity, "[tid:%u] Activating fetch due to cache completion\n",
403 tid);
404
405 switchToActive();
406
407 // Only switch to IcacheAccessComplete if we're not stalled as well.
408 if (checkStall(tid)) {
409 fetchStatus[tid] = Blocked;
410 } else {
411 fetchStatus[tid] = IcacheAccessComplete;
412 }
413
414 pkt->req->setAccessLatency();
415 cpu->ppInstAccessComplete->notify(pkt);
416 // Reset the mem req to NULL.
417 delete pkt;
418 memReq[tid] = NULL;
419}
420
421template <class Impl>
422void
423DefaultFetch<Impl>::drainResume()
424{
425 for (ThreadID i = 0; i < numThreads; ++i) {
426 stalls[i].decode = false;
427 stalls[i].drain = false;
428 }
429}
430
431template <class Impl>
432void
433DefaultFetch<Impl>::drainSanityCheck() const
434{
435 assert(isDrained());
436 assert(retryPkt == NULL);
437 assert(retryTid == InvalidThreadID);
438 assert(!cacheBlocked);
439 assert(!interruptPending);
440
441 for (ThreadID i = 0; i < numThreads; ++i) {
442 assert(!memReq[i]);
443 assert(fetchStatus[i] == Idle || stalls[i].drain);
444 }
445
446 branchPred->drainSanityCheck();
447}
448
449template <class Impl>
450bool
451DefaultFetch<Impl>::isDrained() const
452{
453 /* Make sure that threads are either idle of that the commit stage
454 * has signaled that draining has completed by setting the drain
455 * stall flag. This effectively forces the pipeline to be disabled
456 * until the whole system is drained (simulation may continue to
457 * drain other components).
458 */
459 for (ThreadID i = 0; i < numThreads; ++i) {
460 // Verify fetch queues are drained
461 if (!fetchQueue[i].empty())
462 return false;
463
464 // Return false if not idle or drain stalled
465 if (fetchStatus[i] != Idle) {
466 if (fetchStatus[i] == Blocked && stalls[i].drain)
467 continue;
468 else
469 return false;
470 }
471 }
472
473 /* The pipeline might start up again in the middle of the drain
474 * cycle if the finish translation event is scheduled, so make
475 * sure that's not the case.
476 */
477 return !finishTranslationEvent.scheduled();
478}
479
480template <class Impl>
481void
482DefaultFetch<Impl>::takeOverFrom()
483{
484 assert(cpu->getInstPort().isConnected());
485 resetStage();
486
487}
488
489template <class Impl>
490void
491DefaultFetch<Impl>::drainStall(ThreadID tid)
492{
493 assert(cpu->isDraining());
494 assert(!stalls[tid].drain);
495 DPRINTF(Drain, "%i: Thread drained.\n", tid);
496 stalls[tid].drain = true;
497}
498
499template <class Impl>
500void
501DefaultFetch<Impl>::wakeFromQuiesce()
502{
503 DPRINTF(Fetch, "Waking up from quiesce\n");
504 // Hopefully this is safe
505 // @todo: Allow other threads to wake from quiesce.
506 fetchStatus[0] = Running;
507}
508
509template <class Impl>
510inline void
511DefaultFetch<Impl>::switchToActive()
512{
513 if (_status == Inactive) {
514 DPRINTF(Activity, "Activating stage.\n");
515
516 cpu->activateStage(O3CPU::FetchIdx);
517
518 _status = Active;
519 }
520}
521
522template <class Impl>
523inline void
524DefaultFetch<Impl>::switchToInactive()
525{
526 if (_status == Active) {
527 DPRINTF(Activity, "Deactivating stage.\n");
528
529 cpu->deactivateStage(O3CPU::FetchIdx);
530
531 _status = Inactive;
532 }
533}
534
535template <class Impl>
536void
537DefaultFetch<Impl>::deactivateThread(ThreadID tid)
538{
539 // Update priority list
540 auto thread_it = std::find(priorityList.begin(), priorityList.end(), tid);
541 if (thread_it != priorityList.end()) {
542 priorityList.erase(thread_it);
543 }
544}
545
546template <class Impl>
547bool
548DefaultFetch<Impl>::lookupAndUpdateNextPC(
| 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;
392 return;
393 }
394
395 memcpy(fetchBuffer[tid], pkt->getConstPtr<uint8_t>(), fetchBufferSize);
396 fetchBufferValid[tid] = true;
397
398 // Wake up the CPU (if it went to sleep and was waiting on
399 // this completion event).
400 cpu->wakeCPU();
401
402 DPRINTF(Activity, "[tid:%u] Activating fetch due to cache completion\n",
403 tid);
404
405 switchToActive();
406
407 // Only switch to IcacheAccessComplete if we're not stalled as well.
408 if (checkStall(tid)) {
409 fetchStatus[tid] = Blocked;
410 } else {
411 fetchStatus[tid] = IcacheAccessComplete;
412 }
413
414 pkt->req->setAccessLatency();
415 cpu->ppInstAccessComplete->notify(pkt);
416 // Reset the mem req to NULL.
417 delete pkt;
418 memReq[tid] = NULL;
419}
420
421template <class Impl>
422void
423DefaultFetch<Impl>::drainResume()
424{
425 for (ThreadID i = 0; i < numThreads; ++i) {
426 stalls[i].decode = false;
427 stalls[i].drain = false;
428 }
429}
430
431template <class Impl>
432void
433DefaultFetch<Impl>::drainSanityCheck() const
434{
435 assert(isDrained());
436 assert(retryPkt == NULL);
437 assert(retryTid == InvalidThreadID);
438 assert(!cacheBlocked);
439 assert(!interruptPending);
440
441 for (ThreadID i = 0; i < numThreads; ++i) {
442 assert(!memReq[i]);
443 assert(fetchStatus[i] == Idle || stalls[i].drain);
444 }
445
446 branchPred->drainSanityCheck();
447}
448
449template <class Impl>
450bool
451DefaultFetch<Impl>::isDrained() const
452{
453 /* Make sure that threads are either idle of that the commit stage
454 * has signaled that draining has completed by setting the drain
455 * stall flag. This effectively forces the pipeline to be disabled
456 * until the whole system is drained (simulation may continue to
457 * drain other components).
458 */
459 for (ThreadID i = 0; i < numThreads; ++i) {
460 // Verify fetch queues are drained
461 if (!fetchQueue[i].empty())
462 return false;
463
464 // Return false if not idle or drain stalled
465 if (fetchStatus[i] != Idle) {
466 if (fetchStatus[i] == Blocked && stalls[i].drain)
467 continue;
468 else
469 return false;
470 }
471 }
472
473 /* The pipeline might start up again in the middle of the drain
474 * cycle if the finish translation event is scheduled, so make
475 * sure that's not the case.
476 */
477 return !finishTranslationEvent.scheduled();
478}
479
480template <class Impl>
481void
482DefaultFetch<Impl>::takeOverFrom()
483{
484 assert(cpu->getInstPort().isConnected());
485 resetStage();
486
487}
488
489template <class Impl>
490void
491DefaultFetch<Impl>::drainStall(ThreadID tid)
492{
493 assert(cpu->isDraining());
494 assert(!stalls[tid].drain);
495 DPRINTF(Drain, "%i: Thread drained.\n", tid);
496 stalls[tid].drain = true;
497}
498
499template <class Impl>
500void
501DefaultFetch<Impl>::wakeFromQuiesce()
502{
503 DPRINTF(Fetch, "Waking up from quiesce\n");
504 // Hopefully this is safe
505 // @todo: Allow other threads to wake from quiesce.
506 fetchStatus[0] = Running;
507}
508
509template <class Impl>
510inline void
511DefaultFetch<Impl>::switchToActive()
512{
513 if (_status == Inactive) {
514 DPRINTF(Activity, "Activating stage.\n");
515
516 cpu->activateStage(O3CPU::FetchIdx);
517
518 _status = Active;
519 }
520}
521
522template <class Impl>
523inline void
524DefaultFetch<Impl>::switchToInactive()
525{
526 if (_status == Active) {
527 DPRINTF(Activity, "Deactivating stage.\n");
528
529 cpu->deactivateStage(O3CPU::FetchIdx);
530
531 _status = Inactive;
532 }
533}
534
535template <class Impl>
536void
537DefaultFetch<Impl>::deactivateThread(ThreadID tid)
538{
539 // Update priority list
540 auto thread_it = std::find(priorityList.begin(), priorityList.end(), tid);
541 if (thread_it != priorityList.end()) {
542 priorityList.erase(thread_it);
543 }
544}
545
546template <class Impl>
547bool
548DefaultFetch<Impl>::lookupAndUpdateNextPC(
|
549 DynInstPtr &inst, TheISA::PCState &nextPC)
| 549 const DynInstPtr &inst, TheISA::PCState &nextPC)
|
550{
551 // Do branch prediction check here.
552 // A bit of a misnomer...next_PC is actually the current PC until
553 // this function updates it.
554 bool predict_taken;
555
556 if (!inst->isControl()) {
557 TheISA::advancePC(nextPC, inst->staticInst);
558 inst->setPredTarg(nextPC);
559 inst->setPredTaken(false);
560 return false;
561 }
562
563 ThreadID tid = inst->threadNumber;
564 predict_taken = branchPred->predict(inst->staticInst, inst->seqNum,
565 nextPC, tid);
566
567 if (predict_taken) {
568 DPRINTF(Fetch, "[tid:%i]: [sn:%i]: Branch predicted to be taken to %s.\n",
569 tid, inst->seqNum, nextPC);
570 } else {
571 DPRINTF(Fetch, "[tid:%i]: [sn:%i]:Branch predicted to be not taken.\n",
572 tid, inst->seqNum);
573 }
574
575 DPRINTF(Fetch, "[tid:%i]: [sn:%i] Branch predicted to go to %s.\n",
576 tid, inst->seqNum, nextPC);
577 inst->setPredTarg(nextPC);
578 inst->setPredTaken(predict_taken);
579
580 ++fetchedBranches;
581
582 if (predict_taken) {
583 ++predictedBranches;
584 }
585
586 return predict_taken;
587}
588
589template <class Impl>
590bool
591DefaultFetch<Impl>::fetchCacheLine(Addr vaddr, ThreadID tid, Addr pc)
592{
593 Fault fault = NoFault;
594
595 assert(!cpu->switchedOut());
596
597 // @todo: not sure if these should block translation.
598 //AlphaDep
599 if (cacheBlocked) {
600 DPRINTF(Fetch, "[tid:%i] Can't fetch cache line, cache blocked\n",
601 tid);
602 return false;
603 } else if (checkInterrupt(pc) && !delayedCommit[tid]) {
604 // Hold off fetch from getting new instructions when:
605 // Cache is blocked, or
606 // while an interrupt is pending and we're not in PAL mode, or
607 // fetch is switched out.
608 DPRINTF(Fetch, "[tid:%i] Can't fetch cache line, interrupt pending\n",
609 tid);
610 return false;
611 }
612
613 // Align the fetch address to the start of a fetch buffer segment.
614 Addr fetchBufferBlockPC = fetchBufferAlignPC(vaddr);
615
616 DPRINTF(Fetch, "[tid:%i] Fetching cache line %#x for addr %#x\n",
617 tid, fetchBufferBlockPC, vaddr);
618
619 // Setup the memReq to do a read of the first instruction's address.
620 // Set the appropriate read size and flags as well.
621 // Build request here.
622 RequestPtr mem_req = std::make_shared<Request>(
623 tid, fetchBufferBlockPC, fetchBufferSize,
624 Request::INST_FETCH, cpu->instMasterId(), pc,
625 cpu->thread[tid]->contextId());
626
627 mem_req->taskId(cpu->taskId());
628
629 memReq[tid] = mem_req;
630
631 // Initiate translation of the icache block
632 fetchStatus[tid] = ItlbWait;
633 FetchTranslation *trans = new FetchTranslation(this);
634 cpu->itb->translateTiming(mem_req, cpu->thread[tid]->getTC(),
635 trans, BaseTLB::Execute);
636 return true;
637}
638
639template <class Impl>
640void
641DefaultFetch<Impl>::finishTranslation(const Fault &fault,
642 const RequestPtr &mem_req)
643{
644 ThreadID tid = cpu->contextToThread(mem_req->contextId());
645 Addr fetchBufferBlockPC = mem_req->getVaddr();
646
647 assert(!cpu->switchedOut());
648
649 // Wake up CPU if it was idle
650 cpu->wakeCPU();
651
652 if (fetchStatus[tid] != ItlbWait || mem_req != memReq[tid] ||
653 mem_req->getVaddr() != memReq[tid]->getVaddr()) {
654 DPRINTF(Fetch, "[tid:%i] Ignoring itlb completed after squash\n",
655 tid);
656 ++fetchTlbSquashes;
657 return;
658 }
659
660
661 // If translation was successful, attempt to read the icache block.
662 if (fault == NoFault) {
663 // Check that we're not going off into random memory
664 // If we have, just wait around for commit to squash something and put
665 // us on the right track
666 if (!cpu->system->isMemAddr(mem_req->getPaddr())) {
667 warn("Address %#x is outside of physical memory, stopping fetch\n",
668 mem_req->getPaddr());
669 fetchStatus[tid] = NoGoodAddr;
670 memReq[tid] = NULL;
671 return;
672 }
673
674 // Build packet here.
675 PacketPtr data_pkt = new Packet(mem_req, MemCmd::ReadReq);
676 data_pkt->dataDynamic(new uint8_t[fetchBufferSize]);
677
678 fetchBufferPC[tid] = fetchBufferBlockPC;
679 fetchBufferValid[tid] = false;
680 DPRINTF(Fetch, "Fetch: Doing instruction read.\n");
681
682 fetchedCacheLines++;
683
684 // Access the cache.
685 if (!cpu->getInstPort().sendTimingReq(data_pkt)) {
686 assert(retryPkt == NULL);
687 assert(retryTid == InvalidThreadID);
688 DPRINTF(Fetch, "[tid:%i] Out of MSHRs!\n", tid);
689
690 fetchStatus[tid] = IcacheWaitRetry;
691 retryPkt = data_pkt;
692 retryTid = tid;
693 cacheBlocked = true;
694 } else {
695 DPRINTF(Fetch, "[tid:%i]: Doing Icache access.\n", tid);
696 DPRINTF(Activity, "[tid:%i]: Activity: Waiting on I-cache "
697 "response.\n", tid);
698 lastIcacheStall[tid] = curTick();
699 fetchStatus[tid] = IcacheWaitResponse;
700 // Notify Fetch Request probe when a packet containing a fetch
701 // request is successfully sent
702 ppFetchRequestSent->notify(mem_req);
703 }
704 } else {
705 // Don't send an instruction to decode if we can't handle it.
706 if (!(numInst < fetchWidth) || !(fetchQueue[tid].size() < fetchQueueSize)) {
707 assert(!finishTranslationEvent.scheduled());
708 finishTranslationEvent.setFault(fault);
709 finishTranslationEvent.setReq(mem_req);
710 cpu->schedule(finishTranslationEvent,
711 cpu->clockEdge(Cycles(1)));
712 return;
713 }
714 DPRINTF(Fetch, "[tid:%i] Got back req with addr %#x but expected %#x\n",
715 tid, mem_req->getVaddr(), memReq[tid]->getVaddr());
716 // Translation faulted, icache request won't be sent.
717 memReq[tid] = NULL;
718
719 // Send the fault to commit. This thread will not do anything
720 // until commit handles the fault. The only other way it can
721 // wake up is if a squash comes along and changes the PC.
722 TheISA::PCState fetchPC = pc[tid];
723
724 DPRINTF(Fetch, "[tid:%i]: Translation faulted, building noop.\n", tid);
725 // We will use a nop in ordier to carry the fault.
726 DynInstPtr instruction = buildInst(tid, StaticInst::nopStaticInstPtr,
727 NULL, fetchPC, fetchPC, false);
728 instruction->setNotAnInst();
729
730 instruction->setPredTarg(fetchPC);
731 instruction->fault = fault;
732 wroteToTimeBuffer = true;
733
734 DPRINTF(Activity, "Activity this cycle.\n");
735 cpu->activityThisCycle();
736
737 fetchStatus[tid] = TrapPending;
738
739 DPRINTF(Fetch, "[tid:%i]: Blocked, need to handle the trap.\n", tid);
740 DPRINTF(Fetch, "[tid:%i]: fault (%s) detected @ PC %s.\n",
741 tid, fault->name(), pc[tid]);
742 }
743 _status = updateFetchStatus();
744}
745
746template <class Impl>
747inline void
748DefaultFetch<Impl>::doSquash(const TheISA::PCState &newPC,
749 const DynInstPtr squashInst, ThreadID tid)
750{
751 DPRINTF(Fetch, "[tid:%i]: Squashing, setting PC to: %s.\n",
752 tid, newPC);
753
754 pc[tid] = newPC;
755 fetchOffset[tid] = 0;
756 if (squashInst && squashInst->pcState().instAddr() == newPC.instAddr())
757 macroop[tid] = squashInst->macroop;
758 else
759 macroop[tid] = NULL;
760 decoder[tid]->reset();
761
762 // Clear the icache miss if it's outstanding.
763 if (fetchStatus[tid] == IcacheWaitResponse) {
764 DPRINTF(Fetch, "[tid:%i]: Squashing outstanding Icache miss.\n",
765 tid);
766 memReq[tid] = NULL;
767 } else if (fetchStatus[tid] == ItlbWait) {
768 DPRINTF(Fetch, "[tid:%i]: Squashing outstanding ITLB miss.\n",
769 tid);
770 memReq[tid] = NULL;
771 }
772
773 // Get rid of the retrying packet if it was from this thread.
774 if (retryTid == tid) {
775 assert(cacheBlocked);
776 if (retryPkt) {
777 delete retryPkt;
778 }
779 retryPkt = NULL;
780 retryTid = InvalidThreadID;
781 }
782
783 fetchStatus[tid] = Squashing;
784
785 // Empty fetch queue
786 fetchQueue[tid].clear();
787
788 // microops are being squashed, it is not known wheather the
789 // youngest non-squashed microop was marked delayed commit
790 // or not. Setting the flag to true ensures that the
791 // interrupts are not handled when they cannot be, though
792 // some opportunities to handle interrupts may be missed.
793 delayedCommit[tid] = true;
794
795 ++fetchSquashCycles;
796}
797
798template<class Impl>
799void
800DefaultFetch<Impl>::squashFromDecode(const TheISA::PCState &newPC,
801 const DynInstPtr squashInst,
802 const InstSeqNum seq_num, ThreadID tid)
803{
804 DPRINTF(Fetch, "[tid:%i]: Squashing from decode.\n", tid);
805
806 doSquash(newPC, squashInst, tid);
807
808 // Tell the CPU to remove any instructions that are in flight between
809 // fetch and decode.
810 cpu->removeInstsUntil(seq_num, tid);
811}
812
813template<class Impl>
814bool
815DefaultFetch<Impl>::checkStall(ThreadID tid) const
816{
817 bool ret_val = false;
818
819 if (stalls[tid].drain) {
820 assert(cpu->isDraining());
821 DPRINTF(Fetch,"[tid:%i]: Drain stall detected.\n",tid);
822 ret_val = true;
823 }
824
825 return ret_val;
826}
827
828template<class Impl>
829typename DefaultFetch<Impl>::FetchStatus
830DefaultFetch<Impl>::updateFetchStatus()
831{
832 //Check Running
833 list<ThreadID>::iterator threads = activeThreads->begin();
834 list<ThreadID>::iterator end = activeThreads->end();
835
836 while (threads != end) {
837 ThreadID tid = *threads++;
838
839 if (fetchStatus[tid] == Running ||
840 fetchStatus[tid] == Squashing ||
841 fetchStatus[tid] == IcacheAccessComplete) {
842
843 if (_status == Inactive) {
844 DPRINTF(Activity, "[tid:%i]: Activating stage.\n",tid);
845
846 if (fetchStatus[tid] == IcacheAccessComplete) {
847 DPRINTF(Activity, "[tid:%i]: Activating fetch due to cache"
848 "completion\n",tid);
849 }
850
851 cpu->activateStage(O3CPU::FetchIdx);
852 }
853
854 return Active;
855 }
856 }
857
858 // Stage is switching from active to inactive, notify CPU of it.
859 if (_status == Active) {
860 DPRINTF(Activity, "Deactivating stage.\n");
861
862 cpu->deactivateStage(O3CPU::FetchIdx);
863 }
864
865 return Inactive;
866}
867
868template <class Impl>
869void
870DefaultFetch<Impl>::squash(const TheISA::PCState &newPC,
871 const InstSeqNum seq_num, DynInstPtr squashInst,
872 ThreadID tid)
873{
874 DPRINTF(Fetch, "[tid:%u]: Squash from commit.\n", tid);
875
876 doSquash(newPC, squashInst, tid);
877
878 // Tell the CPU to remove any instructions that are not in the ROB.
879 cpu->removeInstsNotInROB(tid);
880}
881
882template <class Impl>
883void
884DefaultFetch<Impl>::tick()
885{
886 list<ThreadID>::iterator threads = activeThreads->begin();
887 list<ThreadID>::iterator end = activeThreads->end();
888 bool status_change = false;
889
890 wroteToTimeBuffer = false;
891
892 for (ThreadID i = 0; i < numThreads; ++i) {
893 issuePipelinedIfetch[i] = false;
894 }
895
896 while (threads != end) {
897 ThreadID tid = *threads++;
898
899 // Check the signals for each thread to determine the proper status
900 // for each thread.
901 bool updated_status = checkSignalsAndUpdate(tid);
902 status_change = status_change || updated_status;
903 }
904
905 DPRINTF(Fetch, "Running stage.\n");
906
907 if (FullSystem) {
908 if (fromCommit->commitInfo[0].interruptPending) {
909 interruptPending = true;
910 }
911
912 if (fromCommit->commitInfo[0].clearInterrupt) {
913 interruptPending = false;
914 }
915 }
916
917 for (threadFetched = 0; threadFetched < numFetchingThreads;
918 threadFetched++) {
919 // Fetch each of the actively fetching threads.
920 fetch(status_change);
921 }
922
923 // Record number of instructions fetched this cycle for distribution.
924 fetchNisnDist.sample(numInst);
925
926 if (status_change) {
927 // Change the fetch stage status if there was a status change.
928 _status = updateFetchStatus();
929 }
930
931 // Issue the next I-cache request if possible.
932 for (ThreadID i = 0; i < numThreads; ++i) {
933 if (issuePipelinedIfetch[i]) {
934 pipelineIcacheAccesses(i);
935 }
936 }
937
938 // Send instructions enqueued into the fetch queue to decode.
939 // Limit rate by fetchWidth. Stall if decode is stalled.
940 unsigned insts_to_decode = 0;
941 unsigned available_insts = 0;
942
943 for (auto tid : *activeThreads) {
944 if (!stalls[tid].decode) {
945 available_insts += fetchQueue[tid].size();
946 }
947 }
948
949 // Pick a random thread to start trying to grab instructions from
950 auto tid_itr = activeThreads->begin();
951 std::advance(tid_itr, random_mt.random<uint8_t>(0, activeThreads->size() - 1));
952
953 while (available_insts != 0 && insts_to_decode < decodeWidth) {
954 ThreadID tid = *tid_itr;
955 if (!stalls[tid].decode && !fetchQueue[tid].empty()) {
| 550{
551 // Do branch prediction check here.
552 // A bit of a misnomer...next_PC is actually the current PC until
553 // this function updates it.
554 bool predict_taken;
555
556 if (!inst->isControl()) {
557 TheISA::advancePC(nextPC, inst->staticInst);
558 inst->setPredTarg(nextPC);
559 inst->setPredTaken(false);
560 return false;
561 }
562
563 ThreadID tid = inst->threadNumber;
564 predict_taken = branchPred->predict(inst->staticInst, inst->seqNum,
565 nextPC, tid);
566
567 if (predict_taken) {
568 DPRINTF(Fetch, "[tid:%i]: [sn:%i]: Branch predicted to be taken to %s.\n",
569 tid, inst->seqNum, nextPC);
570 } else {
571 DPRINTF(Fetch, "[tid:%i]: [sn:%i]:Branch predicted to be not taken.\n",
572 tid, inst->seqNum);
573 }
574
575 DPRINTF(Fetch, "[tid:%i]: [sn:%i] Branch predicted to go to %s.\n",
576 tid, inst->seqNum, nextPC);
577 inst->setPredTarg(nextPC);
578 inst->setPredTaken(predict_taken);
579
580 ++fetchedBranches;
581
582 if (predict_taken) {
583 ++predictedBranches;
584 }
585
586 return predict_taken;
587}
588
589template <class Impl>
590bool
591DefaultFetch<Impl>::fetchCacheLine(Addr vaddr, ThreadID tid, Addr pc)
592{
593 Fault fault = NoFault;
594
595 assert(!cpu->switchedOut());
596
597 // @todo: not sure if these should block translation.
598 //AlphaDep
599 if (cacheBlocked) {
600 DPRINTF(Fetch, "[tid:%i] Can't fetch cache line, cache blocked\n",
601 tid);
602 return false;
603 } else if (checkInterrupt(pc) && !delayedCommit[tid]) {
604 // Hold off fetch from getting new instructions when:
605 // Cache is blocked, or
606 // while an interrupt is pending and we're not in PAL mode, or
607 // fetch is switched out.
608 DPRINTF(Fetch, "[tid:%i] Can't fetch cache line, interrupt pending\n",
609 tid);
610 return false;
611 }
612
613 // Align the fetch address to the start of a fetch buffer segment.
614 Addr fetchBufferBlockPC = fetchBufferAlignPC(vaddr);
615
616 DPRINTF(Fetch, "[tid:%i] Fetching cache line %#x for addr %#x\n",
617 tid, fetchBufferBlockPC, vaddr);
618
619 // Setup the memReq to do a read of the first instruction's address.
620 // Set the appropriate read size and flags as well.
621 // Build request here.
622 RequestPtr mem_req = std::make_shared<Request>(
623 tid, fetchBufferBlockPC, fetchBufferSize,
624 Request::INST_FETCH, cpu->instMasterId(), pc,
625 cpu->thread[tid]->contextId());
626
627 mem_req->taskId(cpu->taskId());
628
629 memReq[tid] = mem_req;
630
631 // Initiate translation of the icache block
632 fetchStatus[tid] = ItlbWait;
633 FetchTranslation *trans = new FetchTranslation(this);
634 cpu->itb->translateTiming(mem_req, cpu->thread[tid]->getTC(),
635 trans, BaseTLB::Execute);
636 return true;
637}
638
639template <class Impl>
640void
641DefaultFetch<Impl>::finishTranslation(const Fault &fault,
642 const RequestPtr &mem_req)
643{
644 ThreadID tid = cpu->contextToThread(mem_req->contextId());
645 Addr fetchBufferBlockPC = mem_req->getVaddr();
646
647 assert(!cpu->switchedOut());
648
649 // Wake up CPU if it was idle
650 cpu->wakeCPU();
651
652 if (fetchStatus[tid] != ItlbWait || mem_req != memReq[tid] ||
653 mem_req->getVaddr() != memReq[tid]->getVaddr()) {
654 DPRINTF(Fetch, "[tid:%i] Ignoring itlb completed after squash\n",
655 tid);
656 ++fetchTlbSquashes;
657 return;
658 }
659
660
661 // If translation was successful, attempt to read the icache block.
662 if (fault == NoFault) {
663 // Check that we're not going off into random memory
664 // If we have, just wait around for commit to squash something and put
665 // us on the right track
666 if (!cpu->system->isMemAddr(mem_req->getPaddr())) {
667 warn("Address %#x is outside of physical memory, stopping fetch\n",
668 mem_req->getPaddr());
669 fetchStatus[tid] = NoGoodAddr;
670 memReq[tid] = NULL;
671 return;
672 }
673
674 // Build packet here.
675 PacketPtr data_pkt = new Packet(mem_req, MemCmd::ReadReq);
676 data_pkt->dataDynamic(new uint8_t[fetchBufferSize]);
677
678 fetchBufferPC[tid] = fetchBufferBlockPC;
679 fetchBufferValid[tid] = false;
680 DPRINTF(Fetch, "Fetch: Doing instruction read.\n");
681
682 fetchedCacheLines++;
683
684 // Access the cache.
685 if (!cpu->getInstPort().sendTimingReq(data_pkt)) {
686 assert(retryPkt == NULL);
687 assert(retryTid == InvalidThreadID);
688 DPRINTF(Fetch, "[tid:%i] Out of MSHRs!\n", tid);
689
690 fetchStatus[tid] = IcacheWaitRetry;
691 retryPkt = data_pkt;
692 retryTid = tid;
693 cacheBlocked = true;
694 } else {
695 DPRINTF(Fetch, "[tid:%i]: Doing Icache access.\n", tid);
696 DPRINTF(Activity, "[tid:%i]: Activity: Waiting on I-cache "
697 "response.\n", tid);
698 lastIcacheStall[tid] = curTick();
699 fetchStatus[tid] = IcacheWaitResponse;
700 // Notify Fetch Request probe when a packet containing a fetch
701 // request is successfully sent
702 ppFetchRequestSent->notify(mem_req);
703 }
704 } else {
705 // Don't send an instruction to decode if we can't handle it.
706 if (!(numInst < fetchWidth) || !(fetchQueue[tid].size() < fetchQueueSize)) {
707 assert(!finishTranslationEvent.scheduled());
708 finishTranslationEvent.setFault(fault);
709 finishTranslationEvent.setReq(mem_req);
710 cpu->schedule(finishTranslationEvent,
711 cpu->clockEdge(Cycles(1)));
712 return;
713 }
714 DPRINTF(Fetch, "[tid:%i] Got back req with addr %#x but expected %#x\n",
715 tid, mem_req->getVaddr(), memReq[tid]->getVaddr());
716 // Translation faulted, icache request won't be sent.
717 memReq[tid] = NULL;
718
719 // Send the fault to commit. This thread will not do anything
720 // until commit handles the fault. The only other way it can
721 // wake up is if a squash comes along and changes the PC.
722 TheISA::PCState fetchPC = pc[tid];
723
724 DPRINTF(Fetch, "[tid:%i]: Translation faulted, building noop.\n", tid);
725 // We will use a nop in ordier to carry the fault.
726 DynInstPtr instruction = buildInst(tid, StaticInst::nopStaticInstPtr,
727 NULL, fetchPC, fetchPC, false);
728 instruction->setNotAnInst();
729
730 instruction->setPredTarg(fetchPC);
731 instruction->fault = fault;
732 wroteToTimeBuffer = true;
733
734 DPRINTF(Activity, "Activity this cycle.\n");
735 cpu->activityThisCycle();
736
737 fetchStatus[tid] = TrapPending;
738
739 DPRINTF(Fetch, "[tid:%i]: Blocked, need to handle the trap.\n", tid);
740 DPRINTF(Fetch, "[tid:%i]: fault (%s) detected @ PC %s.\n",
741 tid, fault->name(), pc[tid]);
742 }
743 _status = updateFetchStatus();
744}
745
746template <class Impl>
747inline void
748DefaultFetch<Impl>::doSquash(const TheISA::PCState &newPC,
749 const DynInstPtr squashInst, ThreadID tid)
750{
751 DPRINTF(Fetch, "[tid:%i]: Squashing, setting PC to: %s.\n",
752 tid, newPC);
753
754 pc[tid] = newPC;
755 fetchOffset[tid] = 0;
756 if (squashInst && squashInst->pcState().instAddr() == newPC.instAddr())
757 macroop[tid] = squashInst->macroop;
758 else
759 macroop[tid] = NULL;
760 decoder[tid]->reset();
761
762 // Clear the icache miss if it's outstanding.
763 if (fetchStatus[tid] == IcacheWaitResponse) {
764 DPRINTF(Fetch, "[tid:%i]: Squashing outstanding Icache miss.\n",
765 tid);
766 memReq[tid] = NULL;
767 } else if (fetchStatus[tid] == ItlbWait) {
768 DPRINTF(Fetch, "[tid:%i]: Squashing outstanding ITLB miss.\n",
769 tid);
770 memReq[tid] = NULL;
771 }
772
773 // Get rid of the retrying packet if it was from this thread.
774 if (retryTid == tid) {
775 assert(cacheBlocked);
776 if (retryPkt) {
777 delete retryPkt;
778 }
779 retryPkt = NULL;
780 retryTid = InvalidThreadID;
781 }
782
783 fetchStatus[tid] = Squashing;
784
785 // Empty fetch queue
786 fetchQueue[tid].clear();
787
788 // microops are being squashed, it is not known wheather the
789 // youngest non-squashed microop was marked delayed commit
790 // or not. Setting the flag to true ensures that the
791 // interrupts are not handled when they cannot be, though
792 // some opportunities to handle interrupts may be missed.
793 delayedCommit[tid] = true;
794
795 ++fetchSquashCycles;
796}
797
798template<class Impl>
799void
800DefaultFetch<Impl>::squashFromDecode(const TheISA::PCState &newPC,
801 const DynInstPtr squashInst,
802 const InstSeqNum seq_num, ThreadID tid)
803{
804 DPRINTF(Fetch, "[tid:%i]: Squashing from decode.\n", tid);
805
806 doSquash(newPC, squashInst, tid);
807
808 // Tell the CPU to remove any instructions that are in flight between
809 // fetch and decode.
810 cpu->removeInstsUntil(seq_num, tid);
811}
812
813template<class Impl>
814bool
815DefaultFetch<Impl>::checkStall(ThreadID tid) const
816{
817 bool ret_val = false;
818
819 if (stalls[tid].drain) {
820 assert(cpu->isDraining());
821 DPRINTF(Fetch,"[tid:%i]: Drain stall detected.\n",tid);
822 ret_val = true;
823 }
824
825 return ret_val;
826}
827
828template<class Impl>
829typename DefaultFetch<Impl>::FetchStatus
830DefaultFetch<Impl>::updateFetchStatus()
831{
832 //Check Running
833 list<ThreadID>::iterator threads = activeThreads->begin();
834 list<ThreadID>::iterator end = activeThreads->end();
835
836 while (threads != end) {
837 ThreadID tid = *threads++;
838
839 if (fetchStatus[tid] == Running ||
840 fetchStatus[tid] == Squashing ||
841 fetchStatus[tid] == IcacheAccessComplete) {
842
843 if (_status == Inactive) {
844 DPRINTF(Activity, "[tid:%i]: Activating stage.\n",tid);
845
846 if (fetchStatus[tid] == IcacheAccessComplete) {
847 DPRINTF(Activity, "[tid:%i]: Activating fetch due to cache"
848 "completion\n",tid);
849 }
850
851 cpu->activateStage(O3CPU::FetchIdx);
852 }
853
854 return Active;
855 }
856 }
857
858 // Stage is switching from active to inactive, notify CPU of it.
859 if (_status == Active) {
860 DPRINTF(Activity, "Deactivating stage.\n");
861
862 cpu->deactivateStage(O3CPU::FetchIdx);
863 }
864
865 return Inactive;
866}
867
868template <class Impl>
869void
870DefaultFetch<Impl>::squash(const TheISA::PCState &newPC,
871 const InstSeqNum seq_num, DynInstPtr squashInst,
872 ThreadID tid)
873{
874 DPRINTF(Fetch, "[tid:%u]: Squash from commit.\n", tid);
875
876 doSquash(newPC, squashInst, tid);
877
878 // Tell the CPU to remove any instructions that are not in the ROB.
879 cpu->removeInstsNotInROB(tid);
880}
881
882template <class Impl>
883void
884DefaultFetch<Impl>::tick()
885{
886 list<ThreadID>::iterator threads = activeThreads->begin();
887 list<ThreadID>::iterator end = activeThreads->end();
888 bool status_change = false;
889
890 wroteToTimeBuffer = false;
891
892 for (ThreadID i = 0; i < numThreads; ++i) {
893 issuePipelinedIfetch[i] = false;
894 }
895
896 while (threads != end) {
897 ThreadID tid = *threads++;
898
899 // Check the signals for each thread to determine the proper status
900 // for each thread.
901 bool updated_status = checkSignalsAndUpdate(tid);
902 status_change = status_change || updated_status;
903 }
904
905 DPRINTF(Fetch, "Running stage.\n");
906
907 if (FullSystem) {
908 if (fromCommit->commitInfo[0].interruptPending) {
909 interruptPending = true;
910 }
911
912 if (fromCommit->commitInfo[0].clearInterrupt) {
913 interruptPending = false;
914 }
915 }
916
917 for (threadFetched = 0; threadFetched < numFetchingThreads;
918 threadFetched++) {
919 // Fetch each of the actively fetching threads.
920 fetch(status_change);
921 }
922
923 // Record number of instructions fetched this cycle for distribution.
924 fetchNisnDist.sample(numInst);
925
926 if (status_change) {
927 // Change the fetch stage status if there was a status change.
928 _status = updateFetchStatus();
929 }
930
931 // Issue the next I-cache request if possible.
932 for (ThreadID i = 0; i < numThreads; ++i) {
933 if (issuePipelinedIfetch[i]) {
934 pipelineIcacheAccesses(i);
935 }
936 }
937
938 // Send instructions enqueued into the fetch queue to decode.
939 // Limit rate by fetchWidth. Stall if decode is stalled.
940 unsigned insts_to_decode = 0;
941 unsigned available_insts = 0;
942
943 for (auto tid : *activeThreads) {
944 if (!stalls[tid].decode) {
945 available_insts += fetchQueue[tid].size();
946 }
947 }
948
949 // Pick a random thread to start trying to grab instructions from
950 auto tid_itr = activeThreads->begin();
951 std::advance(tid_itr, random_mt.random<uint8_t>(0, activeThreads->size() - 1));
952
953 while (available_insts != 0 && insts_to_decode < decodeWidth) {
954 ThreadID tid = *tid_itr;
955 if (!stalls[tid].decode && !fetchQueue[tid].empty()) {
|
956 auto inst = fetchQueue[tid].front();
| 956 const auto& inst = fetchQueue[tid].front();
|
957 toDecode->insts[toDecode->size++] = inst;
958 DPRINTF(Fetch, "[tid:%i][sn:%i]: Sending instruction to decode from "
959 "fetch queue. Fetch queue size: %i.\n",
960 tid, inst->seqNum, fetchQueue[tid].size());
961
962 wroteToTimeBuffer = true;
963 fetchQueue[tid].pop_front();
964 insts_to_decode++;
965 available_insts--;
966 }
967
968 tid_itr++;
969 // Wrap around if at end of active threads list
970 if (tid_itr == activeThreads->end())
971 tid_itr = activeThreads->begin();
972 }
973
974 // If there was activity this cycle, inform the CPU of it.
975 if (wroteToTimeBuffer) {
976 DPRINTF(Activity, "Activity this cycle.\n");
977 cpu->activityThisCycle();
978 }
979
980 // Reset the number of the instruction we've fetched.
981 numInst = 0;
982}
983
984template <class Impl>
985bool
986DefaultFetch<Impl>::checkSignalsAndUpdate(ThreadID tid)
987{
988 // Update the per thread stall statuses.
989 if (fromDecode->decodeBlock[tid]) {
990 stalls[tid].decode = true;
991 }
992
993 if (fromDecode->decodeUnblock[tid]) {
994 assert(stalls[tid].decode);
995 assert(!fromDecode->decodeBlock[tid]);
996 stalls[tid].decode = false;
997 }
998
999 // Check squash signals from commit.
1000 if (fromCommit->commitInfo[tid].squash) {
1001
1002 DPRINTF(Fetch, "[tid:%u]: Squashing instructions due to squash "
1003 "from commit.\n",tid);
1004 // In any case, squash.
1005 squash(fromCommit->commitInfo[tid].pc,
1006 fromCommit->commitInfo[tid].doneSeqNum,
1007 fromCommit->commitInfo[tid].squashInst, tid);
1008
1009 // If it was a branch mispredict on a control instruction, update the
1010 // branch predictor with that instruction, otherwise just kill the
1011 // invalid state we generated in after sequence number
1012 if (fromCommit->commitInfo[tid].mispredictInst &&
1013 fromCommit->commitInfo[tid].mispredictInst->isControl()) {
1014 branchPred->squash(fromCommit->commitInfo[tid].doneSeqNum,
1015 fromCommit->commitInfo[tid].pc,
1016 fromCommit->commitInfo[tid].branchTaken,
1017 tid);
1018 } else {
1019 branchPred->squash(fromCommit->commitInfo[tid].doneSeqNum,
1020 tid);
1021 }
1022
1023 return true;
1024 } else if (fromCommit->commitInfo[tid].doneSeqNum) {
1025 // Update the branch predictor if it wasn't a squashed instruction
1026 // that was broadcasted.
1027 branchPred->update(fromCommit->commitInfo[tid].doneSeqNum, tid);
1028 }
1029
1030 // Check squash signals from decode.
1031 if (fromDecode->decodeInfo[tid].squash) {
1032 DPRINTF(Fetch, "[tid:%u]: Squashing instructions due to squash "
1033 "from decode.\n",tid);
1034
1035 // Update the branch predictor.
1036 if (fromDecode->decodeInfo[tid].branchMispredict) {
1037 branchPred->squash(fromDecode->decodeInfo[tid].doneSeqNum,
1038 fromDecode->decodeInfo[tid].nextPC,
1039 fromDecode->decodeInfo[tid].branchTaken,
1040 tid);
1041 } else {
1042 branchPred->squash(fromDecode->decodeInfo[tid].doneSeqNum,
1043 tid);
1044 }
1045
1046 if (fetchStatus[tid] != Squashing) {
1047
1048 DPRINTF(Fetch, "Squashing from decode with PC = %s\n",
1049 fromDecode->decodeInfo[tid].nextPC);
1050 // Squash unless we're already squashing
1051 squashFromDecode(fromDecode->decodeInfo[tid].nextPC,
1052 fromDecode->decodeInfo[tid].squashInst,
1053 fromDecode->decodeInfo[tid].doneSeqNum,
1054 tid);
1055
1056 return true;
1057 }
1058 }
1059
1060 if (checkStall(tid) &&
1061 fetchStatus[tid] != IcacheWaitResponse &&
1062 fetchStatus[tid] != IcacheWaitRetry &&
1063 fetchStatus[tid] != ItlbWait &&
1064 fetchStatus[tid] != QuiescePending) {
1065 DPRINTF(Fetch, "[tid:%i]: Setting to blocked\n",tid);
1066
1067 fetchStatus[tid] = Blocked;
1068
1069 return true;
1070 }
1071
1072 if (fetchStatus[tid] == Blocked ||
1073 fetchStatus[tid] == Squashing) {
1074 // Switch status to running if fetch isn't being told to block or
1075 // squash this cycle.
1076 DPRINTF(Fetch, "[tid:%i]: Done squashing, switching to running.\n",
1077 tid);
1078
1079 fetchStatus[tid] = Running;
1080
1081 return true;
1082 }
1083
1084 // If we've reached this point, we have not gotten any signals that
1085 // cause fetch to change its status. Fetch remains the same as before.
1086 return false;
1087}
1088
1089template<class Impl>
1090typename Impl::DynInstPtr
1091DefaultFetch<Impl>::buildInst(ThreadID tid, StaticInstPtr staticInst,
1092 StaticInstPtr curMacroop, TheISA::PCState thisPC,
1093 TheISA::PCState nextPC, bool trace)
1094{
1095 // Get a sequence number.
1096 InstSeqNum seq = cpu->getAndIncrementInstSeq();
1097
1098 // Create a new DynInst from the instruction fetched.
1099 DynInstPtr instruction =
1100 new DynInst(staticInst, curMacroop, thisPC, nextPC, seq, cpu);
1101 instruction->setTid(tid);
1102
1103 instruction->setASID(tid);
1104
1105 instruction->setThreadState(cpu->thread[tid]);
1106
1107 DPRINTF(Fetch, "[tid:%i]: Instruction PC %#x (%d) created "
1108 "[sn:%lli].\n", tid, thisPC.instAddr(),
1109 thisPC.microPC(), seq);
1110
1111 DPRINTF(Fetch, "[tid:%i]: Instruction is: %s\n", tid,
1112 instruction->staticInst->
1113 disassemble(thisPC.instAddr()));
1114
1115#if TRACING_ON
1116 if (trace) {
1117 instruction->traceData =
1118 cpu->getTracer()->getInstRecord(curTick(), cpu->tcBase(tid),
1119 instruction->staticInst, thisPC, curMacroop);
1120 }
1121#else
1122 instruction->traceData = NULL;
1123#endif
1124
1125 // Add instruction to the CPU's list of instructions.
1126 instruction->setInstListIt(cpu->addInst(instruction));
1127
1128 // Write the instruction to the first slot in the queue
1129 // that heads to decode.
1130 assert(numInst < fetchWidth);
1131 fetchQueue[tid].push_back(instruction);
1132 assert(fetchQueue[tid].size() <= fetchQueueSize);
1133 DPRINTF(Fetch, "[tid:%i]: Fetch queue entry created (%i/%i).\n",
1134 tid, fetchQueue[tid].size(), fetchQueueSize);
1135 //toDecode->insts[toDecode->size++] = instruction;
1136
1137 // Keep track of if we can take an interrupt at this boundary
1138 delayedCommit[tid] = instruction->isDelayedCommit();
1139
1140 return instruction;
1141}
1142
1143template<class Impl>
1144void
1145DefaultFetch<Impl>::fetch(bool &status_change)
1146{
1147 //////////////////////////////////////////
1148 // Start actual fetch
1149 //////////////////////////////////////////
1150 ThreadID tid = getFetchingThread(fetchPolicy);
1151
1152 assert(!cpu->switchedOut());
1153
1154 if (tid == InvalidThreadID) {
1155 // Breaks looping condition in tick()
1156 threadFetched = numFetchingThreads;
1157
1158 if (numThreads == 1) { // @todo Per-thread stats
1159 profileStall(0);
1160 }
1161
1162 return;
1163 }
1164
1165 DPRINTF(Fetch, "Attempting to fetch from [tid:%i]\n", tid);
1166
1167 // The current PC.
1168 TheISA::PCState thisPC = pc[tid];
1169
1170 Addr pcOffset = fetchOffset[tid];
1171 Addr fetchAddr = (thisPC.instAddr() + pcOffset) & BaseCPU::PCMask;
1172
1173 bool inRom = isRomMicroPC(thisPC.microPC());
1174
1175 // If returning from the delay of a cache miss, then update the status
1176 // to running, otherwise do the cache access. Possibly move this up
1177 // to tick() function.
1178 if (fetchStatus[tid] == IcacheAccessComplete) {
1179 DPRINTF(Fetch, "[tid:%i]: Icache miss is complete.\n", tid);
1180
1181 fetchStatus[tid] = Running;
1182 status_change = true;
1183 } else if (fetchStatus[tid] == Running) {
1184 // Align the fetch PC so its at the start of a fetch buffer segment.
1185 Addr fetchBufferBlockPC = fetchBufferAlignPC(fetchAddr);
1186
1187 // If buffer is no longer valid or fetchAddr has moved to point
1188 // to the next cache block, AND we have no remaining ucode
1189 // from a macro-op, then start fetch from icache.
1190 if (!(fetchBufferValid[tid] && fetchBufferBlockPC == fetchBufferPC[tid])
1191 && !inRom && !macroop[tid]) {
1192 DPRINTF(Fetch, "[tid:%i]: Attempting to translate and read "
1193 "instruction, starting at PC %s.\n", tid, thisPC);
1194
1195 fetchCacheLine(fetchAddr, tid, thisPC.instAddr());
1196
1197 if (fetchStatus[tid] == IcacheWaitResponse)
1198 ++icacheStallCycles;
1199 else if (fetchStatus[tid] == ItlbWait)
1200 ++fetchTlbCycles;
1201 else
1202 ++fetchMiscStallCycles;
1203 return;
1204 } else if ((checkInterrupt(thisPC.instAddr()) && !delayedCommit[tid])) {
1205 // Stall CPU if an interrupt is posted and we're not issuing
1206 // an delayed commit micro-op currently (delayed commit instructions
1207 // are not interruptable by interrupts, only faults)
1208 ++fetchMiscStallCycles;
1209 DPRINTF(Fetch, "[tid:%i]: Fetch is stalled!\n", tid);
1210 return;
1211 }
1212 } else {
1213 if (fetchStatus[tid] == Idle) {
1214 ++fetchIdleCycles;
1215 DPRINTF(Fetch, "[tid:%i]: Fetch is idle!\n", tid);
1216 }
1217
1218 // Status is Idle, so fetch should do nothing.
1219 return;
1220 }
1221
1222 ++fetchCycles;
1223
1224 TheISA::PCState nextPC = thisPC;
1225
1226 StaticInstPtr staticInst = NULL;
1227 StaticInstPtr curMacroop = macroop[tid];
1228
1229 // If the read of the first instruction was successful, then grab the
1230 // instructions from the rest of the cache line and put them into the
1231 // queue heading to decode.
1232
1233 DPRINTF(Fetch, "[tid:%i]: Adding instructions to queue to "
1234 "decode.\n", tid);
1235
1236 // Need to keep track of whether or not a predicted branch
1237 // ended this fetch block.
1238 bool predictedBranch = false;
1239
1240 // Need to halt fetch if quiesce instruction detected
1241 bool quiesce = false;
1242
1243 TheISA::MachInst *cacheInsts =
1244 reinterpret_cast<TheISA::MachInst *>(fetchBuffer[tid]);
1245
1246 const unsigned numInsts = fetchBufferSize / instSize;
1247 unsigned blkOffset = (fetchAddr - fetchBufferPC[tid]) / instSize;
1248
1249 // Loop through instruction memory from the cache.
1250 // Keep issuing while fetchWidth is available and branch is not
1251 // predicted taken
1252 while (numInst < fetchWidth && fetchQueue[tid].size() < fetchQueueSize
1253 && !predictedBranch && !quiesce) {
1254 // We need to process more memory if we aren't going to get a
1255 // StaticInst from the rom, the current macroop, or what's already
1256 // in the decoder.
1257 bool needMem = !inRom && !curMacroop &&
1258 !decoder[tid]->instReady();
1259 fetchAddr = (thisPC.instAddr() + pcOffset) & BaseCPU::PCMask;
1260 Addr fetchBufferBlockPC = fetchBufferAlignPC(fetchAddr);
1261
1262 if (needMem) {
1263 // If buffer is no longer valid or fetchAddr has moved to point
1264 // to the next cache block then start fetch from icache.
1265 if (!fetchBufferValid[tid] ||
1266 fetchBufferBlockPC != fetchBufferPC[tid])
1267 break;
1268
1269 if (blkOffset >= numInsts) {
1270 // We need to process more memory, but we've run out of the
1271 // current block.
1272 break;
1273 }
1274
1275 MachInst inst = TheISA::gtoh(cacheInsts[blkOffset]);
1276 decoder[tid]->moreBytes(thisPC, fetchAddr, inst);
1277
1278 if (decoder[tid]->needMoreBytes()) {
1279 blkOffset++;
1280 fetchAddr += instSize;
1281 pcOffset += instSize;
1282 }
1283 }
1284
1285 // Extract as many instructions and/or microops as we can from
1286 // the memory we've processed so far.
1287 do {
1288 if (!(curMacroop || inRom)) {
1289 if (decoder[tid]->instReady()) {
1290 staticInst = decoder[tid]->decode(thisPC);
1291
1292 // Increment stat of fetched instructions.
1293 ++fetchedInsts;
1294
1295 if (staticInst->isMacroop()) {
1296 curMacroop = staticInst;
1297 } else {
1298 pcOffset = 0;
1299 }
1300 } else {
1301 // We need more bytes for this instruction so blkOffset and
1302 // pcOffset will be updated
1303 break;
1304 }
1305 }
1306 // Whether we're moving to a new macroop because we're at the
1307 // end of the current one, or the branch predictor incorrectly
1308 // thinks we are...
1309 bool newMacro = false;
1310 if (curMacroop || inRom) {
1311 if (inRom) {
1312 staticInst = cpu->microcodeRom.fetchMicroop(
1313 thisPC.microPC(), curMacroop);
1314 } else {
1315 staticInst = curMacroop->fetchMicroop(thisPC.microPC());
1316 }
1317 newMacro |= staticInst->isLastMicroop();
1318 }
1319
1320 DynInstPtr instruction =
1321 buildInst(tid, staticInst, curMacroop,
1322 thisPC, nextPC, true);
1323
1324 ppFetch->notify(instruction);
1325 numInst++;
1326
1327#if TRACING_ON
1328 if (DTRACE(O3PipeView)) {
1329 instruction->fetchTick = curTick();
1330 }
1331#endif
1332
1333 nextPC = thisPC;
1334
1335 // If we're branching after this instruction, quit fetching
1336 // from the same block.
1337 predictedBranch |= thisPC.branching();
1338 predictedBranch |=
1339 lookupAndUpdateNextPC(instruction, nextPC);
1340 if (predictedBranch) {
1341 DPRINTF(Fetch, "Branch detected with PC = %s\n", thisPC);
1342 }
1343
1344 newMacro |= thisPC.instAddr() != nextPC.instAddr();
1345
1346 // Move to the next instruction, unless we have a branch.
1347 thisPC = nextPC;
1348 inRom = isRomMicroPC(thisPC.microPC());
1349
1350 if (newMacro) {
1351 fetchAddr = thisPC.instAddr() & BaseCPU::PCMask;
1352 blkOffset = (fetchAddr - fetchBufferPC[tid]) / instSize;
1353 pcOffset = 0;
1354 curMacroop = NULL;
1355 }
1356
1357 if (instruction->isQuiesce()) {
1358 DPRINTF(Fetch,
1359 "Quiesce instruction encountered, halting fetch!\n");
1360 fetchStatus[tid] = QuiescePending;
1361 status_change = true;
1362 quiesce = true;
1363 break;
1364 }
1365 } while ((curMacroop || decoder[tid]->instReady()) &&
1366 numInst < fetchWidth &&
1367 fetchQueue[tid].size() < fetchQueueSize);
1368
1369 // Re-evaluate whether the next instruction to fetch is in micro-op ROM
1370 // or not.
1371 inRom = isRomMicroPC(thisPC.microPC());
1372 }
1373
1374 if (predictedBranch) {
1375 DPRINTF(Fetch, "[tid:%i]: Done fetching, predicted branch "
1376 "instruction encountered.\n", tid);
1377 } else if (numInst >= fetchWidth) {
1378 DPRINTF(Fetch, "[tid:%i]: Done fetching, reached fetch bandwidth "
1379 "for this cycle.\n", tid);
1380 } else if (blkOffset >= fetchBufferSize) {
1381 DPRINTF(Fetch, "[tid:%i]: Done fetching, reached the end of the"
1382 "fetch buffer.\n", tid);
1383 }
1384
1385 macroop[tid] = curMacroop;
1386 fetchOffset[tid] = pcOffset;
1387
1388 if (numInst > 0) {
1389 wroteToTimeBuffer = true;
1390 }
1391
1392 pc[tid] = thisPC;
1393
1394 // pipeline a fetch if we're crossing a fetch buffer boundary and not in
1395 // a state that would preclude fetching
1396 fetchAddr = (thisPC.instAddr() + pcOffset) & BaseCPU::PCMask;
1397 Addr fetchBufferBlockPC = fetchBufferAlignPC(fetchAddr);
1398 issuePipelinedIfetch[tid] = fetchBufferBlockPC != fetchBufferPC[tid] &&
1399 fetchStatus[tid] != IcacheWaitResponse &&
1400 fetchStatus[tid] != ItlbWait &&
1401 fetchStatus[tid] != IcacheWaitRetry &&
1402 fetchStatus[tid] != QuiescePending &&
1403 !curMacroop;
1404}
1405
1406template<class Impl>
1407void
1408DefaultFetch<Impl>::recvReqRetry()
1409{
1410 if (retryPkt != NULL) {
1411 assert(cacheBlocked);
1412 assert(retryTid != InvalidThreadID);
1413 assert(fetchStatus[retryTid] == IcacheWaitRetry);
1414
1415 if (cpu->getInstPort().sendTimingReq(retryPkt)) {
1416 fetchStatus[retryTid] = IcacheWaitResponse;
1417 // Notify Fetch Request probe when a retryPkt is successfully sent.
1418 // Note that notify must be called before retryPkt is set to NULL.
1419 ppFetchRequestSent->notify(retryPkt->req);
1420 retryPkt = NULL;
1421 retryTid = InvalidThreadID;
1422 cacheBlocked = false;
1423 }
1424 } else {
1425 assert(retryTid == InvalidThreadID);
1426 // Access has been squashed since it was sent out. Just clear
1427 // the cache being blocked.
1428 cacheBlocked = false;
1429 }
1430}
1431
1432///////////////////////////////////////
1433// //
1434// SMT FETCH POLICY MAINTAINED HERE //
1435// //
1436///////////////////////////////////////
1437template<class Impl>
1438ThreadID
1439DefaultFetch<Impl>::getFetchingThread(FetchPriority &fetch_priority)
1440{
1441 if (numThreads > 1) {
1442 switch (fetch_priority) {
1443
1444 case SingleThread:
1445 return 0;
1446
1447 case RoundRobin:
1448 return roundRobin();
1449
1450 case IQ:
1451 return iqCount();
1452
1453 case LSQ:
1454 return lsqCount();
1455
1456 case Branch:
1457 return branchCount();
1458
1459 default:
1460 return InvalidThreadID;
1461 }
1462 } else {
1463 list<ThreadID>::iterator thread = activeThreads->begin();
1464 if (thread == activeThreads->end()) {
1465 return InvalidThreadID;
1466 }
1467
1468 ThreadID tid = *thread;
1469
1470 if (fetchStatus[tid] == Running ||
1471 fetchStatus[tid] == IcacheAccessComplete ||
1472 fetchStatus[tid] == Idle) {
1473 return tid;
1474 } else {
1475 return InvalidThreadID;
1476 }
1477 }
1478}
1479
1480
1481template<class Impl>
1482ThreadID
1483DefaultFetch<Impl>::roundRobin()
1484{
1485 list<ThreadID>::iterator pri_iter = priorityList.begin();
1486 list<ThreadID>::iterator end = priorityList.end();
1487
1488 ThreadID high_pri;
1489
1490 while (pri_iter != end) {
1491 high_pri = *pri_iter;
1492
1493 assert(high_pri <= numThreads);
1494
1495 if (fetchStatus[high_pri] == Running ||
1496 fetchStatus[high_pri] == IcacheAccessComplete ||
1497 fetchStatus[high_pri] == Idle) {
1498
1499 priorityList.erase(pri_iter);
1500 priorityList.push_back(high_pri);
1501
1502 return high_pri;
1503 }
1504
1505 pri_iter++;
1506 }
1507
1508 return InvalidThreadID;
1509}
1510
1511template<class Impl>
1512ThreadID
1513DefaultFetch<Impl>::iqCount()
1514{
1515 //sorted from lowest->highest
1516 std::priority_queue<unsigned,vector<unsigned>,
1517 std::greater<unsigned> > PQ;
1518 std::map<unsigned, ThreadID> threadMap;
1519
1520 list<ThreadID>::iterator threads = activeThreads->begin();
1521 list<ThreadID>::iterator end = activeThreads->end();
1522
1523 while (threads != end) {
1524 ThreadID tid = *threads++;
1525 unsigned iqCount = fromIEW->iewInfo[tid].iqCount;
1526
1527 //we can potentially get tid collisions if two threads
1528 //have the same iqCount, but this should be rare.
1529 PQ.push(iqCount);
1530 threadMap[iqCount] = tid;
1531 }
1532
1533 while (!PQ.empty()) {
1534 ThreadID high_pri = threadMap[PQ.top()];
1535
1536 if (fetchStatus[high_pri] == Running ||
1537 fetchStatus[high_pri] == IcacheAccessComplete ||
1538 fetchStatus[high_pri] == Idle)
1539 return high_pri;
1540 else
1541 PQ.pop();
1542
1543 }
1544
1545 return InvalidThreadID;
1546}
1547
1548template<class Impl>
1549ThreadID
1550DefaultFetch<Impl>::lsqCount()
1551{
1552 //sorted from lowest->highest
1553 std::priority_queue<unsigned,vector<unsigned>,
1554 std::greater<unsigned> > PQ;
1555 std::map<unsigned, ThreadID> threadMap;
1556
1557 list<ThreadID>::iterator threads = activeThreads->begin();
1558 list<ThreadID>::iterator end = activeThreads->end();
1559
1560 while (threads != end) {
1561 ThreadID tid = *threads++;
1562 unsigned ldstqCount = fromIEW->iewInfo[tid].ldstqCount;
1563
1564 //we can potentially get tid collisions if two threads
1565 //have the same iqCount, but this should be rare.
1566 PQ.push(ldstqCount);
1567 threadMap[ldstqCount] = tid;
1568 }
1569
1570 while (!PQ.empty()) {
1571 ThreadID high_pri = threadMap[PQ.top()];
1572
1573 if (fetchStatus[high_pri] == Running ||
1574 fetchStatus[high_pri] == IcacheAccessComplete ||
1575 fetchStatus[high_pri] == Idle)
1576 return high_pri;
1577 else
1578 PQ.pop();
1579 }
1580
1581 return InvalidThreadID;
1582}
1583
1584template<class Impl>
1585ThreadID
1586DefaultFetch<Impl>::branchCount()
1587{
1588#if 0
1589 list<ThreadID>::iterator thread = activeThreads->begin();
1590 assert(thread != activeThreads->end());
1591 ThreadID tid = *thread;
1592#endif
1593
1594 panic("Branch Count Fetch policy unimplemented\n");
1595 return InvalidThreadID;
1596}
1597
1598template<class Impl>
1599void
1600DefaultFetch<Impl>::pipelineIcacheAccesses(ThreadID tid)
1601{
1602 if (!issuePipelinedIfetch[tid]) {
1603 return;
1604 }
1605
1606 // The next PC to access.
1607 TheISA::PCState thisPC = pc[tid];
1608
1609 if (isRomMicroPC(thisPC.microPC())) {
1610 return;
1611 }
1612
1613 Addr pcOffset = fetchOffset[tid];
1614 Addr fetchAddr = (thisPC.instAddr() + pcOffset) & BaseCPU::PCMask;
1615
1616 // Align the fetch PC so its at the start of a fetch buffer segment.
1617 Addr fetchBufferBlockPC = fetchBufferAlignPC(fetchAddr);
1618
1619 // Unless buffer already got the block, fetch it from icache.
1620 if (!(fetchBufferValid[tid] && fetchBufferBlockPC == fetchBufferPC[tid])) {
1621 DPRINTF(Fetch, "[tid:%i]: Issuing a pipelined I-cache access, "
1622 "starting at PC %s.\n", tid, thisPC);
1623
1624 fetchCacheLine(fetchAddr, tid, thisPC.instAddr());
1625 }
1626}
1627
1628template<class Impl>
1629void
1630DefaultFetch<Impl>::profileStall(ThreadID tid) {
1631 DPRINTF(Fetch,"There are no more threads available to fetch from.\n");
1632
1633 // @todo Per-thread stats
1634
1635 if (stalls[tid].drain) {
1636 ++fetchPendingDrainCycles;
1637 DPRINTF(Fetch, "Fetch is waiting for a drain!\n");
1638 } else if (activeThreads->empty()) {
1639 ++fetchNoActiveThreadStallCycles;
1640 DPRINTF(Fetch, "Fetch has no active thread!\n");
1641 } else if (fetchStatus[tid] == Blocked) {
1642 ++fetchBlockedCycles;
1643 DPRINTF(Fetch, "[tid:%i]: Fetch is blocked!\n", tid);
1644 } else if (fetchStatus[tid] == Squashing) {
1645 ++fetchSquashCycles;
1646 DPRINTF(Fetch, "[tid:%i]: Fetch is squashing!\n", tid);
1647 } else if (fetchStatus[tid] == IcacheWaitResponse) {
1648 ++icacheStallCycles;
1649 DPRINTF(Fetch, "[tid:%i]: Fetch is waiting cache response!\n",
1650 tid);
1651 } else if (fetchStatus[tid] == ItlbWait) {
1652 ++fetchTlbCycles;
1653 DPRINTF(Fetch, "[tid:%i]: Fetch is waiting ITLB walk to "
1654 "finish!\n", tid);
1655 } else if (fetchStatus[tid] == TrapPending) {
1656 ++fetchPendingTrapStallCycles;
1657 DPRINTF(Fetch, "[tid:%i]: Fetch is waiting for a pending trap!\n",
1658 tid);
1659 } else if (fetchStatus[tid] == QuiescePending) {
1660 ++fetchPendingQuiesceStallCycles;
1661 DPRINTF(Fetch, "[tid:%i]: Fetch is waiting for a pending quiesce "
1662 "instruction!\n", tid);
1663 } else if (fetchStatus[tid] == IcacheWaitRetry) {
1664 ++fetchIcacheWaitRetryStallCycles;
1665 DPRINTF(Fetch, "[tid:%i]: Fetch is waiting for an I-cache retry!\n",
1666 tid);
1667 } else if (fetchStatus[tid] == NoGoodAddr) {
1668 DPRINTF(Fetch, "[tid:%i]: Fetch predicted non-executable address\n",
1669 tid);
1670 } else {
1671 DPRINTF(Fetch, "[tid:%i]: Unexpected fetch stall reason (Status: %i).\n",
1672 tid, fetchStatus[tid]);
1673 }
1674}
1675
1676#endif//__CPU_O3_FETCH_IMPL_HH__
| 957 toDecode->insts[toDecode->size++] = inst;
958 DPRINTF(Fetch, "[tid:%i][sn:%i]: Sending instruction to decode from "
959 "fetch queue. Fetch queue size: %i.\n",
960 tid, inst->seqNum, fetchQueue[tid].size());
961
962 wroteToTimeBuffer = true;
963 fetchQueue[tid].pop_front();
964 insts_to_decode++;
965 available_insts--;
966 }
967
968 tid_itr++;
969 // Wrap around if at end of active threads list
970 if (tid_itr == activeThreads->end())
971 tid_itr = activeThreads->begin();
972 }
973
974 // If there was activity this cycle, inform the CPU of it.
975 if (wroteToTimeBuffer) {
976 DPRINTF(Activity, "Activity this cycle.\n");
977 cpu->activityThisCycle();
978 }
979
980 // Reset the number of the instruction we've fetched.
981 numInst = 0;
982}
983
984template <class Impl>
985bool
986DefaultFetch<Impl>::checkSignalsAndUpdate(ThreadID tid)
987{
988 // Update the per thread stall statuses.
989 if (fromDecode->decodeBlock[tid]) {
990 stalls[tid].decode = true;
991 }
992
993 if (fromDecode->decodeUnblock[tid]) {
994 assert(stalls[tid].decode);
995 assert(!fromDecode->decodeBlock[tid]);
996 stalls[tid].decode = false;
997 }
998
999 // Check squash signals from commit.
1000 if (fromCommit->commitInfo[tid].squash) {
1001
1002 DPRINTF(Fetch, "[tid:%u]: Squashing instructions due to squash "
1003 "from commit.\n",tid);
1004 // In any case, squash.
1005 squash(fromCommit->commitInfo[tid].pc,
1006 fromCommit->commitInfo[tid].doneSeqNum,
1007 fromCommit->commitInfo[tid].squashInst, tid);
1008
1009 // If it was a branch mispredict on a control instruction, update the
1010 // branch predictor with that instruction, otherwise just kill the
1011 // invalid state we generated in after sequence number
1012 if (fromCommit->commitInfo[tid].mispredictInst &&
1013 fromCommit->commitInfo[tid].mispredictInst->isControl()) {
1014 branchPred->squash(fromCommit->commitInfo[tid].doneSeqNum,
1015 fromCommit->commitInfo[tid].pc,
1016 fromCommit->commitInfo[tid].branchTaken,
1017 tid);
1018 } else {
1019 branchPred->squash(fromCommit->commitInfo[tid].doneSeqNum,
1020 tid);
1021 }
1022
1023 return true;
1024 } else if (fromCommit->commitInfo[tid].doneSeqNum) {
1025 // Update the branch predictor if it wasn't a squashed instruction
1026 // that was broadcasted.
1027 branchPred->update(fromCommit->commitInfo[tid].doneSeqNum, tid);
1028 }
1029
1030 // Check squash signals from decode.
1031 if (fromDecode->decodeInfo[tid].squash) {
1032 DPRINTF(Fetch, "[tid:%u]: Squashing instructions due to squash "
1033 "from decode.\n",tid);
1034
1035 // Update the branch predictor.
1036 if (fromDecode->decodeInfo[tid].branchMispredict) {
1037 branchPred->squash(fromDecode->decodeInfo[tid].doneSeqNum,
1038 fromDecode->decodeInfo[tid].nextPC,
1039 fromDecode->decodeInfo[tid].branchTaken,
1040 tid);
1041 } else {
1042 branchPred->squash(fromDecode->decodeInfo[tid].doneSeqNum,
1043 tid);
1044 }
1045
1046 if (fetchStatus[tid] != Squashing) {
1047
1048 DPRINTF(Fetch, "Squashing from decode with PC = %s\n",
1049 fromDecode->decodeInfo[tid].nextPC);
1050 // Squash unless we're already squashing
1051 squashFromDecode(fromDecode->decodeInfo[tid].nextPC,
1052 fromDecode->decodeInfo[tid].squashInst,
1053 fromDecode->decodeInfo[tid].doneSeqNum,
1054 tid);
1055
1056 return true;
1057 }
1058 }
1059
1060 if (checkStall(tid) &&
1061 fetchStatus[tid] != IcacheWaitResponse &&
1062 fetchStatus[tid] != IcacheWaitRetry &&
1063 fetchStatus[tid] != ItlbWait &&
1064 fetchStatus[tid] != QuiescePending) {
1065 DPRINTF(Fetch, "[tid:%i]: Setting to blocked\n",tid);
1066
1067 fetchStatus[tid] = Blocked;
1068
1069 return true;
1070 }
1071
1072 if (fetchStatus[tid] == Blocked ||
1073 fetchStatus[tid] == Squashing) {
1074 // Switch status to running if fetch isn't being told to block or
1075 // squash this cycle.
1076 DPRINTF(Fetch, "[tid:%i]: Done squashing, switching to running.\n",
1077 tid);
1078
1079 fetchStatus[tid] = Running;
1080
1081 return true;
1082 }
1083
1084 // If we've reached this point, we have not gotten any signals that
1085 // cause fetch to change its status. Fetch remains the same as before.
1086 return false;
1087}
1088
1089template<class Impl>
1090typename Impl::DynInstPtr
1091DefaultFetch<Impl>::buildInst(ThreadID tid, StaticInstPtr staticInst,
1092 StaticInstPtr curMacroop, TheISA::PCState thisPC,
1093 TheISA::PCState nextPC, bool trace)
1094{
1095 // Get a sequence number.
1096 InstSeqNum seq = cpu->getAndIncrementInstSeq();
1097
1098 // Create a new DynInst from the instruction fetched.
1099 DynInstPtr instruction =
1100 new DynInst(staticInst, curMacroop, thisPC, nextPC, seq, cpu);
1101 instruction->setTid(tid);
1102
1103 instruction->setASID(tid);
1104
1105 instruction->setThreadState(cpu->thread[tid]);
1106
1107 DPRINTF(Fetch, "[tid:%i]: Instruction PC %#x (%d) created "
1108 "[sn:%lli].\n", tid, thisPC.instAddr(),
1109 thisPC.microPC(), seq);
1110
1111 DPRINTF(Fetch, "[tid:%i]: Instruction is: %s\n", tid,
1112 instruction->staticInst->
1113 disassemble(thisPC.instAddr()));
1114
1115#if TRACING_ON
1116 if (trace) {
1117 instruction->traceData =
1118 cpu->getTracer()->getInstRecord(curTick(), cpu->tcBase(tid),
1119 instruction->staticInst, thisPC, curMacroop);
1120 }
1121#else
1122 instruction->traceData = NULL;
1123#endif
1124
1125 // Add instruction to the CPU's list of instructions.
1126 instruction->setInstListIt(cpu->addInst(instruction));
1127
1128 // Write the instruction to the first slot in the queue
1129 // that heads to decode.
1130 assert(numInst < fetchWidth);
1131 fetchQueue[tid].push_back(instruction);
1132 assert(fetchQueue[tid].size() <= fetchQueueSize);
1133 DPRINTF(Fetch, "[tid:%i]: Fetch queue entry created (%i/%i).\n",
1134 tid, fetchQueue[tid].size(), fetchQueueSize);
1135 //toDecode->insts[toDecode->size++] = instruction;
1136
1137 // Keep track of if we can take an interrupt at this boundary
1138 delayedCommit[tid] = instruction->isDelayedCommit();
1139
1140 return instruction;
1141}
1142
1143template<class Impl>
1144void
1145DefaultFetch<Impl>::fetch(bool &status_change)
1146{
1147 //////////////////////////////////////////
1148 // Start actual fetch
1149 //////////////////////////////////////////
1150 ThreadID tid = getFetchingThread(fetchPolicy);
1151
1152 assert(!cpu->switchedOut());
1153
1154 if (tid == InvalidThreadID) {
1155 // Breaks looping condition in tick()
1156 threadFetched = numFetchingThreads;
1157
1158 if (numThreads == 1) { // @todo Per-thread stats
1159 profileStall(0);
1160 }
1161
1162 return;
1163 }
1164
1165 DPRINTF(Fetch, "Attempting to fetch from [tid:%i]\n", tid);
1166
1167 // The current PC.
1168 TheISA::PCState thisPC = pc[tid];
1169
1170 Addr pcOffset = fetchOffset[tid];
1171 Addr fetchAddr = (thisPC.instAddr() + pcOffset) & BaseCPU::PCMask;
1172
1173 bool inRom = isRomMicroPC(thisPC.microPC());
1174
1175 // If returning from the delay of a cache miss, then update the status
1176 // to running, otherwise do the cache access. Possibly move this up
1177 // to tick() function.
1178 if (fetchStatus[tid] == IcacheAccessComplete) {
1179 DPRINTF(Fetch, "[tid:%i]: Icache miss is complete.\n", tid);
1180
1181 fetchStatus[tid] = Running;
1182 status_change = true;
1183 } else if (fetchStatus[tid] == Running) {
1184 // Align the fetch PC so its at the start of a fetch buffer segment.
1185 Addr fetchBufferBlockPC = fetchBufferAlignPC(fetchAddr);
1186
1187 // If buffer is no longer valid or fetchAddr has moved to point
1188 // to the next cache block, AND we have no remaining ucode
1189 // from a macro-op, then start fetch from icache.
1190 if (!(fetchBufferValid[tid] && fetchBufferBlockPC == fetchBufferPC[tid])
1191 && !inRom && !macroop[tid]) {
1192 DPRINTF(Fetch, "[tid:%i]: Attempting to translate and read "
1193 "instruction, starting at PC %s.\n", tid, thisPC);
1194
1195 fetchCacheLine(fetchAddr, tid, thisPC.instAddr());
1196
1197 if (fetchStatus[tid] == IcacheWaitResponse)
1198 ++icacheStallCycles;
1199 else if (fetchStatus[tid] == ItlbWait)
1200 ++fetchTlbCycles;
1201 else
1202 ++fetchMiscStallCycles;
1203 return;
1204 } else if ((checkInterrupt(thisPC.instAddr()) && !delayedCommit[tid])) {
1205 // Stall CPU if an interrupt is posted and we're not issuing
1206 // an delayed commit micro-op currently (delayed commit instructions
1207 // are not interruptable by interrupts, only faults)
1208 ++fetchMiscStallCycles;
1209 DPRINTF(Fetch, "[tid:%i]: Fetch is stalled!\n", tid);
1210 return;
1211 }
1212 } else {
1213 if (fetchStatus[tid] == Idle) {
1214 ++fetchIdleCycles;
1215 DPRINTF(Fetch, "[tid:%i]: Fetch is idle!\n", tid);
1216 }
1217
1218 // Status is Idle, so fetch should do nothing.
1219 return;
1220 }
1221
1222 ++fetchCycles;
1223
1224 TheISA::PCState nextPC = thisPC;
1225
1226 StaticInstPtr staticInst = NULL;
1227 StaticInstPtr curMacroop = macroop[tid];
1228
1229 // If the read of the first instruction was successful, then grab the
1230 // instructions from the rest of the cache line and put them into the
1231 // queue heading to decode.
1232
1233 DPRINTF(Fetch, "[tid:%i]: Adding instructions to queue to "
1234 "decode.\n", tid);
1235
1236 // Need to keep track of whether or not a predicted branch
1237 // ended this fetch block.
1238 bool predictedBranch = false;
1239
1240 // Need to halt fetch if quiesce instruction detected
1241 bool quiesce = false;
1242
1243 TheISA::MachInst *cacheInsts =
1244 reinterpret_cast<TheISA::MachInst *>(fetchBuffer[tid]);
1245
1246 const unsigned numInsts = fetchBufferSize / instSize;
1247 unsigned blkOffset = (fetchAddr - fetchBufferPC[tid]) / instSize;
1248
1249 // Loop through instruction memory from the cache.
1250 // Keep issuing while fetchWidth is available and branch is not
1251 // predicted taken
1252 while (numInst < fetchWidth && fetchQueue[tid].size() < fetchQueueSize
1253 && !predictedBranch && !quiesce) {
1254 // We need to process more memory if we aren't going to get a
1255 // StaticInst from the rom, the current macroop, or what's already
1256 // in the decoder.
1257 bool needMem = !inRom && !curMacroop &&
1258 !decoder[tid]->instReady();
1259 fetchAddr = (thisPC.instAddr() + pcOffset) & BaseCPU::PCMask;
1260 Addr fetchBufferBlockPC = fetchBufferAlignPC(fetchAddr);
1261
1262 if (needMem) {
1263 // If buffer is no longer valid or fetchAddr has moved to point
1264 // to the next cache block then start fetch from icache.
1265 if (!fetchBufferValid[tid] ||
1266 fetchBufferBlockPC != fetchBufferPC[tid])
1267 break;
1268
1269 if (blkOffset >= numInsts) {
1270 // We need to process more memory, but we've run out of the
1271 // current block.
1272 break;
1273 }
1274
1275 MachInst inst = TheISA::gtoh(cacheInsts[blkOffset]);
1276 decoder[tid]->moreBytes(thisPC, fetchAddr, inst);
1277
1278 if (decoder[tid]->needMoreBytes()) {
1279 blkOffset++;
1280 fetchAddr += instSize;
1281 pcOffset += instSize;
1282 }
1283 }
1284
1285 // Extract as many instructions and/or microops as we can from
1286 // the memory we've processed so far.
1287 do {
1288 if (!(curMacroop || inRom)) {
1289 if (decoder[tid]->instReady()) {
1290 staticInst = decoder[tid]->decode(thisPC);
1291
1292 // Increment stat of fetched instructions.
1293 ++fetchedInsts;
1294
1295 if (staticInst->isMacroop()) {
1296 curMacroop = staticInst;
1297 } else {
1298 pcOffset = 0;
1299 }
1300 } else {
1301 // We need more bytes for this instruction so blkOffset and
1302 // pcOffset will be updated
1303 break;
1304 }
1305 }
1306 // Whether we're moving to a new macroop because we're at the
1307 // end of the current one, or the branch predictor incorrectly
1308 // thinks we are...
1309 bool newMacro = false;
1310 if (curMacroop || inRom) {
1311 if (inRom) {
1312 staticInst = cpu->microcodeRom.fetchMicroop(
1313 thisPC.microPC(), curMacroop);
1314 } else {
1315 staticInst = curMacroop->fetchMicroop(thisPC.microPC());
1316 }
1317 newMacro |= staticInst->isLastMicroop();
1318 }
1319
1320 DynInstPtr instruction =
1321 buildInst(tid, staticInst, curMacroop,
1322 thisPC, nextPC, true);
1323
1324 ppFetch->notify(instruction);
1325 numInst++;
1326
1327#if TRACING_ON
1328 if (DTRACE(O3PipeView)) {
1329 instruction->fetchTick = curTick();
1330 }
1331#endif
1332
1333 nextPC = thisPC;
1334
1335 // If we're branching after this instruction, quit fetching
1336 // from the same block.
1337 predictedBranch |= thisPC.branching();
1338 predictedBranch |=
1339 lookupAndUpdateNextPC(instruction, nextPC);
1340 if (predictedBranch) {
1341 DPRINTF(Fetch, "Branch detected with PC = %s\n", thisPC);
1342 }
1343
1344 newMacro |= thisPC.instAddr() != nextPC.instAddr();
1345
1346 // Move to the next instruction, unless we have a branch.
1347 thisPC = nextPC;
1348 inRom = isRomMicroPC(thisPC.microPC());
1349
1350 if (newMacro) {
1351 fetchAddr = thisPC.instAddr() & BaseCPU::PCMask;
1352 blkOffset = (fetchAddr - fetchBufferPC[tid]) / instSize;
1353 pcOffset = 0;
1354 curMacroop = NULL;
1355 }
1356
1357 if (instruction->isQuiesce()) {
1358 DPRINTF(Fetch,
1359 "Quiesce instruction encountered, halting fetch!\n");
1360 fetchStatus[tid] = QuiescePending;
1361 status_change = true;
1362 quiesce = true;
1363 break;
1364 }
1365 } while ((curMacroop || decoder[tid]->instReady()) &&
1366 numInst < fetchWidth &&
1367 fetchQueue[tid].size() < fetchQueueSize);
1368
1369 // Re-evaluate whether the next instruction to fetch is in micro-op ROM
1370 // or not.
1371 inRom = isRomMicroPC(thisPC.microPC());
1372 }
1373
1374 if (predictedBranch) {
1375 DPRINTF(Fetch, "[tid:%i]: Done fetching, predicted branch "
1376 "instruction encountered.\n", tid);
1377 } else if (numInst >= fetchWidth) {
1378 DPRINTF(Fetch, "[tid:%i]: Done fetching, reached fetch bandwidth "
1379 "for this cycle.\n", tid);
1380 } else if (blkOffset >= fetchBufferSize) {
1381 DPRINTF(Fetch, "[tid:%i]: Done fetching, reached the end of the"
1382 "fetch buffer.\n", tid);
1383 }
1384
1385 macroop[tid] = curMacroop;
1386 fetchOffset[tid] = pcOffset;
1387
1388 if (numInst > 0) {
1389 wroteToTimeBuffer = true;
1390 }
1391
1392 pc[tid] = thisPC;
1393
1394 // pipeline a fetch if we're crossing a fetch buffer boundary and not in
1395 // a state that would preclude fetching
1396 fetchAddr = (thisPC.instAddr() + pcOffset) & BaseCPU::PCMask;
1397 Addr fetchBufferBlockPC = fetchBufferAlignPC(fetchAddr);
1398 issuePipelinedIfetch[tid] = fetchBufferBlockPC != fetchBufferPC[tid] &&
1399 fetchStatus[tid] != IcacheWaitResponse &&
1400 fetchStatus[tid] != ItlbWait &&
1401 fetchStatus[tid] != IcacheWaitRetry &&
1402 fetchStatus[tid] != QuiescePending &&
1403 !curMacroop;
1404}
1405
1406template<class Impl>
1407void
1408DefaultFetch<Impl>::recvReqRetry()
1409{
1410 if (retryPkt != NULL) {
1411 assert(cacheBlocked);
1412 assert(retryTid != InvalidThreadID);
1413 assert(fetchStatus[retryTid] == IcacheWaitRetry);
1414
1415 if (cpu->getInstPort().sendTimingReq(retryPkt)) {
1416 fetchStatus[retryTid] = IcacheWaitResponse;
1417 // Notify Fetch Request probe when a retryPkt is successfully sent.
1418 // Note that notify must be called before retryPkt is set to NULL.
1419 ppFetchRequestSent->notify(retryPkt->req);
1420 retryPkt = NULL;
1421 retryTid = InvalidThreadID;
1422 cacheBlocked = false;
1423 }
1424 } else {
1425 assert(retryTid == InvalidThreadID);
1426 // Access has been squashed since it was sent out. Just clear
1427 // the cache being blocked.
1428 cacheBlocked = false;
1429 }
1430}
1431
1432///////////////////////////////////////
1433// //
1434// SMT FETCH POLICY MAINTAINED HERE //
1435// //
1436///////////////////////////////////////
1437template<class Impl>
1438ThreadID
1439DefaultFetch<Impl>::getFetchingThread(FetchPriority &fetch_priority)
1440{
1441 if (numThreads > 1) {
1442 switch (fetch_priority) {
1443
1444 case SingleThread:
1445 return 0;
1446
1447 case RoundRobin:
1448 return roundRobin();
1449
1450 case IQ:
1451 return iqCount();
1452
1453 case LSQ:
1454 return lsqCount();
1455
1456 case Branch:
1457 return branchCount();
1458
1459 default:
1460 return InvalidThreadID;
1461 }
1462 } else {
1463 list<ThreadID>::iterator thread = activeThreads->begin();
1464 if (thread == activeThreads->end()) {
1465 return InvalidThreadID;
1466 }
1467
1468 ThreadID tid = *thread;
1469
1470 if (fetchStatus[tid] == Running ||
1471 fetchStatus[tid] == IcacheAccessComplete ||
1472 fetchStatus[tid] == Idle) {
1473 return tid;
1474 } else {
1475 return InvalidThreadID;
1476 }
1477 }
1478}
1479
1480
1481template<class Impl>
1482ThreadID
1483DefaultFetch<Impl>::roundRobin()
1484{
1485 list<ThreadID>::iterator pri_iter = priorityList.begin();
1486 list<ThreadID>::iterator end = priorityList.end();
1487
1488 ThreadID high_pri;
1489
1490 while (pri_iter != end) {
1491 high_pri = *pri_iter;
1492
1493 assert(high_pri <= numThreads);
1494
1495 if (fetchStatus[high_pri] == Running ||
1496 fetchStatus[high_pri] == IcacheAccessComplete ||
1497 fetchStatus[high_pri] == Idle) {
1498
1499 priorityList.erase(pri_iter);
1500 priorityList.push_back(high_pri);
1501
1502 return high_pri;
1503 }
1504
1505 pri_iter++;
1506 }
1507
1508 return InvalidThreadID;
1509}
1510
1511template<class Impl>
1512ThreadID
1513DefaultFetch<Impl>::iqCount()
1514{
1515 //sorted from lowest->highest
1516 std::priority_queue<unsigned,vector<unsigned>,
1517 std::greater<unsigned> > PQ;
1518 std::map<unsigned, ThreadID> threadMap;
1519
1520 list<ThreadID>::iterator threads = activeThreads->begin();
1521 list<ThreadID>::iterator end = activeThreads->end();
1522
1523 while (threads != end) {
1524 ThreadID tid = *threads++;
1525 unsigned iqCount = fromIEW->iewInfo[tid].iqCount;
1526
1527 //we can potentially get tid collisions if two threads
1528 //have the same iqCount, but this should be rare.
1529 PQ.push(iqCount);
1530 threadMap[iqCount] = tid;
1531 }
1532
1533 while (!PQ.empty()) {
1534 ThreadID high_pri = threadMap[PQ.top()];
1535
1536 if (fetchStatus[high_pri] == Running ||
1537 fetchStatus[high_pri] == IcacheAccessComplete ||
1538 fetchStatus[high_pri] == Idle)
1539 return high_pri;
1540 else
1541 PQ.pop();
1542
1543 }
1544
1545 return InvalidThreadID;
1546}
1547
1548template<class Impl>
1549ThreadID
1550DefaultFetch<Impl>::lsqCount()
1551{
1552 //sorted from lowest->highest
1553 std::priority_queue<unsigned,vector<unsigned>,
1554 std::greater<unsigned> > PQ;
1555 std::map<unsigned, ThreadID> threadMap;
1556
1557 list<ThreadID>::iterator threads = activeThreads->begin();
1558 list<ThreadID>::iterator end = activeThreads->end();
1559
1560 while (threads != end) {
1561 ThreadID tid = *threads++;
1562 unsigned ldstqCount = fromIEW->iewInfo[tid].ldstqCount;
1563
1564 //we can potentially get tid collisions if two threads
1565 //have the same iqCount, but this should be rare.
1566 PQ.push(ldstqCount);
1567 threadMap[ldstqCount] = tid;
1568 }
1569
1570 while (!PQ.empty()) {
1571 ThreadID high_pri = threadMap[PQ.top()];
1572
1573 if (fetchStatus[high_pri] == Running ||
1574 fetchStatus[high_pri] == IcacheAccessComplete ||
1575 fetchStatus[high_pri] == Idle)
1576 return high_pri;
1577 else
1578 PQ.pop();
1579 }
1580
1581 return InvalidThreadID;
1582}
1583
1584template<class Impl>
1585ThreadID
1586DefaultFetch<Impl>::branchCount()
1587{
1588#if 0
1589 list<ThreadID>::iterator thread = activeThreads->begin();
1590 assert(thread != activeThreads->end());
1591 ThreadID tid = *thread;
1592#endif
1593
1594 panic("Branch Count Fetch policy unimplemented\n");
1595 return InvalidThreadID;
1596}
1597
1598template<class Impl>
1599void
1600DefaultFetch<Impl>::pipelineIcacheAccesses(ThreadID tid)
1601{
1602 if (!issuePipelinedIfetch[tid]) {
1603 return;
1604 }
1605
1606 // The next PC to access.
1607 TheISA::PCState thisPC = pc[tid];
1608
1609 if (isRomMicroPC(thisPC.microPC())) {
1610 return;
1611 }
1612
1613 Addr pcOffset = fetchOffset[tid];
1614 Addr fetchAddr = (thisPC.instAddr() + pcOffset) & BaseCPU::PCMask;
1615
1616 // Align the fetch PC so its at the start of a fetch buffer segment.
1617 Addr fetchBufferBlockPC = fetchBufferAlignPC(fetchAddr);
1618
1619 // Unless buffer already got the block, fetch it from icache.
1620 if (!(fetchBufferValid[tid] && fetchBufferBlockPC == fetchBufferPC[tid])) {
1621 DPRINTF(Fetch, "[tid:%i]: Issuing a pipelined I-cache access, "
1622 "starting at PC %s.\n", tid, thisPC);
1623
1624 fetchCacheLine(fetchAddr, tid, thisPC.instAddr());
1625 }
1626}
1627
1628template<class Impl>
1629void
1630DefaultFetch<Impl>::profileStall(ThreadID tid) {
1631 DPRINTF(Fetch,"There are no more threads available to fetch from.\n");
1632
1633 // @todo Per-thread stats
1634
1635 if (stalls[tid].drain) {
1636 ++fetchPendingDrainCycles;
1637 DPRINTF(Fetch, "Fetch is waiting for a drain!\n");
1638 } else if (activeThreads->empty()) {
1639 ++fetchNoActiveThreadStallCycles;
1640 DPRINTF(Fetch, "Fetch has no active thread!\n");
1641 } else if (fetchStatus[tid] == Blocked) {
1642 ++fetchBlockedCycles;
1643 DPRINTF(Fetch, "[tid:%i]: Fetch is blocked!\n", tid);
1644 } else if (fetchStatus[tid] == Squashing) {
1645 ++fetchSquashCycles;
1646 DPRINTF(Fetch, "[tid:%i]: Fetch is squashing!\n", tid);
1647 } else if (fetchStatus[tid] == IcacheWaitResponse) {
1648 ++icacheStallCycles;
1649 DPRINTF(Fetch, "[tid:%i]: Fetch is waiting cache response!\n",
1650 tid);
1651 } else if (fetchStatus[tid] == ItlbWait) {
1652 ++fetchTlbCycles;
1653 DPRINTF(Fetch, "[tid:%i]: Fetch is waiting ITLB walk to "
1654 "finish!\n", tid);
1655 } else if (fetchStatus[tid] == TrapPending) {
1656 ++fetchPendingTrapStallCycles;
1657 DPRINTF(Fetch, "[tid:%i]: Fetch is waiting for a pending trap!\n",
1658 tid);
1659 } else if (fetchStatus[tid] == QuiescePending) {
1660 ++fetchPendingQuiesceStallCycles;
1661 DPRINTF(Fetch, "[tid:%i]: Fetch is waiting for a pending quiesce "
1662 "instruction!\n", tid);
1663 } else if (fetchStatus[tid] == IcacheWaitRetry) {
1664 ++fetchIcacheWaitRetryStallCycles;
1665 DPRINTF(Fetch, "[tid:%i]: Fetch is waiting for an I-cache retry!\n",
1666 tid);
1667 } else if (fetchStatus[tid] == NoGoodAddr) {
1668 DPRINTF(Fetch, "[tid:%i]: Fetch predicted non-executable address\n",
1669 tid);
1670 } else {
1671 DPRINTF(Fetch, "[tid:%i]: Unexpected fetch stall reason (Status: %i).\n",
1672 tid, fetchStatus[tid]);
1673 }
1674}
1675
1676#endif//__CPU_O3_FETCH_IMPL_HH__
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