iew_impl.hh revision 2980:eab855f06b79 
1/*
2 * Copyright (c) 2004-2006 The Regents of The University of Michigan
3 * All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions are
7 * met: redistributions of source code must retain the above copyright
8 * notice, this list of conditions and the following disclaimer;
9 * redistributions in binary form must reproduce the above copyright
10 * notice, this list of conditions and the following disclaimer in the
11 * documentation and/or other materials provided with the distribution;
12 * neither the name of the copyright holders nor the names of its
13 * contributors may be used to endorse or promote products derived from
14 * this software without specific prior written permission.
15 *
16 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
17 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
18 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
19 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
20 * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
21 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
22 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
23 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
24 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
25 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
26 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
27 *
28 * Authors: Kevin Lim
29 */
30
31// @todo: Fix the instantaneous communication among all the stages within
32// iew.  There's a clear delay between issue and execute, yet backwards
33// communication happens simultaneously.
34
35#include <queue>
36
37#include "base/timebuf.hh"
38#include "cpu/o3/fu_pool.hh"
39#include "cpu/o3/iew.hh"
40
41template<class Impl>
42DefaultIEW<Impl>::DefaultIEW(Params *params)
43    : issueToExecQueue(params->backComSize, params->forwardComSize),
44      instQueue(params),
45      ldstQueue(params),
46      fuPool(params->fuPool),
47      commitToIEWDelay(params->commitToIEWDelay),
48      renameToIEWDelay(params->renameToIEWDelay),
49      issueToExecuteDelay(params->issueToExecuteDelay),
50      dispatchWidth(params->dispatchWidth),
51      issueWidth(params->issueWidth),
52      wbOutstanding(0),
53      wbWidth(params->wbWidth),
54      numThreads(params->numberOfThreads),
55      switchedOut(false)
56{
57    _status = Active;
58    exeStatus = Running;
59    wbStatus = Idle;
60
61    // Setup wire to read instructions coming from issue.
62    fromIssue = issueToExecQueue.getWire(-issueToExecuteDelay);
63
64    // Instruction queue needs the queue between issue and execute.
65    instQueue.setIssueToExecuteQueue(&issueToExecQueue);
66
67    instQueue.setIEW(this);
68    ldstQueue.setIEW(this);
69
70    for (int i=0; i < numThreads; i++) {
71        dispatchStatus[i] = Running;
72        stalls[i].commit = false;
73        fetchRedirect[i] = false;
74        bdelayDoneSeqNum[i] = 0;
75    }
76
77    wbMax = wbWidth * params->wbDepth;
78
79    updateLSQNextCycle = false;
80
81    ableToIssue = true;
82
83    skidBufferMax = (3 * (renameToIEWDelay * params->renameWidth)) + issueWidth;
84}
85
86template <class Impl>
87std::string
88DefaultIEW<Impl>::name() const
89{
90    return cpu->name() + ".iew";
91}
92
93template <class Impl>
94void
95DefaultIEW<Impl>::regStats()
96{
97    using namespace Stats;
98
99    instQueue.regStats();
100    ldstQueue.regStats();
101
102    iewIdleCycles
103        .name(name() + ".iewIdleCycles")
104        .desc("Number of cycles IEW is idle");
105
106    iewSquashCycles
107        .name(name() + ".iewSquashCycles")
108        .desc("Number of cycles IEW is squashing");
109
110    iewBlockCycles
111        .name(name() + ".iewBlockCycles")
112        .desc("Number of cycles IEW is blocking");
113
114    iewUnblockCycles
115        .name(name() + ".iewUnblockCycles")
116        .desc("Number of cycles IEW is unblocking");
117
118    iewDispatchedInsts
119        .name(name() + ".iewDispatchedInsts")
120        .desc("Number of instructions dispatched to IQ");
121
122    iewDispSquashedInsts
123        .name(name() + ".iewDispSquashedInsts")
124        .desc("Number of squashed instructions skipped by dispatch");
125
126    iewDispLoadInsts
127        .name(name() + ".iewDispLoadInsts")
128        .desc("Number of dispatched load instructions");
129
130    iewDispStoreInsts
131        .name(name() + ".iewDispStoreInsts")
132        .desc("Number of dispatched store instructions");
133
134    iewDispNonSpecInsts
135        .name(name() + ".iewDispNonSpecInsts")
136        .desc("Number of dispatched non-speculative instructions");
137
138    iewIQFullEvents
139        .name(name() + ".iewIQFullEvents")
140        .desc("Number of times the IQ has become full, causing a stall");
141
142    iewLSQFullEvents
143        .name(name() + ".iewLSQFullEvents")
144        .desc("Number of times the LSQ has become full, causing a stall");
145
146    memOrderViolationEvents
147        .name(name() + ".memOrderViolationEvents")
148        .desc("Number of memory order violations");
149
150    predictedTakenIncorrect
151        .name(name() + ".predictedTakenIncorrect")
152        .desc("Number of branches that were predicted taken incorrectly");
153
154    predictedNotTakenIncorrect
155        .name(name() + ".predictedNotTakenIncorrect")
156        .desc("Number of branches that were predicted not taken incorrectly");
157
158    branchMispredicts
159        .name(name() + ".branchMispredicts")
160        .desc("Number of branch mispredicts detected at execute");
161
162    branchMispredicts = predictedTakenIncorrect + predictedNotTakenIncorrect;
163
164    iewExecutedInsts
165        .name(name() + ".EXEC:insts")
166        .desc("Number of executed instructions");
167
168    iewExecLoadInsts
169        .init(cpu->number_of_threads)
170        .name(name() + ".EXEC:loads")
171        .desc("Number of load instructions executed")
172        .flags(total);
173
174    iewExecSquashedInsts
175        .name(name() + ".EXEC:squashedInsts")
176        .desc("Number of squashed instructions skipped in execute");
177
178    iewExecutedSwp
179        .init(cpu->number_of_threads)
180        .name(name() + ".EXEC:swp")
181        .desc("number of swp insts executed")
182        .flags(total);
183
184    iewExecutedNop
185        .init(cpu->number_of_threads)
186        .name(name() + ".EXEC:nop")
187        .desc("number of nop insts executed")
188        .flags(total);
189
190    iewExecutedRefs
191        .init(cpu->number_of_threads)
192        .name(name() + ".EXEC:refs")
193        .desc("number of memory reference insts executed")
194        .flags(total);
195
196    iewExecutedBranches
197        .init(cpu->number_of_threads)
198        .name(name() + ".EXEC:branches")
199        .desc("Number of branches executed")
200        .flags(total);
201
202    iewExecStoreInsts
203        .name(name() + ".EXEC:stores")
204        .desc("Number of stores executed")
205        .flags(total);
206    iewExecStoreInsts = iewExecutedRefs - iewExecLoadInsts;
207
208    iewExecRate
209        .name(name() + ".EXEC:rate")
210        .desc("Inst execution rate")
211        .flags(total);
212
213    iewExecRate = iewExecutedInsts / cpu->numCycles;
214
215    iewInstsToCommit
216        .init(cpu->number_of_threads)
217        .name(name() + ".WB:sent")
218        .desc("cumulative count of insts sent to commit")
219        .flags(total);
220
221    writebackCount
222        .init(cpu->number_of_threads)
223        .name(name() + ".WB:count")
224        .desc("cumulative count of insts written-back")
225        .flags(total);
226
227    producerInst
228        .init(cpu->number_of_threads)
229        .name(name() + ".WB:producers")
230        .desc("num instructions producing a value")
231        .flags(total);
232
233    consumerInst
234        .init(cpu->number_of_threads)
235        .name(name() + ".WB:consumers")
236        .desc("num instructions consuming a value")
237        .flags(total);
238
239    wbPenalized
240        .init(cpu->number_of_threads)
241        .name(name() + ".WB:penalized")
242        .desc("number of instrctions required to write to 'other' IQ")
243        .flags(total);
244
245    wbPenalizedRate
246        .name(name() + ".WB:penalized_rate")
247        .desc ("fraction of instructions written-back that wrote to 'other' IQ")
248        .flags(total);
249
250    wbPenalizedRate = wbPenalized / writebackCount;
251
252    wbFanout
253        .name(name() + ".WB:fanout")
254        .desc("average fanout of values written-back")
255        .flags(total);
256
257    wbFanout = producerInst / consumerInst;
258
259    wbRate
260        .name(name() + ".WB:rate")
261        .desc("insts written-back per cycle")
262        .flags(total);
263    wbRate = writebackCount / cpu->numCycles;
264}
265
266template<class Impl>
267void
268DefaultIEW<Impl>::initStage()
269{
270    for (int tid=0; tid < numThreads; tid++) {
271        toRename->iewInfo[tid].usedIQ = true;
272        toRename->iewInfo[tid].freeIQEntries =
273            instQueue.numFreeEntries(tid);
274
275        toRename->iewInfo[tid].usedLSQ = true;
276        toRename->iewInfo[tid].freeLSQEntries =
277            ldstQueue.numFreeEntries(tid);
278    }
279}
280
281template<class Impl>
282void
283DefaultIEW<Impl>::setCPU(O3CPU *cpu_ptr)
284{
285    DPRINTF(IEW, "Setting CPU pointer.\n");
286    cpu = cpu_ptr;
287
288    instQueue.setCPU(cpu_ptr);
289    ldstQueue.setCPU(cpu_ptr);
290
291    cpu->activateStage(O3CPU::IEWIdx);
292}
293
294template<class Impl>
295void
296DefaultIEW<Impl>::setTimeBuffer(TimeBuffer<TimeStruct> *tb_ptr)
297{
298    DPRINTF(IEW, "Setting time buffer pointer.\n");
299    timeBuffer = tb_ptr;
300
301    // Setup wire to read information from time buffer, from commit.
302    fromCommit = timeBuffer->getWire(-commitToIEWDelay);
303
304    // Setup wire to write information back to previous stages.
305    toRename = timeBuffer->getWire(0);
306
307    toFetch = timeBuffer->getWire(0);
308
309    // Instruction queue also needs main time buffer.
310    instQueue.setTimeBuffer(tb_ptr);
311}
312
313template<class Impl>
314void
315DefaultIEW<Impl>::setRenameQueue(TimeBuffer<RenameStruct> *rq_ptr)
316{
317    DPRINTF(IEW, "Setting rename queue pointer.\n");
318    renameQueue = rq_ptr;
319
320    // Setup wire to read information from rename queue.
321    fromRename = renameQueue->getWire(-renameToIEWDelay);
322}
323
324template<class Impl>
325void
326DefaultIEW<Impl>::setIEWQueue(TimeBuffer<IEWStruct> *iq_ptr)
327{
328    DPRINTF(IEW, "Setting IEW queue pointer.\n");
329    iewQueue = iq_ptr;
330
331    // Setup wire to write instructions to commit.
332    toCommit = iewQueue->getWire(0);
333}
334
335template<class Impl>
336void
337DefaultIEW<Impl>::setActiveThreads(std::list<unsigned> *at_ptr)
338{
339    DPRINTF(IEW, "Setting active threads list pointer.\n");
340    activeThreads = at_ptr;
341
342    ldstQueue.setActiveThreads(at_ptr);
343    instQueue.setActiveThreads(at_ptr);
344}
345
346template<class Impl>
347void
348DefaultIEW<Impl>::setScoreboard(Scoreboard *sb_ptr)
349{
350    DPRINTF(IEW, "Setting scoreboard pointer.\n");
351    scoreboard = sb_ptr;
352}
353
354template <class Impl>
355bool
356DefaultIEW<Impl>::drain()
357{
358    // IEW is ready to drain at any time.
359    cpu->signalDrained();
360    return true;
361}
362
363template <class Impl>
364void
365DefaultIEW<Impl>::resume()
366{
367}
368
369template <class Impl>
370void
371DefaultIEW<Impl>::switchOut()
372{
373    // Clear any state.
374    switchedOut = true;
375
376    instQueue.switchOut();
377    ldstQueue.switchOut();
378    fuPool->switchOut();
379
380    for (int i = 0; i < numThreads; i++) {
381        while (!insts[i].empty())
382            insts[i].pop();
383        while (!skidBuffer[i].empty())
384            skidBuffer[i].pop();
385    }
386}
387
388template <class Impl>
389void
390DefaultIEW<Impl>::takeOverFrom()
391{
392    // Reset all state.
393    _status = Active;
394    exeStatus = Running;
395    wbStatus = Idle;
396    switchedOut = false;
397
398    instQueue.takeOverFrom();
399    ldstQueue.takeOverFrom();
400    fuPool->takeOverFrom();
401
402    initStage();
403    cpu->activityThisCycle();
404
405    for (int i=0; i < numThreads; i++) {
406        dispatchStatus[i] = Running;
407        stalls[i].commit = false;
408        fetchRedirect[i] = false;
409    }
410
411    updateLSQNextCycle = false;
412
413    // @todo: Fix hardcoded number
414    for (int i = 0; i < issueToExecQueue.getSize(); ++i) {
415        issueToExecQueue.advance();
416    }
417}
418
419template<class Impl>
420void
421DefaultIEW<Impl>::squash(unsigned tid)
422{
423    DPRINTF(IEW, "[tid:%i]: Squashing all instructions.\n",
424            tid);
425
426    // Tell the IQ to start squashing.
427    instQueue.squash(tid);
428
429    // Tell the LDSTQ to start squashing.
430#if THE_ISA == ALPHA_ISA
431    ldstQueue.squash(fromCommit->commitInfo[tid].doneSeqNum, tid);
432#else
433    ldstQueue.squash(fromCommit->commitInfo[tid].bdelayDoneSeqNum, tid);
434#endif
435    updatedQueues = true;
436
437    // Clear the skid buffer in case it has any data in it.
438    DPRINTF(IEW, "[tid:%i]: Removing skidbuffer instructions until [sn:%i].\n",
439            tid, fromCommit->commitInfo[tid].bdelayDoneSeqNum);
440
441    while (!skidBuffer[tid].empty()) {
442#if THE_ISA != ALPHA_ISA
443        if (skidBuffer[tid].front()->seqNum <=
444            fromCommit->commitInfo[tid].bdelayDoneSeqNum) {
445            DPRINTF(IEW, "[tid:%i]: Cannot remove skidbuffer instructions "
446                    "that occur before delay slot [sn:%i].\n",
447                    fromCommit->commitInfo[tid].bdelayDoneSeqNum,
448                    tid);
449            break;
450        } else {
451            DPRINTF(IEW, "[tid:%i]: Removing instruction [sn:%i] from "
452                    "skidBuffer.\n", tid, skidBuffer[tid].front()->seqNum);
453        }
454#endif
455        if (skidBuffer[tid].front()->isLoad() ||
456            skidBuffer[tid].front()->isStore() ) {
457            toRename->iewInfo[tid].dispatchedToLSQ++;
458        }
459
460        toRename->iewInfo[tid].dispatched++;
461
462        skidBuffer[tid].pop();
463    }
464
465    bdelayDoneSeqNum[tid] = fromCommit->commitInfo[tid].bdelayDoneSeqNum;
466
467    emptyRenameInsts(tid);
468}
469
470template<class Impl>
471void
472DefaultIEW<Impl>::squashDueToBranch(DynInstPtr &inst, unsigned tid)
473{
474    DPRINTF(IEW, "[tid:%i]: Squashing from a specific instruction, PC: %#x "
475            "[sn:%i].\n", tid, inst->readPC(), inst->seqNum);
476
477    toCommit->squash[tid] = true;
478    toCommit->squashedSeqNum[tid] = inst->seqNum;
479    toCommit->mispredPC[tid] = inst->readPC();
480    toCommit->branchMispredict[tid] = true;
481
482#if THE_ISA == ALPHA_ISA
483    toCommit->branchTaken[tid] = inst->readNextPC() !=
484        (inst->readPC() + sizeof(TheISA::MachInst));
485    toCommit->nextPC[tid] = inst->readNextPC();
486#else
487    bool branch_taken = inst->readNextNPC() !=
488        (inst->readNextPC() + sizeof(TheISA::MachInst));
489
490    toCommit->branchTaken[tid] = branch_taken;
491
492    toCommit->condDelaySlotBranch[tid] = inst->isCondDelaySlot();
493
494    if (inst->isCondDelaySlot() && branch_taken) {
495        toCommit->nextPC[tid] = inst->readNextPC();
496    } else {
497        toCommit->nextPC[tid] = inst->readNextNPC();
498    }
499#endif
500
501    toCommit->includeSquashInst[tid] = false;
502
503    wroteToTimeBuffer = true;
504}
505
506template<class Impl>
507void
508DefaultIEW<Impl>::squashDueToMemOrder(DynInstPtr &inst, unsigned tid)
509{
510    DPRINTF(IEW, "[tid:%i]: Squashing from a specific instruction, "
511            "PC: %#x [sn:%i].\n", tid, inst->readPC(), inst->seqNum);
512
513    toCommit->squash[tid] = true;
514    toCommit->squashedSeqNum[tid] = inst->seqNum;
515    toCommit->nextPC[tid] = inst->readNextPC();
516
517    toCommit->includeSquashInst[tid] = false;
518
519    wroteToTimeBuffer = true;
520}
521
522template<class Impl>
523void
524DefaultIEW<Impl>::squashDueToMemBlocked(DynInstPtr &inst, unsigned tid)
525{
526    DPRINTF(IEW, "[tid:%i]: Memory blocked, squashing load and younger insts, "
527            "PC: %#x [sn:%i].\n", tid, inst->readPC(), inst->seqNum);
528
529    toCommit->squash[tid] = true;
530    toCommit->squashedSeqNum[tid] = inst->seqNum;
531    toCommit->nextPC[tid] = inst->readPC();
532
533    // Must include the broadcasted SN in the squash.
534    toCommit->includeSquashInst[tid] = true;
535
536    ldstQueue.setLoadBlockedHandled(tid);
537
538    wroteToTimeBuffer = true;
539}
540
541template<class Impl>
542void
543DefaultIEW<Impl>::block(unsigned tid)
544{
545    DPRINTF(IEW, "[tid:%u]: Blocking.\n", tid);
546
547    if (dispatchStatus[tid] != Blocked &&
548        dispatchStatus[tid] != Unblocking) {
549        toRename->iewBlock[tid] = true;
550        wroteToTimeBuffer = true;
551    }
552
553    // Add the current inputs to the skid buffer so they can be
554    // reprocessed when this stage unblocks.
555    skidInsert(tid);
556
557    dispatchStatus[tid] = Blocked;
558}
559
560template<class Impl>
561void
562DefaultIEW<Impl>::unblock(unsigned tid)
563{
564    DPRINTF(IEW, "[tid:%i]: Reading instructions out of the skid "
565            "buffer %u.\n",tid, tid);
566
567    // If the skid bufffer is empty, signal back to previous stages to unblock.
568    // Also switch status to running.
569    if (skidBuffer[tid].empty()) {
570        toRename->iewUnblock[tid] = true;
571        wroteToTimeBuffer = true;
572        DPRINTF(IEW, "[tid:%i]: Done unblocking.\n",tid);
573        dispatchStatus[tid] = Running;
574    }
575}
576
577template<class Impl>
578void
579DefaultIEW<Impl>::wakeDependents(DynInstPtr &inst)
580{
581    instQueue.wakeDependents(inst);
582}
583
584template<class Impl>
585void
586DefaultIEW<Impl>::rescheduleMemInst(DynInstPtr &inst)
587{
588    instQueue.rescheduleMemInst(inst);
589}
590
591template<class Impl>
592void
593DefaultIEW<Impl>::replayMemInst(DynInstPtr &inst)
594{
595    instQueue.replayMemInst(inst);
596}
597
598template<class Impl>
599void
600DefaultIEW<Impl>::instToCommit(DynInstPtr &inst)
601{
602    // First check the time slot that this instruction will write
603    // to.  If there are free write ports at the time, then go ahead
604    // and write the instruction to that time.  If there are not,
605    // keep looking back to see where's the first time there's a
606    // free slot.
607    while ((*iewQueue)[wbCycle].insts[wbNumInst]) {
608        ++wbNumInst;
609        if (wbNumInst == wbWidth) {
610            ++wbCycle;
611            wbNumInst = 0;
612        }
613
614        assert((wbCycle * wbWidth + wbNumInst) < wbMax);
615    }
616
617    // Add finished instruction to queue to commit.
618    (*iewQueue)[wbCycle].insts[wbNumInst] = inst;
619    (*iewQueue)[wbCycle].size++;
620}
621
622template <class Impl>
623unsigned
624DefaultIEW<Impl>::validInstsFromRename()
625{
626    unsigned inst_count = 0;
627
628    for (int i=0; i<fromRename->size; i++) {
629        if (!fromRename->insts[i]->isSquashed())
630            inst_count++;
631    }
632
633    return inst_count;
634}
635
636template<class Impl>
637void
638DefaultIEW<Impl>::skidInsert(unsigned tid)
639{
640    DynInstPtr inst = NULL;
641
642    while (!insts[tid].empty()) {
643        inst = insts[tid].front();
644
645        insts[tid].pop();
646
647        DPRINTF(Decode,"[tid:%i]: Inserting [sn:%lli] PC:%#x into "
648                "dispatch skidBuffer %i\n",tid, inst->seqNum,
649                inst->readPC(),tid);
650
651        skidBuffer[tid].push(inst);
652    }
653
654    assert(skidBuffer[tid].size() <= skidBufferMax &&
655           "Skidbuffer Exceeded Max Size");
656}
657
658template<class Impl>
659int
660DefaultIEW<Impl>::skidCount()
661{
662    int max=0;
663
664    std::list<unsigned>::iterator threads = (*activeThreads).begin();
665
666    while (threads != (*activeThreads).end()) {
667        unsigned thread_count = skidBuffer[*threads++].size();
668        if (max < thread_count)
669            max = thread_count;
670    }
671
672    return max;
673}
674
675template<class Impl>
676bool
677DefaultIEW<Impl>::skidsEmpty()
678{
679    std::list<unsigned>::iterator threads = (*activeThreads).begin();
680
681    while (threads != (*activeThreads).end()) {
682        if (!skidBuffer[*threads++].empty())
683            return false;
684    }
685
686    return true;
687}
688
689template <class Impl>
690void
691DefaultIEW<Impl>::updateStatus()
692{
693    bool any_unblocking = false;
694
695    std::list<unsigned>::iterator threads = (*activeThreads).begin();
696
697    threads = (*activeThreads).begin();
698
699    while (threads != (*activeThreads).end()) {
700        unsigned tid = *threads++;
701
702        if (dispatchStatus[tid] == Unblocking) {
703            any_unblocking = true;
704            break;
705        }
706    }
707
708    // If there are no ready instructions waiting to be scheduled by the IQ,
709    // and there's no stores waiting to write back, and dispatch is not
710    // unblocking, then there is no internal activity for the IEW stage.
711    if (_status == Active && !instQueue.hasReadyInsts() &&
712        !ldstQueue.willWB() && !any_unblocking) {
713        DPRINTF(IEW, "IEW switching to idle\n");
714
715        deactivateStage();
716
717        _status = Inactive;
718    } else if (_status == Inactive && (instQueue.hasReadyInsts() ||
719                                       ldstQueue.willWB() ||
720                                       any_unblocking)) {
721        // Otherwise there is internal activity.  Set to active.
722        DPRINTF(IEW, "IEW switching to active\n");
723
724        activateStage();
725
726        _status = Active;
727    }
728}
729
730template <class Impl>
731void
732DefaultIEW<Impl>::resetEntries()
733{
734    instQueue.resetEntries();
735    ldstQueue.resetEntries();
736}
737
738template <class Impl>
739void
740DefaultIEW<Impl>::readStallSignals(unsigned tid)
741{
742    if (fromCommit->commitBlock[tid]) {
743        stalls[tid].commit = true;
744    }
745
746    if (fromCommit->commitUnblock[tid]) {
747        assert(stalls[tid].commit);
748        stalls[tid].commit = false;
749    }
750}
751
752template <class Impl>
753bool
754DefaultIEW<Impl>::checkStall(unsigned tid)
755{
756    bool ret_val(false);
757
758    if (stalls[tid].commit) {
759        DPRINTF(IEW,"[tid:%i]: Stall from Commit stage detected.\n",tid);
760        ret_val = true;
761    } else if (instQueue.isFull(tid)) {
762        DPRINTF(IEW,"[tid:%i]: Stall: IQ  is full.\n",tid);
763        ret_val = true;
764    } else if (ldstQueue.isFull(tid)) {
765        DPRINTF(IEW,"[tid:%i]: Stall: LSQ is full\n",tid);
766
767        if (ldstQueue.numLoads(tid) > 0 ) {
768
769            DPRINTF(IEW,"[tid:%i]: LSQ oldest load: [sn:%i] \n",
770                    tid,ldstQueue.getLoadHeadSeqNum(tid));
771        }
772
773        if (ldstQueue.numStores(tid) > 0) {
774
775            DPRINTF(IEW,"[tid:%i]: LSQ oldest store: [sn:%i] \n",
776                    tid,ldstQueue.getStoreHeadSeqNum(tid));
777        }
778
779        ret_val = true;
780    } else if (ldstQueue.isStalled(tid)) {
781        DPRINTF(IEW,"[tid:%i]: Stall: LSQ stall detected.\n",tid);
782        ret_val = true;
783    }
784
785    return ret_val;
786}
787
788template <class Impl>
789void
790DefaultIEW<Impl>::checkSignalsAndUpdate(unsigned tid)
791{
792    // Check if there's a squash signal, squash if there is
793    // Check stall signals, block if there is.
794    // If status was Blocked
795    //     if so then go to unblocking
796    // If status was Squashing
797    //     check if squashing is not high.  Switch to running this cycle.
798
799    readStallSignals(tid);
800
801    if (fromCommit->commitInfo[tid].squash) {
802        squash(tid);
803
804        if (dispatchStatus[tid] == Blocked ||
805            dispatchStatus[tid] == Unblocking) {
806            toRename->iewUnblock[tid] = true;
807            wroteToTimeBuffer = true;
808        }
809
810        dispatchStatus[tid] = Squashing;
811
812        fetchRedirect[tid] = false;
813        return;
814    }
815
816    if (fromCommit->commitInfo[tid].robSquashing) {
817        DPRINTF(IEW, "[tid:%i]: ROB is still squashing.\n", tid);
818
819        dispatchStatus[tid] = Squashing;
820
821        emptyRenameInsts(tid);
822        wroteToTimeBuffer = true;
823        return;
824    }
825
826    if (checkStall(tid)) {
827        block(tid);
828        dispatchStatus[tid] = Blocked;
829        return;
830    }
831
832    if (dispatchStatus[tid] == Blocked) {
833        // Status from previous cycle was blocked, but there are no more stall
834        // conditions.  Switch over to unblocking.
835        DPRINTF(IEW, "[tid:%i]: Done blocking, switching to unblocking.\n",
836                tid);
837
838        dispatchStatus[tid] = Unblocking;
839
840        unblock(tid);
841
842        return;
843    }
844
845    if (dispatchStatus[tid] == Squashing) {
846        // Switch status to running if rename isn't being told to block or
847        // squash this cycle.
848        DPRINTF(IEW, "[tid:%i]: Done squashing, switching to running.\n",
849                tid);
850
851        dispatchStatus[tid] = Running;
852
853        return;
854    }
855}
856
857template <class Impl>
858void
859DefaultIEW<Impl>::sortInsts()
860{
861    int insts_from_rename = fromRename->size;
862#ifdef DEBUG
863#if THE_ISA == ALPHA_ISA
864    for (int i = 0; i < numThreads; i++)
865        assert(insts[i].empty());
866#endif
867#endif
868    for (int i = 0; i < insts_from_rename; ++i) {
869        insts[fromRename->insts[i]->threadNumber].push(fromRename->insts[i]);
870    }
871}
872
873template <class Impl>
874void
875DefaultIEW<Impl>::emptyRenameInsts(unsigned tid)
876{
877    DPRINTF(IEW, "[tid:%i]: Removing incoming rename instructions until "
878            "[sn:%i].\n", tid, bdelayDoneSeqNum[tid]);
879
880    while (!insts[tid].empty()) {
881
882#if THE_ISA != ALPHA_ISA
883        if (insts[tid].front()->seqNum <= bdelayDoneSeqNum[tid]) {
884            DPRINTF(IEW, "[tid:%i]: Done removing, cannot remove instruction"
885                    " that occurs at or before delay slot [sn:%i].\n",
886                    tid, bdelayDoneSeqNum[tid]);
887            break;
888        } else {
889            DPRINTF(IEW, "[tid:%i]: Removing incoming rename instruction "
890                    "[sn:%i].\n", tid, insts[tid].front()->seqNum);
891        }
892#endif
893
894        if (insts[tid].front()->isLoad() ||
895            insts[tid].front()->isStore() ) {
896            toRename->iewInfo[tid].dispatchedToLSQ++;
897        }
898
899        toRename->iewInfo[tid].dispatched++;
900
901        insts[tid].pop();
902    }
903}
904
905template <class Impl>
906void
907DefaultIEW<Impl>::wakeCPU()
908{
909    cpu->wakeCPU();
910}
911
912template <class Impl>
913void
914DefaultIEW<Impl>::activityThisCycle()
915{
916    DPRINTF(Activity, "Activity this cycle.\n");
917    cpu->activityThisCycle();
918}
919
920template <class Impl>
921inline void
922DefaultIEW<Impl>::activateStage()
923{
924    DPRINTF(Activity, "Activating stage.\n");
925    cpu->activateStage(O3CPU::IEWIdx);
926}
927
928template <class Impl>
929inline void
930DefaultIEW<Impl>::deactivateStage()
931{
932    DPRINTF(Activity, "Deactivating stage.\n");
933    cpu->deactivateStage(O3CPU::IEWIdx);
934}
935
936template<class Impl>
937void
938DefaultIEW<Impl>::dispatch(unsigned tid)
939{
940    // If status is Running or idle,
941    //     call dispatchInsts()
942    // If status is Unblocking,
943    //     buffer any instructions coming from rename
944    //     continue trying to empty skid buffer
945    //     check if stall conditions have passed
946
947    if (dispatchStatus[tid] == Blocked) {
948        ++iewBlockCycles;
949
950    } else if (dispatchStatus[tid] == Squashing) {
951        ++iewSquashCycles;
952    }
953
954    // Dispatch should try to dispatch as many instructions as its bandwidth
955    // will allow, as long as it is not currently blocked.
956    if (dispatchStatus[tid] == Running ||
957        dispatchStatus[tid] == Idle) {
958        DPRINTF(IEW, "[tid:%i] Not blocked, so attempting to run "
959                "dispatch.\n", tid);
960
961        dispatchInsts(tid);
962    } else if (dispatchStatus[tid] == Unblocking) {
963        // Make sure that the skid buffer has something in it if the
964        // status is unblocking.
965        assert(!skidsEmpty());
966
967        // If the status was unblocking, then instructions from the skid
968        // buffer were used.  Remove those instructions and handle
969        // the rest of unblocking.
970        dispatchInsts(tid);
971
972        ++iewUnblockCycles;
973
974        if (validInstsFromRename() && dispatchedAllInsts) {
975            // Add the current inputs to the skid buffer so they can be
976            // reprocessed when this stage unblocks.
977            skidInsert(tid);
978        }
979
980        unblock(tid);
981    }
982}
983
984template <class Impl>
985void
986DefaultIEW<Impl>::dispatchInsts(unsigned tid)
987{
988    dispatchedAllInsts = true;
989
990    // Obtain instructions from skid buffer if unblocking, or queue from rename
991    // otherwise.
992    std::queue<DynInstPtr> &insts_to_dispatch =
993        dispatchStatus[tid] == Unblocking ?
994        skidBuffer[tid] : insts[tid];
995
996    int insts_to_add = insts_to_dispatch.size();
997
998    DynInstPtr inst;
999    bool add_to_iq = false;
1000    int dis_num_inst = 0;
1001
1002    // Loop through the instructions, putting them in the instruction
1003    // queue.
1004    for ( ; dis_num_inst < insts_to_add &&
1005              dis_num_inst < dispatchWidth;
1006          ++dis_num_inst)
1007    {
1008        inst = insts_to_dispatch.front();
1009
1010        if (dispatchStatus[tid] == Unblocking) {
1011            DPRINTF(IEW, "[tid:%i]: Issue: Examining instruction from skid "
1012                    "buffer\n", tid);
1013        }
1014
1015        // Make sure there's a valid instruction there.
1016        assert(inst);
1017
1018        DPRINTF(IEW, "[tid:%i]: Issue: Adding PC %#x [sn:%lli] [tid:%i] to "
1019                "IQ.\n",
1020                tid, inst->readPC(), inst->seqNum, inst->threadNumber);
1021
1022        // Be sure to mark these instructions as ready so that the
1023        // commit stage can go ahead and execute them, and mark
1024        // them as issued so the IQ doesn't reprocess them.
1025
1026        // Check for squashed instructions.
1027        if (inst->isSquashed()) {
1028            DPRINTF(IEW, "[tid:%i]: Issue: Squashed instruction encountered, "
1029                    "not adding to IQ.\n", tid);
1030
1031            ++iewDispSquashedInsts;
1032
1033            insts_to_dispatch.pop();
1034
1035            //Tell Rename That An Instruction has been processed
1036            if (inst->isLoad() || inst->isStore()) {
1037                toRename->iewInfo[tid].dispatchedToLSQ++;
1038            }
1039            toRename->iewInfo[tid].dispatched++;
1040
1041            continue;
1042        }
1043
1044        // Check for full conditions.
1045        if (instQueue.isFull(tid)) {
1046            DPRINTF(IEW, "[tid:%i]: Issue: IQ has become full.\n", tid);
1047
1048            // Call function to start blocking.
1049            block(tid);
1050
1051            // Set unblock to false. Special case where we are using
1052            // skidbuffer (unblocking) instructions but then we still
1053            // get full in the IQ.
1054            toRename->iewUnblock[tid] = false;
1055
1056            dispatchedAllInsts = false;
1057
1058            ++iewIQFullEvents;
1059            break;
1060        } else if (ldstQueue.isFull(tid)) {
1061            DPRINTF(IEW, "[tid:%i]: Issue: LSQ has become full.\n",tid);
1062
1063            // Call function to start blocking.
1064            block(tid);
1065
1066            // Set unblock to false. Special case where we are using
1067            // skidbuffer (unblocking) instructions but then we still
1068            // get full in the IQ.
1069            toRename->iewUnblock[tid] = false;
1070
1071            dispatchedAllInsts = false;
1072
1073            ++iewLSQFullEvents;
1074            break;
1075        }
1076
1077        // Otherwise issue the instruction just fine.
1078        if (inst->isLoad()) {
1079            DPRINTF(IEW, "[tid:%i]: Issue: Memory instruction "
1080                    "encountered, adding to LSQ.\n", tid);
1081
1082            // Reserve a spot in the load store queue for this
1083            // memory access.
1084            ldstQueue.insertLoad(inst);
1085
1086            ++iewDispLoadInsts;
1087
1088            add_to_iq = true;
1089
1090            toRename->iewInfo[tid].dispatchedToLSQ++;
1091        } else if (inst->isStore()) {
1092            DPRINTF(IEW, "[tid:%i]: Issue: Memory instruction "
1093                    "encountered, adding to LSQ.\n", tid);
1094
1095            ldstQueue.insertStore(inst);
1096
1097            ++iewDispStoreInsts;
1098
1099            if (inst->isStoreConditional()) {
1100                // Store conditionals need to be set as "canCommit()"
1101                // so that commit can process them when they reach the
1102                // head of commit.
1103                // @todo: This is somewhat specific to Alpha.
1104                inst->setCanCommit();
1105                instQueue.insertNonSpec(inst);
1106                add_to_iq = false;
1107
1108                ++iewDispNonSpecInsts;
1109            } else {
1110                add_to_iq = true;
1111            }
1112
1113            toRename->iewInfo[tid].dispatchedToLSQ++;
1114#if FULL_SYSTEM
1115        } else if (inst->isMemBarrier() || inst->isWriteBarrier()) {
1116            // Same as non-speculative stores.
1117            inst->setCanCommit();
1118            instQueue.insertBarrier(inst);
1119            add_to_iq = false;
1120#endif
1121        } else if (inst->isNonSpeculative()) {
1122            DPRINTF(IEW, "[tid:%i]: Issue: Nonspeculative instruction "
1123                    "encountered, skipping.\n", tid);
1124
1125            // Same as non-speculative stores.
1126            inst->setCanCommit();
1127
1128            // Specifically insert it as nonspeculative.
1129            instQueue.insertNonSpec(inst);
1130
1131            ++iewDispNonSpecInsts;
1132
1133            add_to_iq = false;
1134        } else if (inst->isNop()) {
1135            DPRINTF(IEW, "[tid:%i]: Issue: Nop instruction encountered, "
1136                    "skipping.\n", tid);
1137
1138            inst->setIssued();
1139            inst->setExecuted();
1140            inst->setCanCommit();
1141
1142            instQueue.recordProducer(inst);
1143
1144            iewExecutedNop[tid]++;
1145
1146            add_to_iq = false;
1147        } else if (inst->isExecuted()) {
1148            assert(0 && "Instruction shouldn't be executed.\n");
1149            DPRINTF(IEW, "Issue: Executed branch encountered, "
1150                    "skipping.\n");
1151
1152            inst->setIssued();
1153            inst->setCanCommit();
1154
1155            instQueue.recordProducer(inst);
1156
1157            add_to_iq = false;
1158        } else {
1159            add_to_iq = true;
1160        }
1161
1162        // If the instruction queue is not full, then add the
1163        // instruction.
1164        if (add_to_iq) {
1165            instQueue.insert(inst);
1166        }
1167
1168        insts_to_dispatch.pop();
1169
1170        toRename->iewInfo[tid].dispatched++;
1171
1172        ++iewDispatchedInsts;
1173    }
1174
1175    if (!insts_to_dispatch.empty()) {
1176        DPRINTF(IEW,"[tid:%i]: Issue: Bandwidth Full. Blocking.\n", tid);
1177        block(tid);
1178        toRename->iewUnblock[tid] = false;
1179    }
1180
1181    if (dispatchStatus[tid] == Idle && dis_num_inst) {
1182        dispatchStatus[tid] = Running;
1183
1184        updatedQueues = true;
1185    }
1186
1187    dis_num_inst = 0;
1188}
1189
1190template <class Impl>
1191void
1192DefaultIEW<Impl>::printAvailableInsts()
1193{
1194    int inst = 0;
1195
1196    std::cout << "Available Instructions: ";
1197
1198    while (fromIssue->insts[inst]) {
1199
1200        if (inst%3==0) std::cout << "\n\t";
1201
1202        std::cout << "PC: " << fromIssue->insts[inst]->readPC()
1203             << " TN: " << fromIssue->insts[inst]->threadNumber
1204             << " SN: " << fromIssue->insts[inst]->seqNum << " | ";
1205
1206        inst++;
1207
1208    }
1209
1210    std::cout << "\n";
1211}
1212
1213template <class Impl>
1214void
1215DefaultIEW<Impl>::executeInsts()
1216{
1217    wbNumInst = 0;
1218    wbCycle = 0;
1219
1220    std::list<unsigned>::iterator threads = (*activeThreads).begin();
1221
1222    while (threads != (*activeThreads).end()) {
1223        unsigned tid = *threads++;
1224        fetchRedirect[tid] = false;
1225    }
1226
1227    // Uncomment this if you want to see all available instructions.
1228//    printAvailableInsts();
1229
1230    // Execute/writeback any instructions that are available.
1231    int insts_to_execute = fromIssue->size;
1232    int inst_num = 0;
1233    for (; inst_num < insts_to_execute;
1234          ++inst_num) {
1235
1236        DPRINTF(IEW, "Execute: Executing instructions from IQ.\n");
1237
1238        DynInstPtr inst = instQueue.getInstToExecute();
1239
1240        DPRINTF(IEW, "Execute: Processing PC %#x, [tid:%i] [sn:%i].\n",
1241                inst->readPC(), inst->threadNumber,inst->seqNum);
1242
1243        // Check if the instruction is squashed; if so then skip it
1244        if (inst->isSquashed()) {
1245            DPRINTF(IEW, "Execute: Instruction was squashed.\n");
1246
1247            // Consider this instruction executed so that commit can go
1248            // ahead and retire the instruction.
1249            inst->setExecuted();
1250
1251            // Not sure if I should set this here or just let commit try to
1252            // commit any squashed instructions.  I like the latter a bit more.
1253            inst->setCanCommit();
1254
1255            ++iewExecSquashedInsts;
1256
1257            decrWb(inst->seqNum);
1258            continue;
1259        }
1260
1261        Fault fault = NoFault;
1262
1263        // Execute instruction.
1264        // Note that if the instruction faults, it will be handled
1265        // at the commit stage.
1266        if (inst->isMemRef() &&
1267            (!inst->isDataPrefetch() && !inst->isInstPrefetch())) {
1268            DPRINTF(IEW, "Execute: Calculating address for memory "
1269                    "reference.\n");
1270
1271            // Tell the LDSTQ to execute this instruction (if it is a load).
1272            if (inst->isLoad()) {
1273                // Loads will mark themselves as executed, and their writeback
1274                // event adds the instruction to the queue to commit
1275                fault = ldstQueue.executeLoad(inst);
1276            } else if (inst->isStore()) {
1277                ldstQueue.executeStore(inst);
1278
1279                // If the store had a fault then it may not have a mem req
1280                if (inst->req && !(inst->req->getFlags() & LOCKED)) {
1281                    inst->setExecuted();
1282
1283                    instToCommit(inst);
1284                }
1285
1286                // Store conditionals will mark themselves as
1287                // executed, and their writeback event will add the
1288                // instruction to the queue to commit.
1289            } else {
1290                panic("Unexpected memory type!\n");
1291            }
1292
1293        } else {
1294            inst->execute();
1295
1296            inst->setExecuted();
1297
1298            instToCommit(inst);
1299        }
1300
1301        updateExeInstStats(inst);
1302
1303        // Check if branch prediction was correct, if not then we need
1304        // to tell commit to squash in flight instructions.  Only
1305        // handle this if there hasn't already been something that
1306        // redirects fetch in this group of instructions.
1307
1308        // This probably needs to prioritize the redirects if a different
1309        // scheduler is used.  Currently the scheduler schedules the oldest
1310        // instruction first, so the branch resolution order will be correct.
1311        unsigned tid = inst->threadNumber;
1312
1313        if (!fetchRedirect[tid]) {
1314
1315            if (inst->mispredicted()) {
1316                fetchRedirect[tid] = true;
1317
1318                DPRINTF(IEW, "Execute: Branch mispredict detected.\n");
1319#if THE_ISA == ALPHA_ISA
1320                DPRINTF(IEW, "Execute: Redirecting fetch to PC: %#x.\n",
1321                        inst->nextPC);
1322#else
1323                DPRINTF(IEW, "Execute: Redirecting fetch to PC: %#x.\n",
1324                        inst->nextNPC);
1325#endif
1326                // If incorrect, then signal the ROB that it must be squashed.
1327                squashDueToBranch(inst, tid);
1328
1329                if (inst->predTaken()) {
1330                    predictedTakenIncorrect++;
1331                } else {
1332                    predictedNotTakenIncorrect++;
1333                }
1334            } else if (ldstQueue.violation(tid)) {
1335                fetchRedirect[tid] = true;
1336
1337                // If there was an ordering violation, then get the
1338                // DynInst that caused the violation.  Note that this
1339                // clears the violation signal.
1340                DynInstPtr violator;
1341                violator = ldstQueue.getMemDepViolator(tid);
1342
1343                DPRINTF(IEW, "LDSTQ detected a violation.  Violator PC: "
1344                        "%#x, inst PC: %#x.  Addr is: %#x.\n",
1345                        violator->readPC(), inst->readPC(), inst->physEffAddr);
1346
1347                // Tell the instruction queue that a violation has occured.
1348                instQueue.violation(inst, violator);
1349
1350                // Squash.
1351                squashDueToMemOrder(inst,tid);
1352
1353                ++memOrderViolationEvents;
1354            } else if (ldstQueue.loadBlocked(tid) &&
1355                       !ldstQueue.isLoadBlockedHandled(tid)) {
1356                fetchRedirect[tid] = true;
1357
1358                DPRINTF(IEW, "Load operation couldn't execute because the "
1359                        "memory system is blocked.  PC: %#x [sn:%lli]\n",
1360                        inst->readPC(), inst->seqNum);
1361
1362                squashDueToMemBlocked(inst, tid);
1363            }
1364        }
1365    }
1366
1367    // Update and record activity if we processed any instructions.
1368    if (inst_num) {
1369        if (exeStatus == Idle) {
1370            exeStatus = Running;
1371        }
1372
1373        updatedQueues = true;
1374
1375        cpu->activityThisCycle();
1376    }
1377
1378    // Need to reset this in case a writeback event needs to write into the
1379    // iew queue.  That way the writeback event will write into the correct
1380    // spot in the queue.
1381    wbNumInst = 0;
1382}
1383
1384template <class Impl>
1385void
1386DefaultIEW<Impl>::writebackInsts()
1387{
1388    // Loop through the head of the time buffer and wake any
1389    // dependents.  These instructions are about to write back.  Also
1390    // mark scoreboard that this instruction is finally complete.
1391    // Either have IEW have direct access to scoreboard, or have this
1392    // as part of backwards communication.
1393    for (int inst_num = 0; inst_num < issueWidth &&
1394             toCommit->insts[inst_num]; inst_num++) {
1395        DynInstPtr inst = toCommit->insts[inst_num];
1396        int tid = inst->threadNumber;
1397
1398        DPRINTF(IEW, "Sending instructions to commit, [sn:%lli] PC %#x.\n",
1399                inst->seqNum, inst->readPC());
1400
1401        iewInstsToCommit[tid]++;
1402
1403        // Some instructions will be sent to commit without having
1404        // executed because they need commit to handle them.
1405        // E.g. Uncached loads have not actually executed when they
1406        // are first sent to commit.  Instead commit must tell the LSQ
1407        // when it's ready to execute the uncached load.
1408        if (!inst->isSquashed() && inst->isExecuted()) {
1409            int dependents = instQueue.wakeDependents(inst);
1410
1411            for (int i = 0; i < inst->numDestRegs(); i++) {
1412                //mark as Ready
1413                DPRINTF(IEW,"Setting Destination Register %i\n",
1414                        inst->renamedDestRegIdx(i));
1415                scoreboard->setReg(inst->renamedDestRegIdx(i));
1416            }
1417
1418            if (dependents) {
1419                producerInst[tid]++;
1420                consumerInst[tid]+= dependents;
1421            }
1422            writebackCount[tid]++;
1423        }
1424
1425        decrWb(inst->seqNum);
1426    }
1427}
1428
1429template<class Impl>
1430void
1431DefaultIEW<Impl>::tick()
1432{
1433    wbNumInst = 0;
1434    wbCycle = 0;
1435
1436    wroteToTimeBuffer = false;
1437    updatedQueues = false;
1438
1439    sortInsts();
1440
1441    // Free function units marked as being freed this cycle.
1442    fuPool->processFreeUnits();
1443
1444    std::list<unsigned>::iterator threads = (*activeThreads).begin();
1445
1446    // Check stall and squash signals, dispatch any instructions.
1447    while (threads != (*activeThreads).end()) {
1448           unsigned tid = *threads++;
1449
1450        DPRINTF(IEW,"Issue: Processing [tid:%i]\n",tid);
1451
1452        checkSignalsAndUpdate(tid);
1453        dispatch(tid);
1454    }
1455
1456    if (exeStatus != Squashing) {
1457        executeInsts();
1458
1459        writebackInsts();
1460
1461        // Have the instruction queue try to schedule any ready instructions.
1462        // (In actuality, this scheduling is for instructions that will
1463        // be executed next cycle.)
1464        instQueue.scheduleReadyInsts();
1465
1466        // Also should advance its own time buffers if the stage ran.
1467        // Not the best place for it, but this works (hopefully).
1468        issueToExecQueue.advance();
1469    }
1470
1471    bool broadcast_free_entries = false;
1472
1473    if (updatedQueues || exeStatus == Running || updateLSQNextCycle) {
1474        exeStatus = Idle;
1475        updateLSQNextCycle = false;
1476
1477        broadcast_free_entries = true;
1478    }
1479
1480    // Writeback any stores using any leftover bandwidth.
1481    ldstQueue.writebackStores();
1482
1483    // Check the committed load/store signals to see if there's a load
1484    // or store to commit.  Also check if it's being told to execute a
1485    // nonspeculative instruction.
1486    // This is pretty inefficient...
1487
1488    threads = (*activeThreads).begin();
1489    while (threads != (*activeThreads).end()) {
1490        unsigned tid = (*threads++);
1491
1492        DPRINTF(IEW,"Processing [tid:%i]\n",tid);
1493
1494        // Update structures based on instructions committed.
1495        if (fromCommit->commitInfo[tid].doneSeqNum != 0 &&
1496            !fromCommit->commitInfo[tid].squash &&
1497            !fromCommit->commitInfo[tid].robSquashing) {
1498
1499            ldstQueue.commitStores(fromCommit->commitInfo[tid].doneSeqNum,tid);
1500
1501            ldstQueue.commitLoads(fromCommit->commitInfo[tid].doneSeqNum,tid);
1502
1503            updateLSQNextCycle = true;
1504            instQueue.commit(fromCommit->commitInfo[tid].doneSeqNum,tid);
1505        }
1506
1507        if (fromCommit->commitInfo[tid].nonSpecSeqNum != 0) {
1508
1509            //DPRINTF(IEW,"NonspecInst from thread %i",tid);
1510            if (fromCommit->commitInfo[tid].uncached) {
1511                instQueue.replayMemInst(fromCommit->commitInfo[tid].uncachedLoad);
1512            } else {
1513                instQueue.scheduleNonSpec(
1514                    fromCommit->commitInfo[tid].nonSpecSeqNum);
1515            }
1516        }
1517
1518        if (broadcast_free_entries) {
1519            toFetch->iewInfo[tid].iqCount =
1520                instQueue.getCount(tid);
1521            toFetch->iewInfo[tid].ldstqCount =
1522                ldstQueue.getCount(tid);
1523
1524            toRename->iewInfo[tid].usedIQ = true;
1525            toRename->iewInfo[tid].freeIQEntries =
1526                instQueue.numFreeEntries();
1527            toRename->iewInfo[tid].usedLSQ = true;
1528            toRename->iewInfo[tid].freeLSQEntries =
1529                ldstQueue.numFreeEntries(tid);
1530
1531            wroteToTimeBuffer = true;
1532        }
1533
1534        DPRINTF(IEW, "[tid:%i], Dispatch dispatched %i instructions.\n",
1535                tid, toRename->iewInfo[tid].dispatched);
1536    }
1537
1538    DPRINTF(IEW, "IQ has %i free entries (Can schedule: %i).  "
1539            "LSQ has %i free entries.\n",
1540            instQueue.numFreeEntries(), instQueue.hasReadyInsts(),
1541            ldstQueue.numFreeEntries());
1542
1543    updateStatus();
1544
1545    if (wroteToTimeBuffer) {
1546        DPRINTF(Activity, "Activity this cycle.\n");
1547        cpu->activityThisCycle();
1548    }
1549}
1550
1551template <class Impl>
1552void
1553DefaultIEW<Impl>::updateExeInstStats(DynInstPtr &inst)
1554{
1555    int thread_number = inst->threadNumber;
1556
1557    //
1558    //  Pick off the software prefetches
1559    //
1560#ifdef TARGET_ALPHA
1561    if (inst->isDataPrefetch())
1562        iewExecutedSwp[thread_number]++;
1563    else
1564        iewIewExecutedcutedInsts++;
1565#else
1566    iewExecutedInsts++;
1567#endif
1568
1569    //
1570    //  Control operations
1571    //
1572    if (inst->isControl())
1573        iewExecutedBranches[thread_number]++;
1574
1575    //
1576    //  Memory operations
1577    //
1578    if (inst->isMemRef()) {
1579        iewExecutedRefs[thread_number]++;
1580
1581        if (inst->isLoad()) {
1582            iewExecLoadInsts[thread_number]++;
1583        }
1584    }
1585}
1586