iew_impl.hh revision 4636:afc8da9f526e 
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(O3CPU *_cpu, Params *params)
43    : issueToExecQueue(params->backComSize, params->forwardComSize),
44      cpu(_cpu),
45      instQueue(_cpu, this, params),
46      ldstQueue(_cpu, this, params),
47      fuPool(params->fuPool),
48      commitToIEWDelay(params->commitToIEWDelay),
49      renameToIEWDelay(params->renameToIEWDelay),
50      issueToExecuteDelay(params->issueToExecuteDelay),
51      dispatchWidth(params->dispatchWidth),
52      issueWidth(params->issueWidth),
53      wbOutstanding(0),
54      wbWidth(params->wbWidth),
55      numThreads(params->numberOfThreads),
56      switchedOut(false)
57{
58    _status = Active;
59    exeStatus = Running;
60    wbStatus = Idle;
61
62    // Setup wire to read instructions coming from issue.
63    fromIssue = issueToExecQueue.getWire(-issueToExecuteDelay);
64
65    // Instruction queue needs the queue between issue and execute.
66    instQueue.setIssueToExecuteQueue(&issueToExecQueue);
67
68    for (int i=0; i < numThreads; i++) {
69        dispatchStatus[i] = Running;
70        stalls[i].commit = false;
71        fetchRedirect[i] = false;
72    }
73
74    wbMax = wbWidth * params->wbDepth;
75
76    updateLSQNextCycle = false;
77
78    ableToIssue = true;
79
80    skidBufferMax = (3 * (renameToIEWDelay * params->renameWidth)) + issueWidth;
81}
82
83template <class Impl>
84std::string
85DefaultIEW<Impl>::name() const
86{
87    return cpu->name() + ".iew";
88}
89
90template <class Impl>
91void
92DefaultIEW<Impl>::regStats()
93{
94    using namespace Stats;
95
96    instQueue.regStats();
97    ldstQueue.regStats();
98
99    iewIdleCycles
100        .name(name() + ".iewIdleCycles")
101        .desc("Number of cycles IEW is idle");
102
103    iewSquashCycles
104        .name(name() + ".iewSquashCycles")
105        .desc("Number of cycles IEW is squashing");
106
107    iewBlockCycles
108        .name(name() + ".iewBlockCycles")
109        .desc("Number of cycles IEW is blocking");
110
111    iewUnblockCycles
112        .name(name() + ".iewUnblockCycles")
113        .desc("Number of cycles IEW is unblocking");
114
115    iewDispatchedInsts
116        .name(name() + ".iewDispatchedInsts")
117        .desc("Number of instructions dispatched to IQ");
118
119    iewDispSquashedInsts
120        .name(name() + ".iewDispSquashedInsts")
121        .desc("Number of squashed instructions skipped by dispatch");
122
123    iewDispLoadInsts
124        .name(name() + ".iewDispLoadInsts")
125        .desc("Number of dispatched load instructions");
126
127    iewDispStoreInsts
128        .name(name() + ".iewDispStoreInsts")
129        .desc("Number of dispatched store instructions");
130
131    iewDispNonSpecInsts
132        .name(name() + ".iewDispNonSpecInsts")
133        .desc("Number of dispatched non-speculative instructions");
134
135    iewIQFullEvents
136        .name(name() + ".iewIQFullEvents")
137        .desc("Number of times the IQ has become full, causing a stall");
138
139    iewLSQFullEvents
140        .name(name() + ".iewLSQFullEvents")
141        .desc("Number of times the LSQ has become full, causing a stall");
142
143    memOrderViolationEvents
144        .name(name() + ".memOrderViolationEvents")
145        .desc("Number of memory order violations");
146
147    predictedTakenIncorrect
148        .name(name() + ".predictedTakenIncorrect")
149        .desc("Number of branches that were predicted taken incorrectly");
150
151    predictedNotTakenIncorrect
152        .name(name() + ".predictedNotTakenIncorrect")
153        .desc("Number of branches that were predicted not taken incorrectly");
154
155    branchMispredicts
156        .name(name() + ".branchMispredicts")
157        .desc("Number of branch mispredicts detected at execute");
158
159    branchMispredicts = predictedTakenIncorrect + predictedNotTakenIncorrect;
160
161    iewExecutedInsts
162        .name(name() + ".iewExecutedInsts")
163        .desc("Number of executed instructions");
164
165    iewExecLoadInsts
166        .init(cpu->number_of_threads)
167        .name(name() + ".iewExecLoadInsts")
168        .desc("Number of load instructions executed")
169        .flags(total);
170
171    iewExecSquashedInsts
172        .name(name() + ".iewExecSquashedInsts")
173        .desc("Number of squashed instructions skipped in execute");
174
175    iewExecutedSwp
176        .init(cpu->number_of_threads)
177        .name(name() + ".EXEC:swp")
178        .desc("number of swp insts executed")
179        .flags(total);
180
181    iewExecutedNop
182        .init(cpu->number_of_threads)
183        .name(name() + ".EXEC:nop")
184        .desc("number of nop insts executed")
185        .flags(total);
186
187    iewExecutedRefs
188        .init(cpu->number_of_threads)
189        .name(name() + ".EXEC:refs")
190        .desc("number of memory reference insts executed")
191        .flags(total);
192
193    iewExecutedBranches
194        .init(cpu->number_of_threads)
195        .name(name() + ".EXEC:branches")
196        .desc("Number of branches executed")
197        .flags(total);
198
199    iewExecStoreInsts
200        .name(name() + ".EXEC:stores")
201        .desc("Number of stores executed")
202        .flags(total);
203    iewExecStoreInsts = iewExecutedRefs - iewExecLoadInsts;
204
205    iewExecRate
206        .name(name() + ".EXEC:rate")
207        .desc("Inst execution rate")
208        .flags(total);
209
210    iewExecRate = iewExecutedInsts / cpu->numCycles;
211
212    iewInstsToCommit
213        .init(cpu->number_of_threads)
214        .name(name() + ".WB:sent")
215        .desc("cumulative count of insts sent to commit")
216        .flags(total);
217
218    writebackCount
219        .init(cpu->number_of_threads)
220        .name(name() + ".WB:count")
221        .desc("cumulative count of insts written-back")
222        .flags(total);
223
224    producerInst
225        .init(cpu->number_of_threads)
226        .name(name() + ".WB:producers")
227        .desc("num instructions producing a value")
228        .flags(total);
229
230    consumerInst
231        .init(cpu->number_of_threads)
232        .name(name() + ".WB:consumers")
233        .desc("num instructions consuming a value")
234        .flags(total);
235
236    wbPenalized
237        .init(cpu->number_of_threads)
238        .name(name() + ".WB:penalized")
239        .desc("number of instrctions required to write to 'other' IQ")
240        .flags(total);
241
242    wbPenalizedRate
243        .name(name() + ".WB:penalized_rate")
244        .desc ("fraction of instructions written-back that wrote to 'other' IQ")
245        .flags(total);
246
247    wbPenalizedRate = wbPenalized / writebackCount;
248
249    wbFanout
250        .name(name() + ".WB:fanout")
251        .desc("average fanout of values written-back")
252        .flags(total);
253
254    wbFanout = producerInst / consumerInst;
255
256    wbRate
257        .name(name() + ".WB:rate")
258        .desc("insts written-back per cycle")
259        .flags(total);
260    wbRate = writebackCount / cpu->numCycles;
261}
262
263template<class Impl>
264void
265DefaultIEW<Impl>::initStage()
266{
267    for (int tid=0; tid < numThreads; tid++) {
268        toRename->iewInfo[tid].usedIQ = true;
269        toRename->iewInfo[tid].freeIQEntries =
270            instQueue.numFreeEntries(tid);
271
272        toRename->iewInfo[tid].usedLSQ = true;
273        toRename->iewInfo[tid].freeLSQEntries =
274            ldstQueue.numFreeEntries(tid);
275    }
276
277    cpu->activateStage(O3CPU::IEWIdx);
278}
279
280template<class Impl>
281void
282DefaultIEW<Impl>::setTimeBuffer(TimeBuffer<TimeStruct> *tb_ptr)
283{
284    timeBuffer = tb_ptr;
285
286    // Setup wire to read information from time buffer, from commit.
287    fromCommit = timeBuffer->getWire(-commitToIEWDelay);
288
289    // Setup wire to write information back to previous stages.
290    toRename = timeBuffer->getWire(0);
291
292    toFetch = timeBuffer->getWire(0);
293
294    // Instruction queue also needs main time buffer.
295    instQueue.setTimeBuffer(tb_ptr);
296}
297
298template<class Impl>
299void
300DefaultIEW<Impl>::setRenameQueue(TimeBuffer<RenameStruct> *rq_ptr)
301{
302    renameQueue = rq_ptr;
303
304    // Setup wire to read information from rename queue.
305    fromRename = renameQueue->getWire(-renameToIEWDelay);
306}
307
308template<class Impl>
309void
310DefaultIEW<Impl>::setIEWQueue(TimeBuffer<IEWStruct> *iq_ptr)
311{
312    iewQueue = iq_ptr;
313
314    // Setup wire to write instructions to commit.
315    toCommit = iewQueue->getWire(0);
316}
317
318template<class Impl>
319void
320DefaultIEW<Impl>::setActiveThreads(std::list<unsigned> *at_ptr)
321{
322    activeThreads = at_ptr;
323
324    ldstQueue.setActiveThreads(at_ptr);
325    instQueue.setActiveThreads(at_ptr);
326}
327
328template<class Impl>
329void
330DefaultIEW<Impl>::setScoreboard(Scoreboard *sb_ptr)
331{
332    scoreboard = sb_ptr;
333}
334
335template <class Impl>
336bool
337DefaultIEW<Impl>::drain()
338{
339    // IEW is ready to drain at any time.
340    cpu->signalDrained();
341    return true;
342}
343
344template <class Impl>
345void
346DefaultIEW<Impl>::resume()
347{
348}
349
350template <class Impl>
351void
352DefaultIEW<Impl>::switchOut()
353{
354    // Clear any state.
355    switchedOut = true;
356    assert(insts[0].empty());
357    assert(skidBuffer[0].empty());
358
359    instQueue.switchOut();
360    ldstQueue.switchOut();
361    fuPool->switchOut();
362
363    for (int i = 0; i < numThreads; i++) {
364        while (!insts[i].empty())
365            insts[i].pop();
366        while (!skidBuffer[i].empty())
367            skidBuffer[i].pop();
368    }
369}
370
371template <class Impl>
372void
373DefaultIEW<Impl>::takeOverFrom()
374{
375    // Reset all state.
376    _status = Active;
377    exeStatus = Running;
378    wbStatus = Idle;
379    switchedOut = false;
380
381    instQueue.takeOverFrom();
382    ldstQueue.takeOverFrom();
383    fuPool->takeOverFrom();
384
385    initStage();
386    cpu->activityThisCycle();
387
388    for (int i=0; i < numThreads; i++) {
389        dispatchStatus[i] = Running;
390        stalls[i].commit = false;
391        fetchRedirect[i] = false;
392    }
393
394    updateLSQNextCycle = false;
395
396    for (int i = 0; i < issueToExecQueue.getSize(); ++i) {
397        issueToExecQueue.advance();
398    }
399}
400
401template<class Impl>
402void
403DefaultIEW<Impl>::squash(unsigned tid)
404{
405    DPRINTF(IEW, "[tid:%i]: Squashing all instructions.\n",
406            tid);
407
408    // Tell the IQ to start squashing.
409    instQueue.squash(tid);
410
411    // Tell the LDSTQ to start squashing.
412    ldstQueue.squash(fromCommit->commitInfo[tid].doneSeqNum, tid);
413    updatedQueues = true;
414
415    // Clear the skid buffer in case it has any data in it.
416    DPRINTF(IEW, "[tid:%i]: Removing skidbuffer instructions until [sn:%i].\n",
417            tid, fromCommit->commitInfo[tid].doneSeqNum);
418
419    while (!skidBuffer[tid].empty()) {
420        if (skidBuffer[tid].front()->isLoad() ||
421            skidBuffer[tid].front()->isStore() ) {
422            toRename->iewInfo[tid].dispatchedToLSQ++;
423        }
424
425        toRename->iewInfo[tid].dispatched++;
426
427        skidBuffer[tid].pop();
428    }
429
430    emptyRenameInsts(tid);
431}
432
433template<class Impl>
434void
435DefaultIEW<Impl>::squashDueToBranch(DynInstPtr &inst, unsigned tid)
436{
437    DPRINTF(IEW, "[tid:%i]: Squashing from a specific instruction, PC: %#x "
438            "[sn:%i].\n", tid, inst->readPC(), inst->seqNum);
439
440    toCommit->squash[tid] = true;
441    toCommit->squashedSeqNum[tid] = inst->seqNum;
442    toCommit->mispredPC[tid] = inst->readPC();
443    toCommit->branchMispredict[tid] = true;
444
445#if ISA_HAS_DELAY_SLOT
446    int instSize = sizeof(TheISA::MachInst);
447    toCommit->branchTaken[tid] =
448        !(inst->readNextPC() + instSize == inst->readNextNPC() &&
449          (inst->readNextPC() == inst->readPC() + instSize ||
450           inst->readNextPC() == inst->readPC() + 2 * instSize));
451#else
452    toCommit->branchTaken[tid] = inst->readNextPC() !=
453        (inst->readPC() + sizeof(TheISA::MachInst));
454#endif
455    toCommit->nextPC[tid] = inst->readNextPC();
456    toCommit->nextNPC[tid] = inst->readNextNPC();
457    toCommit->nextMicroPC[tid] = inst->readNextMicroPC();
458
459    toCommit->includeSquashInst[tid] = false;
460
461    wroteToTimeBuffer = true;
462}
463
464template<class Impl>
465void
466DefaultIEW<Impl>::squashDueToMemOrder(DynInstPtr &inst, unsigned tid)
467{
468    DPRINTF(IEW, "[tid:%i]: Squashing from a specific instruction, "
469            "PC: %#x [sn:%i].\n", tid, inst->readPC(), inst->seqNum);
470
471    toCommit->squash[tid] = true;
472    toCommit->squashedSeqNum[tid] = inst->seqNum;
473    toCommit->nextPC[tid] = inst->readNextPC();
474    toCommit->nextNPC[tid] = inst->readNextNPC();
475    toCommit->branchMispredict[tid] = false;
476
477    toCommit->includeSquashInst[tid] = false;
478
479    wroteToTimeBuffer = true;
480}
481
482template<class Impl>
483void
484DefaultIEW<Impl>::squashDueToMemBlocked(DynInstPtr &inst, unsigned tid)
485{
486    DPRINTF(IEW, "[tid:%i]: Memory blocked, squashing load and younger insts, "
487            "PC: %#x [sn:%i].\n", tid, inst->readPC(), inst->seqNum);
488
489    toCommit->squash[tid] = true;
490    toCommit->squashedSeqNum[tid] = inst->seqNum;
491    toCommit->nextPC[tid] = inst->readPC();
492    toCommit->nextNPC[tid] = inst->readNextPC();
493    toCommit->branchMispredict[tid] = false;
494
495    // Must include the broadcasted SN in the squash.
496    toCommit->includeSquashInst[tid] = true;
497
498    ldstQueue.setLoadBlockedHandled(tid);
499
500    wroteToTimeBuffer = true;
501}
502
503template<class Impl>
504void
505DefaultIEW<Impl>::block(unsigned tid)
506{
507    DPRINTF(IEW, "[tid:%u]: Blocking.\n", tid);
508
509    if (dispatchStatus[tid] != Blocked &&
510        dispatchStatus[tid] != Unblocking) {
511        toRename->iewBlock[tid] = true;
512        wroteToTimeBuffer = true;
513    }
514
515    // Add the current inputs to the skid buffer so they can be
516    // reprocessed when this stage unblocks.
517    skidInsert(tid);
518
519    dispatchStatus[tid] = Blocked;
520}
521
522template<class Impl>
523void
524DefaultIEW<Impl>::unblock(unsigned tid)
525{
526    DPRINTF(IEW, "[tid:%i]: Reading instructions out of the skid "
527            "buffer %u.\n",tid, tid);
528
529    // If the skid bufffer is empty, signal back to previous stages to unblock.
530    // Also switch status to running.
531    if (skidBuffer[tid].empty()) {
532        toRename->iewUnblock[tid] = true;
533        wroteToTimeBuffer = true;
534        DPRINTF(IEW, "[tid:%i]: Done unblocking.\n",tid);
535        dispatchStatus[tid] = Running;
536    }
537}
538
539template<class Impl>
540void
541DefaultIEW<Impl>::wakeDependents(DynInstPtr &inst)
542{
543    instQueue.wakeDependents(inst);
544}
545
546template<class Impl>
547void
548DefaultIEW<Impl>::rescheduleMemInst(DynInstPtr &inst)
549{
550    instQueue.rescheduleMemInst(inst);
551}
552
553template<class Impl>
554void
555DefaultIEW<Impl>::replayMemInst(DynInstPtr &inst)
556{
557    instQueue.replayMemInst(inst);
558}
559
560template<class Impl>
561void
562DefaultIEW<Impl>::instToCommit(DynInstPtr &inst)
563{
564    // This function should not be called after writebackInsts in a
565    // single cycle.  That will cause problems with an instruction
566    // being added to the queue to commit without being processed by
567    // writebackInsts prior to being sent to commit.
568
569    // First check the time slot that this instruction will write
570    // to.  If there are free write ports at the time, then go ahead
571    // and write the instruction to that time.  If there are not,
572    // keep looking back to see where's the first time there's a
573    // free slot.
574    while ((*iewQueue)[wbCycle].insts[wbNumInst]) {
575        ++wbNumInst;
576        if (wbNumInst == wbWidth) {
577            ++wbCycle;
578            wbNumInst = 0;
579        }
580
581        assert((wbCycle * wbWidth + wbNumInst) <= wbMax);
582    }
583
584    DPRINTF(IEW, "Current wb cycle: %i, width: %i, numInst: %i\nwbActual:%i\n",
585            wbCycle, wbWidth, wbNumInst, wbCycle * wbWidth + wbNumInst);
586    // Add finished instruction to queue to commit.
587    (*iewQueue)[wbCycle].insts[wbNumInst] = inst;
588    (*iewQueue)[wbCycle].size++;
589}
590
591template <class Impl>
592unsigned
593DefaultIEW<Impl>::validInstsFromRename()
594{
595    unsigned inst_count = 0;
596
597    for (int i=0; i<fromRename->size; i++) {
598        if (!fromRename->insts[i]->isSquashed())
599            inst_count++;
600    }
601
602    return inst_count;
603}
604
605template<class Impl>
606void
607DefaultIEW<Impl>::skidInsert(unsigned tid)
608{
609    DynInstPtr inst = NULL;
610
611    while (!insts[tid].empty()) {
612        inst = insts[tid].front();
613
614        insts[tid].pop();
615
616        DPRINTF(Decode,"[tid:%i]: Inserting [sn:%lli] PC:%#x into "
617                "dispatch skidBuffer %i\n",tid, inst->seqNum,
618                inst->readPC(),tid);
619
620        skidBuffer[tid].push(inst);
621    }
622
623    assert(skidBuffer[tid].size() <= skidBufferMax &&
624           "Skidbuffer Exceeded Max Size");
625}
626
627template<class Impl>
628int
629DefaultIEW<Impl>::skidCount()
630{
631    int max=0;
632
633    std::list<unsigned>::iterator threads = activeThreads->begin();
634    std::list<unsigned>::iterator end = activeThreads->end();
635
636    while (threads != end) {
637        unsigned tid = *threads++;
638        unsigned thread_count = skidBuffer[tid].size();
639        if (max < thread_count)
640            max = thread_count;
641    }
642
643    return max;
644}
645
646template<class Impl>
647bool
648DefaultIEW<Impl>::skidsEmpty()
649{
650    std::list<unsigned>::iterator threads = activeThreads->begin();
651    std::list<unsigned>::iterator end = activeThreads->end();
652
653    while (threads != end) {
654        unsigned tid = *threads++;
655
656        if (!skidBuffer[tid].empty())
657            return false;
658    }
659
660    return true;
661}
662
663template <class Impl>
664void
665DefaultIEW<Impl>::updateStatus()
666{
667    bool any_unblocking = false;
668
669    std::list<unsigned>::iterator threads = activeThreads->begin();
670    std::list<unsigned>::iterator end = activeThreads->end();
671
672    while (threads != end) {
673        unsigned tid = *threads++;
674
675        if (dispatchStatus[tid] == Unblocking) {
676            any_unblocking = true;
677            break;
678        }
679    }
680
681    // If there are no ready instructions waiting to be scheduled by the IQ,
682    // and there's no stores waiting to write back, and dispatch is not
683    // unblocking, then there is no internal activity for the IEW stage.
684    if (_status == Active && !instQueue.hasReadyInsts() &&
685        !ldstQueue.willWB() && !any_unblocking) {
686        DPRINTF(IEW, "IEW switching to idle\n");
687
688        deactivateStage();
689
690        _status = Inactive;
691    } else if (_status == Inactive && (instQueue.hasReadyInsts() ||
692                                       ldstQueue.willWB() ||
693                                       any_unblocking)) {
694        // Otherwise there is internal activity.  Set to active.
695        DPRINTF(IEW, "IEW switching to active\n");
696
697        activateStage();
698
699        _status = Active;
700    }
701}
702
703template <class Impl>
704void
705DefaultIEW<Impl>::resetEntries()
706{
707    instQueue.resetEntries();
708    ldstQueue.resetEntries();
709}
710
711template <class Impl>
712void
713DefaultIEW<Impl>::readStallSignals(unsigned tid)
714{
715    if (fromCommit->commitBlock[tid]) {
716        stalls[tid].commit = true;
717    }
718
719    if (fromCommit->commitUnblock[tid]) {
720        assert(stalls[tid].commit);
721        stalls[tid].commit = false;
722    }
723}
724
725template <class Impl>
726bool
727DefaultIEW<Impl>::checkStall(unsigned tid)
728{
729    bool ret_val(false);
730
731    if (stalls[tid].commit) {
732        DPRINTF(IEW,"[tid:%i]: Stall from Commit stage detected.\n",tid);
733        ret_val = true;
734    } else if (instQueue.isFull(tid)) {
735        DPRINTF(IEW,"[tid:%i]: Stall: IQ  is full.\n",tid);
736        ret_val = true;
737    } else if (ldstQueue.isFull(tid)) {
738        DPRINTF(IEW,"[tid:%i]: Stall: LSQ is full\n",tid);
739
740        if (ldstQueue.numLoads(tid) > 0 ) {
741
742            DPRINTF(IEW,"[tid:%i]: LSQ oldest load: [sn:%i] \n",
743                    tid,ldstQueue.getLoadHeadSeqNum(tid));
744        }
745
746        if (ldstQueue.numStores(tid) > 0) {
747
748            DPRINTF(IEW,"[tid:%i]: LSQ oldest store: [sn:%i] \n",
749                    tid,ldstQueue.getStoreHeadSeqNum(tid));
750        }
751
752        ret_val = true;
753    } else if (ldstQueue.isStalled(tid)) {
754        DPRINTF(IEW,"[tid:%i]: Stall: LSQ stall detected.\n",tid);
755        ret_val = true;
756    }
757
758    return ret_val;
759}
760
761template <class Impl>
762void
763DefaultIEW<Impl>::checkSignalsAndUpdate(unsigned tid)
764{
765    // Check if there's a squash signal, squash if there is
766    // Check stall signals, block if there is.
767    // If status was Blocked
768    //     if so then go to unblocking
769    // If status was Squashing
770    //     check if squashing is not high.  Switch to running this cycle.
771
772    readStallSignals(tid);
773
774    if (fromCommit->commitInfo[tid].squash) {
775        squash(tid);
776
777        if (dispatchStatus[tid] == Blocked ||
778            dispatchStatus[tid] == Unblocking) {
779            toRename->iewUnblock[tid] = true;
780            wroteToTimeBuffer = true;
781        }
782
783        dispatchStatus[tid] = Squashing;
784
785        fetchRedirect[tid] = false;
786        return;
787    }
788
789    if (fromCommit->commitInfo[tid].robSquashing) {
790        DPRINTF(IEW, "[tid:%i]: ROB is still squashing.\n", tid);
791
792        dispatchStatus[tid] = Squashing;
793
794        emptyRenameInsts(tid);
795        wroteToTimeBuffer = true;
796        return;
797    }
798
799    if (checkStall(tid)) {
800        block(tid);
801        dispatchStatus[tid] = Blocked;
802        return;
803    }
804
805    if (dispatchStatus[tid] == Blocked) {
806        // Status from previous cycle was blocked, but there are no more stall
807        // conditions.  Switch over to unblocking.
808        DPRINTF(IEW, "[tid:%i]: Done blocking, switching to unblocking.\n",
809                tid);
810
811        dispatchStatus[tid] = Unblocking;
812
813        unblock(tid);
814
815        return;
816    }
817
818    if (dispatchStatus[tid] == Squashing) {
819        // Switch status to running if rename isn't being told to block or
820        // squash this cycle.
821        DPRINTF(IEW, "[tid:%i]: Done squashing, switching to running.\n",
822                tid);
823
824        dispatchStatus[tid] = Running;
825
826        return;
827    }
828}
829
830template <class Impl>
831void
832DefaultIEW<Impl>::sortInsts()
833{
834    int insts_from_rename = fromRename->size;
835#ifdef DEBUG
836    for (int i = 0; i < numThreads; i++)
837        assert(insts[i].empty());
838#endif
839    for (int i = 0; i < insts_from_rename; ++i) {
840        insts[fromRename->insts[i]->threadNumber].push(fromRename->insts[i]);
841    }
842}
843
844template <class Impl>
845void
846DefaultIEW<Impl>::emptyRenameInsts(unsigned tid)
847{
848    DPRINTF(IEW, "[tid:%i]: Removing incoming rename instructions\n", tid);
849
850    while (!insts[tid].empty()) {
851
852        if (insts[tid].front()->isLoad() ||
853            insts[tid].front()->isStore() ) {
854            toRename->iewInfo[tid].dispatchedToLSQ++;
855        }
856
857        toRename->iewInfo[tid].dispatched++;
858
859        insts[tid].pop();
860    }
861}
862
863template <class Impl>
864void
865DefaultIEW<Impl>::wakeCPU()
866{
867    cpu->wakeCPU();
868}
869
870template <class Impl>
871void
872DefaultIEW<Impl>::activityThisCycle()
873{
874    DPRINTF(Activity, "Activity this cycle.\n");
875    cpu->activityThisCycle();
876}
877
878template <class Impl>
879inline void
880DefaultIEW<Impl>::activateStage()
881{
882    DPRINTF(Activity, "Activating stage.\n");
883    cpu->activateStage(O3CPU::IEWIdx);
884}
885
886template <class Impl>
887inline void
888DefaultIEW<Impl>::deactivateStage()
889{
890    DPRINTF(Activity, "Deactivating stage.\n");
891    cpu->deactivateStage(O3CPU::IEWIdx);
892}
893
894template<class Impl>
895void
896DefaultIEW<Impl>::dispatch(unsigned tid)
897{
898    // If status is Running or idle,
899    //     call dispatchInsts()
900    // If status is Unblocking,
901    //     buffer any instructions coming from rename
902    //     continue trying to empty skid buffer
903    //     check if stall conditions have passed
904
905    if (dispatchStatus[tid] == Blocked) {
906        ++iewBlockCycles;
907
908    } else if (dispatchStatus[tid] == Squashing) {
909        ++iewSquashCycles;
910    }
911
912    // Dispatch should try to dispatch as many instructions as its bandwidth
913    // will allow, as long as it is not currently blocked.
914    if (dispatchStatus[tid] == Running ||
915        dispatchStatus[tid] == Idle) {
916        DPRINTF(IEW, "[tid:%i] Not blocked, so attempting to run "
917                "dispatch.\n", tid);
918
919        dispatchInsts(tid);
920    } else if (dispatchStatus[tid] == Unblocking) {
921        // Make sure that the skid buffer has something in it if the
922        // status is unblocking.
923        assert(!skidsEmpty());
924
925        // If the status was unblocking, then instructions from the skid
926        // buffer were used.  Remove those instructions and handle
927        // the rest of unblocking.
928        dispatchInsts(tid);
929
930        ++iewUnblockCycles;
931
932        if (validInstsFromRename() && dispatchedAllInsts) {
933            // Add the current inputs to the skid buffer so they can be
934            // reprocessed when this stage unblocks.
935            skidInsert(tid);
936        }
937
938        unblock(tid);
939    }
940}
941
942template <class Impl>
943void
944DefaultIEW<Impl>::dispatchInsts(unsigned tid)
945{
946    dispatchedAllInsts = true;
947
948    // Obtain instructions from skid buffer if unblocking, or queue from rename
949    // otherwise.
950    std::queue<DynInstPtr> &insts_to_dispatch =
951        dispatchStatus[tid] == Unblocking ?
952        skidBuffer[tid] : insts[tid];
953
954    int insts_to_add = insts_to_dispatch.size();
955
956    DynInstPtr inst;
957    bool add_to_iq = false;
958    int dis_num_inst = 0;
959
960    // Loop through the instructions, putting them in the instruction
961    // queue.
962    for ( ; dis_num_inst < insts_to_add &&
963              dis_num_inst < dispatchWidth;
964          ++dis_num_inst)
965    {
966        inst = insts_to_dispatch.front();
967
968        if (dispatchStatus[tid] == Unblocking) {
969            DPRINTF(IEW, "[tid:%i]: Issue: Examining instruction from skid "
970                    "buffer\n", tid);
971        }
972
973        // Make sure there's a valid instruction there.
974        assert(inst);
975
976        DPRINTF(IEW, "[tid:%i]: Issue: Adding PC %#x [sn:%lli] [tid:%i] to "
977                "IQ.\n",
978                tid, inst->readPC(), inst->seqNum, inst->threadNumber);
979
980        // Be sure to mark these instructions as ready so that the
981        // commit stage can go ahead and execute them, and mark
982        // them as issued so the IQ doesn't reprocess them.
983
984        // Check for squashed instructions.
985        if (inst->isSquashed()) {
986            DPRINTF(IEW, "[tid:%i]: Issue: Squashed instruction encountered, "
987                    "not adding to IQ.\n", tid);
988
989            ++iewDispSquashedInsts;
990
991            insts_to_dispatch.pop();
992
993            //Tell Rename That An Instruction has been processed
994            if (inst->isLoad() || inst->isStore()) {
995                toRename->iewInfo[tid].dispatchedToLSQ++;
996            }
997            toRename->iewInfo[tid].dispatched++;
998
999            continue;
1000        }
1001
1002        // Check for full conditions.
1003        if (instQueue.isFull(tid)) {
1004            DPRINTF(IEW, "[tid:%i]: Issue: IQ has become full.\n", tid);
1005
1006            // Call function to start blocking.
1007            block(tid);
1008
1009            // Set unblock to false. Special case where we are using
1010            // skidbuffer (unblocking) instructions but then we still
1011            // get full in the IQ.
1012            toRename->iewUnblock[tid] = false;
1013
1014            dispatchedAllInsts = false;
1015
1016            ++iewIQFullEvents;
1017            break;
1018        } else if (ldstQueue.isFull(tid)) {
1019            DPRINTF(IEW, "[tid:%i]: Issue: LSQ has become full.\n",tid);
1020
1021            // Call function to start blocking.
1022            block(tid);
1023
1024            // Set unblock to false. Special case where we are using
1025            // skidbuffer (unblocking) instructions but then we still
1026            // get full in the IQ.
1027            toRename->iewUnblock[tid] = false;
1028
1029            dispatchedAllInsts = false;
1030
1031            ++iewLSQFullEvents;
1032            break;
1033        }
1034
1035        // Otherwise issue the instruction just fine.
1036        if (inst->isLoad()) {
1037            DPRINTF(IEW, "[tid:%i]: Issue: Memory instruction "
1038                    "encountered, adding to LSQ.\n", tid);
1039
1040            // Reserve a spot in the load store queue for this
1041            // memory access.
1042            ldstQueue.insertLoad(inst);
1043
1044            ++iewDispLoadInsts;
1045
1046            add_to_iq = true;
1047
1048            toRename->iewInfo[tid].dispatchedToLSQ++;
1049        } else if (inst->isStore()) {
1050            DPRINTF(IEW, "[tid:%i]: Issue: Memory instruction "
1051                    "encountered, adding to LSQ.\n", tid);
1052
1053            ldstQueue.insertStore(inst);
1054
1055            ++iewDispStoreInsts;
1056
1057            if (inst->isStoreConditional()) {
1058                // Store conditionals need to be set as "canCommit()"
1059                // so that commit can process them when they reach the
1060                // head of commit.
1061                // @todo: This is somewhat specific to Alpha.
1062                inst->setCanCommit();
1063                instQueue.insertNonSpec(inst);
1064                add_to_iq = false;
1065
1066                ++iewDispNonSpecInsts;
1067            } else {
1068                add_to_iq = true;
1069            }
1070
1071            toRename->iewInfo[tid].dispatchedToLSQ++;
1072        } else if (inst->isMemBarrier() || inst->isWriteBarrier()) {
1073            // Same as non-speculative stores.
1074            inst->setCanCommit();
1075            instQueue.insertBarrier(inst);
1076            add_to_iq = false;
1077        } else if (inst->isNop()) {
1078            DPRINTF(IEW, "[tid:%i]: Issue: Nop instruction encountered, "
1079                    "skipping.\n", tid);
1080
1081            inst->setIssued();
1082            inst->setExecuted();
1083            inst->setCanCommit();
1084
1085            instQueue.recordProducer(inst);
1086
1087            iewExecutedNop[tid]++;
1088
1089            add_to_iq = false;
1090        } else if (inst->isExecuted()) {
1091            assert(0 && "Instruction shouldn't be executed.\n");
1092            DPRINTF(IEW, "Issue: Executed branch encountered, "
1093                    "skipping.\n");
1094
1095            inst->setIssued();
1096            inst->setCanCommit();
1097
1098            instQueue.recordProducer(inst);
1099
1100            add_to_iq = false;
1101        } else {
1102            add_to_iq = true;
1103        }
1104        if (inst->isNonSpeculative()) {
1105            DPRINTF(IEW, "[tid:%i]: Issue: Nonspeculative instruction "
1106                    "encountered, skipping.\n", tid);
1107
1108            // Same as non-speculative stores.
1109            inst->setCanCommit();
1110
1111            // Specifically insert it as nonspeculative.
1112            instQueue.insertNonSpec(inst);
1113
1114            ++iewDispNonSpecInsts;
1115
1116            add_to_iq = false;
1117        }
1118
1119        // If the instruction queue is not full, then add the
1120        // instruction.
1121        if (add_to_iq) {
1122            instQueue.insert(inst);
1123        }
1124
1125        insts_to_dispatch.pop();
1126
1127        toRename->iewInfo[tid].dispatched++;
1128
1129        ++iewDispatchedInsts;
1130    }
1131
1132    if (!insts_to_dispatch.empty()) {
1133        DPRINTF(IEW,"[tid:%i]: Issue: Bandwidth Full. Blocking.\n", tid);
1134        block(tid);
1135        toRename->iewUnblock[tid] = false;
1136    }
1137
1138    if (dispatchStatus[tid] == Idle && dis_num_inst) {
1139        dispatchStatus[tid] = Running;
1140
1141        updatedQueues = true;
1142    }
1143
1144    dis_num_inst = 0;
1145}
1146
1147template <class Impl>
1148void
1149DefaultIEW<Impl>::printAvailableInsts()
1150{
1151    int inst = 0;
1152
1153    std::cout << "Available Instructions: ";
1154
1155    while (fromIssue->insts[inst]) {
1156
1157        if (inst%3==0) std::cout << "\n\t";
1158
1159        std::cout << "PC: " << fromIssue->insts[inst]->readPC()
1160             << " TN: " << fromIssue->insts[inst]->threadNumber
1161             << " SN: " << fromIssue->insts[inst]->seqNum << " | ";
1162
1163        inst++;
1164
1165    }
1166
1167    std::cout << "\n";
1168}
1169
1170template <class Impl>
1171void
1172DefaultIEW<Impl>::executeInsts()
1173{
1174    wbNumInst = 0;
1175    wbCycle = 0;
1176
1177    std::list<unsigned>::iterator threads = activeThreads->begin();
1178    std::list<unsigned>::iterator end = activeThreads->end();
1179
1180    while (threads != end) {
1181        unsigned tid = *threads++;
1182        fetchRedirect[tid] = false;
1183    }
1184
1185    // Uncomment this if you want to see all available instructions.
1186//    printAvailableInsts();
1187
1188    // Execute/writeback any instructions that are available.
1189    int insts_to_execute = fromIssue->size;
1190    int inst_num = 0;
1191    for (; inst_num < insts_to_execute;
1192          ++inst_num) {
1193
1194        DPRINTF(IEW, "Execute: Executing instructions from IQ.\n");
1195
1196        DynInstPtr inst = instQueue.getInstToExecute();
1197
1198        DPRINTF(IEW, "Execute: Processing PC %#x, [tid:%i] [sn:%i].\n",
1199                inst->readPC(), inst->threadNumber,inst->seqNum);
1200
1201        // Check if the instruction is squashed; if so then skip it
1202        if (inst->isSquashed()) {
1203            DPRINTF(IEW, "Execute: Instruction was squashed.\n");
1204
1205            // Consider this instruction executed so that commit can go
1206            // ahead and retire the instruction.
1207            inst->setExecuted();
1208
1209            // Not sure if I should set this here or just let commit try to
1210            // commit any squashed instructions.  I like the latter a bit more.
1211            inst->setCanCommit();
1212
1213            ++iewExecSquashedInsts;
1214
1215            decrWb(inst->seqNum);
1216            continue;
1217        }
1218
1219        Fault fault = NoFault;
1220
1221        // Execute instruction.
1222        // Note that if the instruction faults, it will be handled
1223        // at the commit stage.
1224        if (inst->isMemRef() &&
1225            (!inst->isDataPrefetch() && !inst->isInstPrefetch())) {
1226            DPRINTF(IEW, "Execute: Calculating address for memory "
1227                    "reference.\n");
1228
1229            // Tell the LDSTQ to execute this instruction (if it is a load).
1230            if (inst->isLoad()) {
1231                // Loads will mark themselves as executed, and their writeback
1232                // event adds the instruction to the queue to commit
1233                fault = ldstQueue.executeLoad(inst);
1234            } else if (inst->isStore()) {
1235                fault = ldstQueue.executeStore(inst);
1236
1237                // If the store had a fault then it may not have a mem req
1238                if (!inst->isStoreConditional() && fault == NoFault) {
1239                    inst->setExecuted();
1240
1241                    instToCommit(inst);
1242                } else if (fault != NoFault) {
1243                    // If the instruction faulted, then we need to send it along to commit
1244                    // without the instruction completing.
1245                    DPRINTF(IEW, "Store has fault %s! [sn:%lli]\n",
1246                            fault->name(), inst->seqNum);
1247
1248                    // Send this instruction to commit, also make sure iew stage
1249                    // realizes there is activity.
1250                    inst->setExecuted();
1251
1252                    instToCommit(inst);
1253                    activityThisCycle();
1254                }
1255
1256                // Store conditionals will mark themselves as
1257                // executed, and their writeback event will add the
1258                // instruction to the queue to commit.
1259            } else {
1260                panic("Unexpected memory type!\n");
1261            }
1262
1263        } else {
1264            inst->execute();
1265
1266            inst->setExecuted();
1267
1268            instToCommit(inst);
1269        }
1270
1271        updateExeInstStats(inst);
1272
1273        // Check if branch prediction was correct, if not then we need
1274        // to tell commit to squash in flight instructions.  Only
1275        // handle this if there hasn't already been something that
1276        // redirects fetch in this group of instructions.
1277
1278        // This probably needs to prioritize the redirects if a different
1279        // scheduler is used.  Currently the scheduler schedules the oldest
1280        // instruction first, so the branch resolution order will be correct.
1281        unsigned tid = inst->threadNumber;
1282
1283        if (!fetchRedirect[tid] ||
1284            toCommit->squashedSeqNum[tid] > inst->seqNum) {
1285
1286            if (inst->mispredicted()) {
1287                fetchRedirect[tid] = true;
1288
1289                DPRINTF(IEW, "Execute: Branch mispredict detected.\n");
1290                DPRINTF(IEW, "Predicted target was %#x, %#x.\n",
1291                        inst->readPredPC(), inst->readPredNPC());
1292                DPRINTF(IEW, "Execute: Redirecting fetch to PC: %#x,"
1293                        " NPC: %#x.\n", inst->readNextPC(),
1294                        inst->readNextNPC());
1295                // If incorrect, then signal the ROB that it must be squashed.
1296                squashDueToBranch(inst, tid);
1297
1298                if (inst->readPredTaken()) {
1299                    predictedTakenIncorrect++;
1300                } else {
1301                    predictedNotTakenIncorrect++;
1302                }
1303            } else if (ldstQueue.violation(tid)) {
1304                assert(inst->isMemRef());
1305                // If there was an ordering violation, then get the
1306                // DynInst that caused the violation.  Note that this
1307                // clears the violation signal.
1308                DynInstPtr violator;
1309                violator = ldstQueue.getMemDepViolator(tid);
1310
1311                DPRINTF(IEW, "LDSTQ detected a violation.  Violator PC: "
1312                        "%#x, inst PC: %#x.  Addr is: %#x.\n",
1313                        violator->readPC(), inst->readPC(), inst->physEffAddr);
1314
1315                // Ensure the violating instruction is older than
1316                // current squash
1317/*                if (fetchRedirect[tid] &&
1318                    violator->seqNum >= toCommit->squashedSeqNum[tid] + 1)
1319                    continue;
1320*/
1321                fetchRedirect[tid] = true;
1322
1323                // Tell the instruction queue that a violation has occured.
1324                instQueue.violation(inst, violator);
1325
1326                // Squash.
1327                squashDueToMemOrder(inst,tid);
1328
1329                ++memOrderViolationEvents;
1330            } else if (ldstQueue.loadBlocked(tid) &&
1331                       !ldstQueue.isLoadBlockedHandled(tid)) {
1332                fetchRedirect[tid] = true;
1333
1334                DPRINTF(IEW, "Load operation couldn't execute because the "
1335                        "memory system is blocked.  PC: %#x [sn:%lli]\n",
1336                        inst->readPC(), inst->seqNum);
1337
1338                squashDueToMemBlocked(inst, tid);
1339            }
1340        } else {
1341            // Reset any state associated with redirects that will not
1342            // be used.
1343            if (ldstQueue.violation(tid)) {
1344                assert(inst->isMemRef());
1345
1346                DynInstPtr violator = ldstQueue.getMemDepViolator(tid);
1347
1348                DPRINTF(IEW, "LDSTQ detected a violation.  Violator PC: "
1349                        "%#x, inst PC: %#x.  Addr is: %#x.\n",
1350                        violator->readPC(), inst->readPC(), inst->physEffAddr);
1351                DPRINTF(IEW, "Violation will not be handled because "
1352                        "already squashing\n");
1353
1354                ++memOrderViolationEvents;
1355            }
1356            if (ldstQueue.loadBlocked(tid) &&
1357                !ldstQueue.isLoadBlockedHandled(tid)) {
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                DPRINTF(IEW, "Blocked load will not be handled because "
1362                        "already squashing\n");
1363
1364                ldstQueue.setLoadBlockedHandled(tid);
1365            }
1366
1367        }
1368    }
1369
1370    // Update and record activity if we processed any instructions.
1371    if (inst_num) {
1372        if (exeStatus == Idle) {
1373            exeStatus = Running;
1374        }
1375
1376        updatedQueues = true;
1377
1378        cpu->activityThisCycle();
1379    }
1380
1381    // Need to reset this in case a writeback event needs to write into the
1382    // iew queue.  That way the writeback event will write into the correct
1383    // spot in the queue.
1384    wbNumInst = 0;
1385}
1386
1387template <class Impl>
1388void
1389DefaultIEW<Impl>::writebackInsts()
1390{
1391    // Loop through the head of the time buffer and wake any
1392    // dependents.  These instructions are about to write back.  Also
1393    // mark scoreboard that this instruction is finally complete.
1394    // Either have IEW have direct access to scoreboard, or have this
1395    // as part of backwards communication.
1396    for (int inst_num = 0; inst_num < wbWidth &&
1397             toCommit->insts[inst_num]; inst_num++) {
1398        DynInstPtr inst = toCommit->insts[inst_num];
1399        int tid = inst->threadNumber;
1400
1401        DPRINTF(IEW, "Sending instructions to commit, [sn:%lli] PC %#x.\n",
1402                inst->seqNum, inst->readPC());
1403
1404        iewInstsToCommit[tid]++;
1405
1406        // Some instructions will be sent to commit without having
1407        // executed because they need commit to handle them.
1408        // E.g. Uncached loads have not actually executed when they
1409        // are first sent to commit.  Instead commit must tell the LSQ
1410        // when it's ready to execute the uncached load.
1411        if (!inst->isSquashed() && inst->isExecuted() && inst->getFault() == NoFault) {
1412            int dependents = instQueue.wakeDependents(inst);
1413
1414            for (int i = 0; i < inst->numDestRegs(); i++) {
1415                //mark as Ready
1416                DPRINTF(IEW,"Setting Destination Register %i\n",
1417                        inst->renamedDestRegIdx(i));
1418                scoreboard->setReg(inst->renamedDestRegIdx(i));
1419            }
1420
1421            if (dependents) {
1422                producerInst[tid]++;
1423                consumerInst[tid]+= dependents;
1424            }
1425            writebackCount[tid]++;
1426        }
1427
1428        decrWb(inst->seqNum);
1429    }
1430}
1431
1432template<class Impl>
1433void
1434DefaultIEW<Impl>::tick()
1435{
1436    wbNumInst = 0;
1437    wbCycle = 0;
1438
1439    wroteToTimeBuffer = false;
1440    updatedQueues = false;
1441
1442    sortInsts();
1443
1444    // Free function units marked as being freed this cycle.
1445    fuPool->processFreeUnits();
1446
1447    std::list<unsigned>::iterator threads = activeThreads->begin();
1448    std::list<unsigned>::iterator end = activeThreads->end();
1449
1450    // Check stall and squash signals, dispatch any instructions.
1451    while (threads != end) {
1452        unsigned tid = *threads++;
1453
1454        DPRINTF(IEW,"Issue: Processing [tid:%i]\n",tid);
1455
1456        checkSignalsAndUpdate(tid);
1457        dispatch(tid);
1458    }
1459
1460    if (exeStatus != Squashing) {
1461        executeInsts();
1462
1463        writebackInsts();
1464
1465        // Have the instruction queue try to schedule any ready instructions.
1466        // (In actuality, this scheduling is for instructions that will
1467        // be executed next cycle.)
1468        instQueue.scheduleReadyInsts();
1469
1470        // Also should advance its own time buffers if the stage ran.
1471        // Not the best place for it, but this works (hopefully).
1472        issueToExecQueue.advance();
1473    }
1474
1475    bool broadcast_free_entries = false;
1476
1477    if (updatedQueues || exeStatus == Running || updateLSQNextCycle) {
1478        exeStatus = Idle;
1479        updateLSQNextCycle = false;
1480
1481        broadcast_free_entries = true;
1482    }
1483
1484    // Writeback any stores using any leftover bandwidth.
1485    ldstQueue.writebackStores();
1486
1487    // Check the committed load/store signals to see if there's a load
1488    // or store to commit.  Also check if it's being told to execute a
1489    // nonspeculative instruction.
1490    // This is pretty inefficient...
1491
1492    threads = activeThreads->begin();
1493    while (threads != end) {
1494        unsigned tid = (*threads++);
1495
1496        DPRINTF(IEW,"Processing [tid:%i]\n",tid);
1497
1498        // Update structures based on instructions committed.
1499        if (fromCommit->commitInfo[tid].doneSeqNum != 0 &&
1500            !fromCommit->commitInfo[tid].squash &&
1501            !fromCommit->commitInfo[tid].robSquashing) {
1502
1503            ldstQueue.commitStores(fromCommit->commitInfo[tid].doneSeqNum,tid);
1504
1505            ldstQueue.commitLoads(fromCommit->commitInfo[tid].doneSeqNum,tid);
1506
1507            updateLSQNextCycle = true;
1508            instQueue.commit(fromCommit->commitInfo[tid].doneSeqNum,tid);
1509        }
1510
1511        if (fromCommit->commitInfo[tid].nonSpecSeqNum != 0) {
1512
1513            //DPRINTF(IEW,"NonspecInst from thread %i",tid);
1514            if (fromCommit->commitInfo[tid].uncached) {
1515                instQueue.replayMemInst(fromCommit->commitInfo[tid].uncachedLoad);
1516                fromCommit->commitInfo[tid].uncachedLoad->setAtCommit();
1517            } else {
1518                instQueue.scheduleNonSpec(
1519                    fromCommit->commitInfo[tid].nonSpecSeqNum);
1520            }
1521        }
1522
1523        if (broadcast_free_entries) {
1524            toFetch->iewInfo[tid].iqCount =
1525                instQueue.getCount(tid);
1526            toFetch->iewInfo[tid].ldstqCount =
1527                ldstQueue.getCount(tid);
1528
1529            toRename->iewInfo[tid].usedIQ = true;
1530            toRename->iewInfo[tid].freeIQEntries =
1531                instQueue.numFreeEntries();
1532            toRename->iewInfo[tid].usedLSQ = true;
1533            toRename->iewInfo[tid].freeLSQEntries =
1534                ldstQueue.numFreeEntries(tid);
1535
1536            wroteToTimeBuffer = true;
1537        }
1538
1539        DPRINTF(IEW, "[tid:%i], Dispatch dispatched %i instructions.\n",
1540                tid, toRename->iewInfo[tid].dispatched);
1541    }
1542
1543    DPRINTF(IEW, "IQ has %i free entries (Can schedule: %i).  "
1544            "LSQ has %i free entries.\n",
1545            instQueue.numFreeEntries(), instQueue.hasReadyInsts(),
1546            ldstQueue.numFreeEntries());
1547
1548    updateStatus();
1549
1550    if (wroteToTimeBuffer) {
1551        DPRINTF(Activity, "Activity this cycle.\n");
1552        cpu->activityThisCycle();
1553    }
1554}
1555
1556template <class Impl>
1557void
1558DefaultIEW<Impl>::updateExeInstStats(DynInstPtr &inst)
1559{
1560    int thread_number = inst->threadNumber;
1561
1562    //
1563    //  Pick off the software prefetches
1564    //
1565#ifdef TARGET_ALPHA
1566    if (inst->isDataPrefetch())
1567        iewExecutedSwp[thread_number]++;
1568    else
1569        iewIewExecutedcutedInsts++;
1570#else
1571    iewExecutedInsts++;
1572#endif
1573
1574    //
1575    //  Control operations
1576    //
1577    if (inst->isControl())
1578        iewExecutedBranches[thread_number]++;
1579
1580    //
1581    //  Memory operations
1582    //
1583    if (inst->isMemRef()) {
1584        iewExecutedRefs[thread_number]++;
1585
1586        if (inst->isLoad()) {
1587            iewExecLoadInsts[thread_number]++;
1588        }
1589    }
1590}
1591