1/*
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2 * Copyright (c) 2004-2006 The Regents of The University of Michigan
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2 * Copyright (c) 2004-2005 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.
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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.
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34// Update the statuses for each stage. |
35 36#include <queue> 37 38#include "base/timebuf.hh"
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36#include "cpu/o3/fu_pool.hh"
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39#include "cpu/o3/iew.hh" 40
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39using namespace std;
40
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41template<class Impl>
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42DefaultIEW<Impl>::LdWritebackEvent::LdWritebackEvent(DynInstPtr &_inst,
43 DefaultIEW<Impl> *_iew)
44 : Event(&mainEventQueue), inst(_inst), iewStage(_iew)
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42SimpleIEW<Impl>::WritebackEvent::WritebackEvent(DynInstPtr &_inst, 43 SimpleIEW<Impl> *_iew) 44 : Event(&mainEventQueue, CPU_Tick_Pri), inst(_inst), iewStage(_iew) |
45{ 46 this->setFlags(Event::AutoDelete); 47} 48 49template<class Impl> 50void
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51DefaultIEW<Impl>::LdWritebackEvent::process()
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51SimpleIEW<Impl>::WritebackEvent::process() |
52{
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53 DPRINTF(IEW, "Load writeback event [sn:%lli]\n", inst->seqNum);
54 DPRINTF(Activity, "Activity: Ld Writeback event [sn:%lli]\n", inst->seqNum);
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53 DPRINTF(IEW, "IEW: WRITEBACK EVENT!!!!\n"); |
54
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56 //iewStage->ldstQueue.removeMSHR(inst->threadNumber,inst->seqNum);
57
58 if (iewStage->isSwitchedOut()) {
59 inst = NULL;
60 return;
61 } else if (inst->isSquashed()) {
62 iewStage->wakeCPU();
63 inst = NULL;
64 return;
65 }
66
67 iewStage->wakeCPU();
68
69 if (!inst->isExecuted()) {
70 inst->setExecuted();
71
72 // Complete access to copy data to proper place.
73 if (inst->isStore()) {
74 inst->completeAcc();
75 }
76 }
77
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55 // Need to insert instruction into queue to commit 56 iewStage->instToCommit(inst);
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80
81 iewStage->activityThisCycle();
82
83 inst = NULL;
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57 // Need to execute second half of the instruction, do actual writing to 58 // registers and such 59 inst->execute(); |
60} 61 62template<class Impl> 63const char *
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88DefaultIEW<Impl>::LdWritebackEvent::description()
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64SimpleIEW<Impl>::WritebackEvent::description() |
65{
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90 return "Load writeback event";
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66 return "LSQ writeback event"; |
67} 68 69template<class Impl>
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94DefaultIEW<Impl>::DefaultIEW(Params *params)
95 : // @todo: Make this into a parameter.
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70SimpleIEW<Impl>::SimpleIEW(Params ¶ms) 71 : // Just make this time buffer really big for now |
72 issueToExecQueue(5, 5), 73 instQueue(params), 74 ldstQueue(params),
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99 fuPool(params->fuPool),
100 commitToIEWDelay(params->commitToIEWDelay),
101 renameToIEWDelay(params->renameToIEWDelay),
102 issueToExecuteDelay(params->issueToExecuteDelay),
103 issueReadWidth(params->issueWidth),
104 issueWidth(params->issueWidth),
105 executeWidth(params->executeWidth),
106 numThreads(params->numberOfThreads),
107 switchedOut(false)
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75 commitToIEWDelay(params.commitToIEWDelay), 76 renameToIEWDelay(params.renameToIEWDelay), 77 issueToExecuteDelay(params.issueToExecuteDelay), 78 issueReadWidth(params.issueWidth), 79 issueWidth(params.issueWidth), 80 executeWidth(params.executeWidth) |
81{
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109 _status = Active;
110 exeStatus = Running;
111 wbStatus = Idle;
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82 DPRINTF(IEW, "IEW: executeIntWidth: %i.\n", params.executeIntWidth); 83 _status = Idle; 84 _issueStatus = Idle; 85 _exeStatus = Idle; 86 _wbStatus = Idle; |
87 88 // Setup wire to read instructions coming from issue. 89 fromIssue = issueToExecQueue.getWire(-issueToExecuteDelay); 90 91 // Instruction queue needs the queue between issue and execute. 92 instQueue.setIssueToExecuteQueue(&issueToExecQueue); 93
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119 instQueue.setIEW(this);
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94 ldstQueue.setIEW(this);
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121
122 for (int i=0; i < numThreads; i++) {
123 dispatchStatus[i] = Running;
124 stalls[i].commit = false;
125 fetchRedirect[i] = false;
126 }
127
128 updateLSQNextCycle = false;
129
130 skidBufferMax = (3 * (renameToIEWDelay * params->renameWidth)) + issueWidth;
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95} 96 97template <class Impl>
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134std::string
135DefaultIEW<Impl>::name() const
136{
137 return cpu->name() + ".iew";
138}
139
140template <class Impl>
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98void
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142DefaultIEW<Impl>::regStats()
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99SimpleIEW<Impl>::regStats() |
100{
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144 using namespace Stats;
145
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101 instQueue.regStats(); 102 103 iewIdleCycles 104 .name(name() + ".iewIdleCycles") 105 .desc("Number of cycles IEW is idle"); 106 107 iewSquashCycles 108 .name(name() + ".iewSquashCycles") 109 .desc("Number of cycles IEW is squashing"); 110 111 iewBlockCycles 112 .name(name() + ".iewBlockCycles") 113 .desc("Number of cycles IEW is blocking"); 114 115 iewUnblockCycles 116 .name(name() + ".iewUnblockCycles") 117 .desc("Number of cycles IEW is unblocking"); 118
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119// iewWBInsts; 120 |
121 iewDispatchedInsts 122 .name(name() + ".iewDispatchedInsts") 123 .desc("Number of instructions dispatched to IQ"); 124 125 iewDispSquashedInsts 126 .name(name() + ".iewDispSquashedInsts") 127 .desc("Number of squashed instructions skipped by dispatch"); 128 129 iewDispLoadInsts 130 .name(name() + ".iewDispLoadInsts") 131 .desc("Number of dispatched load instructions"); 132 133 iewDispStoreInsts 134 .name(name() + ".iewDispStoreInsts") 135 .desc("Number of dispatched store instructions"); 136 137 iewDispNonSpecInsts 138 .name(name() + ".iewDispNonSpecInsts") 139 .desc("Number of dispatched non-speculative instructions"); 140 141 iewIQFullEvents 142 .name(name() + ".iewIQFullEvents") 143 .desc("Number of times the IQ has become full, causing a stall"); 144
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188 iewLSQFullEvents
189 .name(name() + ".iewLSQFullEvents")
190 .desc("Number of times the LSQ has become full, causing a stall");
191
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145 iewExecutedInsts 146 .name(name() + ".iewExecutedInsts") 147 .desc("Number of executed instructions"); 148 149 iewExecLoadInsts
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197 .init(cpu->number_of_threads)
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150 .name(name() + ".iewExecLoadInsts")
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199 .desc("Number of load instructions executed")
200 .flags(total);
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151 .desc("Number of load instructions executed"); |
152
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153 iewExecStoreInsts 154 .name(name() + ".iewExecStoreInsts") 155 .desc("Number of store instructions executed"); 156 |
157 iewExecSquashedInsts 158 .name(name() + ".iewExecSquashedInsts") 159 .desc("Number of squashed instructions skipped in execute"); 160 161 memOrderViolationEvents 162 .name(name() + ".memOrderViolationEvents") 163 .desc("Number of memory order violations"); 164 165 predictedTakenIncorrect 166 .name(name() + ".predictedTakenIncorrect") 167 .desc("Number of branches that were predicted taken incorrectly");
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213
214 predictedNotTakenIncorrect
215 .name(name() + ".predictedNotTakenIncorrect")
216 .desc("Number of branches that were predicted not taken incorrectly");
217
218 branchMispredicts
219 .name(name() + ".branchMispredicts")
220 .desc("Number of branch mispredicts detected at execute");
221
222 branchMispredicts = predictedTakenIncorrect + predictedNotTakenIncorrect;
223
224 exeSwp
225 .init(cpu->number_of_threads)
226 .name(name() + ".EXEC:swp")
227 .desc("number of swp insts executed")
228 .flags(total)
229 ;
230
231 exeNop
232 .init(cpu->number_of_threads)
233 .name(name() + ".EXEC:nop")
234 .desc("number of nop insts executed")
235 .flags(total)
236 ;
237
238 exeRefs
239 .init(cpu->number_of_threads)
240 .name(name() + ".EXEC:refs")
241 .desc("number of memory reference insts executed")
242 .flags(total)
243 ;
244
245 exeBranches
246 .init(cpu->number_of_threads)
247 .name(name() + ".EXEC:branches")
248 .desc("Number of branches executed")
249 .flags(total)
250 ;
251
252 issueRate
253 .name(name() + ".EXEC:rate")
254 .desc("Inst execution rate")
255 .flags(total)
256 ;
257 issueRate = iewExecutedInsts / cpu->numCycles;
258
259 iewExecStoreInsts
260 .name(name() + ".EXEC:stores")
261 .desc("Number of stores executed")
262 .flags(total)
263 ;
264 iewExecStoreInsts = exeRefs - iewExecLoadInsts;
265/*
266 for (int i=0; i<Num_OpClasses; ++i) {
267 stringstream subname;
268 subname << opClassStrings[i] << "_delay";
269 issue_delay_dist.subname(i, subname.str());
270 }
271*/
272 //
273 // Other stats
274 //
275
276 iewInstsToCommit
277 .init(cpu->number_of_threads)
278 .name(name() + ".WB:sent")
279 .desc("cumulative count of insts sent to commit")
280 .flags(total)
281 ;
282
283 writebackCount
284 .init(cpu->number_of_threads)
285 .name(name() + ".WB:count")
286 .desc("cumulative count of insts written-back")
287 .flags(total)
288 ;
289
290 producerInst
291 .init(cpu->number_of_threads)
292 .name(name() + ".WB:producers")
293 .desc("num instructions producing a value")
294 .flags(total)
295 ;
296
297 consumerInst
298 .init(cpu->number_of_threads)
299 .name(name() + ".WB:consumers")
300 .desc("num instructions consuming a value")
301 .flags(total)
302 ;
303
304 wbPenalized
305 .init(cpu->number_of_threads)
306 .name(name() + ".WB:penalized")
307 .desc("number of instrctions required to write to 'other' IQ")
308 .flags(total)
309 ;
310
311 wbPenalizedRate
312 .name(name() + ".WB:penalized_rate")
313 .desc ("fraction of instructions written-back that wrote to 'other' IQ")
314 .flags(total)
315 ;
316
317 wbPenalizedRate = wbPenalized / writebackCount;
318
319 wbFanout
320 .name(name() + ".WB:fanout")
321 .desc("average fanout of values written-back")
322 .flags(total)
323 ;
324
325 wbFanout = producerInst / consumerInst;
326
327 wbRate
328 .name(name() + ".WB:rate")
329 .desc("insts written-back per cycle")
330 .flags(total)
331 ;
332 wbRate = writebackCount / cpu->numCycles;
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168} 169 170template<class Impl> 171void
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337DefaultIEW<Impl>::initStage()
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172SimpleIEW<Impl>::setCPU(FullCPU *cpu_ptr) |
173{
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339 for (int tid=0; tid < numThreads; tid++) {
340 toRename->iewInfo[tid].usedIQ = true;
341 toRename->iewInfo[tid].freeIQEntries =
342 instQueue.numFreeEntries(tid);
343
344 toRename->iewInfo[tid].usedLSQ = true;
345 toRename->iewInfo[tid].freeLSQEntries =
346 ldstQueue.numFreeEntries(tid);
347 }
348}
349
350template<class Impl>
351void
352DefaultIEW<Impl>::setCPU(FullCPU *cpu_ptr)
353{
354 DPRINTF(IEW, "Setting CPU pointer.\n");
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174 DPRINTF(IEW, "IEW: Setting CPU pointer.\n"); |
175 cpu = cpu_ptr; 176 177 instQueue.setCPU(cpu_ptr); 178 ldstQueue.setCPU(cpu_ptr);
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359
360 cpu->activateStage(FullCPU::IEWIdx);
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179} 180 181template<class Impl> 182void
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365DefaultIEW<Impl>::setTimeBuffer(TimeBuffer<TimeStruct> *tb_ptr)
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183SimpleIEW<Impl>::setTimeBuffer(TimeBuffer<TimeStruct> *tb_ptr) |
184{
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367 DPRINTF(IEW, "Setting time buffer pointer.\n");
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185 DPRINTF(IEW, "IEW: Setting time buffer pointer.\n"); |
186 timeBuffer = tb_ptr; 187 188 // Setup wire to read information from time buffer, from commit. 189 fromCommit = timeBuffer->getWire(-commitToIEWDelay); 190 191 // Setup wire to write information back to previous stages. 192 toRename = timeBuffer->getWire(0); 193
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376 toFetch = timeBuffer->getWire(0);
377
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194 // Instruction queue also needs main time buffer. 195 instQueue.setTimeBuffer(tb_ptr); 196} 197 198template<class Impl> 199void
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384DefaultIEW<Impl>::setRenameQueue(TimeBuffer<RenameStruct> *rq_ptr)
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200SimpleIEW<Impl>::setRenameQueue(TimeBuffer<RenameStruct> *rq_ptr) |
201{
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386 DPRINTF(IEW, "Setting rename queue pointer.\n");
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202 DPRINTF(IEW, "IEW: Setting rename queue pointer.\n"); |
203 renameQueue = rq_ptr; 204 205 // Setup wire to read information from rename queue. 206 fromRename = renameQueue->getWire(-renameToIEWDelay); 207} 208 209template<class Impl> 210void
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395DefaultIEW<Impl>::setIEWQueue(TimeBuffer<IEWStruct> *iq_ptr)
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211SimpleIEW<Impl>::setIEWQueue(TimeBuffer<IEWStruct> *iq_ptr) |
212{
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397 DPRINTF(IEW, "Setting IEW queue pointer.\n");
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213 DPRINTF(IEW, "IEW: Setting IEW queue pointer.\n"); |
214 iewQueue = iq_ptr; 215 216 // Setup wire to write instructions to commit. 217 toCommit = iewQueue->getWire(0); 218} 219 220template<class Impl> 221void
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406DefaultIEW<Impl>::setActiveThreads(list<unsigned> *at_ptr)
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222SimpleIEW<Impl>::setRenameMap(RenameMap *rm_ptr) |
223{
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408 DPRINTF(IEW, "Setting active threads list pointer.\n");
409 activeThreads = at_ptr;
410
411 ldstQueue.setActiveThreads(at_ptr);
412 instQueue.setActiveThreads(at_ptr);
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224 DPRINTF(IEW, "IEW: Setting rename map pointer.\n"); 225 renameMap = rm_ptr; |
226} 227 228template<class Impl> 229void
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417DefaultIEW<Impl>::setScoreboard(Scoreboard *sb_ptr)
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230SimpleIEW<Impl>::squash() |
231{
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419 DPRINTF(IEW, "Setting scoreboard pointer.\n");
420 scoreboard = sb_ptr;
421}
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232 DPRINTF(IEW, "IEW: Squashing all instructions.\n"); 233 _status = Squashing; |
234
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423#if 0
424template<class Impl>
425void
426DefaultIEW<Impl>::setPageTable(PageTable *pt_ptr)
427{
428 ldstQueue.setPageTable(pt_ptr);
429}
430#endif
431
432template <class Impl>
433void
434DefaultIEW<Impl>::switchOut()
435{
436 cpu->signalSwitched();
437}
438
439template <class Impl>
440void
441DefaultIEW<Impl>::doSwitchOut()
442{
443 switchedOut = true;
444
445 instQueue.switchOut();
446 ldstQueue.switchOut();
447 fuPool->switchOut();
448
449 for (int i = 0; i < numThreads; i++) {
450 while (!insts[i].empty())
451 insts[i].pop();
452 while (!skidBuffer[i].empty())
453 skidBuffer[i].pop();
454 }
455}
456
457template <class Impl>
458void
459DefaultIEW<Impl>::takeOverFrom()
460{
461 _status = Active;
462 exeStatus = Running;
463 wbStatus = Idle;
464 switchedOut = false;
465
466 instQueue.takeOverFrom();
467 ldstQueue.takeOverFrom();
468 fuPool->takeOverFrom();
469
470 initStage();
471 cpu->activityThisCycle();
472
473 for (int i=0; i < numThreads; i++) {
474 dispatchStatus[i] = Running;
475 stalls[i].commit = false;
476 fetchRedirect[i] = false;
477 }
478
479 updateLSQNextCycle = false;
480
481 // @todo: Fix hardcoded number
482 for (int i = 0; i < 6; ++i) {
483 issueToExecQueue.advance();
484 }
485}
486
487template<class Impl>
488void
489DefaultIEW<Impl>::squash(unsigned tid)
490{
491 DPRINTF(IEW, "[tid:%i]: Squashing all instructions.\n",
492 tid);
493
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235 // Tell the IQ to start squashing.
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495 instQueue.squash(tid);
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236 instQueue.squash(); |
237 238 // Tell the LDSTQ to start squashing.
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498 ldstQueue.squash(fromCommit->commitInfo[tid].doneSeqNum, tid);
499
500 updatedQueues = true;
501
502 // Clear the skid buffer in case it has any data in it.
503 while (!skidBuffer[tid].empty()) {
504
505 if (skidBuffer[tid].front()->isLoad() ||
506 skidBuffer[tid].front()->isStore() ) {
507 toRename->iewInfo[tid].dispatchedToLSQ++;
508 }
509
510 toRename->iewInfo[tid].dispatched++;
511
512 skidBuffer[tid].pop();
513 }
514
515 while (!insts[tid].empty()) {
516 if (insts[tid].front()->isLoad() ||
517 insts[tid].front()->isStore() ) {
518 toRename->iewInfo[tid].dispatchedToLSQ++;
519 }
520
521 toRename->iewInfo[tid].dispatched++;
522
523 insts[tid].pop();
524 }
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239 ldstQueue.squash(fromCommit->commitInfo.doneSeqNum); |
240} 241 242template<class Impl> 243void
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529DefaultIEW<Impl>::squashDueToBranch(DynInstPtr &inst, unsigned tid)
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244SimpleIEW<Impl>::squashDueToBranch(DynInstPtr &inst) |
245{
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531 DPRINTF(IEW, "[tid:%i]: Squashing from a specific instruction, PC: %#x "
532 "[sn:%i].\n", tid, inst->readPC(), inst->seqNum);
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246 DPRINTF(IEW, "IEW: Squashing from a specific instruction, PC: %#x.\n", 247 inst->PC); 248 // Perhaps leave the squashing up to the ROB stage to tell it when to 249 // squash? 250 _status = Squashing; |
251
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534 toCommit->squash[tid] = true;
535 toCommit->squashedSeqNum[tid] = inst->seqNum;
536 toCommit->mispredPC[tid] = inst->readPC();
537 toCommit->nextPC[tid] = inst->readNextPC();
538 toCommit->branchMispredict[tid] = true;
539 toCommit->branchTaken[tid] = inst->readNextPC() !=
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252 // Tell rename to squash through the time buffer. 253 toCommit->squash = true; 254 // Also send PC update information back to prior stages. 255 toCommit->squashedSeqNum = inst->seqNum; 256 toCommit->mispredPC = inst->readPC(); 257 toCommit->nextPC = inst->readNextPC(); 258 toCommit->branchMispredict = true; 259 // Prediction was incorrect, so send back inverse. 260 toCommit->branchTaken = inst->readNextPC() != |
261 (inst->readPC() + sizeof(TheISA::MachInst));
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541
542 toCommit->includeSquashInst[tid] = false;
543
544 wroteToTimeBuffer = true;
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262} 263 264template<class Impl> 265void
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549DefaultIEW<Impl>::squashDueToMemOrder(DynInstPtr &inst, unsigned tid)
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266SimpleIEW<Impl>::squashDueToMem(DynInstPtr &inst) |
267{
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551 DPRINTF(IEW, "[tid:%i]: Squashing from a specific instruction, "
552 "PC: %#x [sn:%i].\n", tid, inst->readPC(), inst->seqNum);
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268 DPRINTF(IEW, "IEW: Squashing from a specific instruction, PC: %#x.\n", 269 inst->PC); 270 // Perhaps leave the squashing up to the ROB stage to tell it when to 271 // squash? 272 _status = Squashing; |
273
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554 toCommit->squash[tid] = true;
555 toCommit->squashedSeqNum[tid] = inst->seqNum;
556 toCommit->nextPC[tid] = inst->readNextPC();
557
558 toCommit->includeSquashInst[tid] = false;
559
560 wroteToTimeBuffer = true;
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274 // Tell rename to squash through the time buffer. 275 toCommit->squash = true; 276 // Also send PC update information back to prior stages. 277 toCommit->squashedSeqNum = inst->seqNum; 278 toCommit->nextPC = inst->readNextPC(); |
279} 280 281template<class Impl> 282void
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565DefaultIEW<Impl>::squashDueToMemBlocked(DynInstPtr &inst, unsigned tid)
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283SimpleIEW<Impl>::block() |
284{
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567 DPRINTF(IEW, "[tid:%i]: Memory blocked, squashing load and younger insts, "
568 "PC: %#x [sn:%i].\n", tid, inst->readPC(), inst->seqNum);
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285 DPRINTF(IEW, "IEW: Blocking.\n"); 286 // Set the status to Blocked. 287 _status = Blocked; |
288
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570 toCommit->squash[tid] = true;
571 toCommit->squashedSeqNum[tid] = inst->seqNum;
572 toCommit->nextPC[tid] = inst->readPC();
573
574 toCommit->includeSquashInst[tid] = true;
575
576 ldstQueue.setLoadBlockedHandled(tid);
577
578 wroteToTimeBuffer = true;
579}
580
581template<class Impl>
582void
583DefaultIEW<Impl>::block(unsigned tid)
584{
585 DPRINTF(IEW, "[tid:%u]: Blocking.\n", tid);
586
587 if (dispatchStatus[tid] != Blocked &&
588 dispatchStatus[tid] != Unblocking) {
589 toRename->iewBlock[tid] = true;
590 wroteToTimeBuffer = true;
591 }
592
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289 // Add the current inputs to the skid buffer so they can be 290 // reprocessed when this stage unblocks.
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595 skidInsert(tid);
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291 skidBuffer.push(*fromRename); |
292
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597 dispatchStatus[tid] = Blocked;
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293 // Note that this stage only signals previous stages to stall when 294 // it is the cause of the stall originates at this stage. Otherwise 295 // the previous stages are expected to check all possible stall signals. |
296} 297 298template<class Impl>
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601void
602DefaultIEW<Impl>::unblock(unsigned tid)
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299inline void 300SimpleIEW<Impl>::unblock() |
301{
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604 DPRINTF(IEW, "[tid:%i]: Reading instructions out of the skid "
605 "buffer %u.\n",tid, tid);
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302 // Check if there's information in the skid buffer. If there is, then 303 // set status to unblocking, otherwise set it directly to running. 304 DPRINTF(IEW, "IEW: Reading instructions out of the skid " 305 "buffer.\n"); 306 // Remove the now processed instructions from the skid buffer. 307 skidBuffer.pop(); |
308
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607 // If the skid bufffer is empty, signal back to previous stages to unblock.
608 // Also switch status to running.
609 if (skidBuffer[tid].empty()) {
610 toRename->iewUnblock[tid] = true;
611 wroteToTimeBuffer = true;
612 DPRINTF(IEW, "[tid:%i]: Done unblocking.\n",tid);
613 dispatchStatus[tid] = Running;
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309 // If there's still information in the skid buffer, then 310 // continue to tell previous stages to stall. They will be 311 // able to restart once the skid buffer is empty. 312 if (!skidBuffer.empty()) { 313 toRename->iewInfo.stall = true; 314 } else { 315 DPRINTF(IEW, "IEW: Stage is done unblocking.\n"); 316 _status = Running; |
317 } 318} 319 320template<class Impl> 321void
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619DefaultIEW<Impl>::wakeDependents(DynInstPtr &inst)
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322SimpleIEW<Impl>::wakeDependents(DynInstPtr &inst) |
323{ 324 instQueue.wakeDependents(inst); 325} 326
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624template<class Impl>
625void
626DefaultIEW<Impl>::rescheduleMemInst(DynInstPtr &inst)
627{
628 instQueue.rescheduleMemInst(inst);
629}
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327 328template<class Impl> 329void
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633DefaultIEW<Impl>::replayMemInst(DynInstPtr &inst)
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330SimpleIEW<Impl>::instToCommit(DynInstPtr &inst) |
331{
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635 instQueue.replayMemInst(inst);
636}
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332
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638template<class Impl>
639void
640DefaultIEW<Impl>::instToCommit(DynInstPtr &inst)
641{
642 // First check the time slot that this instruction will write
643 // to. If there are free write ports at the time, then go ahead
644 // and write the instruction to that time. If there are not,
645 // keep looking back to see where's the first time there's a
646 // free slot.
647 while ((*iewQueue)[wbCycle].insts[wbNumInst]) {
648 ++wbNumInst;
649 if (wbNumInst == issueWidth) {
650 ++wbCycle;
651 wbNumInst = 0;
652 }
653
654 assert(wbCycle < 5);
655 }
656
657 // Add finished instruction to queue to commit.
658 (*iewQueue)[wbCycle].insts[wbNumInst] = inst;
659 (*iewQueue)[wbCycle].size++;
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333} 334 335template <class Impl>
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663unsigned
664DefaultIEW<Impl>::validInstsFromRename()
665{
666 unsigned inst_count = 0;
667
668 for (int i=0; i<fromRename->size; i++) {
669 if (!fromRename->insts[i]->squashed)
670 inst_count++;
671 }
672
673 return inst_count;
674}
675
676template<class Impl>
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336void
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678DefaultIEW<Impl>::skidInsert(unsigned tid)
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337SimpleIEW<Impl>::dispatchInsts() |
338{
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680 DynInstPtr inst = NULL;
|
339 //////////////////////////////////////// 340 // DISPATCH/ISSUE stage 341 //////////////////////////////////////// |
342
|
682 while (!insts[tid].empty()) {
683 inst = insts[tid].front();
|
343 //Put into its own function? 344 //Add instructions to IQ if there are any instructions there |
345
|
685 insts[tid].pop();
|
346 // Check if there are any instructions coming from rename, and we're. 347 // not squashing. 348 if (fromRename->size > 0) { 349 int insts_to_add = fromRename->size; |
350
|
687 DPRINTF(Decode,"[tid:%i]: Inserting [sn:%lli] PC:%#x into "
688 "dispatch skidBuffer %i\n",tid, inst->seqNum,
689 inst->readPC(),tid);
|
351 // Loop through the instructions, putting them in the instruction 352 // queue. 353 for (int inst_num = 0; inst_num < insts_to_add; ++inst_num) 354 { 355 DynInstPtr inst = fromRename->insts[inst_num]; |
356
|
691 skidBuffer[tid].push(inst);
692 }
|
357 // Make sure there's a valid instruction there. 358 assert(inst); |
359
|
694 assert(skidBuffer[tid].size() <= skidBufferMax &&
695 "Skidbuffer Exceeded Max Size");
696}
|
360 DPRINTF(IEW, "IEW: Issue: Adding PC %#x to IQ.\n", 361 inst->readPC()); |
362
|
698template<class Impl>
699int
700DefaultIEW<Impl>::skidCount()
701{
702 int max=0;
|
363 // Be sure to mark these instructions as ready so that the 364 // commit stage can go ahead and execute them, and mark 365 // them as issued so the IQ doesn't reprocess them. 366 if (inst->isSquashed()) { 367 ++iewDispSquashedInsts; 368 continue; 369 } else if (instQueue.isFull()) { 370 DPRINTF(IEW, "IEW: Issue: IQ has become full.\n"); 371 // Call function to start blocking. 372 block(); 373 // Tell previous stage to stall. 374 toRename->iewInfo.stall = true; |
375
|
704 list<unsigned>::iterator threads = (*activeThreads).begin();
|
376 ++iewIQFullEvents; 377 break; 378 } else if (inst->isLoad()) { 379 DPRINTF(IEW, "IEW: Issue: Memory instruction " 380 "encountered, adding to LDSTQ.\n"); |
381
|
706 while (threads != (*activeThreads).end()) {
707 unsigned thread_count = skidBuffer[*threads++].size();
708 if (max < thread_count)
709 max = thread_count;
710 }
|
382 // Reserve a spot in the load store queue for this 383 // memory access. 384 ldstQueue.insertLoad(inst); |
385
|
712 return max;
713}
|
386 ++iewDispLoadInsts; 387 } else if (inst->isStore()) { 388 ldstQueue.insertStore(inst); |
389
|
715template<class Impl>
716bool
717DefaultIEW<Impl>::skidsEmpty()
718{
719 list<unsigned>::iterator threads = (*activeThreads).begin();
|
390 ++iewDispStoreInsts; 391 } else if (inst->isNonSpeculative()) { 392 DPRINTF(IEW, "IEW: Issue: Nonspeculative instruction " 393 "encountered, skipping.\n"); |
394
|
721 while (threads != (*activeThreads).end()) {
722 if (!skidBuffer[*threads++].empty())
723 return false;
724 }
725
726 return true;
727}
728
729template <class Impl>
730void
731DefaultIEW<Impl>::updateStatus()
732{
733 bool any_unblocking = false;
734
735 list<unsigned>::iterator threads = (*activeThreads).begin();
736
737 threads = (*activeThreads).begin();
738
739 while (threads != (*activeThreads).end()) {
740 unsigned tid = *threads++;
741
742 if (dispatchStatus[tid] == Unblocking) {
743 any_unblocking = true;
744 break;
745 }
746 }
747
748 // If there are no ready instructions waiting to be scheduled by the IQ,
749 // and there's no stores waiting to write back, and dispatch is not
750 // unblocking, then there is no internal activity for the IEW stage.
751 if (_status == Active && !instQueue.hasReadyInsts() &&
752 !ldstQueue.willWB() && !any_unblocking) {
753 DPRINTF(IEW, "IEW switching to idle\n");
754
755 deactivateStage();
756
757 _status = Inactive;
758 } else if (_status == Inactive && (instQueue.hasReadyInsts() ||
759 ldstQueue.willWB() ||
760 any_unblocking)) {
761 // Otherwise there is internal activity. Set to active.
762 DPRINTF(IEW, "IEW switching to active\n");
763
764 activateStage();
765
766 _status = Active;
767 }
768}
769
770template <class Impl>
771void
772DefaultIEW<Impl>::resetEntries()
773{
774 instQueue.resetEntries();
775 ldstQueue.resetEntries();
776}
777
778template <class Impl>
779void
780DefaultIEW<Impl>::readStallSignals(unsigned tid)
781{
782 if (fromCommit->commitBlock[tid]) {
783 stalls[tid].commit = true;
784 }
785
786 if (fromCommit->commitUnblock[tid]) {
787 assert(stalls[tid].commit);
788 stalls[tid].commit = false;
789 }
790}
791
792template <class Impl>
793bool
794DefaultIEW<Impl>::checkStall(unsigned tid)
795{
796 bool ret_val(false);
797
798 if (stalls[tid].commit) {
799 DPRINTF(IEW,"[tid:%i]: Stall from Commit stage detected.\n",tid);
800 ret_val = true;
801 } else if (instQueue.isFull(tid)) {
802 DPRINTF(IEW,"[tid:%i]: Stall: IQ is full.\n",tid);
803 ret_val = true;
804 } else if (ldstQueue.isFull(tid)) {
805 DPRINTF(IEW,"[tid:%i]: Stall: LSQ is full\n",tid);
806
807 if (ldstQueue.numLoads(tid) > 0 ) {
808
809 DPRINTF(IEW,"[tid:%i]: LSQ oldest load: [sn:%i] \n",
810 tid,ldstQueue.getLoadHeadSeqNum(tid));
811 }
812
813 if (ldstQueue.numStores(tid) > 0) {
814
815 DPRINTF(IEW,"[tid:%i]: LSQ oldest store: [sn:%i] \n",
816 tid,ldstQueue.getStoreHeadSeqNum(tid));
817 }
818
819 ret_val = true;
820 } else if (ldstQueue.isStalled(tid)) {
821 DPRINTF(IEW,"[tid:%i]: Stall: LSQ stall detected.\n",tid);
822 ret_val = true;
823 }
824
825 return ret_val;
826}
827
828template <class Impl>
829void
830DefaultIEW<Impl>::checkSignalsAndUpdate(unsigned tid)
831{
832 // Check if there's a squash signal, squash if there is
833 // Check stall signals, block if there is.
834 // If status was Blocked
835 // if so then go to unblocking
836 // If status was Squashing
837 // check if squashing is not high. Switch to running this cycle.
838
839 readStallSignals(tid);
840
841 if (fromCommit->commitInfo[tid].squash) {
842 squash(tid);
843
844 if (dispatchStatus[tid] == Blocked ||
845 dispatchStatus[tid] == Unblocking) {
846 toRename->iewUnblock[tid] = true;
847 wroteToTimeBuffer = true;
848 }
849
850 dispatchStatus[tid] = Squashing;
851
852 fetchRedirect[tid] = false;
853 return;
854 }
855
856 if (fromCommit->commitInfo[tid].robSquashing) {
857 DPRINTF(IEW, "[tid:%i]: ROB is still squashing.\n");
858
859 dispatchStatus[tid] = Squashing;
860
861 return;
862 }
863
864 if (checkStall(tid)) {
865 block(tid);
866 dispatchStatus[tid] = Blocked;
867 return;
868 }
869
870 if (dispatchStatus[tid] == Blocked) {
871 // Status from previous cycle was blocked, but there are no more stall
872 // conditions. Switch over to unblocking.
873 DPRINTF(IEW, "[tid:%i]: Done blocking, switching to unblocking.\n",
874 tid);
875
876 dispatchStatus[tid] = Unblocking;
877
878 unblock(tid);
879
880 return;
881 }
882
883 if (dispatchStatus[tid] == Squashing) {
884 // Switch status to running if rename isn't being told to block or
885 // squash this cycle.
886 DPRINTF(IEW, "[tid:%i]: Done squashing, switching to running.\n",
887 tid);
888
889 dispatchStatus[tid] = Running;
890
891 return;
892 }
893}
894
895template <class Impl>
896void
897DefaultIEW<Impl>::sortInsts()
898{
899 int insts_from_rename = fromRename->size;
900#ifdef DEBUG
901 for (int i = 0; i < numThreads; i++)
902 assert(insts[i].empty());
903#endif
904 for (int i = 0; i < insts_from_rename; ++i) {
905 insts[fromRename->insts[i]->threadNumber].push(fromRename->insts[i]);
906 }
907}
908
909template <class Impl>
910void
911DefaultIEW<Impl>::wakeCPU()
912{
913 cpu->wakeCPU();
914}
915
916template <class Impl>
917void
918DefaultIEW<Impl>::activityThisCycle()
919{
920 DPRINTF(Activity, "Activity this cycle.\n");
921 cpu->activityThisCycle();
922}
923
924template <class Impl>
925inline void
926DefaultIEW<Impl>::activateStage()
927{
928 DPRINTF(Activity, "Activating stage.\n");
929 cpu->activateStage(FullCPU::IEWIdx);
930}
931
932template <class Impl>
933inline void
934DefaultIEW<Impl>::deactivateStage()
935{
936 DPRINTF(Activity, "Deactivating stage.\n");
937 cpu->deactivateStage(FullCPU::IEWIdx);
938}
939
940template<class Impl>
941void
942DefaultIEW<Impl>::dispatch(unsigned tid)
943{
944 // If status is Running or idle,
945 // call dispatchInsts()
946 // If status is Unblocking,
947 // buffer any instructions coming from rename
948 // continue trying to empty skid buffer
949 // check if stall conditions have passed
950
951 if (dispatchStatus[tid] == Blocked) {
952 ++iewBlockCycles;
953
954 } else if (dispatchStatus[tid] == Squashing) {
955 ++iewSquashCycles;
956 }
957
958 // Dispatch should try to dispatch as many instructions as its bandwidth
959 // will allow, as long as it is not currently blocked.
960 if (dispatchStatus[tid] == Running ||
961 dispatchStatus[tid] == Idle) {
962 DPRINTF(IEW, "[tid:%i] Not blocked, so attempting to run "
963 "dispatch.\n", tid);
964
965 dispatchInsts(tid);
966 } else if (dispatchStatus[tid] == Unblocking) {
967 // Make sure that the skid buffer has something in it if the
968 // status is unblocking.
969 assert(!skidsEmpty());
970
971 // If the status was unblocking, then instructions from the skid
972 // buffer were used. Remove those instructions and handle
973 // the rest of unblocking.
974 dispatchInsts(tid);
975
976 ++iewUnblockCycles;
977
978 if (validInstsFromRename() && dispatchedAllInsts) {
979 // Add the current inputs to the skid buffer so they can be
980 // reprocessed when this stage unblocks.
981 skidInsert(tid);
982 }
983
984 unblock(tid);
985 }
986}
987
988template <class Impl>
989void
990DefaultIEW<Impl>::dispatchInsts(unsigned tid)
991{
992 dispatchedAllInsts = true;
993
994 // Obtain instructions from skid buffer if unblocking, or queue from rename
995 // otherwise.
996 std::queue<DynInstPtr> &insts_to_dispatch =
997 dispatchStatus[tid] == Unblocking ?
998 skidBuffer[tid] : insts[tid];
999
1000 int insts_to_add = insts_to_dispatch.size();
1001
1002 DynInstPtr inst;
1003 bool add_to_iq = false;
1004 int dis_num_inst = 0;
1005
1006 // Loop through the instructions, putting them in the instruction
1007 // queue.
1008 for ( ; dis_num_inst < insts_to_add &&
1009 dis_num_inst < issueReadWidth;
1010 ++dis_num_inst)
1011 {
1012 inst = insts_to_dispatch.front();
1013
1014 if (dispatchStatus[tid] == Unblocking) {
1015 DPRINTF(IEW, "[tid:%i]: Issue: Examining instruction from skid "
1016 "buffer\n", tid);
1017 }
1018
1019 // Make sure there's a valid instruction there.
1020 assert(inst);
1021
1022 DPRINTF(IEW, "[tid:%i]: Issue: Adding PC %#x [sn:%lli] [tid:%i] to "
1023 "IQ.\n",
1024 tid, inst->readPC(), inst->seqNum, inst->threadNumber);
1025
1026 // Be sure to mark these instructions as ready so that the
1027 // commit stage can go ahead and execute them, and mark
1028 // them as issued so the IQ doesn't reprocess them.
1029
1030 // Check for squashed instructions.
1031 if (inst->isSquashed()) {
1032 DPRINTF(IEW, "[tid:%i]: Issue: Squashed instruction encountered, "
1033 "not adding to IQ.\n", tid);
1034
1035 ++iewDispSquashedInsts;
1036
1037 insts_to_dispatch.pop();
1038
1039 //Tell Rename That An Instruction has been processed
1040 if (inst->isLoad() || inst->isStore()) {
1041 toRename->iewInfo[tid].dispatchedToLSQ++;
1042 }
1043 toRename->iewInfo[tid].dispatched++;
1044
1045 continue;
1046 }
1047
1048 // Check for full conditions.
1049 if (instQueue.isFull(tid)) {
1050 DPRINTF(IEW, "[tid:%i]: Issue: IQ has become full.\n", tid);
1051
1052 // Call function to start blocking.
1053 block(tid);
1054
1055 // Set unblock to false. Special case where we are using
1056 // skidbuffer (unblocking) instructions but then we still
1057 // get full in the IQ.
1058 toRename->iewUnblock[tid] = false;
1059
1060 dispatchedAllInsts = false;
1061
1062 ++iewIQFullEvents;
1063 break;
1064 } else if (ldstQueue.isFull(tid)) {
1065 DPRINTF(IEW, "[tid:%i]: Issue: LSQ has become full.\n",tid);
1066
1067 // Call function to start blocking.
1068 block(tid);
1069
1070 // Set unblock to false. Special case where we are using
1071 // skidbuffer (unblocking) instructions but then we still
1072 // get full in the IQ.
1073 toRename->iewUnblock[tid] = false;
1074
1075 dispatchedAllInsts = false;
1076
1077 ++iewLSQFullEvents;
1078 break;
1079 }
1080
1081 // Otherwise issue the instruction just fine.
1082 if (inst->isLoad()) {
1083 DPRINTF(IEW, "[tid:%i]: Issue: Memory instruction "
1084 "encountered, adding to LSQ.\n", tid);
1085
1086 // Reserve a spot in the load store queue for this
1087 // memory access.
1088 ldstQueue.insertLoad(inst);
1089
1090 ++iewDispLoadInsts;
1091
1092 add_to_iq = true;
1093
1094 toRename->iewInfo[tid].dispatchedToLSQ++;
1095 } else if (inst->isStore()) {
1096 DPRINTF(IEW, "[tid:%i]: Issue: Memory instruction "
1097 "encountered, adding to LSQ.\n", tid);
1098
1099 ldstQueue.insertStore(inst);
1100
1101 ++iewDispStoreInsts;
1102
1103 if (inst->isStoreConditional()) {
1104 // Store conditionals need to be set as "canCommit()"
1105 // so that commit can process them when they reach the
1106 // head of commit.
|
395 // Same hack as with stores. |
396 inst->setCanCommit();
|
397 398 // Specificall insert it as nonspeculative. |
399 instQueue.insertNonSpec(inst);
|
1109 add_to_iq = false;
|
400 401 ++iewDispNonSpecInsts;
|
1112 } else {
1113 add_to_iq = true;
1114 }
|
402
|
1116 toRename->iewInfo[tid].dispatchedToLSQ++;
1117#if FULL_SYSTEM
1118 } else if (inst->isMemBarrier() || inst->isWriteBarrier()) {
1119 // Same as non-speculative stores.
1120 inst->setCanCommit();
1121 instQueue.insertBarrier(inst);
1122 add_to_iq = false;
1123#endif
1124 } else if (inst->isNonSpeculative()) {
1125 DPRINTF(IEW, "[tid:%i]: Issue: Nonspeculative instruction "
1126 "encountered, skipping.\n", tid);
|
403 continue; 404 } else if (inst->isNop()) { 405 DPRINTF(IEW, "IEW: Issue: Nop instruction encountered " 406 ", skipping.\n"); |
407
|
1128 // Same as non-speculative stores.
1129 inst->setCanCommit();
|
408 inst->setIssued(); 409 inst->setExecuted(); 410 inst->setCanCommit(); |
411
|
1131 // Specifically insert it as nonspeculative.
1132 instQueue.insertNonSpec(inst);
|
412 instQueue.advanceTail(inst); |
413
|
1134 ++iewDispNonSpecInsts;
|
414 continue; 415 } else if (inst->isExecuted()) { 416 assert(0 && "Instruction shouldn't be executed.\n"); 417 DPRINTF(IEW, "IEW: Issue: Executed branch encountered, " 418 "skipping.\n"); |
419
|
1136 add_to_iq = false;
1137 } else if (inst->isNop()) {
1138 DPRINTF(IEW, "[tid:%i]: Issue: Nop instruction encountered, "
1139 "skipping.\n", tid);
|
420 inst->setIssued(); 421 inst->setCanCommit(); |
422
|
1141 inst->setIssued();
1142 inst->setExecuted();
1143 inst->setCanCommit();
|
423 instQueue.advanceTail(inst); |
424
|
1145 instQueue.recordProducer(inst);
|
425 continue; 426 } |
427
|
1147 exeNop[tid]++;
|
428 // If the instruction queue is not full, then add the 429 // instruction. 430 instQueue.insert(fromRename->insts[inst_num]); |
431
|
1149 add_to_iq = false;
1150 } else if (inst->isExecuted()) {
1151 assert(0 && "Instruction shouldn't be executed.\n");
1152 DPRINTF(IEW, "Issue: Executed branch encountered, "
1153 "skipping.\n");
1154
1155 inst->setIssued();
1156 inst->setCanCommit();
1157
1158 instQueue.recordProducer(inst);
1159
1160 add_to_iq = false;
1161 } else {
1162 add_to_iq = true;
|
432 ++iewDispatchedInsts; |
433 }
|
1164
1165 // If the instruction queue is not full, then add the
1166 // instruction.
1167 if (add_to_iq) {
1168 instQueue.insert(inst);
1169 }
1170
1171 insts_to_dispatch.pop();
1172
1173 toRename->iewInfo[tid].dispatched++;
1174
1175 ++iewDispatchedInsts;
|
434 }
|
1177
1178 if (!insts_to_dispatch.empty()) {
1179 DPRINTF(IEW,"[tid:%i]: Issue: Bandwidth Full. Blocking.\n");
1180 block(tid);
1181 toRename->iewUnblock[tid] = false;
1182 }
1183
1184 if (dispatchStatus[tid] == Idle && dis_num_inst) {
1185 dispatchStatus[tid] = Running;
1186
1187 updatedQueues = true;
1188 }
1189
1190 dis_num_inst = 0;
|
435} 436 437template <class Impl> 438void
|
1195DefaultIEW<Impl>::printAvailableInsts()
|
439SimpleIEW<Impl>::executeInsts() |
440{
|
1197 int inst = 0;
|
441 //////////////////////////////////////// 442 //EXECUTE/WRITEBACK stage 443 //////////////////////////////////////// |
444
|
1199 cout << "Available Instructions: ";
|
445 //Put into its own function? 446 //Similarly should probably have separate execution for int vs FP. 447 // Above comment is handled by the issue queue only issuing a valid 448 // mix of int/fp instructions. 449 //Actually okay to just have one execution, buuuuuut will need 450 //somewhere that defines the execution latency of all instructions. 451 // @todo: Move to the FU pool used in the current full cpu. |
452
|
1201 while (fromIssue->insts[inst]) {
|
453 int fu_usage = 0; 454 bool fetch_redirect = false; 455 int inst_slot = 0; 456 int time_slot = 0; |
457
|
1203 if (inst%3==0) cout << "\n\t";
1204
1205 cout << "PC: " << fromIssue->insts[inst]->readPC()
1206 << " TN: " << fromIssue->insts[inst]->threadNumber
1207 << " SN: " << fromIssue->insts[inst]->seqNum << " | ";
1208
1209 inst++;
1210
1211 }
1212
1213 cout << "\n";
1214}
1215
1216template <class Impl>
1217void
1218DefaultIEW<Impl>::executeInsts()
1219{
1220 wbNumInst = 0;
1221 wbCycle = 0;
1222
1223 list<unsigned>::iterator threads = (*activeThreads).begin();
1224
1225 while (threads != (*activeThreads).end()) {
1226 unsigned tid = *threads++;
1227 fetchRedirect[tid] = false;
1228 }
1229
1230#if 0
1231 printAvailableInsts();
1232#endif
1233
|
458 // Execute/writeback any instructions that are available.
|
1235 int insts_to_execute = fromIssue->size;
1236 int inst_num = 0;
1237 for (; inst_num < insts_to_execute;
1238 ++inst_num) {
|
459 for (int inst_num = 0; 460 fu_usage < executeWidth && /* Haven't exceeded available FU's. */ 461 inst_num < issueWidth && 462 fromIssue->insts[inst_num]; 463 ++inst_num) { |
464
|
1240 DPRINTF(IEW, "Execute: Executing instructions from IQ.\n");
|
465 DPRINTF(IEW, "IEW: Execute: Executing instructions from IQ.\n"); |
466
|
1242 DynInstPtr inst = instQueue.getInstToExecute();
|
467 // Get instruction from issue's queue. 468 DynInstPtr inst = fromIssue->insts[inst_num]; |
469
|
1244 DPRINTF(IEW, "Execute: Processing PC %#x, [tid:%i] [sn:%i].\n",
1245 inst->readPC(), inst->threadNumber,inst->seqNum);
|
470 DPRINTF(IEW, "IEW: Execute: Processing PC %#x.\n", inst->readPC()); |
471 472 // Check if the instruction is squashed; if so then skip it
|
473 // and don't count it towards the FU usage. |
474 if (inst->isSquashed()) {
|
1249 DPRINTF(IEW, "Execute: Instruction was squashed.\n");
|
475 DPRINTF(IEW, "IEW: Execute: Instruction was squashed.\n"); |
476 477 // Consider this instruction executed so that commit can go 478 // ahead and retire the instruction. 479 inst->setExecuted(); 480
|
1255 // Not sure if I should set this here or just let commit try to
1256 // commit any squashed instructions. I like the latter a bit more.
1257 inst->setCanCommit();
|
481 toCommit->insts[inst_num] = inst; |
482 483 ++iewExecSquashedInsts; 484 485 continue; 486 } 487
|
1264 Fault fault = NoFault;
|
488 inst->setExecuted(); |
489
|
490 // If an instruction is executed, then count it towards FU usage. 491 ++fu_usage; 492 |
493 // Execute instruction. 494 // Note that if the instruction faults, it will be handled 495 // at the commit stage.
|
1269 if (inst->isMemRef() &&
1270 (!inst->isDataPrefetch() && !inst->isInstPrefetch())) {
1271 DPRINTF(IEW, "Execute: Calculating address for memory "
|
496 if (inst->isMemRef()) { 497 DPRINTF(IEW, "IEW: Execute: Calculating address for memory " |
498 "reference.\n"); 499 500 // Tell the LDSTQ to execute this instruction (if it is a load). 501 if (inst->isLoad()) {
|
1276 // Loads will mark themselves as executed, and their writeback
1277 // event adds the instruction to the queue to commit
1278 fault = ldstQueue.executeLoad(inst);
|
502 ldstQueue.executeLoad(inst); 503 504 ++iewExecLoadInsts; |
505 } else if (inst->isStore()) { 506 ldstQueue.executeStore(inst); 507
|
1282 // If the store had a fault then it may not have a mem req
1283 if (inst->req && !(inst->req->flags & LOCKED)) {
1284 inst->setExecuted();
1285
1286 instToCommit(inst);
1287 }
1288
1289 // Store conditionals will mark themselves as
1290 // executed, and their writeback event will add the
1291 // instruction to the queue to commit.
|
508 ++iewExecStoreInsts; |
509 } else {
|
1293 panic("Unexpected memory type!\n");
|
510 panic("IEW: Unexpected memory type!\n"); |
511 } 512 513 } else { 514 inst->execute(); 515
|
1299 inst->setExecuted();
1300
1301 instToCommit(inst);
|
516 ++iewExecutedInsts; |
517 } 518
|
1304 updateExeInstStats(inst);
|
519 // First check the time slot that this instruction will write 520 // to. If there are free write ports at the time, then go ahead 521 // and write the instruction to that time. If there are not, 522 // keep looking back to see where's the first time there's a 523 // free slot. What happens if you run out of free spaces? 524 // For now naively assume that all instructions take one cycle. 525 // Otherwise would have to look into the time buffer based on the 526 // latency of the instruction. 527 (*iewQueue)[time_slot].insts[inst_slot]; 528 while ((*iewQueue)[time_slot].insts[inst_slot]) { 529 if (inst_slot < issueWidth) { 530 ++inst_slot; 531 } else { 532 ++time_slot; 533 inst_slot = 0; 534 } |
535
|
1306 // Check if branch prediction was correct, if not then we need
1307 // to tell commit to squash in flight instructions. Only
1308 // handle this if there hasn't already been something that
1309 // redirects fetch in this group of instructions.
|
536 assert(time_slot < 5); 537 } |
538
|
1311 // This probably needs to prioritize the redirects if a different
1312 // scheduler is used. Currently the scheduler schedules the oldest
1313 // instruction first, so the branch resolution order will be correct.
1314 unsigned tid = inst->threadNumber;
|
539 // May actually have to work this out, especially with loads and stores |
540
|
1316 if (!fetchRedirect[tid]) {
|
541 // Add finished instruction to queue to commit. 542 (*iewQueue)[time_slot].insts[inst_slot] = inst; 543 (*iewQueue)[time_slot].size++; |
544
|
545 // Check if branch was correct. This check happens after the 546 // instruction is added to the queue because even if the branch 547 // is mispredicted, the branch instruction itself is still valid. 548 // Only handle this if there hasn't already been something that 549 // redirects fetch in this group of instructions. 550 if (!fetch_redirect) { |
551 if (inst->mispredicted()) {
|
1319 fetchRedirect[tid] = true;
|
552 fetch_redirect = true; |
553
|
1321 DPRINTF(IEW, "Execute: Branch mispredict detected.\n");
1322 DPRINTF(IEW, "Execute: Redirecting fetch to PC: %#x.\n",
|
554 DPRINTF(IEW, "IEW: Execute: Branch mispredict detected.\n"); 555 DPRINTF(IEW, "IEW: Execute: Redirecting fetch to PC: %#x.\n", |
556 inst->nextPC); 557 558 // If incorrect, then signal the ROB that it must be squashed.
|
1326 squashDueToBranch(inst, tid);
|
559 squashDueToBranch(inst); |
560 561 if (inst->predTaken()) { 562 predictedTakenIncorrect++;
|
1330 } else {
1331 predictedNotTakenIncorrect++;
|
563 }
|
1333 } else if (ldstQueue.violation(tid)) {
1334 fetchRedirect[tid] = true;
|
564 } else if (ldstQueue.violation()) { 565 fetch_redirect = true; |
566
|
1336 // If there was an ordering violation, then get the
1337 // DynInst that caused the violation. Note that this
1338 // clears the violation signal.
1339 DynInstPtr violator;
1340 violator = ldstQueue.getMemDepViolator(tid);
|
567 // Get the DynInst that caused the violation. 568 DynInstPtr violator = ldstQueue.getMemDepViolator(); |
569
|
1342 DPRINTF(IEW, "LDSTQ detected a violation. Violator PC: "
|
570 DPRINTF(IEW, "IEW: LDSTQ detected a violation. Violator PC: " |
571 "%#x, inst PC: %#x. Addr is: %#x.\n", 572 violator->readPC(), inst->readPC(), inst->physEffAddr); 573 574 // Tell the instruction queue that a violation has occured. 575 instQueue.violation(inst, violator); 576 577 // Squash.
|
1350 squashDueToMemOrder(inst,tid);
|
578 squashDueToMem(inst); |
579 580 ++memOrderViolationEvents;
|
1353 } else if (ldstQueue.loadBlocked(tid) &&
1354 !ldstQueue.isLoadBlockedHandled(tid)) {
1355 fetchRedirect[tid] = true;
1356
1357 DPRINTF(IEW, "Load operation couldn't execute because the "
1358 "memory system is blocked. PC: %#x [sn:%lli]\n",
1359 inst->readPC(), inst->seqNum);
1360
1361 squashDueToMemBlocked(inst, tid);
|
581 } 582 } 583 }
|
1365
1366 if (inst_num) {
1367 if (exeStatus == Idle) {
1368 exeStatus = Running;
1369 }
1370
1371 updatedQueues = true;
1372
1373 cpu->activityThisCycle();
1374 }
1375
1376 // Need to reset this in case a writeback event needs to write into the
1377 // iew queue. That way the writeback event will write into the correct
1378 // spot in the queue.
1379 wbNumInst = 0;
|
584} 585
|
1382template <class Impl>
|
586template |
587void
|
1384DefaultIEW<Impl>::writebackInsts()
|
588SimpleIEW<Impl>::tick() |
589{
|
1386 // Loop through the head of the time buffer and wake any
1387 // dependents. These instructions are about to write back. Also
1388 // mark scoreboard that this instruction is finally complete.
1389 // Either have IEW have direct access to scoreboard, or have this
1390 // as part of backwards communication.
1391 for (int inst_num = 0; inst_num < issueWidth &&
1392 toCommit->insts[inst_num]; inst_num++) {
1393 DynInstPtr inst = toCommit->insts[inst_num];
1394 int tid = inst->threadNumber;
|
590 // Considering putting all the state-determining stuff in this section. |
591
|
1396 DPRINTF(IEW, "Sending instructions to commit, PC %#x.\n",
1397 inst->readPC());
|
592 // Try to fill up issue queue with as many instructions as bandwidth 593 // allows. 594 // Decode should try to execute as many instructions as its bandwidth 595 // will allow, as long as it is not currently blocked. |
596
|
1399 iewInstsToCommit[tid]++;
|
597 // Check if the stage is in a running status. 598 if (_status != Blocked && _status != Squashing) { 599 DPRINTF(IEW, "IEW: Status is not blocked, attempting to run " 600 "stage.\n"); 601 iew(); |
602
|
1401 // Some instructions will be sent to commit without having
1402 // executed because they need commit to handle them.
1403 // E.g. Uncached loads have not actually executed when they
1404 // are first sent to commit. Instead commit must tell the LSQ
1405 // when it's ready to execute the uncached load.
1406 if (!inst->isSquashed() && inst->isExecuted()) {
1407 int dependents = instQueue.wakeDependents(inst);
|
603 // If it's currently unblocking, check to see if it should switch 604 // to running. 605 if (_status == Unblocking) { 606 unblock(); |
607
|
1409 for (int i = 0; i < inst->numDestRegs(); i++) {
1410 //mark as Ready
1411 DPRINTF(IEW,"Setting Destination Register %i\n",
1412 inst->renamedDestRegIdx(i));
1413 scoreboard->setReg(inst->renamedDestRegIdx(i));
1414 }
1415
1416 producerInst[tid]++;
1417 consumerInst[tid]+= dependents;
1418 writebackCount[tid]++;
|
608 ++iewUnblockCycles; |
609 }
|
1420 }
1421}
|
610 } else if (_status == Squashing) { |
611
|
1423template<class Impl>
1424void
1425DefaultIEW<Impl>::tick()
1426{
1427 wbNumInst = 0;
1428 wbCycle = 0;
|
612 DPRINTF(IEW, "IEW: Still squashing.\n"); |
613
|
1430 wroteToTimeBuffer = false;
1431 updatedQueues = false;
|
614 // Check if stage should remain squashing. Stop squashing if the 615 // squash signal clears. 616 if (!fromCommit->commitInfo.squash && 617 !fromCommit->commitInfo.robSquashing) { 618 DPRINTF(IEW, "IEW: Done squashing, changing status to " 619 "running.\n"); |
620
|
1433 sortInsts();
|
621 _status = Running; 622 instQueue.stopSquash(); 623 } else { 624 instQueue.doSquash(); 625 } |
626
|
1435 // Free function units marked as being freed this cycle.
1436 fuPool->processFreeUnits();
|
627 ++iewSquashCycles; 628 } else if (_status == Blocked) { 629 // Continue to tell previous stage to stall. 630 toRename->iewInfo.stall = true; |
631
|
1438 list<unsigned>::iterator threads = (*activeThreads).begin();
|
632 // Check if possible stall conditions have cleared. 633 if (!fromCommit->commitInfo.stall && 634 !instQueue.isFull()) { 635 DPRINTF(IEW, "IEW: Stall signals cleared, going to unblock.\n"); 636 _status = Unblocking; 637 } |
638
|
1440 // Check stall and squash signals, dispatch any instructions.
1441 while (threads != (*activeThreads).end()) {
1442 unsigned tid = *threads++;
|
639 // If there's still instructions coming from rename, continue to 640 // put them on the skid buffer. 641 if (fromRename->size == 0) { 642 block(); 643 } |
644
|
1444 DPRINTF(IEW,"Issue: Processing [tid:%i]\n",tid);
|
645 if (fromCommit->commitInfo.squash || 646 fromCommit->commitInfo.robSquashing) { 647 squash(); 648 } |
649
|
1446 checkSignalsAndUpdate(tid);
1447 dispatch(tid);
|
650 ++iewBlockCycles; |
651 } 652
|
1450 if (exeStatus != Squashing) {
1451 executeInsts();
|
653 // @todo: Maybe put these at the beginning, so if it's idle it can 654 // return early. 655 // Write back number of free IQ entries here. 656 toRename->iewInfo.freeIQEntries = instQueue.numFreeEntries(); |
657
|
1453 writebackInsts();
1454
1455 // Have the instruction queue try to schedule any ready instructions.
1456 // (In actuality, this scheduling is for instructions that will
1457 // be executed next cycle.)
1458 instQueue.scheduleReadyInsts();
1459
1460 // Also should advance its own time buffers if the stage ran.
1461 // Not the best place for it, but this works (hopefully).
1462 issueToExecQueue.advance();
1463 }
1464
1465 bool broadcast_free_entries = false;
1466
1467 if (updatedQueues || exeStatus == Running || updateLSQNextCycle) {
1468 exeStatus = Idle;
1469 updateLSQNextCycle = false;
1470
1471 broadcast_free_entries = true;
1472 }
1473
1474 // Writeback any stores using any leftover bandwidth.
|
658 ldstQueue.writebackStores(); 659 660 // Check the committed load/store signals to see if there's a load 661 // or store to commit. Also check if it's being told to execute a 662 // nonspeculative instruction. 663 // This is pretty inefficient...
|
664 if (!fromCommit->commitInfo.squash && 665 !fromCommit->commitInfo.robSquashing) { 666 ldstQueue.commitStores(fromCommit->commitInfo.doneSeqNum); 667 ldstQueue.commitLoads(fromCommit->commitInfo.doneSeqNum); 668 } |
669
|
1482 threads = (*activeThreads).begin();
1483 while (threads != (*activeThreads).end()) {
1484 unsigned tid = (*threads++);
|
670 if (fromCommit->commitInfo.nonSpecSeqNum != 0) { 671 instQueue.scheduleNonSpec(fromCommit->commitInfo.nonSpecSeqNum); 672 } |
673
|
1486 DPRINTF(IEW,"Processing [tid:%i]\n",tid);
|
674 DPRINTF(IEW, "IEW: IQ has %i free entries.\n", 675 instQueue.numFreeEntries()); 676} |
677
|
1488 if (fromCommit->commitInfo[tid].doneSeqNum != 0 &&
1489 !fromCommit->commitInfo[tid].squash &&
1490 !fromCommit->commitInfo[tid].robSquashing) {
|
678template<class Impl> 679void 680SimpleIEW<Impl>::iew() 681{ 682 // Might want to put all state checks in the tick() function. 683 // Check if being told to stall from commit. 684 if (fromCommit->commitInfo.stall) { 685 block(); 686 return; 687 } else if (fromCommit->commitInfo.squash || 688 fromCommit->commitInfo.robSquashing) { 689 // Also check if commit is telling this stage to squash. 690 squash(); 691 return; 692 } |
693
|
1492 ldstQueue.commitStores(fromCommit->commitInfo[tid].doneSeqNum,tid);
|
694 dispatchInsts(); |
695
|
1494 ldstQueue.commitLoads(fromCommit->commitInfo[tid].doneSeqNum,tid);
|
696 // Have the instruction queue try to schedule any ready instructions. 697 instQueue.scheduleReadyInsts(); |
698
|
1496 updateLSQNextCycle = true;
1497 instQueue.commit(fromCommit->commitInfo[tid].doneSeqNum,tid);
1498 }
|
699 executeInsts(); |
700
|
1500 if (fromCommit->commitInfo[tid].nonSpecSeqNum != 0) {
|
701 // Loop through the head of the time buffer and wake any dependents. 702 // These instructions are about to write back. In the simple model 703 // this loop can really happen within the previous loop, but when 704 // instructions have actual latencies, this loop must be separate. 705 // Also mark scoreboard that this instruction is finally complete. 706 // Either have IEW have direct access to rename map, or have this as 707 // part of backwards communication. 708 for (int inst_num = 0; inst_num < issueWidth && 709 toCommit->insts[inst_num]; inst_num++) 710 { 711 DynInstPtr inst = toCommit->insts[inst_num]; |
712
|
1502 //DPRINTF(IEW,"NonspecInst from thread %i",tid);
1503 if (fromCommit->commitInfo[tid].uncached) {
1504 instQueue.replayMemInst(fromCommit->commitInfo[tid].uncachedLoad);
1505 } else {
1506 instQueue.scheduleNonSpec(
1507 fromCommit->commitInfo[tid].nonSpecSeqNum);
1508 }
1509 }
|
713 DPRINTF(IEW, "IEW: Sending instructions to commit, PC %#x.\n", 714 inst->readPC()); |
715
|
1511 if (broadcast_free_entries) {
1512 toFetch->iewInfo[tid].iqCount =
1513 instQueue.getCount(tid);
1514 toFetch->iewInfo[tid].ldstqCount =
1515 ldstQueue.getCount(tid);
|
716 if(!inst->isSquashed()) { 717 instQueue.wakeDependents(inst); |
718
|
1517 toRename->iewInfo[tid].usedIQ = true;
1518 toRename->iewInfo[tid].freeIQEntries =
1519 instQueue.numFreeEntries();
1520 toRename->iewInfo[tid].usedLSQ = true;
1521 toRename->iewInfo[tid].freeLSQEntries =
1522 ldstQueue.numFreeEntries(tid);
1523
1524 wroteToTimeBuffer = true;
|
719 for (int i = 0; i < inst->numDestRegs(); i++) 720 { 721 renameMap->markAsReady(inst->renamedDestRegIdx(i)); 722 } |
723 }
|
1526
1527 DPRINTF(IEW, "[tid:%i], Dispatch dispatched %i instructions.\n",
1528 tid, toRename->iewInfo[tid].dispatched);
|
724 } 725
|
1531 DPRINTF(IEW, "IQ has %i free entries (Can schedule: %i). "
1532 "LSQ has %i free entries.\n",
1533 instQueue.numFreeEntries(), instQueue.hasReadyInsts(),
1534 ldstQueue.numFreeEntries());
1535
1536 updateStatus();
1537
1538 if (wroteToTimeBuffer) {
1539 DPRINTF(Activity, "Activity this cycle.\n");
1540 cpu->activityThisCycle();
1541 }
|
726 // Also should advance its own time buffers if the stage ran. 727 // Not the best place for it, but this works (hopefully). 728 issueToExecQueue.advance(); |
729} 730
|
1544template <class Impl>
|
731#if !FULL_SYSTEM 732template<class Impl> |
733void
|
1546DefaultIEW<Impl>::updateExeInstStats(DynInstPtr &inst)
|
734SimpleIEW<Impl>::lsqWriteback() |
735{
|
1548 int thread_number = inst->threadNumber;
1549
1550 //
1551 // Pick off the software prefetches
1552 //
1553#ifdef TARGET_ALPHA
1554 if (inst->isDataPrefetch())
1555 exeSwp[thread_number]++;
1556 else
1557 iewExecutedInsts++;
1558#else
1559 iewExecutedInsts[thread_number]++;
1560#endif
1561
1562 //
1563 // Control operations
1564 //
1565 if (inst->isControl())
1566 exeBranches[thread_number]++;
1567
1568 //
1569 // Memory operations
1570 //
1571 if (inst->isMemRef()) {
1572 exeRefs[thread_number]++;
1573
1574 if (inst->isLoad()) {
1575 iewExecLoadInsts[thread_number]++;
1576 }
1577 }
|
736 ldstQueue.writebackAllInsts(); |
737}
|
738#endif |
|