iew_impl.hh revision 3732:e84a6e9ebd3d
1/* 2 * Copyright (c) 2004-2006 The Regents of The University of Michigan 3 * All rights reserved. 4 * 5 * Redistribution and use in source and binary forms, with or without 6 * modification, are permitted provided that the following conditions are 7 * met: redistributions of source code must retain the above copyright 8 * notice, this list of conditions and the following disclaimer; 9 * redistributions in binary form must reproduce the above copyright 10 * notice, this list of conditions and the following disclaimer in the 11 * documentation and/or other materials provided with the distribution; 12 * neither the name of the copyright holders nor the names of its 13 * contributors may be used to endorse or promote products derived from 14 * this software without specific prior written permission. 15 * 16 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS 17 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT 18 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR 19 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT 20 * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, 21 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT 22 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 23 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 24 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 25 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE 26 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 27 * 28 * Authors: Kevin Lim 29 */ 30 31// @todo: Fix the instantaneous communication among all the stages within 32// iew. There's a clear delay between issue and execute, yet backwards 33// communication happens simultaneously. 34 35#include <queue> 36 37#include "base/timebuf.hh" 38#include "cpu/o3/fu_pool.hh" 39#include "cpu/o3/iew.hh" 40 41template<class Impl> 42DefaultIEW<Impl>::DefaultIEW(Params *params) 43 : issueToExecQueue(params->backComSize, params->forwardComSize), 44 instQueue(params), 45 ldstQueue(params), 46 fuPool(params->fuPool), 47 commitToIEWDelay(params->commitToIEWDelay), 48 renameToIEWDelay(params->renameToIEWDelay), 49 issueToExecuteDelay(params->issueToExecuteDelay), 50 dispatchWidth(params->dispatchWidth), 51 issueWidth(params->issueWidth), 52 wbOutstanding(0), 53 wbWidth(params->wbWidth), 54 numThreads(params->numberOfThreads), 55 switchedOut(false) 56{ 57 _status = Active; 58 exeStatus = Running; 59 wbStatus = Idle; 60 61 // Setup wire to read instructions coming from issue. 62 fromIssue = issueToExecQueue.getWire(-issueToExecuteDelay); 63 64 // Instruction queue needs the queue between issue and execute. 65 instQueue.setIssueToExecuteQueue(&issueToExecQueue); 66 67 instQueue.setIEW(this); 68 ldstQueue.setIEW(this); 69 70 for (int i=0; i < numThreads; i++) { 71 dispatchStatus[i] = Running; 72 stalls[i].commit = false; 73 fetchRedirect[i] = false; 74 bdelayDoneSeqNum[i] = 0; 75 } 76 77 wbMax = wbWidth * params->wbDepth; 78 79 updateLSQNextCycle = false; 80 81 ableToIssue = true; 82 83 skidBufferMax = (3 * (renameToIEWDelay * params->renameWidth)) + issueWidth; 84} 85 86template <class Impl> 87std::string 88DefaultIEW<Impl>::name() const 89{ 90 return cpu->name() + ".iew"; 91} 92 93template <class Impl> 94void 95DefaultIEW<Impl>::regStats() 96{ 97 using namespace Stats; 98 99 instQueue.regStats(); 100 ldstQueue.regStats(); 101 102 iewIdleCycles 103 .name(name() + ".iewIdleCycles") 104 .desc("Number of cycles IEW is idle"); 105 106 iewSquashCycles 107 .name(name() + ".iewSquashCycles") 108 .desc("Number of cycles IEW is squashing"); 109 110 iewBlockCycles 111 .name(name() + ".iewBlockCycles") 112 .desc("Number of cycles IEW is blocking"); 113 114 iewUnblockCycles 115 .name(name() + ".iewUnblockCycles") 116 .desc("Number of cycles IEW is unblocking"); 117 118 iewDispatchedInsts 119 .name(name() + ".iewDispatchedInsts") 120 .desc("Number of instructions dispatched to IQ"); 121 122 iewDispSquashedInsts 123 .name(name() + ".iewDispSquashedInsts") 124 .desc("Number of squashed instructions skipped by dispatch"); 125 126 iewDispLoadInsts 127 .name(name() + ".iewDispLoadInsts") 128 .desc("Number of dispatched load instructions"); 129 130 iewDispStoreInsts 131 .name(name() + ".iewDispStoreInsts") 132 .desc("Number of dispatched store instructions"); 133 134 iewDispNonSpecInsts 135 .name(name() + ".iewDispNonSpecInsts") 136 .desc("Number of dispatched non-speculative instructions"); 137 138 iewIQFullEvents 139 .name(name() + ".iewIQFullEvents") 140 .desc("Number of times the IQ has become full, causing a stall"); 141 142 iewLSQFullEvents 143 .name(name() + ".iewLSQFullEvents") 144 .desc("Number of times the LSQ has become full, causing a stall"); 145 146 memOrderViolationEvents 147 .name(name() + ".memOrderViolationEvents") 148 .desc("Number of memory order violations"); 149 150 predictedTakenIncorrect 151 .name(name() + ".predictedTakenIncorrect") 152 .desc("Number of branches that were predicted taken incorrectly"); 153 154 predictedNotTakenIncorrect 155 .name(name() + ".predictedNotTakenIncorrect") 156 .desc("Number of branches that were predicted not taken incorrectly"); 157 158 branchMispredicts 159 .name(name() + ".branchMispredicts") 160 .desc("Number of branch mispredicts detected at execute"); 161 162 branchMispredicts = predictedTakenIncorrect + predictedNotTakenIncorrect; 163 164 iewExecutedInsts 165 .name(name() + ".iewExecutedInsts") 166 .desc("Number of executed instructions"); 167 168 iewExecLoadInsts 169 .init(cpu->number_of_threads) 170 .name(name() + ".iewExecLoadInsts") 171 .desc("Number of load instructions executed") 172 .flags(total); 173 174 iewExecSquashedInsts 175 .name(name() + ".iewExecSquashedInsts") 176 .desc("Number of squashed instructions skipped in execute"); 177 178 iewExecutedSwp 179 .init(cpu->number_of_threads) 180 .name(name() + ".EXEC:swp") 181 .desc("number of swp insts executed") 182 .flags(total); 183 184 iewExecutedNop 185 .init(cpu->number_of_threads) 186 .name(name() + ".EXEC:nop") 187 .desc("number of nop insts executed") 188 .flags(total); 189 190 iewExecutedRefs 191 .init(cpu->number_of_threads) 192 .name(name() + ".EXEC:refs") 193 .desc("number of memory reference insts executed") 194 .flags(total); 195 196 iewExecutedBranches 197 .init(cpu->number_of_threads) 198 .name(name() + ".EXEC:branches") 199 .desc("Number of branches executed") 200 .flags(total); 201 202 iewExecStoreInsts 203 .name(name() + ".EXEC:stores") 204 .desc("Number of stores executed") 205 .flags(total); 206 iewExecStoreInsts = iewExecutedRefs - iewExecLoadInsts; 207 208 iewExecRate 209 .name(name() + ".EXEC:rate") 210 .desc("Inst execution rate") 211 .flags(total); 212 213 iewExecRate = iewExecutedInsts / cpu->numCycles; 214 215 iewInstsToCommit 216 .init(cpu->number_of_threads) 217 .name(name() + ".WB:sent") 218 .desc("cumulative count of insts sent to commit") 219 .flags(total); 220 221 writebackCount 222 .init(cpu->number_of_threads) 223 .name(name() + ".WB:count") 224 .desc("cumulative count of insts written-back") 225 .flags(total); 226 227 producerInst 228 .init(cpu->number_of_threads) 229 .name(name() + ".WB:producers") 230 .desc("num instructions producing a value") 231 .flags(total); 232 233 consumerInst 234 .init(cpu->number_of_threads) 235 .name(name() + ".WB:consumers") 236 .desc("num instructions consuming a value") 237 .flags(total); 238 239 wbPenalized 240 .init(cpu->number_of_threads) 241 .name(name() + ".WB:penalized") 242 .desc("number of instrctions required to write to 'other' IQ") 243 .flags(total); 244 245 wbPenalizedRate 246 .name(name() + ".WB:penalized_rate") 247 .desc ("fraction of instructions written-back that wrote to 'other' IQ") 248 .flags(total); 249 250 wbPenalizedRate = wbPenalized / writebackCount; 251 252 wbFanout 253 .name(name() + ".WB:fanout") 254 .desc("average fanout of values written-back") 255 .flags(total); 256 257 wbFanout = producerInst / consumerInst; 258 259 wbRate 260 .name(name() + ".WB:rate") 261 .desc("insts written-back per cycle") 262 .flags(total); 263 wbRate = writebackCount / cpu->numCycles; 264} 265 266template<class Impl> 267void 268DefaultIEW<Impl>::initStage() 269{ 270 for (int tid=0; tid < numThreads; tid++) { 271 toRename->iewInfo[tid].usedIQ = true; 272 toRename->iewInfo[tid].freeIQEntries = 273 instQueue.numFreeEntries(tid); 274 275 toRename->iewInfo[tid].usedLSQ = true; 276 toRename->iewInfo[tid].freeLSQEntries = 277 ldstQueue.numFreeEntries(tid); 278 } 279} 280 281template<class Impl> 282void 283DefaultIEW<Impl>::setCPU(O3CPU *cpu_ptr) 284{ 285 DPRINTF(IEW, "Setting CPU pointer.\n"); 286 cpu = cpu_ptr; 287 288 instQueue.setCPU(cpu_ptr); 289 ldstQueue.setCPU(cpu_ptr); 290 291 cpu->activateStage(O3CPU::IEWIdx); 292} 293 294template<class Impl> 295void 296DefaultIEW<Impl>::setTimeBuffer(TimeBuffer<TimeStruct> *tb_ptr) 297{ 298 DPRINTF(IEW, "Setting time buffer pointer.\n"); 299 timeBuffer = tb_ptr; 300 301 // Setup wire to read information from time buffer, from commit. 302 fromCommit = timeBuffer->getWire(-commitToIEWDelay); 303 304 // Setup wire to write information back to previous stages. 305 toRename = timeBuffer->getWire(0); 306 307 toFetch = timeBuffer->getWire(0); 308 309 // Instruction queue also needs main time buffer. 310 instQueue.setTimeBuffer(tb_ptr); 311} 312 313template<class Impl> 314void 315DefaultIEW<Impl>::setRenameQueue(TimeBuffer<RenameStruct> *rq_ptr) 316{ 317 DPRINTF(IEW, "Setting rename queue pointer.\n"); 318 renameQueue = rq_ptr; 319 320 // Setup wire to read information from rename queue. 321 fromRename = renameQueue->getWire(-renameToIEWDelay); 322} 323 324template<class Impl> 325void 326DefaultIEW<Impl>::setIEWQueue(TimeBuffer<IEWStruct> *iq_ptr) 327{ 328 DPRINTF(IEW, "Setting IEW queue pointer.\n"); 329 iewQueue = iq_ptr; 330 331 // Setup wire to write instructions to commit. 332 toCommit = iewQueue->getWire(0); 333} 334 335template<class Impl> 336void 337DefaultIEW<Impl>::setActiveThreads(std::list<unsigned> *at_ptr) 338{ 339 DPRINTF(IEW, "Setting active threads list pointer.\n"); 340 activeThreads = at_ptr; 341 342 ldstQueue.setActiveThreads(at_ptr); 343 instQueue.setActiveThreads(at_ptr); 344} 345 346template<class Impl> 347void 348DefaultIEW<Impl>::setScoreboard(Scoreboard *sb_ptr) 349{ 350 DPRINTF(IEW, "Setting scoreboard pointer.\n"); 351 scoreboard = sb_ptr; 352} 353 354template <class Impl> 355bool 356DefaultIEW<Impl>::drain() 357{ 358 // IEW is ready to drain at any time. 359 cpu->signalDrained(); 360 return true; 361} 362 363template <class Impl> 364void 365DefaultIEW<Impl>::resume() 366{ 367} 368 369template <class Impl> 370void 371DefaultIEW<Impl>::switchOut() 372{ 373 // Clear any state. 374 switchedOut = true; 375 assert(insts[0].empty()); 376 assert(skidBuffer[0].empty()); 377 378 instQueue.switchOut(); 379 ldstQueue.switchOut(); 380 fuPool->switchOut(); 381 382 for (int i = 0; i < numThreads; i++) { 383 while (!insts[i].empty()) 384 insts[i].pop(); 385 while (!skidBuffer[i].empty()) 386 skidBuffer[i].pop(); 387 } 388} 389 390template <class Impl> 391void 392DefaultIEW<Impl>::takeOverFrom() 393{ 394 // Reset all state. 395 _status = Active; 396 exeStatus = Running; 397 wbStatus = Idle; 398 switchedOut = false; 399 400 instQueue.takeOverFrom(); 401 ldstQueue.takeOverFrom(); 402 fuPool->takeOverFrom(); 403 404 initStage(); 405 cpu->activityThisCycle(); 406 407 for (int i=0; i < numThreads; i++) { 408 dispatchStatus[i] = Running; 409 stalls[i].commit = false; 410 fetchRedirect[i] = false; 411 } 412 413 updateLSQNextCycle = false; 414 415 for (int i = 0; i < issueToExecQueue.getSize(); ++i) { 416 issueToExecQueue.advance(); 417 } 418} 419 420template<class Impl> 421void 422DefaultIEW<Impl>::squash(unsigned tid) 423{ 424 DPRINTF(IEW, "[tid:%i]: Squashing all instructions.\n", 425 tid); 426 427 // Tell the IQ to start squashing. 428 instQueue.squash(tid); 429 430 // Tell the LDSTQ to start squashing. 431#if ISA_HAS_DELAY_SLOT 432 ldstQueue.squash(fromCommit->commitInfo[tid].bdelayDoneSeqNum, tid); 433#else 434 ldstQueue.squash(fromCommit->commitInfo[tid].doneSeqNum, tid); 435#endif 436 updatedQueues = true; 437 438 // Clear the skid buffer in case it has any data in it. 439 DPRINTF(IEW, "[tid:%i]: Removing skidbuffer instructions until [sn:%i].\n", 440 tid, fromCommit->commitInfo[tid].bdelayDoneSeqNum); 441 442 while (!skidBuffer[tid].empty()) { 443#if ISA_HAS_DELAY_SLOT 444 if (skidBuffer[tid].front()->seqNum <= 445 fromCommit->commitInfo[tid].bdelayDoneSeqNum) { 446 DPRINTF(IEW, "[tid:%i]: Cannot remove skidbuffer instructions " 447 "that occur before delay slot [sn:%i].\n", 448 fromCommit->commitInfo[tid].bdelayDoneSeqNum, 449 tid); 450 break; 451 } else { 452 DPRINTF(IEW, "[tid:%i]: Removing instruction [sn:%i] from " 453 "skidBuffer.\n", tid, skidBuffer[tid].front()->seqNum); 454 } 455#endif 456 if (skidBuffer[tid].front()->isLoad() || 457 skidBuffer[tid].front()->isStore() ) { 458 toRename->iewInfo[tid].dispatchedToLSQ++; 459 } 460 461 toRename->iewInfo[tid].dispatched++; 462 463 skidBuffer[tid].pop(); 464 } 465 466 bdelayDoneSeqNum[tid] = fromCommit->commitInfo[tid].bdelayDoneSeqNum; 467 468 emptyRenameInsts(tid); 469} 470 471template<class Impl> 472void 473DefaultIEW<Impl>::squashDueToBranch(DynInstPtr &inst, unsigned tid) 474{ 475 DPRINTF(IEW, "[tid:%i]: Squashing from a specific instruction, PC: %#x " 476 "[sn:%i].\n", tid, inst->readPC(), inst->seqNum); 477 478 toCommit->squash[tid] = true; 479 toCommit->squashedSeqNum[tid] = inst->seqNum; 480 toCommit->mispredPC[tid] = inst->readPC(); 481 toCommit->branchMispredict[tid] = true; 482 483#if ISA_HAS_DELAY_SLOT 484 bool branch_taken = inst->readNextNPC() != 485 (inst->readNextPC() + sizeof(TheISA::MachInst)); 486 487 toCommit->branchTaken[tid] = branch_taken; 488 489 toCommit->condDelaySlotBranch[tid] = inst->isCondDelaySlot(); 490 491 if (inst->isCondDelaySlot() && branch_taken) { 492 toCommit->nextPC[tid] = inst->readNextPC(); 493 } else { 494 toCommit->nextPC[tid] = inst->readNextNPC(); 495 } 496#else 497 toCommit->branchTaken[tid] = inst->readNextPC() != 498 (inst->readPC() + sizeof(TheISA::MachInst)); 499 toCommit->nextPC[tid] = inst->readNextPC(); 500#endif 501 502 toCommit->includeSquashInst[tid] = false; 503 504 wroteToTimeBuffer = true; 505} 506 507template<class Impl> 508void 509DefaultIEW<Impl>::squashDueToMemOrder(DynInstPtr &inst, unsigned tid) 510{ 511 DPRINTF(IEW, "[tid:%i]: Squashing from a specific instruction, " 512 "PC: %#x [sn:%i].\n", tid, inst->readPC(), inst->seqNum); 513 514 toCommit->squash[tid] = true; 515 toCommit->squashedSeqNum[tid] = inst->seqNum; 516 toCommit->nextPC[tid] = inst->readNextPC(); 517 toCommit->branchMispredict[tid] = false; 518 519 toCommit->includeSquashInst[tid] = false; 520 521 wroteToTimeBuffer = true; 522} 523 524template<class Impl> 525void 526DefaultIEW<Impl>::squashDueToMemBlocked(DynInstPtr &inst, unsigned tid) 527{ 528 DPRINTF(IEW, "[tid:%i]: Memory blocked, squashing load and younger insts, " 529 "PC: %#x [sn:%i].\n", tid, inst->readPC(), inst->seqNum); 530 531 toCommit->squash[tid] = true; 532 toCommit->squashedSeqNum[tid] = inst->seqNum; 533 toCommit->nextPC[tid] = inst->readPC(); 534 toCommit->branchMispredict[tid] = false; 535 536 // Must include the broadcasted SN in the squash. 537 toCommit->includeSquashInst[tid] = true; 538 539 ldstQueue.setLoadBlockedHandled(tid); 540 541 wroteToTimeBuffer = true; 542} 543 544template<class Impl> 545void 546DefaultIEW<Impl>::block(unsigned tid) 547{ 548 DPRINTF(IEW, "[tid:%u]: Blocking.\n", tid); 549 550 if (dispatchStatus[tid] != Blocked && 551 dispatchStatus[tid] != Unblocking) { 552 toRename->iewBlock[tid] = true; 553 wroteToTimeBuffer = true; 554 } 555 556 // Add the current inputs to the skid buffer so they can be 557 // reprocessed when this stage unblocks. 558 skidInsert(tid); 559 560 dispatchStatus[tid] = Blocked; 561} 562 563template<class Impl> 564void 565DefaultIEW<Impl>::unblock(unsigned tid) 566{ 567 DPRINTF(IEW, "[tid:%i]: Reading instructions out of the skid " 568 "buffer %u.\n",tid, tid); 569 570 // If the skid bufffer is empty, signal back to previous stages to unblock. 571 // Also switch status to running. 572 if (skidBuffer[tid].empty()) { 573 toRename->iewUnblock[tid] = true; 574 wroteToTimeBuffer = true; 575 DPRINTF(IEW, "[tid:%i]: Done unblocking.\n",tid); 576 dispatchStatus[tid] = Running; 577 } 578} 579 580template<class Impl> 581void 582DefaultIEW<Impl>::wakeDependents(DynInstPtr &inst) 583{ 584 instQueue.wakeDependents(inst); 585} 586 587template<class Impl> 588void 589DefaultIEW<Impl>::rescheduleMemInst(DynInstPtr &inst) 590{ 591 instQueue.rescheduleMemInst(inst); 592} 593 594template<class Impl> 595void 596DefaultIEW<Impl>::replayMemInst(DynInstPtr &inst) 597{ 598 instQueue.replayMemInst(inst); 599} 600 601template<class Impl> 602void 603DefaultIEW<Impl>::instToCommit(DynInstPtr &inst) 604{ 605 // This function should not be called after writebackInsts in a 606 // single cycle. That will cause problems with an instruction 607 // being added to the queue to commit without being processed by 608 // writebackInsts prior to being sent to commit. 609 610 // First check the time slot that this instruction will write 611 // to. If there are free write ports at the time, then go ahead 612 // and write the instruction to that time. If there are not, 613 // keep looking back to see where's the first time there's a 614 // free slot. 615 while ((*iewQueue)[wbCycle].insts[wbNumInst]) { 616 ++wbNumInst; 617 if (wbNumInst == wbWidth) { 618 ++wbCycle; 619 wbNumInst = 0; 620 } 621 622 assert((wbCycle * wbWidth + wbNumInst) <= wbMax); 623 } 624 625 DPRINTF(IEW, "Current wb cycle: %i, width: %i, numInst: %i\nwbActual:%i\n", 626 wbCycle, wbWidth, wbNumInst, wbCycle * wbWidth + wbNumInst); 627 // Add finished instruction to queue to commit. 628 (*iewQueue)[wbCycle].insts[wbNumInst] = inst; 629 (*iewQueue)[wbCycle].size++; 630} 631 632template <class Impl> 633unsigned 634DefaultIEW<Impl>::validInstsFromRename() 635{ 636 unsigned inst_count = 0; 637 638 for (int i=0; i<fromRename->size; i++) { 639 if (!fromRename->insts[i]->isSquashed()) 640 inst_count++; 641 } 642 643 return inst_count; 644} 645 646template<class Impl> 647void 648DefaultIEW<Impl>::skidInsert(unsigned tid) 649{ 650 DynInstPtr inst = NULL; 651 652 while (!insts[tid].empty()) { 653 inst = insts[tid].front(); 654 655 insts[tid].pop(); 656 657 DPRINTF(Decode,"[tid:%i]: Inserting [sn:%lli] PC:%#x into " 658 "dispatch skidBuffer %i\n",tid, inst->seqNum, 659 inst->readPC(),tid); 660 661 skidBuffer[tid].push(inst); 662 } 663 664 assert(skidBuffer[tid].size() <= skidBufferMax && 665 "Skidbuffer Exceeded Max Size"); 666} 667 668template<class Impl> 669int 670DefaultIEW<Impl>::skidCount() 671{ 672 int max=0; 673 674 std::list<unsigned>::iterator threads = (*activeThreads).begin(); 675 676 while (threads != (*activeThreads).end()) { 677 unsigned thread_count = skidBuffer[*threads++].size(); 678 if (max < thread_count) 679 max = thread_count; 680 } 681 682 return max; 683} 684 685template<class Impl> 686bool 687DefaultIEW<Impl>::skidsEmpty() 688{ 689 std::list<unsigned>::iterator threads = (*activeThreads).begin(); 690 691 while (threads != (*activeThreads).end()) { 692 if (!skidBuffer[*threads++].empty()) 693 return false; 694 } 695 696 return true; 697} 698 699template <class Impl> 700void 701DefaultIEW<Impl>::updateStatus() 702{ 703 bool any_unblocking = false; 704 705 std::list<unsigned>::iterator threads = (*activeThreads).begin(); 706 707 threads = (*activeThreads).begin(); 708 709 while (threads != (*activeThreads).end()) { 710 unsigned tid = *threads++; 711 712 if (dispatchStatus[tid] == Unblocking) { 713 any_unblocking = true; 714 break; 715 } 716 } 717 718 // If there are no ready instructions waiting to be scheduled by the IQ, 719 // and there's no stores waiting to write back, and dispatch is not 720 // unblocking, then there is no internal activity for the IEW stage. 721 if (_status == Active && !instQueue.hasReadyInsts() && 722 !ldstQueue.willWB() && !any_unblocking) { 723 DPRINTF(IEW, "IEW switching to idle\n"); 724 725 deactivateStage(); 726 727 _status = Inactive; 728 } else if (_status == Inactive && (instQueue.hasReadyInsts() || 729 ldstQueue.willWB() || 730 any_unblocking)) { 731 // Otherwise there is internal activity. Set to active. 732 DPRINTF(IEW, "IEW switching to active\n"); 733 734 activateStage(); 735 736 _status = Active; 737 } 738} 739 740template <class Impl> 741void 742DefaultIEW<Impl>::resetEntries() 743{ 744 instQueue.resetEntries(); 745 ldstQueue.resetEntries(); 746} 747 748template <class Impl> 749void 750DefaultIEW<Impl>::readStallSignals(unsigned tid) 751{ 752 if (fromCommit->commitBlock[tid]) { 753 stalls[tid].commit = true; 754 } 755 756 if (fromCommit->commitUnblock[tid]) { 757 assert(stalls[tid].commit); 758 stalls[tid].commit = false; 759 } 760} 761 762template <class Impl> 763bool 764DefaultIEW<Impl>::checkStall(unsigned tid) 765{ 766 bool ret_val(false); 767 768 if (stalls[tid].commit) { 769 DPRINTF(IEW,"[tid:%i]: Stall from Commit stage detected.\n",tid); 770 ret_val = true; 771 } else if (instQueue.isFull(tid)) { 772 DPRINTF(IEW,"[tid:%i]: Stall: IQ is full.\n",tid); 773 ret_val = true; 774 } else if (ldstQueue.isFull(tid)) { 775 DPRINTF(IEW,"[tid:%i]: Stall: LSQ is full\n",tid); 776 777 if (ldstQueue.numLoads(tid) > 0 ) { 778 779 DPRINTF(IEW,"[tid:%i]: LSQ oldest load: [sn:%i] \n", 780 tid,ldstQueue.getLoadHeadSeqNum(tid)); 781 } 782 783 if (ldstQueue.numStores(tid) > 0) { 784 785 DPRINTF(IEW,"[tid:%i]: LSQ oldest store: [sn:%i] \n", 786 tid,ldstQueue.getStoreHeadSeqNum(tid)); 787 } 788 789 ret_val = true; 790 } else if (ldstQueue.isStalled(tid)) { 791 DPRINTF(IEW,"[tid:%i]: Stall: LSQ stall detected.\n",tid); 792 ret_val = true; 793 } 794 795 return ret_val; 796} 797 798template <class Impl> 799void 800DefaultIEW<Impl>::checkSignalsAndUpdate(unsigned tid) 801{ 802 // Check if there's a squash signal, squash if there is 803 // Check stall signals, block if there is. 804 // If status was Blocked 805 // if so then go to unblocking 806 // If status was Squashing 807 // check if squashing is not high. Switch to running this cycle. 808 809 readStallSignals(tid); 810 811 if (fromCommit->commitInfo[tid].squash) { 812 squash(tid); 813 814 if (dispatchStatus[tid] == Blocked || 815 dispatchStatus[tid] == Unblocking) { 816 toRename->iewUnblock[tid] = true; 817 wroteToTimeBuffer = true; 818 } 819 820 dispatchStatus[tid] = Squashing; 821 822 fetchRedirect[tid] = false; 823 return; 824 } 825 826 if (fromCommit->commitInfo[tid].robSquashing) { 827 DPRINTF(IEW, "[tid:%i]: ROB is still squashing.\n", tid); 828 829 dispatchStatus[tid] = Squashing; 830 831 emptyRenameInsts(tid); 832 wroteToTimeBuffer = true; 833 return; 834 } 835 836 if (checkStall(tid)) { 837 block(tid); 838 dispatchStatus[tid] = Blocked; 839 return; 840 } 841 842 if (dispatchStatus[tid] == Blocked) { 843 // Status from previous cycle was blocked, but there are no more stall 844 // conditions. Switch over to unblocking. 845 DPRINTF(IEW, "[tid:%i]: Done blocking, switching to unblocking.\n", 846 tid); 847 848 dispatchStatus[tid] = Unblocking; 849 850 unblock(tid); 851 852 return; 853 } 854 855 if (dispatchStatus[tid] == Squashing) { 856 // Switch status to running if rename isn't being told to block or 857 // squash this cycle. 858 DPRINTF(IEW, "[tid:%i]: Done squashing, switching to running.\n", 859 tid); 860 861 dispatchStatus[tid] = Running; 862 863 return; 864 } 865} 866 867template <class Impl> 868void 869DefaultIEW<Impl>::sortInsts() 870{ 871 int insts_from_rename = fromRename->size; 872#ifdef DEBUG 873#if !ISA_HAS_DELAY_SLOT 874 for (int i = 0; i < numThreads; i++) 875 assert(insts[i].empty()); 876#endif 877#endif 878 for (int i = 0; i < insts_from_rename; ++i) { 879 insts[fromRename->insts[i]->threadNumber].push(fromRename->insts[i]); 880 } 881} 882 883template <class Impl> 884void 885DefaultIEW<Impl>::emptyRenameInsts(unsigned tid) 886{ 887 DPRINTF(IEW, "[tid:%i]: Removing incoming rename instructions until " 888 "[sn:%i].\n", tid, bdelayDoneSeqNum[tid]); 889 890 while (!insts[tid].empty()) { 891#if ISA_HAS_DELAY_SLOT 892 if (insts[tid].front()->seqNum <= bdelayDoneSeqNum[tid]) { 893 DPRINTF(IEW, "[tid:%i]: Done removing, cannot remove instruction" 894 " that occurs at or before delay slot [sn:%i].\n", 895 tid, bdelayDoneSeqNum[tid]); 896 break; 897 } else { 898 DPRINTF(IEW, "[tid:%i]: Removing incoming rename instruction " 899 "[sn:%i].\n", tid, insts[tid].front()->seqNum); 900 } 901#endif 902 903 if (insts[tid].front()->isLoad() || 904 insts[tid].front()->isStore() ) { 905 toRename->iewInfo[tid].dispatchedToLSQ++; 906 } 907 908 toRename->iewInfo[tid].dispatched++; 909 910 insts[tid].pop(); 911 } 912} 913 914template <class Impl> 915void 916DefaultIEW<Impl>::wakeCPU() 917{ 918 cpu->wakeCPU(); 919} 920 921template <class Impl> 922void 923DefaultIEW<Impl>::activityThisCycle() 924{ 925 DPRINTF(Activity, "Activity this cycle.\n"); 926 cpu->activityThisCycle(); 927} 928 929template <class Impl> 930inline void 931DefaultIEW<Impl>::activateStage() 932{ 933 DPRINTF(Activity, "Activating stage.\n"); 934 cpu->activateStage(O3CPU::IEWIdx); 935} 936 937template <class Impl> 938inline void 939DefaultIEW<Impl>::deactivateStage() 940{ 941 DPRINTF(Activity, "Deactivating stage.\n"); 942 cpu->deactivateStage(O3CPU::IEWIdx); 943} 944 945template<class Impl> 946void 947DefaultIEW<Impl>::dispatch(unsigned tid) 948{ 949 // If status is Running or idle, 950 // call dispatchInsts() 951 // If status is Unblocking, 952 // buffer any instructions coming from rename 953 // continue trying to empty skid buffer 954 // check if stall conditions have passed 955 956 if (dispatchStatus[tid] == Blocked) { 957 ++iewBlockCycles; 958 959 } else if (dispatchStatus[tid] == Squashing) { 960 ++iewSquashCycles; 961 } 962 963 // Dispatch should try to dispatch as many instructions as its bandwidth 964 // will allow, as long as it is not currently blocked. 965 if (dispatchStatus[tid] == Running || 966 dispatchStatus[tid] == Idle) { 967 DPRINTF(IEW, "[tid:%i] Not blocked, so attempting to run " 968 "dispatch.\n", tid); 969 970 dispatchInsts(tid); 971 } else if (dispatchStatus[tid] == Unblocking) { 972 // Make sure that the skid buffer has something in it if the 973 // status is unblocking. 974 assert(!skidsEmpty()); 975 976 // If the status was unblocking, then instructions from the skid 977 // buffer were used. Remove those instructions and handle 978 // the rest of unblocking. 979 dispatchInsts(tid); 980 981 ++iewUnblockCycles; 982 983 if (validInstsFromRename() && dispatchedAllInsts) { 984 // Add the current inputs to the skid buffer so they can be 985 // reprocessed when this stage unblocks. 986 skidInsert(tid); 987 } 988 989 unblock(tid); 990 } 991} 992 993template <class Impl> 994void 995DefaultIEW<Impl>::dispatchInsts(unsigned tid) 996{ 997 dispatchedAllInsts = true; 998 999 // Obtain instructions from skid buffer if unblocking, or queue from rename 1000 // otherwise. 1001 std::queue<DynInstPtr> &insts_to_dispatch = 1002 dispatchStatus[tid] == Unblocking ? 1003 skidBuffer[tid] : insts[tid]; 1004 1005 int insts_to_add = insts_to_dispatch.size(); 1006 1007 DynInstPtr inst; 1008 bool add_to_iq = false; 1009 int dis_num_inst = 0; 1010 1011 // Loop through the instructions, putting them in the instruction 1012 // queue. 1013 for ( ; dis_num_inst < insts_to_add && 1014 dis_num_inst < dispatchWidth; 1015 ++dis_num_inst) 1016 { 1017 inst = insts_to_dispatch.front(); 1018 1019 if (dispatchStatus[tid] == Unblocking) { 1020 DPRINTF(IEW, "[tid:%i]: Issue: Examining instruction from skid " 1021 "buffer\n", tid); 1022 } 1023 1024 // Make sure there's a valid instruction there. 1025 assert(inst); 1026 1027 DPRINTF(IEW, "[tid:%i]: Issue: Adding PC %#x [sn:%lli] [tid:%i] to " 1028 "IQ.\n", 1029 tid, inst->readPC(), inst->seqNum, inst->threadNumber); 1030 1031 // Be sure to mark these instructions as ready so that the 1032 // commit stage can go ahead and execute them, and mark 1033 // them as issued so the IQ doesn't reprocess them. 1034 1035 // Check for squashed instructions. 1036 if (inst->isSquashed()) { 1037 DPRINTF(IEW, "[tid:%i]: Issue: Squashed instruction encountered, " 1038 "not adding to IQ.\n", tid); 1039 1040 ++iewDispSquashedInsts; 1041 1042 insts_to_dispatch.pop(); 1043 1044 //Tell Rename That An Instruction has been processed 1045 if (inst->isLoad() || inst->isStore()) { 1046 toRename->iewInfo[tid].dispatchedToLSQ++; 1047 } 1048 toRename->iewInfo[tid].dispatched++; 1049 1050 continue; 1051 } 1052 1053 // Check for full conditions. 1054 if (instQueue.isFull(tid)) { 1055 DPRINTF(IEW, "[tid:%i]: Issue: IQ has become full.\n", tid); 1056 1057 // Call function to start blocking. 1058 block(tid); 1059 1060 // Set unblock to false. Special case where we are using 1061 // skidbuffer (unblocking) instructions but then we still 1062 // get full in the IQ. 1063 toRename->iewUnblock[tid] = false; 1064 1065 dispatchedAllInsts = false; 1066 1067 ++iewIQFullEvents; 1068 break; 1069 } else if (ldstQueue.isFull(tid)) { 1070 DPRINTF(IEW, "[tid:%i]: Issue: LSQ has become full.\n",tid); 1071 1072 // Call function to start blocking. 1073 block(tid); 1074 1075 // Set unblock to false. Special case where we are using 1076 // skidbuffer (unblocking) instructions but then we still 1077 // get full in the IQ. 1078 toRename->iewUnblock[tid] = false; 1079 1080 dispatchedAllInsts = false; 1081 1082 ++iewLSQFullEvents; 1083 break; 1084 } 1085 1086 // Otherwise issue the instruction just fine. 1087 if (inst->isLoad()) { 1088 DPRINTF(IEW, "[tid:%i]: Issue: Memory instruction " 1089 "encountered, adding to LSQ.\n", tid); 1090 1091 // Reserve a spot in the load store queue for this 1092 // memory access. 1093 ldstQueue.insertLoad(inst); 1094 1095 ++iewDispLoadInsts; 1096 1097 add_to_iq = true; 1098 1099 toRename->iewInfo[tid].dispatchedToLSQ++; 1100 } else if (inst->isStore()) { 1101 DPRINTF(IEW, "[tid:%i]: Issue: Memory instruction " 1102 "encountered, adding to LSQ.\n", tid); 1103 1104 ldstQueue.insertStore(inst); 1105 1106 ++iewDispStoreInsts; 1107 1108 if (inst->isStoreConditional()) { 1109 // Store conditionals need to be set as "canCommit()" 1110 // so that commit can process them when they reach the 1111 // head of commit. 1112 // @todo: This is somewhat specific to Alpha. 1113 inst->setCanCommit(); 1114 instQueue.insertNonSpec(inst); 1115 add_to_iq = false; 1116 1117 ++iewDispNonSpecInsts; 1118 } else { 1119 add_to_iq = true; 1120 } 1121 1122 toRename->iewInfo[tid].dispatchedToLSQ++; 1123#if FULL_SYSTEM 1124 } else if (inst->isMemBarrier() || inst->isWriteBarrier()) { 1125 // Same as non-speculative stores. 1126 inst->setCanCommit(); 1127 instQueue.insertBarrier(inst); 1128 add_to_iq = false; 1129#endif 1130 } else if (inst->isNonSpeculative()) { 1131 DPRINTF(IEW, "[tid:%i]: Issue: Nonspeculative instruction " 1132 "encountered, skipping.\n", tid); 1133 1134 // Same as non-speculative stores. 1135 inst->setCanCommit(); 1136 1137 // Specifically insert it as nonspeculative. 1138 instQueue.insertNonSpec(inst); 1139 1140 ++iewDispNonSpecInsts; 1141 1142 add_to_iq = false; 1143 } else if (inst->isNop()) { 1144 DPRINTF(IEW, "[tid:%i]: Issue: Nop instruction encountered, " 1145 "skipping.\n", tid); 1146 1147 inst->setIssued(); 1148 inst->setExecuted(); 1149 inst->setCanCommit(); 1150 1151 instQueue.recordProducer(inst); 1152 1153 iewExecutedNop[tid]++; 1154 1155 add_to_iq = false; 1156 } else if (inst->isExecuted()) { 1157 assert(0 && "Instruction shouldn't be executed.\n"); 1158 DPRINTF(IEW, "Issue: Executed branch encountered, " 1159 "skipping.\n"); 1160 1161 inst->setIssued(); 1162 inst->setCanCommit(); 1163 1164 instQueue.recordProducer(inst); 1165 1166 add_to_iq = false; 1167 } else { 1168 add_to_iq = true; 1169 } 1170 1171 // If the instruction queue is not full, then add the 1172 // instruction. 1173 if (add_to_iq) { 1174 instQueue.insert(inst); 1175 } 1176 1177 insts_to_dispatch.pop(); 1178 1179 toRename->iewInfo[tid].dispatched++; 1180 1181 ++iewDispatchedInsts; 1182 } 1183 1184 if (!insts_to_dispatch.empty()) { 1185 DPRINTF(IEW,"[tid:%i]: Issue: Bandwidth Full. Blocking.\n", tid); 1186 block(tid); 1187 toRename->iewUnblock[tid] = false; 1188 } 1189 1190 if (dispatchStatus[tid] == Idle && dis_num_inst) { 1191 dispatchStatus[tid] = Running; 1192 1193 updatedQueues = true; 1194 } 1195 1196 dis_num_inst = 0; 1197} 1198 1199template <class Impl> 1200void 1201DefaultIEW<Impl>::printAvailableInsts() 1202{ 1203 int inst = 0; 1204 1205 std::cout << "Available Instructions: "; 1206 1207 while (fromIssue->insts[inst]) { 1208 1209 if (inst%3==0) std::cout << "\n\t"; 1210 1211 std::cout << "PC: " << fromIssue->insts[inst]->readPC() 1212 << " TN: " << fromIssue->insts[inst]->threadNumber 1213 << " SN: " << fromIssue->insts[inst]->seqNum << " | "; 1214 1215 inst++; 1216 1217 } 1218 1219 std::cout << "\n"; 1220} 1221 1222template <class Impl> 1223void 1224DefaultIEW<Impl>::executeInsts() 1225{ 1226 wbNumInst = 0; 1227 wbCycle = 0; 1228 1229 std::list<unsigned>::iterator threads = (*activeThreads).begin(); 1230 1231 while (threads != (*activeThreads).end()) { 1232 unsigned tid = *threads++; 1233 fetchRedirect[tid] = false; 1234 } 1235 1236 // Uncomment this if you want to see all available instructions. 1237// printAvailableInsts(); 1238 1239 // Execute/writeback any instructions that are available. 1240 int insts_to_execute = fromIssue->size; 1241 int inst_num = 0; 1242 for (; inst_num < insts_to_execute; 1243 ++inst_num) { 1244 1245 DPRINTF(IEW, "Execute: Executing instructions from IQ.\n"); 1246 1247 DynInstPtr inst = instQueue.getInstToExecute(); 1248 1249 DPRINTF(IEW, "Execute: Processing PC %#x, [tid:%i] [sn:%i].\n", 1250 inst->readPC(), inst->threadNumber,inst->seqNum); 1251 1252 // Check if the instruction is squashed; if so then skip it 1253 if (inst->isSquashed()) { 1254 DPRINTF(IEW, "Execute: Instruction was squashed.\n"); 1255 1256 // Consider this instruction executed so that commit can go 1257 // ahead and retire the instruction. 1258 inst->setExecuted(); 1259 1260 // Not sure if I should set this here or just let commit try to 1261 // commit any squashed instructions. I like the latter a bit more. 1262 inst->setCanCommit(); 1263 1264 ++iewExecSquashedInsts; 1265 1266 decrWb(inst->seqNum); 1267 continue; 1268 } 1269 1270 Fault fault = NoFault; 1271 1272 // Execute instruction. 1273 // Note that if the instruction faults, it will be handled 1274 // at the commit stage. 1275 if (inst->isMemRef() && 1276 (!inst->isDataPrefetch() && !inst->isInstPrefetch())) { 1277 DPRINTF(IEW, "Execute: Calculating address for memory " 1278 "reference.\n"); 1279 1280 // Tell the LDSTQ to execute this instruction (if it is a load). 1281 if (inst->isLoad()) { 1282 // Loads will mark themselves as executed, and their writeback 1283 // event adds the instruction to the queue to commit 1284 fault = ldstQueue.executeLoad(inst); 1285 } else if (inst->isStore()) { 1286 fault = ldstQueue.executeStore(inst); 1287 1288 // If the store had a fault then it may not have a mem req 1289 if (!inst->isStoreConditional() && fault == NoFault) { 1290 inst->setExecuted(); 1291 1292 instToCommit(inst); 1293 } else if (fault != NoFault) { 1294 // If the instruction faulted, then we need to send it along to commit 1295 // without the instruction completing. 1296 DPRINTF(IEW, "Store has fault %s! [sn:%lli]\n", 1297 fault->name(), inst->seqNum); 1298 1299 // Send this instruction to commit, also make sure iew stage 1300 // realizes there is activity. 1301 inst->setExecuted(); 1302 1303 instToCommit(inst); 1304 activityThisCycle(); 1305 } 1306 1307 // Store conditionals will mark themselves as 1308 // executed, and their writeback event will add the 1309 // instruction to the queue to commit. 1310 } else { 1311 panic("Unexpected memory type!\n"); 1312 } 1313 1314 } else { 1315 inst->execute(); 1316 1317 inst->setExecuted(); 1318 1319 instToCommit(inst); 1320 } 1321 1322 updateExeInstStats(inst); 1323 1324 // Check if branch prediction was correct, if not then we need 1325 // to tell commit to squash in flight instructions. Only 1326 // handle this if there hasn't already been something that 1327 // redirects fetch in this group of instructions. 1328 1329 // This probably needs to prioritize the redirects if a different 1330 // scheduler is used. Currently the scheduler schedules the oldest 1331 // instruction first, so the branch resolution order will be correct. 1332 unsigned tid = inst->threadNumber; 1333 1334 if (!fetchRedirect[tid] || 1335 toCommit->squashedSeqNum[tid] > inst->seqNum) { 1336 1337 if (inst->mispredicted()) { 1338 fetchRedirect[tid] = true; 1339 1340 DPRINTF(IEW, "Execute: Branch mispredict detected.\n"); 1341#if ISA_HAS_DELAY_SLOT 1342 DPRINTF(IEW, "Execute: Redirecting fetch to PC: %#x.\n", 1343 inst->nextNPC); 1344#else 1345 DPRINTF(IEW, "Execute: Redirecting fetch to PC: %#x.\n", 1346 inst->nextPC); 1347#endif 1348 // If incorrect, then signal the ROB that it must be squashed. 1349 squashDueToBranch(inst, tid); 1350 1351 if (inst->predTaken()) { 1352 predictedTakenIncorrect++; 1353 } else { 1354 predictedNotTakenIncorrect++; 1355 } 1356 } else if (ldstQueue.violation(tid)) { 1357 // If there was an ordering violation, then get the 1358 // DynInst that caused the violation. Note that this 1359 // clears the violation signal. 1360 DynInstPtr violator; 1361 violator = ldstQueue.getMemDepViolator(tid); 1362 1363 DPRINTF(IEW, "LDSTQ detected a violation. Violator PC: " 1364 "%#x, inst PC: %#x. Addr is: %#x.\n", 1365 violator->readPC(), inst->readPC(), inst->physEffAddr); 1366 1367 // Ensure the violating instruction is older than 1368 // current squash 1369 if (fetchRedirect[tid] && 1370 violator->seqNum >= toCommit->squashedSeqNum[tid]) 1371 continue; 1372 1373 fetchRedirect[tid] = true; 1374 1375 // Tell the instruction queue that a violation has occured. 1376 instQueue.violation(inst, violator); 1377 1378 // Squash. 1379 squashDueToMemOrder(inst,tid); 1380 1381 ++memOrderViolationEvents; 1382 } else if (ldstQueue.loadBlocked(tid) && 1383 !ldstQueue.isLoadBlockedHandled(tid)) { 1384 fetchRedirect[tid] = true; 1385 1386 DPRINTF(IEW, "Load operation couldn't execute because the " 1387 "memory system is blocked. PC: %#x [sn:%lli]\n", 1388 inst->readPC(), inst->seqNum); 1389 1390 squashDueToMemBlocked(inst, tid); 1391 } 1392 } 1393 } 1394 1395 // Update and record activity if we processed any instructions. 1396 if (inst_num) { 1397 if (exeStatus == Idle) { 1398 exeStatus = Running; 1399 } 1400 1401 updatedQueues = true; 1402 1403 cpu->activityThisCycle(); 1404 } 1405 1406 // Need to reset this in case a writeback event needs to write into the 1407 // iew queue. That way the writeback event will write into the correct 1408 // spot in the queue. 1409 wbNumInst = 0; 1410} 1411 1412template <class Impl> 1413void 1414DefaultIEW<Impl>::writebackInsts() 1415{ 1416 // Loop through the head of the time buffer and wake any 1417 // dependents. These instructions are about to write back. Also 1418 // mark scoreboard that this instruction is finally complete. 1419 // Either have IEW have direct access to scoreboard, or have this 1420 // as part of backwards communication. 1421 for (int inst_num = 0; inst_num < issueWidth && 1422 toCommit->insts[inst_num]; inst_num++) { 1423 DynInstPtr inst = toCommit->insts[inst_num]; 1424 int tid = inst->threadNumber; 1425 1426 DPRINTF(IEW, "Sending instructions to commit, [sn:%lli] PC %#x.\n", 1427 inst->seqNum, inst->readPC()); 1428 1429 iewInstsToCommit[tid]++; 1430 1431 // Some instructions will be sent to commit without having 1432 // executed because they need commit to handle them. 1433 // E.g. Uncached loads have not actually executed when they 1434 // are first sent to commit. Instead commit must tell the LSQ 1435 // when it's ready to execute the uncached load. 1436 if (!inst->isSquashed() && inst->isExecuted() && inst->getFault() == NoFault) { 1437 int dependents = instQueue.wakeDependents(inst); 1438 1439 for (int i = 0; i < inst->numDestRegs(); i++) { 1440 //mark as Ready 1441 DPRINTF(IEW,"Setting Destination Register %i\n", 1442 inst->renamedDestRegIdx(i)); 1443 scoreboard->setReg(inst->renamedDestRegIdx(i)); 1444 } 1445 1446 if (dependents) { 1447 producerInst[tid]++; 1448 consumerInst[tid]+= dependents; 1449 } 1450 writebackCount[tid]++; 1451 } 1452 1453 decrWb(inst->seqNum); 1454 } 1455} 1456 1457template<class Impl> 1458void 1459DefaultIEW<Impl>::tick() 1460{ 1461 wbNumInst = 0; 1462 wbCycle = 0; 1463 1464 wroteToTimeBuffer = false; 1465 updatedQueues = false; 1466 1467 sortInsts(); 1468 1469 // Free function units marked as being freed this cycle. 1470 fuPool->processFreeUnits(); 1471 1472 std::list<unsigned>::iterator threads = (*activeThreads).begin(); 1473 1474 // Check stall and squash signals, dispatch any instructions. 1475 while (threads != (*activeThreads).end()) { 1476 unsigned tid = *threads++; 1477 1478 DPRINTF(IEW,"Issue: Processing [tid:%i]\n",tid); 1479 1480 checkSignalsAndUpdate(tid); 1481 dispatch(tid); 1482 } 1483 1484 if (exeStatus != Squashing) { 1485 executeInsts(); 1486 1487 writebackInsts(); 1488 1489 // Have the instruction queue try to schedule any ready instructions. 1490 // (In actuality, this scheduling is for instructions that will 1491 // be executed next cycle.) 1492 instQueue.scheduleReadyInsts(); 1493 1494 // Also should advance its own time buffers if the stage ran. 1495 // Not the best place for it, but this works (hopefully). 1496 issueToExecQueue.advance(); 1497 } 1498 1499 bool broadcast_free_entries = false; 1500 1501 if (updatedQueues || exeStatus == Running || updateLSQNextCycle) { 1502 exeStatus = Idle; 1503 updateLSQNextCycle = false; 1504 1505 broadcast_free_entries = true; 1506 } 1507 1508 // Writeback any stores using any leftover bandwidth. 1509 ldstQueue.writebackStores(); 1510 1511 // Check the committed load/store signals to see if there's a load 1512 // or store to commit. Also check if it's being told to execute a 1513 // nonspeculative instruction. 1514 // This is pretty inefficient... 1515 1516 threads = (*activeThreads).begin(); 1517 while (threads != (*activeThreads).end()) { 1518 unsigned tid = (*threads++); 1519 1520 DPRINTF(IEW,"Processing [tid:%i]\n",tid); 1521 1522 // Update structures based on instructions committed. 1523 if (fromCommit->commitInfo[tid].doneSeqNum != 0 && 1524 !fromCommit->commitInfo[tid].squash && 1525 !fromCommit->commitInfo[tid].robSquashing) { 1526 1527 ldstQueue.commitStores(fromCommit->commitInfo[tid].doneSeqNum,tid); 1528 1529 ldstQueue.commitLoads(fromCommit->commitInfo[tid].doneSeqNum,tid); 1530 1531 updateLSQNextCycle = true; 1532 instQueue.commit(fromCommit->commitInfo[tid].doneSeqNum,tid); 1533 } 1534 1535 if (fromCommit->commitInfo[tid].nonSpecSeqNum != 0) { 1536 1537 //DPRINTF(IEW,"NonspecInst from thread %i",tid); 1538 if (fromCommit->commitInfo[tid].uncached) { 1539 instQueue.replayMemInst(fromCommit->commitInfo[tid].uncachedLoad); 1540 } else { 1541 instQueue.scheduleNonSpec( 1542 fromCommit->commitInfo[tid].nonSpecSeqNum); 1543 } 1544 } 1545 1546 if (broadcast_free_entries) { 1547 toFetch->iewInfo[tid].iqCount = 1548 instQueue.getCount(tid); 1549 toFetch->iewInfo[tid].ldstqCount = 1550 ldstQueue.getCount(tid); 1551 1552 toRename->iewInfo[tid].usedIQ = true; 1553 toRename->iewInfo[tid].freeIQEntries = 1554 instQueue.numFreeEntries(); 1555 toRename->iewInfo[tid].usedLSQ = true; 1556 toRename->iewInfo[tid].freeLSQEntries = 1557 ldstQueue.numFreeEntries(tid); 1558 1559 wroteToTimeBuffer = true; 1560 } 1561 1562 DPRINTF(IEW, "[tid:%i], Dispatch dispatched %i instructions.\n", 1563 tid, toRename->iewInfo[tid].dispatched); 1564 } 1565 1566 DPRINTF(IEW, "IQ has %i free entries (Can schedule: %i). " 1567 "LSQ has %i free entries.\n", 1568 instQueue.numFreeEntries(), instQueue.hasReadyInsts(), 1569 ldstQueue.numFreeEntries()); 1570 1571 updateStatus(); 1572 1573 if (wroteToTimeBuffer) { 1574 DPRINTF(Activity, "Activity this cycle.\n"); 1575 cpu->activityThisCycle(); 1576 } 1577} 1578 1579template <class Impl> 1580void 1581DefaultIEW<Impl>::updateExeInstStats(DynInstPtr &inst) 1582{ 1583 int thread_number = inst->threadNumber; 1584 1585 // 1586 // Pick off the software prefetches 1587 // 1588#ifdef TARGET_ALPHA 1589 if (inst->isDataPrefetch()) 1590 iewExecutedSwp[thread_number]++; 1591 else 1592 iewIewExecutedcutedInsts++; 1593#else 1594 iewExecutedInsts++; 1595#endif 1596 1597 // 1598 // Control operations 1599 // 1600 if (inst->isControl()) 1601 iewExecutedBranches[thread_number]++; 1602 1603 // 1604 // Memory operations 1605 // 1606 if (inst->isMemRef()) { 1607 iewExecutedRefs[thread_number]++; 1608 1609 if (inst->isLoad()) { 1610 iewExecLoadInsts[thread_number]++; 1611 } 1612 } 1613} 1614