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(); 517 518 toCommit->includeSquashInst[tid] = false; 519 520 wroteToTimeBuffer = true; 521} 522 523template<class Impl> 524void 525DefaultIEW<Impl>::squashDueToMemBlocked(DynInstPtr &inst, unsigned tid) 526{ 527 DPRINTF(IEW, "[tid:%i]: Memory blocked, squashing load and younger insts, " 528 "PC: %#x [sn:%i].\n", tid, inst->readPC(), inst->seqNum); 529 530 toCommit->squash[tid] = true; 531 toCommit->squashedSeqNum[tid] = inst->seqNum; 532 toCommit->nextPC[tid] = inst->readPC(); 533 534 // Must include the broadcasted SN in the squash. 535 toCommit->includeSquashInst[tid] = true; 536 537 ldstQueue.setLoadBlockedHandled(tid); 538 539 wroteToTimeBuffer = true; 540} 541 542template<class Impl> 543void 544DefaultIEW<Impl>::block(unsigned tid) 545{ 546 DPRINTF(IEW, "[tid:%u]: Blocking.\n", tid); 547 548 if (dispatchStatus[tid] != Blocked && 549 dispatchStatus[tid] != Unblocking) { 550 toRename->iewBlock[tid] = true; 551 wroteToTimeBuffer = true; 552 } 553 554 // Add the current inputs to the skid buffer so they can be 555 // reprocessed when this stage unblocks. 556 skidInsert(tid); 557 558 dispatchStatus[tid] = Blocked; 559} 560 561template<class Impl> 562void 563DefaultIEW<Impl>::unblock(unsigned tid) 564{ 565 DPRINTF(IEW, "[tid:%i]: Reading instructions out of the skid " 566 "buffer %u.\n",tid, tid); 567 568 // If the skid bufffer is empty, signal back to previous stages to unblock. 569 // Also switch status to running. 570 if (skidBuffer[tid].empty()) { 571 toRename->iewUnblock[tid] = true; 572 wroteToTimeBuffer = true; 573 DPRINTF(IEW, "[tid:%i]: Done unblocking.\n",tid); 574 dispatchStatus[tid] = Running; 575 } 576} 577 578template<class Impl> 579void 580DefaultIEW<Impl>::wakeDependents(DynInstPtr &inst) 581{ 582 instQueue.wakeDependents(inst); 583} 584 585template<class Impl> 586void 587DefaultIEW<Impl>::rescheduleMemInst(DynInstPtr &inst) 588{ 589 instQueue.rescheduleMemInst(inst); 590} 591 592template<class Impl> 593void 594DefaultIEW<Impl>::replayMemInst(DynInstPtr &inst) 595{ 596 instQueue.replayMemInst(inst); 597} 598 599template<class Impl> 600void 601DefaultIEW<Impl>::instToCommit(DynInstPtr &inst) 602{
| 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(); 517 518 toCommit->includeSquashInst[tid] = false; 519 520 wroteToTimeBuffer = true; 521} 522 523template<class Impl> 524void 525DefaultIEW<Impl>::squashDueToMemBlocked(DynInstPtr &inst, unsigned tid) 526{ 527 DPRINTF(IEW, "[tid:%i]: Memory blocked, squashing load and younger insts, " 528 "PC: %#x [sn:%i].\n", tid, inst->readPC(), inst->seqNum); 529 530 toCommit->squash[tid] = true; 531 toCommit->squashedSeqNum[tid] = inst->seqNum; 532 toCommit->nextPC[tid] = inst->readPC(); 533 534 // Must include the broadcasted SN in the squash. 535 toCommit->includeSquashInst[tid] = true; 536 537 ldstQueue.setLoadBlockedHandled(tid); 538 539 wroteToTimeBuffer = true; 540} 541 542template<class Impl> 543void 544DefaultIEW<Impl>::block(unsigned tid) 545{ 546 DPRINTF(IEW, "[tid:%u]: Blocking.\n", tid); 547 548 if (dispatchStatus[tid] != Blocked && 549 dispatchStatus[tid] != Unblocking) { 550 toRename->iewBlock[tid] = true; 551 wroteToTimeBuffer = true; 552 } 553 554 // Add the current inputs to the skid buffer so they can be 555 // reprocessed when this stage unblocks. 556 skidInsert(tid); 557 558 dispatchStatus[tid] = Blocked; 559} 560 561template<class Impl> 562void 563DefaultIEW<Impl>::unblock(unsigned tid) 564{ 565 DPRINTF(IEW, "[tid:%i]: Reading instructions out of the skid " 566 "buffer %u.\n",tid, tid); 567 568 // If the skid bufffer is empty, signal back to previous stages to unblock. 569 // Also switch status to running. 570 if (skidBuffer[tid].empty()) { 571 toRename->iewUnblock[tid] = true; 572 wroteToTimeBuffer = true; 573 DPRINTF(IEW, "[tid:%i]: Done unblocking.\n",tid); 574 dispatchStatus[tid] = Running; 575 } 576} 577 578template<class Impl> 579void 580DefaultIEW<Impl>::wakeDependents(DynInstPtr &inst) 581{ 582 instQueue.wakeDependents(inst); 583} 584 585template<class Impl> 586void 587DefaultIEW<Impl>::rescheduleMemInst(DynInstPtr &inst) 588{ 589 instQueue.rescheduleMemInst(inst); 590} 591 592template<class Impl> 593void 594DefaultIEW<Impl>::replayMemInst(DynInstPtr &inst) 595{ 596 instQueue.replayMemInst(inst); 597} 598 599template<class Impl> 600void 601DefaultIEW<Impl>::instToCommit(DynInstPtr &inst) 602{
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| 603 // This function should not be called after writebackInsts in a 604 // single cycle. That will cause problems with an instruction 605 // being added to the queue to commit without being processed by 606 // writebackInsts prior to being sent to commit. 607
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603 // First check the time slot that this instruction will write 604 // to. If there are free write ports at the time, then go ahead 605 // and write the instruction to that time. If there are not, 606 // keep looking back to see where's the first time there's a 607 // free slot. 608 while ((*iewQueue)[wbCycle].insts[wbNumInst]) { 609 ++wbNumInst; 610 if (wbNumInst == wbWidth) { 611 ++wbCycle; 612 wbNumInst = 0; 613 } 614 615 assert((wbCycle * wbWidth + wbNumInst) <= wbMax); 616 } 617 618 DPRINTF(IEW, "Current wb cycle: %i, width: %i, numInst: %i\nwbActual:%i\n", 619 wbCycle, wbWidth, wbNumInst, wbCycle * wbWidth + wbNumInst); 620 // Add finished instruction to queue to commit. 621 (*iewQueue)[wbCycle].insts[wbNumInst] = inst; 622 (*iewQueue)[wbCycle].size++; 623} 624 625template <class Impl> 626unsigned 627DefaultIEW<Impl>::validInstsFromRename() 628{ 629 unsigned inst_count = 0; 630 631 for (int i=0; i<fromRename->size; i++) { 632 if (!fromRename->insts[i]->isSquashed()) 633 inst_count++; 634 } 635 636 return inst_count; 637} 638 639template<class Impl> 640void 641DefaultIEW<Impl>::skidInsert(unsigned tid) 642{ 643 DynInstPtr inst = NULL; 644 645 while (!insts[tid].empty()) { 646 inst = insts[tid].front(); 647 648 insts[tid].pop(); 649 650 DPRINTF(Decode,"[tid:%i]: Inserting [sn:%lli] PC:%#x into " 651 "dispatch skidBuffer %i\n",tid, inst->seqNum, 652 inst->readPC(),tid); 653 654 skidBuffer[tid].push(inst); 655 } 656 657 assert(skidBuffer[tid].size() <= skidBufferMax && 658 "Skidbuffer Exceeded Max Size"); 659} 660 661template<class Impl> 662int 663DefaultIEW<Impl>::skidCount() 664{ 665 int max=0; 666 667 std::list<unsigned>::iterator threads = (*activeThreads).begin(); 668 669 while (threads != (*activeThreads).end()) { 670 unsigned thread_count = skidBuffer[*threads++].size(); 671 if (max < thread_count) 672 max = thread_count; 673 } 674 675 return max; 676} 677 678template<class Impl> 679bool 680DefaultIEW<Impl>::skidsEmpty() 681{ 682 std::list<unsigned>::iterator threads = (*activeThreads).begin(); 683 684 while (threads != (*activeThreads).end()) { 685 if (!skidBuffer[*threads++].empty()) 686 return false; 687 } 688 689 return true; 690} 691 692template <class Impl> 693void 694DefaultIEW<Impl>::updateStatus() 695{ 696 bool any_unblocking = false; 697 698 std::list<unsigned>::iterator threads = (*activeThreads).begin(); 699 700 threads = (*activeThreads).begin(); 701 702 while (threads != (*activeThreads).end()) { 703 unsigned tid = *threads++; 704 705 if (dispatchStatus[tid] == Unblocking) { 706 any_unblocking = true; 707 break; 708 } 709 } 710 711 // If there are no ready instructions waiting to be scheduled by the IQ, 712 // and there's no stores waiting to write back, and dispatch is not 713 // unblocking, then there is no internal activity for the IEW stage. 714 if (_status == Active && !instQueue.hasReadyInsts() && 715 !ldstQueue.willWB() && !any_unblocking) { 716 DPRINTF(IEW, "IEW switching to idle\n"); 717 718 deactivateStage(); 719 720 _status = Inactive; 721 } else if (_status == Inactive && (instQueue.hasReadyInsts() || 722 ldstQueue.willWB() || 723 any_unblocking)) { 724 // Otherwise there is internal activity. Set to active. 725 DPRINTF(IEW, "IEW switching to active\n"); 726 727 activateStage(); 728 729 _status = Active; 730 } 731} 732 733template <class Impl> 734void 735DefaultIEW<Impl>::resetEntries() 736{ 737 instQueue.resetEntries(); 738 ldstQueue.resetEntries(); 739} 740 741template <class Impl> 742void 743DefaultIEW<Impl>::readStallSignals(unsigned tid) 744{ 745 if (fromCommit->commitBlock[tid]) { 746 stalls[tid].commit = true; 747 } 748 749 if (fromCommit->commitUnblock[tid]) { 750 assert(stalls[tid].commit); 751 stalls[tid].commit = false; 752 } 753} 754 755template <class Impl> 756bool 757DefaultIEW<Impl>::checkStall(unsigned tid) 758{ 759 bool ret_val(false); 760 761 if (stalls[tid].commit) { 762 DPRINTF(IEW,"[tid:%i]: Stall from Commit stage detected.\n",tid); 763 ret_val = true; 764 } else if (instQueue.isFull(tid)) { 765 DPRINTF(IEW,"[tid:%i]: Stall: IQ is full.\n",tid); 766 ret_val = true; 767 } else if (ldstQueue.isFull(tid)) { 768 DPRINTF(IEW,"[tid:%i]: Stall: LSQ is full\n",tid); 769 770 if (ldstQueue.numLoads(tid) > 0 ) { 771 772 DPRINTF(IEW,"[tid:%i]: LSQ oldest load: [sn:%i] \n", 773 tid,ldstQueue.getLoadHeadSeqNum(tid)); 774 } 775 776 if (ldstQueue.numStores(tid) > 0) { 777 778 DPRINTF(IEW,"[tid:%i]: LSQ oldest store: [sn:%i] \n", 779 tid,ldstQueue.getStoreHeadSeqNum(tid)); 780 } 781 782 ret_val = true; 783 } else if (ldstQueue.isStalled(tid)) { 784 DPRINTF(IEW,"[tid:%i]: Stall: LSQ stall detected.\n",tid); 785 ret_val = true; 786 } 787 788 return ret_val; 789} 790 791template <class Impl> 792void 793DefaultIEW<Impl>::checkSignalsAndUpdate(unsigned tid) 794{ 795 // Check if there's a squash signal, squash if there is 796 // Check stall signals, block if there is. 797 // If status was Blocked 798 // if so then go to unblocking 799 // If status was Squashing 800 // check if squashing is not high. Switch to running this cycle. 801 802 readStallSignals(tid); 803 804 if (fromCommit->commitInfo[tid].squash) { 805 squash(tid); 806 807 if (dispatchStatus[tid] == Blocked || 808 dispatchStatus[tid] == Unblocking) { 809 toRename->iewUnblock[tid] = true; 810 wroteToTimeBuffer = true; 811 } 812 813 dispatchStatus[tid] = Squashing; 814 815 fetchRedirect[tid] = false; 816 return; 817 } 818 819 if (fromCommit->commitInfo[tid].robSquashing) { 820 DPRINTF(IEW, "[tid:%i]: ROB is still squashing.\n", tid); 821 822 dispatchStatus[tid] = Squashing; 823 824 emptyRenameInsts(tid); 825 wroteToTimeBuffer = true; 826 return; 827 } 828 829 if (checkStall(tid)) { 830 block(tid); 831 dispatchStatus[tid] = Blocked; 832 return; 833 } 834 835 if (dispatchStatus[tid] == Blocked) { 836 // Status from previous cycle was blocked, but there are no more stall 837 // conditions. Switch over to unblocking. 838 DPRINTF(IEW, "[tid:%i]: Done blocking, switching to unblocking.\n", 839 tid); 840 841 dispatchStatus[tid] = Unblocking; 842 843 unblock(tid); 844 845 return; 846 } 847 848 if (dispatchStatus[tid] == Squashing) { 849 // Switch status to running if rename isn't being told to block or 850 // squash this cycle. 851 DPRINTF(IEW, "[tid:%i]: Done squashing, switching to running.\n", 852 tid); 853 854 dispatchStatus[tid] = Running; 855 856 return; 857 } 858} 859 860template <class Impl> 861void 862DefaultIEW<Impl>::sortInsts() 863{ 864 int insts_from_rename = fromRename->size; 865#ifdef DEBUG 866#if !ISA_HAS_DELAY_SLOT 867 for (int i = 0; i < numThreads; i++) 868 assert(insts[i].empty()); 869#endif 870#endif 871 for (int i = 0; i < insts_from_rename; ++i) { 872 insts[fromRename->insts[i]->threadNumber].push(fromRename->insts[i]); 873 } 874} 875 876template <class Impl> 877void 878DefaultIEW<Impl>::emptyRenameInsts(unsigned tid) 879{ 880 DPRINTF(IEW, "[tid:%i]: Removing incoming rename instructions until " 881 "[sn:%i].\n", tid, bdelayDoneSeqNum[tid]); 882 883 while (!insts[tid].empty()) { 884#if ISA_HAS_DELAY_SLOT 885 if (insts[tid].front()->seqNum <= bdelayDoneSeqNum[tid]) { 886 DPRINTF(IEW, "[tid:%i]: Done removing, cannot remove instruction" 887 " that occurs at or before delay slot [sn:%i].\n", 888 tid, bdelayDoneSeqNum[tid]); 889 break; 890 } else { 891 DPRINTF(IEW, "[tid:%i]: Removing incoming rename instruction " 892 "[sn:%i].\n", tid, insts[tid].front()->seqNum); 893 } 894#endif 895 896 if (insts[tid].front()->isLoad() || 897 insts[tid].front()->isStore() ) { 898 toRename->iewInfo[tid].dispatchedToLSQ++; 899 } 900 901 toRename->iewInfo[tid].dispatched++; 902 903 insts[tid].pop(); 904 } 905} 906 907template <class Impl> 908void 909DefaultIEW<Impl>::wakeCPU() 910{ 911 cpu->wakeCPU(); 912} 913 914template <class Impl> 915void 916DefaultIEW<Impl>::activityThisCycle() 917{ 918 DPRINTF(Activity, "Activity this cycle.\n"); 919 cpu->activityThisCycle(); 920} 921 922template <class Impl> 923inline void 924DefaultIEW<Impl>::activateStage() 925{ 926 DPRINTF(Activity, "Activating stage.\n"); 927 cpu->activateStage(O3CPU::IEWIdx); 928} 929 930template <class Impl> 931inline void 932DefaultIEW<Impl>::deactivateStage() 933{ 934 DPRINTF(Activity, "Deactivating stage.\n"); 935 cpu->deactivateStage(O3CPU::IEWIdx); 936} 937 938template<class Impl> 939void 940DefaultIEW<Impl>::dispatch(unsigned tid) 941{ 942 // If status is Running or idle, 943 // call dispatchInsts() 944 // If status is Unblocking, 945 // buffer any instructions coming from rename 946 // continue trying to empty skid buffer 947 // check if stall conditions have passed 948 949 if (dispatchStatus[tid] == Blocked) { 950 ++iewBlockCycles; 951 952 } else if (dispatchStatus[tid] == Squashing) { 953 ++iewSquashCycles; 954 } 955 956 // Dispatch should try to dispatch as many instructions as its bandwidth 957 // will allow, as long as it is not currently blocked. 958 if (dispatchStatus[tid] == Running || 959 dispatchStatus[tid] == Idle) { 960 DPRINTF(IEW, "[tid:%i] Not blocked, so attempting to run " 961 "dispatch.\n", tid); 962 963 dispatchInsts(tid); 964 } else if (dispatchStatus[tid] == Unblocking) { 965 // Make sure that the skid buffer has something in it if the 966 // status is unblocking. 967 assert(!skidsEmpty()); 968 969 // If the status was unblocking, then instructions from the skid 970 // buffer were used. Remove those instructions and handle 971 // the rest of unblocking. 972 dispatchInsts(tid); 973 974 ++iewUnblockCycles; 975 976 if (validInstsFromRename() && dispatchedAllInsts) { 977 // Add the current inputs to the skid buffer so they can be 978 // reprocessed when this stage unblocks. 979 skidInsert(tid); 980 } 981 982 unblock(tid); 983 } 984} 985 986template <class Impl> 987void 988DefaultIEW<Impl>::dispatchInsts(unsigned tid) 989{ 990 dispatchedAllInsts = true; 991 992 // Obtain instructions from skid buffer if unblocking, or queue from rename 993 // otherwise. 994 std::queue<DynInstPtr> &insts_to_dispatch = 995 dispatchStatus[tid] == Unblocking ? 996 skidBuffer[tid] : insts[tid]; 997 998 int insts_to_add = insts_to_dispatch.size(); 999 1000 DynInstPtr inst; 1001 bool add_to_iq = false; 1002 int dis_num_inst = 0; 1003 1004 // Loop through the instructions, putting them in the instruction 1005 // queue. 1006 for ( ; dis_num_inst < insts_to_add && 1007 dis_num_inst < dispatchWidth; 1008 ++dis_num_inst) 1009 { 1010 inst = insts_to_dispatch.front(); 1011 1012 if (dispatchStatus[tid] == Unblocking) { 1013 DPRINTF(IEW, "[tid:%i]: Issue: Examining instruction from skid " 1014 "buffer\n", tid); 1015 } 1016 1017 // Make sure there's a valid instruction there. 1018 assert(inst); 1019 1020 DPRINTF(IEW, "[tid:%i]: Issue: Adding PC %#x [sn:%lli] [tid:%i] to " 1021 "IQ.\n", 1022 tid, inst->readPC(), inst->seqNum, inst->threadNumber); 1023 1024 // Be sure to mark these instructions as ready so that the 1025 // commit stage can go ahead and execute them, and mark 1026 // them as issued so the IQ doesn't reprocess them. 1027 1028 // Check for squashed instructions. 1029 if (inst->isSquashed()) { 1030 DPRINTF(IEW, "[tid:%i]: Issue: Squashed instruction encountered, " 1031 "not adding to IQ.\n", tid); 1032 1033 ++iewDispSquashedInsts; 1034 1035 insts_to_dispatch.pop(); 1036 1037 //Tell Rename That An Instruction has been processed 1038 if (inst->isLoad() || inst->isStore()) { 1039 toRename->iewInfo[tid].dispatchedToLSQ++; 1040 } 1041 toRename->iewInfo[tid].dispatched++; 1042 1043 continue; 1044 } 1045 1046 // Check for full conditions. 1047 if (instQueue.isFull(tid)) { 1048 DPRINTF(IEW, "[tid:%i]: Issue: IQ has become full.\n", tid); 1049 1050 // Call function to start blocking. 1051 block(tid); 1052 1053 // Set unblock to false. Special case where we are using 1054 // skidbuffer (unblocking) instructions but then we still 1055 // get full in the IQ. 1056 toRename->iewUnblock[tid] = false; 1057 1058 dispatchedAllInsts = false; 1059 1060 ++iewIQFullEvents; 1061 break; 1062 } else if (ldstQueue.isFull(tid)) { 1063 DPRINTF(IEW, "[tid:%i]: Issue: LSQ has become full.\n",tid); 1064 1065 // Call function to start blocking. 1066 block(tid); 1067 1068 // Set unblock to false. Special case where we are using 1069 // skidbuffer (unblocking) instructions but then we still 1070 // get full in the IQ. 1071 toRename->iewUnblock[tid] = false; 1072 1073 dispatchedAllInsts = false; 1074 1075 ++iewLSQFullEvents; 1076 break; 1077 } 1078 1079 // Otherwise issue the instruction just fine. 1080 if (inst->isLoad()) { 1081 DPRINTF(IEW, "[tid:%i]: Issue: Memory instruction " 1082 "encountered, adding to LSQ.\n", tid); 1083 1084 // Reserve a spot in the load store queue for this 1085 // memory access. 1086 ldstQueue.insertLoad(inst); 1087 1088 ++iewDispLoadInsts; 1089 1090 add_to_iq = true; 1091 1092 toRename->iewInfo[tid].dispatchedToLSQ++; 1093 } else if (inst->isStore()) { 1094 DPRINTF(IEW, "[tid:%i]: Issue: Memory instruction " 1095 "encountered, adding to LSQ.\n", tid); 1096 1097 ldstQueue.insertStore(inst); 1098 1099 ++iewDispStoreInsts; 1100 1101 if (inst->isStoreConditional()) { 1102 // Store conditionals need to be set as "canCommit()" 1103 // so that commit can process them when they reach the 1104 // head of commit. 1105 // @todo: This is somewhat specific to Alpha. 1106 inst->setCanCommit(); 1107 instQueue.insertNonSpec(inst); 1108 add_to_iq = false; 1109 1110 ++iewDispNonSpecInsts; 1111 } else { 1112 add_to_iq = true; 1113 } 1114 1115 toRename->iewInfo[tid].dispatchedToLSQ++; 1116#if FULL_SYSTEM 1117 } else if (inst->isMemBarrier() || inst->isWriteBarrier()) { 1118 // Same as non-speculative stores. 1119 inst->setCanCommit(); 1120 instQueue.insertBarrier(inst); 1121 add_to_iq = false; 1122#endif 1123 } else if (inst->isNonSpeculative()) { 1124 DPRINTF(IEW, "[tid:%i]: Issue: Nonspeculative instruction " 1125 "encountered, skipping.\n", tid); 1126 1127 // Same as non-speculative stores. 1128 inst->setCanCommit(); 1129 1130 // Specifically insert it as nonspeculative. 1131 instQueue.insertNonSpec(inst); 1132 1133 ++iewDispNonSpecInsts; 1134 1135 add_to_iq = false; 1136 } else if (inst->isNop()) { 1137 DPRINTF(IEW, "[tid:%i]: Issue: Nop instruction encountered, " 1138 "skipping.\n", tid); 1139 1140 inst->setIssued(); 1141 inst->setExecuted(); 1142 inst->setCanCommit(); 1143 1144 instQueue.recordProducer(inst); 1145 1146 iewExecutedNop[tid]++; 1147 1148 add_to_iq = false; 1149 } else if (inst->isExecuted()) { 1150 assert(0 && "Instruction shouldn't be executed.\n"); 1151 DPRINTF(IEW, "Issue: Executed branch encountered, " 1152 "skipping.\n"); 1153 1154 inst->setIssued(); 1155 inst->setCanCommit(); 1156 1157 instQueue.recordProducer(inst); 1158 1159 add_to_iq = false; 1160 } else { 1161 add_to_iq = true; 1162 } 1163 1164 // If the instruction queue is not full, then add the 1165 // instruction. 1166 if (add_to_iq) { 1167 instQueue.insert(inst); 1168 } 1169 1170 insts_to_dispatch.pop(); 1171 1172 toRename->iewInfo[tid].dispatched++; 1173 1174 ++iewDispatchedInsts; 1175 } 1176 1177 if (!insts_to_dispatch.empty()) { 1178 DPRINTF(IEW,"[tid:%i]: Issue: Bandwidth Full. Blocking.\n", tid); 1179 block(tid); 1180 toRename->iewUnblock[tid] = false; 1181 } 1182 1183 if (dispatchStatus[tid] == Idle && dis_num_inst) { 1184 dispatchStatus[tid] = Running; 1185 1186 updatedQueues = true; 1187 } 1188 1189 dis_num_inst = 0; 1190} 1191 1192template <class Impl> 1193void 1194DefaultIEW<Impl>::printAvailableInsts() 1195{ 1196 int inst = 0; 1197 1198 std::cout << "Available Instructions: "; 1199 1200 while (fromIssue->insts[inst]) { 1201 1202 if (inst%3==0) std::cout << "\n\t"; 1203 1204 std::cout << "PC: " << fromIssue->insts[inst]->readPC() 1205 << " TN: " << fromIssue->insts[inst]->threadNumber 1206 << " SN: " << fromIssue->insts[inst]->seqNum << " | "; 1207 1208 inst++; 1209 1210 } 1211 1212 std::cout << "\n"; 1213} 1214 1215template <class Impl> 1216void 1217DefaultIEW<Impl>::executeInsts() 1218{ 1219 wbNumInst = 0; 1220 wbCycle = 0; 1221 1222 std::list<unsigned>::iterator threads = (*activeThreads).begin(); 1223 1224 while (threads != (*activeThreads).end()) { 1225 unsigned tid = *threads++; 1226 fetchRedirect[tid] = false; 1227 } 1228 1229 // Uncomment this if you want to see all available instructions. 1230// printAvailableInsts(); 1231 1232 // Execute/writeback any instructions that are available. 1233 int insts_to_execute = fromIssue->size; 1234 int inst_num = 0; 1235 for (; inst_num < insts_to_execute; 1236 ++inst_num) { 1237 1238 DPRINTF(IEW, "Execute: Executing instructions from IQ.\n"); 1239 1240 DynInstPtr inst = instQueue.getInstToExecute(); 1241 1242 DPRINTF(IEW, "Execute: Processing PC %#x, [tid:%i] [sn:%i].\n", 1243 inst->readPC(), inst->threadNumber,inst->seqNum); 1244 1245 // Check if the instruction is squashed; if so then skip it 1246 if (inst->isSquashed()) { 1247 DPRINTF(IEW, "Execute: Instruction was squashed.\n"); 1248 1249 // Consider this instruction executed so that commit can go 1250 // ahead and retire the instruction. 1251 inst->setExecuted(); 1252 1253 // Not sure if I should set this here or just let commit try to 1254 // commit any squashed instructions. I like the latter a bit more. 1255 inst->setCanCommit(); 1256 1257 ++iewExecSquashedInsts; 1258 1259 decrWb(inst->seqNum); 1260 continue; 1261 } 1262 1263 Fault fault = NoFault; 1264 1265 // Execute instruction. 1266 // Note that if the instruction faults, it will be handled 1267 // at the commit stage. 1268 if (inst->isMemRef() && 1269 (!inst->isDataPrefetch() && !inst->isInstPrefetch())) { 1270 DPRINTF(IEW, "Execute: Calculating address for memory " 1271 "reference.\n"); 1272 1273 // Tell the LDSTQ to execute this instruction (if it is a load). 1274 if (inst->isLoad()) { 1275 // Loads will mark themselves as executed, and their writeback 1276 // event adds the instruction to the queue to commit 1277 fault = ldstQueue.executeLoad(inst); 1278 } else if (inst->isStore()) { 1279 fault = ldstQueue.executeStore(inst); 1280 1281 // If the store had a fault then it may not have a mem req 1282 if (!inst->isStoreConditional() && fault == NoFault) { 1283 inst->setExecuted(); 1284 1285 instToCommit(inst); 1286 } else if (fault != NoFault) { 1287 // If the instruction faulted, then we need to send it along to commit 1288 // without the instruction completing.
| 608 // First check the time slot that this instruction will write 609 // to. If there are free write ports at the time, then go ahead 610 // and write the instruction to that time. If there are not, 611 // keep looking back to see where's the first time there's a 612 // free slot. 613 while ((*iewQueue)[wbCycle].insts[wbNumInst]) { 614 ++wbNumInst; 615 if (wbNumInst == wbWidth) { 616 ++wbCycle; 617 wbNumInst = 0; 618 } 619 620 assert((wbCycle * wbWidth + wbNumInst) <= wbMax); 621 } 622 623 DPRINTF(IEW, "Current wb cycle: %i, width: %i, numInst: %i\nwbActual:%i\n", 624 wbCycle, wbWidth, wbNumInst, wbCycle * wbWidth + wbNumInst); 625 // Add finished instruction to queue to commit. 626 (*iewQueue)[wbCycle].insts[wbNumInst] = inst; 627 (*iewQueue)[wbCycle].size++; 628} 629 630template <class Impl> 631unsigned 632DefaultIEW<Impl>::validInstsFromRename() 633{ 634 unsigned inst_count = 0; 635 636 for (int i=0; i<fromRename->size; i++) { 637 if (!fromRename->insts[i]->isSquashed()) 638 inst_count++; 639 } 640 641 return inst_count; 642} 643 644template<class Impl> 645void 646DefaultIEW<Impl>::skidInsert(unsigned tid) 647{ 648 DynInstPtr inst = NULL; 649 650 while (!insts[tid].empty()) { 651 inst = insts[tid].front(); 652 653 insts[tid].pop(); 654 655 DPRINTF(Decode,"[tid:%i]: Inserting [sn:%lli] PC:%#x into " 656 "dispatch skidBuffer %i\n",tid, inst->seqNum, 657 inst->readPC(),tid); 658 659 skidBuffer[tid].push(inst); 660 } 661 662 assert(skidBuffer[tid].size() <= skidBufferMax && 663 "Skidbuffer Exceeded Max Size"); 664} 665 666template<class Impl> 667int 668DefaultIEW<Impl>::skidCount() 669{ 670 int max=0; 671 672 std::list<unsigned>::iterator threads = (*activeThreads).begin(); 673 674 while (threads != (*activeThreads).end()) { 675 unsigned thread_count = skidBuffer[*threads++].size(); 676 if (max < thread_count) 677 max = thread_count; 678 } 679 680 return max; 681} 682 683template<class Impl> 684bool 685DefaultIEW<Impl>::skidsEmpty() 686{ 687 std::list<unsigned>::iterator threads = (*activeThreads).begin(); 688 689 while (threads != (*activeThreads).end()) { 690 if (!skidBuffer[*threads++].empty()) 691 return false; 692 } 693 694 return true; 695} 696 697template <class Impl> 698void 699DefaultIEW<Impl>::updateStatus() 700{ 701 bool any_unblocking = false; 702 703 std::list<unsigned>::iterator threads = (*activeThreads).begin(); 704 705 threads = (*activeThreads).begin(); 706 707 while (threads != (*activeThreads).end()) { 708 unsigned tid = *threads++; 709 710 if (dispatchStatus[tid] == Unblocking) { 711 any_unblocking = true; 712 break; 713 } 714 } 715 716 // If there are no ready instructions waiting to be scheduled by the IQ, 717 // and there's no stores waiting to write back, and dispatch is not 718 // unblocking, then there is no internal activity for the IEW stage. 719 if (_status == Active && !instQueue.hasReadyInsts() && 720 !ldstQueue.willWB() && !any_unblocking) { 721 DPRINTF(IEW, "IEW switching to idle\n"); 722 723 deactivateStage(); 724 725 _status = Inactive; 726 } else if (_status == Inactive && (instQueue.hasReadyInsts() || 727 ldstQueue.willWB() || 728 any_unblocking)) { 729 // Otherwise there is internal activity. Set to active. 730 DPRINTF(IEW, "IEW switching to active\n"); 731 732 activateStage(); 733 734 _status = Active; 735 } 736} 737 738template <class Impl> 739void 740DefaultIEW<Impl>::resetEntries() 741{ 742 instQueue.resetEntries(); 743 ldstQueue.resetEntries(); 744} 745 746template <class Impl> 747void 748DefaultIEW<Impl>::readStallSignals(unsigned tid) 749{ 750 if (fromCommit->commitBlock[tid]) { 751 stalls[tid].commit = true; 752 } 753 754 if (fromCommit->commitUnblock[tid]) { 755 assert(stalls[tid].commit); 756 stalls[tid].commit = false; 757 } 758} 759 760template <class Impl> 761bool 762DefaultIEW<Impl>::checkStall(unsigned tid) 763{ 764 bool ret_val(false); 765 766 if (stalls[tid].commit) { 767 DPRINTF(IEW,"[tid:%i]: Stall from Commit stage detected.\n",tid); 768 ret_val = true; 769 } else if (instQueue.isFull(tid)) { 770 DPRINTF(IEW,"[tid:%i]: Stall: IQ is full.\n",tid); 771 ret_val = true; 772 } else if (ldstQueue.isFull(tid)) { 773 DPRINTF(IEW,"[tid:%i]: Stall: LSQ is full\n",tid); 774 775 if (ldstQueue.numLoads(tid) > 0 ) { 776 777 DPRINTF(IEW,"[tid:%i]: LSQ oldest load: [sn:%i] \n", 778 tid,ldstQueue.getLoadHeadSeqNum(tid)); 779 } 780 781 if (ldstQueue.numStores(tid) > 0) { 782 783 DPRINTF(IEW,"[tid:%i]: LSQ oldest store: [sn:%i] \n", 784 tid,ldstQueue.getStoreHeadSeqNum(tid)); 785 } 786 787 ret_val = true; 788 } else if (ldstQueue.isStalled(tid)) { 789 DPRINTF(IEW,"[tid:%i]: Stall: LSQ stall detected.\n",tid); 790 ret_val = true; 791 } 792 793 return ret_val; 794} 795 796template <class Impl> 797void 798DefaultIEW<Impl>::checkSignalsAndUpdate(unsigned tid) 799{ 800 // Check if there's a squash signal, squash if there is 801 // Check stall signals, block if there is. 802 // If status was Blocked 803 // if so then go to unblocking 804 // If status was Squashing 805 // check if squashing is not high. Switch to running this cycle. 806 807 readStallSignals(tid); 808 809 if (fromCommit->commitInfo[tid].squash) { 810 squash(tid); 811 812 if (dispatchStatus[tid] == Blocked || 813 dispatchStatus[tid] == Unblocking) { 814 toRename->iewUnblock[tid] = true; 815 wroteToTimeBuffer = true; 816 } 817 818 dispatchStatus[tid] = Squashing; 819 820 fetchRedirect[tid] = false; 821 return; 822 } 823 824 if (fromCommit->commitInfo[tid].robSquashing) { 825 DPRINTF(IEW, "[tid:%i]: ROB is still squashing.\n", tid); 826 827 dispatchStatus[tid] = Squashing; 828 829 emptyRenameInsts(tid); 830 wroteToTimeBuffer = true; 831 return; 832 } 833 834 if (checkStall(tid)) { 835 block(tid); 836 dispatchStatus[tid] = Blocked; 837 return; 838 } 839 840 if (dispatchStatus[tid] == Blocked) { 841 // Status from previous cycle was blocked, but there are no more stall 842 // conditions. Switch over to unblocking. 843 DPRINTF(IEW, "[tid:%i]: Done blocking, switching to unblocking.\n", 844 tid); 845 846 dispatchStatus[tid] = Unblocking; 847 848 unblock(tid); 849 850 return; 851 } 852 853 if (dispatchStatus[tid] == Squashing) { 854 // Switch status to running if rename isn't being told to block or 855 // squash this cycle. 856 DPRINTF(IEW, "[tid:%i]: Done squashing, switching to running.\n", 857 tid); 858 859 dispatchStatus[tid] = Running; 860 861 return; 862 } 863} 864 865template <class Impl> 866void 867DefaultIEW<Impl>::sortInsts() 868{ 869 int insts_from_rename = fromRename->size; 870#ifdef DEBUG 871#if !ISA_HAS_DELAY_SLOT 872 for (int i = 0; i < numThreads; i++) 873 assert(insts[i].empty()); 874#endif 875#endif 876 for (int i = 0; i < insts_from_rename; ++i) { 877 insts[fromRename->insts[i]->threadNumber].push(fromRename->insts[i]); 878 } 879} 880 881template <class Impl> 882void 883DefaultIEW<Impl>::emptyRenameInsts(unsigned tid) 884{ 885 DPRINTF(IEW, "[tid:%i]: Removing incoming rename instructions until " 886 "[sn:%i].\n", tid, bdelayDoneSeqNum[tid]); 887 888 while (!insts[tid].empty()) { 889#if ISA_HAS_DELAY_SLOT 890 if (insts[tid].front()->seqNum <= bdelayDoneSeqNum[tid]) { 891 DPRINTF(IEW, "[tid:%i]: Done removing, cannot remove instruction" 892 " that occurs at or before delay slot [sn:%i].\n", 893 tid, bdelayDoneSeqNum[tid]); 894 break; 895 } else { 896 DPRINTF(IEW, "[tid:%i]: Removing incoming rename instruction " 897 "[sn:%i].\n", tid, insts[tid].front()->seqNum); 898 } 899#endif 900 901 if (insts[tid].front()->isLoad() || 902 insts[tid].front()->isStore() ) { 903 toRename->iewInfo[tid].dispatchedToLSQ++; 904 } 905 906 toRename->iewInfo[tid].dispatched++; 907 908 insts[tid].pop(); 909 } 910} 911 912template <class Impl> 913void 914DefaultIEW<Impl>::wakeCPU() 915{ 916 cpu->wakeCPU(); 917} 918 919template <class Impl> 920void 921DefaultIEW<Impl>::activityThisCycle() 922{ 923 DPRINTF(Activity, "Activity this cycle.\n"); 924 cpu->activityThisCycle(); 925} 926 927template <class Impl> 928inline void 929DefaultIEW<Impl>::activateStage() 930{ 931 DPRINTF(Activity, "Activating stage.\n"); 932 cpu->activateStage(O3CPU::IEWIdx); 933} 934 935template <class Impl> 936inline void 937DefaultIEW<Impl>::deactivateStage() 938{ 939 DPRINTF(Activity, "Deactivating stage.\n"); 940 cpu->deactivateStage(O3CPU::IEWIdx); 941} 942 943template<class Impl> 944void 945DefaultIEW<Impl>::dispatch(unsigned tid) 946{ 947 // If status is Running or idle, 948 // call dispatchInsts() 949 // If status is Unblocking, 950 // buffer any instructions coming from rename 951 // continue trying to empty skid buffer 952 // check if stall conditions have passed 953 954 if (dispatchStatus[tid] == Blocked) { 955 ++iewBlockCycles; 956 957 } else if (dispatchStatus[tid] == Squashing) { 958 ++iewSquashCycles; 959 } 960 961 // Dispatch should try to dispatch as many instructions as its bandwidth 962 // will allow, as long as it is not currently blocked. 963 if (dispatchStatus[tid] == Running || 964 dispatchStatus[tid] == Idle) { 965 DPRINTF(IEW, "[tid:%i] Not blocked, so attempting to run " 966 "dispatch.\n", tid); 967 968 dispatchInsts(tid); 969 } else if (dispatchStatus[tid] == Unblocking) { 970 // Make sure that the skid buffer has something in it if the 971 // status is unblocking. 972 assert(!skidsEmpty()); 973 974 // If the status was unblocking, then instructions from the skid 975 // buffer were used. Remove those instructions and handle 976 // the rest of unblocking. 977 dispatchInsts(tid); 978 979 ++iewUnblockCycles; 980 981 if (validInstsFromRename() && dispatchedAllInsts) { 982 // Add the current inputs to the skid buffer so they can be 983 // reprocessed when this stage unblocks. 984 skidInsert(tid); 985 } 986 987 unblock(tid); 988 } 989} 990 991template <class Impl> 992void 993DefaultIEW<Impl>::dispatchInsts(unsigned tid) 994{ 995 dispatchedAllInsts = true; 996 997 // Obtain instructions from skid buffer if unblocking, or queue from rename 998 // otherwise. 999 std::queue<DynInstPtr> &insts_to_dispatch = 1000 dispatchStatus[tid] == Unblocking ? 1001 skidBuffer[tid] : insts[tid]; 1002 1003 int insts_to_add = insts_to_dispatch.size(); 1004 1005 DynInstPtr inst; 1006 bool add_to_iq = false; 1007 int dis_num_inst = 0; 1008 1009 // Loop through the instructions, putting them in the instruction 1010 // queue. 1011 for ( ; dis_num_inst < insts_to_add && 1012 dis_num_inst < dispatchWidth; 1013 ++dis_num_inst) 1014 { 1015 inst = insts_to_dispatch.front(); 1016 1017 if (dispatchStatus[tid] == Unblocking) { 1018 DPRINTF(IEW, "[tid:%i]: Issue: Examining instruction from skid " 1019 "buffer\n", tid); 1020 } 1021 1022 // Make sure there's a valid instruction there. 1023 assert(inst); 1024 1025 DPRINTF(IEW, "[tid:%i]: Issue: Adding PC %#x [sn:%lli] [tid:%i] to " 1026 "IQ.\n", 1027 tid, inst->readPC(), inst->seqNum, inst->threadNumber); 1028 1029 // Be sure to mark these instructions as ready so that the 1030 // commit stage can go ahead and execute them, and mark 1031 // them as issued so the IQ doesn't reprocess them. 1032 1033 // Check for squashed instructions. 1034 if (inst->isSquashed()) { 1035 DPRINTF(IEW, "[tid:%i]: Issue: Squashed instruction encountered, " 1036 "not adding to IQ.\n", tid); 1037 1038 ++iewDispSquashedInsts; 1039 1040 insts_to_dispatch.pop(); 1041 1042 //Tell Rename That An Instruction has been processed 1043 if (inst->isLoad() || inst->isStore()) { 1044 toRename->iewInfo[tid].dispatchedToLSQ++; 1045 } 1046 toRename->iewInfo[tid].dispatched++; 1047 1048 continue; 1049 } 1050 1051 // Check for full conditions. 1052 if (instQueue.isFull(tid)) { 1053 DPRINTF(IEW, "[tid:%i]: Issue: IQ has become full.\n", tid); 1054 1055 // Call function to start blocking. 1056 block(tid); 1057 1058 // Set unblock to false. Special case where we are using 1059 // skidbuffer (unblocking) instructions but then we still 1060 // get full in the IQ. 1061 toRename->iewUnblock[tid] = false; 1062 1063 dispatchedAllInsts = false; 1064 1065 ++iewIQFullEvents; 1066 break; 1067 } else if (ldstQueue.isFull(tid)) { 1068 DPRINTF(IEW, "[tid:%i]: Issue: LSQ has become full.\n",tid); 1069 1070 // Call function to start blocking. 1071 block(tid); 1072 1073 // Set unblock to false. Special case where we are using 1074 // skidbuffer (unblocking) instructions but then we still 1075 // get full in the IQ. 1076 toRename->iewUnblock[tid] = false; 1077 1078 dispatchedAllInsts = false; 1079 1080 ++iewLSQFullEvents; 1081 break; 1082 } 1083 1084 // Otherwise issue the instruction just fine. 1085 if (inst->isLoad()) { 1086 DPRINTF(IEW, "[tid:%i]: Issue: Memory instruction " 1087 "encountered, adding to LSQ.\n", tid); 1088 1089 // Reserve a spot in the load store queue for this 1090 // memory access. 1091 ldstQueue.insertLoad(inst); 1092 1093 ++iewDispLoadInsts; 1094 1095 add_to_iq = true; 1096 1097 toRename->iewInfo[tid].dispatchedToLSQ++; 1098 } else if (inst->isStore()) { 1099 DPRINTF(IEW, "[tid:%i]: Issue: Memory instruction " 1100 "encountered, adding to LSQ.\n", tid); 1101 1102 ldstQueue.insertStore(inst); 1103 1104 ++iewDispStoreInsts; 1105 1106 if (inst->isStoreConditional()) { 1107 // Store conditionals need to be set as "canCommit()" 1108 // so that commit can process them when they reach the 1109 // head of commit. 1110 // @todo: This is somewhat specific to Alpha. 1111 inst->setCanCommit(); 1112 instQueue.insertNonSpec(inst); 1113 add_to_iq = false; 1114 1115 ++iewDispNonSpecInsts; 1116 } else { 1117 add_to_iq = true; 1118 } 1119 1120 toRename->iewInfo[tid].dispatchedToLSQ++; 1121#if FULL_SYSTEM 1122 } else if (inst->isMemBarrier() || inst->isWriteBarrier()) { 1123 // Same as non-speculative stores. 1124 inst->setCanCommit(); 1125 instQueue.insertBarrier(inst); 1126 add_to_iq = false; 1127#endif 1128 } else if (inst->isNonSpeculative()) { 1129 DPRINTF(IEW, "[tid:%i]: Issue: Nonspeculative instruction " 1130 "encountered, skipping.\n", tid); 1131 1132 // Same as non-speculative stores. 1133 inst->setCanCommit(); 1134 1135 // Specifically insert it as nonspeculative. 1136 instQueue.insertNonSpec(inst); 1137 1138 ++iewDispNonSpecInsts; 1139 1140 add_to_iq = false; 1141 } else if (inst->isNop()) { 1142 DPRINTF(IEW, "[tid:%i]: Issue: Nop instruction encountered, " 1143 "skipping.\n", tid); 1144 1145 inst->setIssued(); 1146 inst->setExecuted(); 1147 inst->setCanCommit(); 1148 1149 instQueue.recordProducer(inst); 1150 1151 iewExecutedNop[tid]++; 1152 1153 add_to_iq = false; 1154 } else if (inst->isExecuted()) { 1155 assert(0 && "Instruction shouldn't be executed.\n"); 1156 DPRINTF(IEW, "Issue: Executed branch encountered, " 1157 "skipping.\n"); 1158 1159 inst->setIssued(); 1160 inst->setCanCommit(); 1161 1162 instQueue.recordProducer(inst); 1163 1164 add_to_iq = false; 1165 } else { 1166 add_to_iq = true; 1167 } 1168 1169 // If the instruction queue is not full, then add the 1170 // instruction. 1171 if (add_to_iq) { 1172 instQueue.insert(inst); 1173 } 1174 1175 insts_to_dispatch.pop(); 1176 1177 toRename->iewInfo[tid].dispatched++; 1178 1179 ++iewDispatchedInsts; 1180 } 1181 1182 if (!insts_to_dispatch.empty()) { 1183 DPRINTF(IEW,"[tid:%i]: Issue: Bandwidth Full. Blocking.\n", tid); 1184 block(tid); 1185 toRename->iewUnblock[tid] = false; 1186 } 1187 1188 if (dispatchStatus[tid] == Idle && dis_num_inst) { 1189 dispatchStatus[tid] = Running; 1190 1191 updatedQueues = true; 1192 } 1193 1194 dis_num_inst = 0; 1195} 1196 1197template <class Impl> 1198void 1199DefaultIEW<Impl>::printAvailableInsts() 1200{ 1201 int inst = 0; 1202 1203 std::cout << "Available Instructions: "; 1204 1205 while (fromIssue->insts[inst]) { 1206 1207 if (inst%3==0) std::cout << "\n\t"; 1208 1209 std::cout << "PC: " << fromIssue->insts[inst]->readPC() 1210 << " TN: " << fromIssue->insts[inst]->threadNumber 1211 << " SN: " << fromIssue->insts[inst]->seqNum << " | "; 1212 1213 inst++; 1214 1215 } 1216 1217 std::cout << "\n"; 1218} 1219 1220template <class Impl> 1221void 1222DefaultIEW<Impl>::executeInsts() 1223{ 1224 wbNumInst = 0; 1225 wbCycle = 0; 1226 1227 std::list<unsigned>::iterator threads = (*activeThreads).begin(); 1228 1229 while (threads != (*activeThreads).end()) { 1230 unsigned tid = *threads++; 1231 fetchRedirect[tid] = false; 1232 } 1233 1234 // Uncomment this if you want to see all available instructions. 1235// printAvailableInsts(); 1236 1237 // Execute/writeback any instructions that are available. 1238 int insts_to_execute = fromIssue->size; 1239 int inst_num = 0; 1240 for (; inst_num < insts_to_execute; 1241 ++inst_num) { 1242 1243 DPRINTF(IEW, "Execute: Executing instructions from IQ.\n"); 1244 1245 DynInstPtr inst = instQueue.getInstToExecute(); 1246 1247 DPRINTF(IEW, "Execute: Processing PC %#x, [tid:%i] [sn:%i].\n", 1248 inst->readPC(), inst->threadNumber,inst->seqNum); 1249 1250 // Check if the instruction is squashed; if so then skip it 1251 if (inst->isSquashed()) { 1252 DPRINTF(IEW, "Execute: Instruction was squashed.\n"); 1253 1254 // Consider this instruction executed so that commit can go 1255 // ahead and retire the instruction. 1256 inst->setExecuted(); 1257 1258 // Not sure if I should set this here or just let commit try to 1259 // commit any squashed instructions. I like the latter a bit more. 1260 inst->setCanCommit(); 1261 1262 ++iewExecSquashedInsts; 1263 1264 decrWb(inst->seqNum); 1265 continue; 1266 } 1267 1268 Fault fault = NoFault; 1269 1270 // Execute instruction. 1271 // Note that if the instruction faults, it will be handled 1272 // at the commit stage. 1273 if (inst->isMemRef() && 1274 (!inst->isDataPrefetch() && !inst->isInstPrefetch())) { 1275 DPRINTF(IEW, "Execute: Calculating address for memory " 1276 "reference.\n"); 1277 1278 // Tell the LDSTQ to execute this instruction (if it is a load). 1279 if (inst->isLoad()) { 1280 // Loads will mark themselves as executed, and their writeback 1281 // event adds the instruction to the queue to commit 1282 fault = ldstQueue.executeLoad(inst); 1283 } else if (inst->isStore()) { 1284 fault = ldstQueue.executeStore(inst); 1285 1286 // If the store had a fault then it may not have a mem req 1287 if (!inst->isStoreConditional() && fault == NoFault) { 1288 inst->setExecuted(); 1289 1290 instToCommit(inst); 1291 } else if (fault != NoFault) { 1292 // If the instruction faulted, then we need to send it along to commit 1293 // without the instruction completing.
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| 1294 DPRINTF(IEW, "Store has fault! [sn:%lli]\n", inst->seqNum);
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1289 1290 // Send this instruction to commit, also make sure iew stage 1291 // realizes there is activity. 1292 inst->setExecuted(); 1293 1294 instToCommit(inst); 1295 activityThisCycle(); 1296 } 1297 1298 // Store conditionals will mark themselves as 1299 // executed, and their writeback event will add the 1300 // instruction to the queue to commit. 1301 } else { 1302 panic("Unexpected memory type!\n"); 1303 } 1304 1305 } else { 1306 inst->execute(); 1307 1308 inst->setExecuted(); 1309 1310 instToCommit(inst); 1311 } 1312 1313 updateExeInstStats(inst); 1314 1315 // Check if branch prediction was correct, if not then we need 1316 // to tell commit to squash in flight instructions. Only 1317 // handle this if there hasn't already been something that 1318 // redirects fetch in this group of instructions. 1319 1320 // This probably needs to prioritize the redirects if a different 1321 // scheduler is used. Currently the scheduler schedules the oldest 1322 // instruction first, so the branch resolution order will be correct. 1323 unsigned tid = inst->threadNumber; 1324 1325 if (!fetchRedirect[tid]) { 1326 1327 if (inst->mispredicted()) { 1328 fetchRedirect[tid] = true; 1329 1330 DPRINTF(IEW, "Execute: Branch mispredict detected.\n"); 1331#if ISA_HAS_DELAY_SLOT 1332 DPRINTF(IEW, "Execute: Redirecting fetch to PC: %#x.\n", 1333 inst->nextNPC); 1334#else 1335 DPRINTF(IEW, "Execute: Redirecting fetch to PC: %#x.\n", 1336 inst->nextPC); 1337#endif 1338 // If incorrect, then signal the ROB that it must be squashed. 1339 squashDueToBranch(inst, tid); 1340 1341 if (inst->predTaken()) { 1342 predictedTakenIncorrect++; 1343 } else { 1344 predictedNotTakenIncorrect++; 1345 } 1346 } else if (ldstQueue.violation(tid)) { 1347 fetchRedirect[tid] = true; 1348 1349 // If there was an ordering violation, then get the 1350 // DynInst that caused the violation. Note that this 1351 // clears the violation signal. 1352 DynInstPtr violator; 1353 violator = ldstQueue.getMemDepViolator(tid); 1354 1355 DPRINTF(IEW, "LDSTQ detected a violation. Violator PC: " 1356 "%#x, inst PC: %#x. Addr is: %#x.\n", 1357 violator->readPC(), inst->readPC(), inst->physEffAddr); 1358 1359 // Tell the instruction queue that a violation has occured. 1360 instQueue.violation(inst, violator); 1361 1362 // Squash. 1363 squashDueToMemOrder(inst,tid); 1364 1365 ++memOrderViolationEvents; 1366 } else if (ldstQueue.loadBlocked(tid) && 1367 !ldstQueue.isLoadBlockedHandled(tid)) { 1368 fetchRedirect[tid] = true; 1369 1370 DPRINTF(IEW, "Load operation couldn't execute because the " 1371 "memory system is blocked. PC: %#x [sn:%lli]\n", 1372 inst->readPC(), inst->seqNum); 1373 1374 squashDueToMemBlocked(inst, tid); 1375 } 1376 } 1377 } 1378 1379 // Update and record activity if we processed any instructions. 1380 if (inst_num) { 1381 if (exeStatus == Idle) { 1382 exeStatus = Running; 1383 } 1384 1385 updatedQueues = true; 1386 1387 cpu->activityThisCycle(); 1388 } 1389 1390 // Need to reset this in case a writeback event needs to write into the 1391 // iew queue. That way the writeback event will write into the correct 1392 // spot in the queue. 1393 wbNumInst = 0; 1394} 1395 1396template <class Impl> 1397void 1398DefaultIEW<Impl>::writebackInsts() 1399{ 1400 // Loop through the head of the time buffer and wake any 1401 // dependents. These instructions are about to write back. Also 1402 // mark scoreboard that this instruction is finally complete. 1403 // Either have IEW have direct access to scoreboard, or have this 1404 // as part of backwards communication. 1405 for (int inst_num = 0; inst_num < issueWidth && 1406 toCommit->insts[inst_num]; inst_num++) { 1407 DynInstPtr inst = toCommit->insts[inst_num]; 1408 int tid = inst->threadNumber; 1409 1410 DPRINTF(IEW, "Sending instructions to commit, [sn:%lli] PC %#x.\n", 1411 inst->seqNum, inst->readPC()); 1412 1413 iewInstsToCommit[tid]++; 1414 1415 // Some instructions will be sent to commit without having 1416 // executed because they need commit to handle them. 1417 // E.g. Uncached loads have not actually executed when they 1418 // are first sent to commit. Instead commit must tell the LSQ 1419 // when it's ready to execute the uncached load. 1420 if (!inst->isSquashed() && inst->isExecuted() && inst->getFault() == NoFault) { 1421 int dependents = instQueue.wakeDependents(inst); 1422 1423 for (int i = 0; i < inst->numDestRegs(); i++) { 1424 //mark as Ready 1425 DPRINTF(IEW,"Setting Destination Register %i\n", 1426 inst->renamedDestRegIdx(i)); 1427 scoreboard->setReg(inst->renamedDestRegIdx(i)); 1428 } 1429 1430 if (dependents) { 1431 producerInst[tid]++; 1432 consumerInst[tid]+= dependents; 1433 } 1434 writebackCount[tid]++; 1435 } 1436 1437 decrWb(inst->seqNum); 1438 } 1439} 1440 1441template<class Impl> 1442void 1443DefaultIEW<Impl>::tick() 1444{ 1445 wbNumInst = 0; 1446 wbCycle = 0; 1447 1448 wroteToTimeBuffer = false; 1449 updatedQueues = false; 1450 1451 sortInsts(); 1452 1453 // Free function units marked as being freed this cycle. 1454 fuPool->processFreeUnits(); 1455 1456 std::list<unsigned>::iterator threads = (*activeThreads).begin(); 1457 1458 // Check stall and squash signals, dispatch any instructions. 1459 while (threads != (*activeThreads).end()) { 1460 unsigned tid = *threads++; 1461 1462 DPRINTF(IEW,"Issue: Processing [tid:%i]\n",tid); 1463 1464 checkSignalsAndUpdate(tid); 1465 dispatch(tid); 1466 } 1467 1468 if (exeStatus != Squashing) { 1469 executeInsts(); 1470 1471 writebackInsts(); 1472 1473 // Have the instruction queue try to schedule any ready instructions. 1474 // (In actuality, this scheduling is for instructions that will 1475 // be executed next cycle.) 1476 instQueue.scheduleReadyInsts(); 1477 1478 // Also should advance its own time buffers if the stage ran. 1479 // Not the best place for it, but this works (hopefully). 1480 issueToExecQueue.advance(); 1481 } 1482 1483 bool broadcast_free_entries = false; 1484 1485 if (updatedQueues || exeStatus == Running || updateLSQNextCycle) { 1486 exeStatus = Idle; 1487 updateLSQNextCycle = false; 1488 1489 broadcast_free_entries = true; 1490 } 1491 1492 // Writeback any stores using any leftover bandwidth. 1493 ldstQueue.writebackStores(); 1494 1495 // Check the committed load/store signals to see if there's a load 1496 // or store to commit. Also check if it's being told to execute a 1497 // nonspeculative instruction. 1498 // This is pretty inefficient... 1499 1500 threads = (*activeThreads).begin(); 1501 while (threads != (*activeThreads).end()) { 1502 unsigned tid = (*threads++); 1503 1504 DPRINTF(IEW,"Processing [tid:%i]\n",tid); 1505 1506 // Update structures based on instructions committed. 1507 if (fromCommit->commitInfo[tid].doneSeqNum != 0 && 1508 !fromCommit->commitInfo[tid].squash && 1509 !fromCommit->commitInfo[tid].robSquashing) { 1510 1511 ldstQueue.commitStores(fromCommit->commitInfo[tid].doneSeqNum,tid); 1512 1513 ldstQueue.commitLoads(fromCommit->commitInfo[tid].doneSeqNum,tid); 1514 1515 updateLSQNextCycle = true; 1516 instQueue.commit(fromCommit->commitInfo[tid].doneSeqNum,tid); 1517 } 1518 1519 if (fromCommit->commitInfo[tid].nonSpecSeqNum != 0) { 1520 1521 //DPRINTF(IEW,"NonspecInst from thread %i",tid); 1522 if (fromCommit->commitInfo[tid].uncached) { 1523 instQueue.replayMemInst(fromCommit->commitInfo[tid].uncachedLoad); 1524 } else { 1525 instQueue.scheduleNonSpec( 1526 fromCommit->commitInfo[tid].nonSpecSeqNum); 1527 } 1528 } 1529 1530 if (broadcast_free_entries) { 1531 toFetch->iewInfo[tid].iqCount = 1532 instQueue.getCount(tid); 1533 toFetch->iewInfo[tid].ldstqCount = 1534 ldstQueue.getCount(tid); 1535 1536 toRename->iewInfo[tid].usedIQ = true; 1537 toRename->iewInfo[tid].freeIQEntries = 1538 instQueue.numFreeEntries(); 1539 toRename->iewInfo[tid].usedLSQ = true; 1540 toRename->iewInfo[tid].freeLSQEntries = 1541 ldstQueue.numFreeEntries(tid); 1542 1543 wroteToTimeBuffer = true; 1544 } 1545 1546 DPRINTF(IEW, "[tid:%i], Dispatch dispatched %i instructions.\n", 1547 tid, toRename->iewInfo[tid].dispatched); 1548 } 1549 1550 DPRINTF(IEW, "IQ has %i free entries (Can schedule: %i). " 1551 "LSQ has %i free entries.\n", 1552 instQueue.numFreeEntries(), instQueue.hasReadyInsts(), 1553 ldstQueue.numFreeEntries()); 1554 1555 updateStatus(); 1556 1557 if (wroteToTimeBuffer) { 1558 DPRINTF(Activity, "Activity this cycle.\n"); 1559 cpu->activityThisCycle(); 1560 } 1561} 1562 1563template <class Impl> 1564void 1565DefaultIEW<Impl>::updateExeInstStats(DynInstPtr &inst) 1566{ 1567 int thread_number = inst->threadNumber; 1568 1569 // 1570 // Pick off the software prefetches 1571 // 1572#ifdef TARGET_ALPHA 1573 if (inst->isDataPrefetch()) 1574 iewExecutedSwp[thread_number]++; 1575 else 1576 iewIewExecutedcutedInsts++; 1577#else 1578 iewExecutedInsts++; 1579#endif 1580 1581 // 1582 // Control operations 1583 // 1584 if (inst->isControl()) 1585 iewExecutedBranches[thread_number]++; 1586 1587 // 1588 // Memory operations 1589 // 1590 if (inst->isMemRef()) { 1591 iewExecutedRefs[thread_number]++; 1592 1593 if (inst->isLoad()) { 1594 iewExecLoadInsts[thread_number]++; 1595 } 1596 } 1597}
| 1295 1296 // Send this instruction to commit, also make sure iew stage 1297 // realizes there is activity. 1298 inst->setExecuted(); 1299 1300 instToCommit(inst); 1301 activityThisCycle(); 1302 } 1303 1304 // Store conditionals will mark themselves as 1305 // executed, and their writeback event will add the 1306 // instruction to the queue to commit. 1307 } else { 1308 panic("Unexpected memory type!\n"); 1309 } 1310 1311 } else { 1312 inst->execute(); 1313 1314 inst->setExecuted(); 1315 1316 instToCommit(inst); 1317 } 1318 1319 updateExeInstStats(inst); 1320 1321 // Check if branch prediction was correct, if not then we need 1322 // to tell commit to squash in flight instructions. Only 1323 // handle this if there hasn't already been something that 1324 // redirects fetch in this group of instructions. 1325 1326 // This probably needs to prioritize the redirects if a different 1327 // scheduler is used. Currently the scheduler schedules the oldest 1328 // instruction first, so the branch resolution order will be correct. 1329 unsigned tid = inst->threadNumber; 1330 1331 if (!fetchRedirect[tid]) { 1332 1333 if (inst->mispredicted()) { 1334 fetchRedirect[tid] = true; 1335 1336 DPRINTF(IEW, "Execute: Branch mispredict detected.\n"); 1337#if ISA_HAS_DELAY_SLOT 1338 DPRINTF(IEW, "Execute: Redirecting fetch to PC: %#x.\n", 1339 inst->nextNPC); 1340#else 1341 DPRINTF(IEW, "Execute: Redirecting fetch to PC: %#x.\n", 1342 inst->nextPC); 1343#endif 1344 // If incorrect, then signal the ROB that it must be squashed. 1345 squashDueToBranch(inst, tid); 1346 1347 if (inst->predTaken()) { 1348 predictedTakenIncorrect++; 1349 } else { 1350 predictedNotTakenIncorrect++; 1351 } 1352 } else if (ldstQueue.violation(tid)) { 1353 fetchRedirect[tid] = true; 1354 1355 // If there was an ordering violation, then get the 1356 // DynInst that caused the violation. Note that this 1357 // clears the violation signal. 1358 DynInstPtr violator; 1359 violator = ldstQueue.getMemDepViolator(tid); 1360 1361 DPRINTF(IEW, "LDSTQ detected a violation. Violator PC: " 1362 "%#x, inst PC: %#x. Addr is: %#x.\n", 1363 violator->readPC(), inst->readPC(), inst->physEffAddr); 1364 1365 // Tell the instruction queue that a violation has occured. 1366 instQueue.violation(inst, violator); 1367 1368 // Squash. 1369 squashDueToMemOrder(inst,tid); 1370 1371 ++memOrderViolationEvents; 1372 } else if (ldstQueue.loadBlocked(tid) && 1373 !ldstQueue.isLoadBlockedHandled(tid)) { 1374 fetchRedirect[tid] = true; 1375 1376 DPRINTF(IEW, "Load operation couldn't execute because the " 1377 "memory system is blocked. PC: %#x [sn:%lli]\n", 1378 inst->readPC(), inst->seqNum); 1379 1380 squashDueToMemBlocked(inst, tid); 1381 } 1382 } 1383 } 1384 1385 // Update and record activity if we processed any instructions. 1386 if (inst_num) { 1387 if (exeStatus == Idle) { 1388 exeStatus = Running; 1389 } 1390 1391 updatedQueues = true; 1392 1393 cpu->activityThisCycle(); 1394 } 1395 1396 // Need to reset this in case a writeback event needs to write into the 1397 // iew queue. That way the writeback event will write into the correct 1398 // spot in the queue. 1399 wbNumInst = 0; 1400} 1401 1402template <class Impl> 1403void 1404DefaultIEW<Impl>::writebackInsts() 1405{ 1406 // Loop through the head of the time buffer and wake any 1407 // dependents. These instructions are about to write back. Also 1408 // mark scoreboard that this instruction is finally complete. 1409 // Either have IEW have direct access to scoreboard, or have this 1410 // as part of backwards communication. 1411 for (int inst_num = 0; inst_num < issueWidth && 1412 toCommit->insts[inst_num]; inst_num++) { 1413 DynInstPtr inst = toCommit->insts[inst_num]; 1414 int tid = inst->threadNumber; 1415 1416 DPRINTF(IEW, "Sending instructions to commit, [sn:%lli] PC %#x.\n", 1417 inst->seqNum, inst->readPC()); 1418 1419 iewInstsToCommit[tid]++; 1420 1421 // Some instructions will be sent to commit without having 1422 // executed because they need commit to handle them. 1423 // E.g. Uncached loads have not actually executed when they 1424 // are first sent to commit. Instead commit must tell the LSQ 1425 // when it's ready to execute the uncached load. 1426 if (!inst->isSquashed() && inst->isExecuted() && inst->getFault() == NoFault) { 1427 int dependents = instQueue.wakeDependents(inst); 1428 1429 for (int i = 0; i < inst->numDestRegs(); i++) { 1430 //mark as Ready 1431 DPRINTF(IEW,"Setting Destination Register %i\n", 1432 inst->renamedDestRegIdx(i)); 1433 scoreboard->setReg(inst->renamedDestRegIdx(i)); 1434 } 1435 1436 if (dependents) { 1437 producerInst[tid]++; 1438 consumerInst[tid]+= dependents; 1439 } 1440 writebackCount[tid]++; 1441 } 1442 1443 decrWb(inst->seqNum); 1444 } 1445} 1446 1447template<class Impl> 1448void 1449DefaultIEW<Impl>::tick() 1450{ 1451 wbNumInst = 0; 1452 wbCycle = 0; 1453 1454 wroteToTimeBuffer = false; 1455 updatedQueues = false; 1456 1457 sortInsts(); 1458 1459 // Free function units marked as being freed this cycle. 1460 fuPool->processFreeUnits(); 1461 1462 std::list<unsigned>::iterator threads = (*activeThreads).begin(); 1463 1464 // Check stall and squash signals, dispatch any instructions. 1465 while (threads != (*activeThreads).end()) { 1466 unsigned tid = *threads++; 1467 1468 DPRINTF(IEW,"Issue: Processing [tid:%i]\n",tid); 1469 1470 checkSignalsAndUpdate(tid); 1471 dispatch(tid); 1472 } 1473 1474 if (exeStatus != Squashing) { 1475 executeInsts(); 1476 1477 writebackInsts(); 1478 1479 // Have the instruction queue try to schedule any ready instructions. 1480 // (In actuality, this scheduling is for instructions that will 1481 // be executed next cycle.) 1482 instQueue.scheduleReadyInsts(); 1483 1484 // Also should advance its own time buffers if the stage ran. 1485 // Not the best place for it, but this works (hopefully). 1486 issueToExecQueue.advance(); 1487 } 1488 1489 bool broadcast_free_entries = false; 1490 1491 if (updatedQueues || exeStatus == Running || updateLSQNextCycle) { 1492 exeStatus = Idle; 1493 updateLSQNextCycle = false; 1494 1495 broadcast_free_entries = true; 1496 } 1497 1498 // Writeback any stores using any leftover bandwidth. 1499 ldstQueue.writebackStores(); 1500 1501 // Check the committed load/store signals to see if there's a load 1502 // or store to commit. Also check if it's being told to execute a 1503 // nonspeculative instruction. 1504 // This is pretty inefficient... 1505 1506 threads = (*activeThreads).begin(); 1507 while (threads != (*activeThreads).end()) { 1508 unsigned tid = (*threads++); 1509 1510 DPRINTF(IEW,"Processing [tid:%i]\n",tid); 1511 1512 // Update structures based on instructions committed. 1513 if (fromCommit->commitInfo[tid].doneSeqNum != 0 && 1514 !fromCommit->commitInfo[tid].squash && 1515 !fromCommit->commitInfo[tid].robSquashing) { 1516 1517 ldstQueue.commitStores(fromCommit->commitInfo[tid].doneSeqNum,tid); 1518 1519 ldstQueue.commitLoads(fromCommit->commitInfo[tid].doneSeqNum,tid); 1520 1521 updateLSQNextCycle = true; 1522 instQueue.commit(fromCommit->commitInfo[tid].doneSeqNum,tid); 1523 } 1524 1525 if (fromCommit->commitInfo[tid].nonSpecSeqNum != 0) { 1526 1527 //DPRINTF(IEW,"NonspecInst from thread %i",tid); 1528 if (fromCommit->commitInfo[tid].uncached) { 1529 instQueue.replayMemInst(fromCommit->commitInfo[tid].uncachedLoad); 1530 } else { 1531 instQueue.scheduleNonSpec( 1532 fromCommit->commitInfo[tid].nonSpecSeqNum); 1533 } 1534 } 1535 1536 if (broadcast_free_entries) { 1537 toFetch->iewInfo[tid].iqCount = 1538 instQueue.getCount(tid); 1539 toFetch->iewInfo[tid].ldstqCount = 1540 ldstQueue.getCount(tid); 1541 1542 toRename->iewInfo[tid].usedIQ = true; 1543 toRename->iewInfo[tid].freeIQEntries = 1544 instQueue.numFreeEntries(); 1545 toRename->iewInfo[tid].usedLSQ = true; 1546 toRename->iewInfo[tid].freeLSQEntries = 1547 ldstQueue.numFreeEntries(tid); 1548 1549 wroteToTimeBuffer = true; 1550 } 1551 1552 DPRINTF(IEW, "[tid:%i], Dispatch dispatched %i instructions.\n", 1553 tid, toRename->iewInfo[tid].dispatched); 1554 } 1555 1556 DPRINTF(IEW, "IQ has %i free entries (Can schedule: %i). " 1557 "LSQ has %i free entries.\n", 1558 instQueue.numFreeEntries(), instQueue.hasReadyInsts(), 1559 ldstQueue.numFreeEntries()); 1560 1561 updateStatus(); 1562 1563 if (wroteToTimeBuffer) { 1564 DPRINTF(Activity, "Activity this cycle.\n"); 1565 cpu->activityThisCycle(); 1566 } 1567} 1568 1569template <class Impl> 1570void 1571DefaultIEW<Impl>::updateExeInstStats(DynInstPtr &inst) 1572{ 1573 int thread_number = inst->threadNumber; 1574 1575 // 1576 // Pick off the software prefetches 1577 // 1578#ifdef TARGET_ALPHA 1579 if (inst->isDataPrefetch()) 1580 iewExecutedSwp[thread_number]++; 1581 else 1582 iewIewExecutedcutedInsts++; 1583#else 1584 iewExecutedInsts++; 1585#endif 1586 1587 // 1588 // Control operations 1589 // 1590 if (inst->isControl()) 1591 iewExecutedBranches[thread_number]++; 1592 1593 // 1594 // Memory operations 1595 // 1596 if (inst->isMemRef()) { 1597 iewExecutedRefs[thread_number]++; 1598 1599 if (inst->isLoad()) { 1600 iewExecLoadInsts[thread_number]++; 1601 } 1602 } 1603}
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