src/cpu/ozone/inorder_back_end_impl.hh - testing/jenkins-gem5-prod - Git at Google

 /*
  * Copyright (c) 2006 The Regents of The University of Michigan
  * All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions are
  * met: redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer;
  * redistributions in binary form must reproduce the above copyright
  * notice, this list of conditions and the following disclaimer in the
  * documentation and/or other materials provided with the distribution;
  * neither the name of the copyright holders nor the names of its
  * contributors may be used to endorse or promote products derived from
  * this software without specific prior written permission.
  *
  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
  * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
  * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
  * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
  * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
  * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
  * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  *
  * Authors: Kevin Lim
  */

 #include "arch/types.hh"
 #include "config/the_isa.hh"
 #include "cpu/ozone/inorder_back_end.hh"
 #include "cpu/ozone/thread_state.hh"
 #include "sim/faults.hh"

 template <class Impl>
 InorderBackEnd<Impl>::InorderBackEnd(Params *params)
     : squashPending(false),
       squashSeqNum(0),
       squashNextPC(0),
       faultFromFetch(NoFault),
       interruptBlocked(false),
       cacheCompletionEvent(this),
       dcacheInterface(params->dcacheInterface),
       width(params->backEndWidth),
       latency(params->backEndLatency),
       squashLatency(params->backEndSquashLatency),
       numInstsToWB(0, latency + 1)
 {
     instsAdded = numInstsToWB.getWire(latency);
     instsToExecute = numInstsToWB.getWire(0);

     memReq = new MemReq;
     memReq->data = new uint8_t[64];
     status = Running;
 }

 template <class Impl>
 std::string
 InorderBackEnd<Impl>::name() const
 {
     return cpu->name() + ".inorderbackend";
 }

 template <class Impl>
 void
 InorderBackEnd<Impl>::setXC(ExecContext *xc_ptr)
 {
     xc = xc_ptr;
     memReq->xc = xc;
 }

 template <class Impl>
 void
 InorderBackEnd<Impl>::setThreadState(OzoneThreadState<Impl> *thread_ptr)
 {
     thread = thread_ptr;
     thread->setFuncExeInst(0);
 }

 #if FULL_SYSTEM
 template <class Impl>
 void
 InorderBackEnd<Impl>::checkInterrupts()
 {
     //Check if there are any outstanding interrupts
     //Handle the interrupts
     int ipl = 0;
     int summary = 0;


     if (thread->readMiscRegNoEffect(IPR_ASTRR))
         panic("asynchronous traps not implemented\n");

     if (thread->readMiscRegNoEffect(IPR_SIRR)) {
         for (int i = INTLEVEL_SOFTWARE_MIN;
              i < INTLEVEL_SOFTWARE_MAX; i++) {
             if (thread->readMiscRegNoEffect(IPR_SIRR) & (ULL(1) << i)) {
                 // See table 4-19 of the 21164 hardware reference
                 ipl = (i - INTLEVEL_SOFTWARE_MIN) + 1;
                 summary |= (ULL(1) << i);
             }
         }
     }

     uint64_t interrupts = cpu->intr_status();

     if (interrupts) {
         for (int i = INTLEVEL_EXTERNAL_MIN;
              i < INTLEVEL_EXTERNAL_MAX; i++) {
             if (interrupts & (ULL(1) << i)) {
                 // See table 4-19 of the 21164 hardware reference
                 ipl = i;
                 summary |= (ULL(1) << i);
             }
         }
     }

     if (ipl && ipl > thread->readMiscRegNoEffect(IPR_IPLR)) {
         thread->inSyscall = true;

         thread->setMiscRegNoEffect(IPR_ISR, summary);
         thread->setMiscRegNoEffect(IPR_INTID, ipl);
         Fault(new InterruptFault)->invoke(xc);
         DPRINTF(Flow, "Interrupt! IPLR=%d ipl=%d summary=%x\n",
                 thread->readMiscRegNoEffect(IPR_IPLR), ipl, summary);

         // May need to go 1 inst prior
         squashPending = true;

         thread->inSyscall = false;

         setSquashInfoFromXC();
     }
 }
 #endif

 template <class Impl>
 void
 InorderBackEnd<Impl>::tick()
 {
     // Squash due to an external source
     // Not sure if this or an interrupt has higher priority
     if (squashPending) {
         squash(squashSeqNum, squashNextPC);
         return;
     }

     // if (interrupt) then set thread PC, stall front end, record that
     // I'm waiting for it to drain.  (for now just squash)
 #if FULL_SYSTEM
     if (interruptBlocked || cpu->checkInterrupts(tc)) {
         if (!robEmpty()) {
             interruptBlocked = true;
         //AlphaDep
         } else if (robEmpty() && (PC & 0x3)) {
             // Will need to let the front end continue a bit until
             // we're out of pal mode.  Hopefully we never get into an
             // infinite loop...
             interruptBlocked = false;
         } else {
             interruptBlocked = false;
             checkInterrupts();
             return;
         }
     }
 #endif

     if (status != DcacheMissLoadStall &&
         status != DcacheMissStoreStall) {
         for (int i = 0; i < width && (*instsAdded) < width; ++i) {
             DynInstPtr inst = frontEnd->getInst();

             if (!inst)
                 break;

             instList.push_back(inst);

             (*instsAdded)++;
         }

 #if FULL_SYSTEM
         if (faultFromFetch && robEmpty() && frontEnd->isEmpty()) {
             handleFault();
         } else {
             executeInsts();
         }
 #else
         executeInsts();
 #endif
     }
 }

 template <class Impl>
 void
 InorderBackEnd<Impl>::executeInsts()
 {
     bool completed_last_inst = true;
     int insts_to_execute = *instsToExecute;
     int freed_regs = 0;

     while (insts_to_execute > 0) {
         assert(!instList.empty());
         DynInstPtr inst = instList.front();

         commitPC = inst->readPC();

         thread->setPC(commitPC);
         thread->setNextPC(inst->readNextPC());

 #if FULL_SYSTEM
         int count = 0;
         Addr oldpc;
         do {
             if (count == 0)
                 assert(!thread->inSyscall && !thread->trapPending);
             oldpc = thread->readPC();
             cpu->system->pcEventQueue.service(
                 thread->getXCProxy());
             count++;
         } while (oldpc != thread->readPC());
         if (count > 1) {
             DPRINTF(IBE, "PC skip function event, stopping commit\n");
             completed_last_inst = false;
             squashPending = true;
             break;
         }
 #endif

         Fault inst_fault = NoFault;

         if (status == DcacheMissComplete) {
             DPRINTF(IBE, "Completing inst [sn:%lli]\n", inst->seqNum);
             status = Running;
         } else if (inst->isMemRef() && status != DcacheMissComplete &&
             (!inst->isDataPrefetch() && !inst->isInstPrefetch())) {
             DPRINTF(IBE, "Initiating mem op inst [sn:%lli] PC: %#x\n",
                     inst->seqNum, inst->readPC());

             cacheCompletionEvent.inst = inst;
             inst_fault = inst->initiateAcc();
             if (inst_fault == NoFault &&
                 status != DcacheMissLoadStall &&
                 status != DcacheMissStoreStall) {
                 inst_fault = inst->completeAcc();
             }
             ++thread->funcExeInst;
         } else {
             DPRINTF(IBE, "Executing inst [sn:%lli] PC: %#x\n",
                     inst->seqNum, inst->readPC());
             inst_fault = inst->execute();
             ++thread->funcExeInst;
         }

         // Will need to be able to break this loop in case the load
         // misses.  Split access/complete ops would be useful here
         // with writeback events.
         if (status == DcacheMissLoadStall) {
             *instsToExecute = insts_to_execute;

             completed_last_inst = false;
             break;
         } else if (status == DcacheMissStoreStall) {
             // Figure out how to fix this hack.  Probably have DcacheMissLoad
             // vs DcacheMissStore.
             *instsToExecute = insts_to_execute;
             completed_last_inst = false;
 /*
             instList.pop_front();
             --insts_to_execute;
             if (inst->traceData) {
                 inst->traceData->finalize();
             }
 */

             // Don't really need to stop for a store stall as long as
             // the memory system is able to handle store forwarding
             // and such.  Breaking out might help avoid the cache
             // interface becoming blocked.
             break;
         }

         inst->setExecuted();
         inst->setResultReady();
         inst->setCanCommit();

         instList.pop_front();

         --insts_to_execute;
         --(*instsToExecute);

         if (inst->traceData) {
             inst->traceData->finalize();
             inst->traceData = NULL;
         }

         if (inst_fault != NoFault) {
 #if FULL_SYSTEM
             DPRINTF(IBE, "Inst [sn:%lli] PC %#x has a fault\n",
                     inst->seqNum, inst->readPC());

             assert(!thread->inSyscall);

             thread->inSyscall = true;

             // Consider holding onto the trap and waiting until the trap event
             // happens for this to be executed.
             inst_fault->invoke(xc);

             // Exit state update mode to avoid accidental updating.
             thread->inSyscall = false;

             squashPending = true;

             // Generate trap squash event.
 //            generateTrapEvent(tid);
             completed_last_inst = false;
             break;
 #else // !FULL_SYSTEM
             panic("fault (%d) detected @ PC %08p", inst_fault,
                   inst->PC);
 #endif // FULL_SYSTEM
         }

         for (int i = 0; i < inst->numDestRegs(); ++i) {
             renameTable[inst->destRegIdx(i)] = inst;
             thread->renameTable[inst->destRegIdx(i)] = inst;
             ++freed_regs;
         }

         inst->clearDependents();

         comm->access(0)->doneSeqNum = inst->seqNum;

         if (inst->mispredicted()) {
             squash(inst->seqNum, inst->readNextPC());

             thread->setNextPC(inst->readNextPC());

             break;
         } else if (squashPending) {
             // Something external happened that caused the CPU to squash.
             // Break out of commit and handle the squash next cycle.
             break;
         }
         // If it didn't mispredict, then it executed fine.  Send back its
         // registers and BP info?  What about insts that may still have
         // latency, like loads?  Probably can send back the information after
         // it is completed.

         // keep an instruction count
         cpu->numInst++;
         thread->numInsts++;
     }

     frontEnd->addFreeRegs(freed_regs);

     assert(insts_to_execute >= 0);

     // Should only advance this if I have executed all instructions.
     if (insts_to_execute == 0) {
         numInstsToWB.advance();
     }

     // Should I set the PC to the next PC here?  What do I set next PC to?
     if (completed_last_inst) {
         thread->setPC(thread->readNextPC());
         thread->setNextPC(thread->readPC() + sizeof(MachInst));
     }

     if (squashPending) {
         setSquashInfoFromXC();
     }
 }

 template <class Impl>
 void
 InorderBackEnd<Impl>::handleFault()
 {
     DPRINTF(Commit, "Handling fault from fetch\n");

     assert(!thread->inSyscall);

     thread->inSyscall = true;

     // Consider holding onto the trap and waiting until the trap event
     // happens for this to be executed.
     faultFromFetch->invoke(xc);

     // Exit state update mode to avoid accidental updating.
     thread->inSyscall = false;

     squashPending = true;

     setSquashInfoFromXC();
 }

 template <class Impl>
 void
 InorderBackEnd<Impl>::squash(const InstSeqNum &squash_num, const Addr &next_PC)
 {
     DPRINTF(IBE, "Squashing from [sn:%lli], setting PC to %#x\n",
             squash_num, next_PC);

     InstListIt squash_it = --(instList.end());

     int freed_regs = 0;

     while (!instList.empty() && (*squash_it)->seqNum > squash_num) {
         DynInstPtr inst = *squash_it;

         DPRINTF(IBE, "Squashing instruction PC %#x, [sn:%lli].\n",
                 inst->readPC(),
                 inst->seqNum);

         // May cause problems with misc regs
         freed_regs+= inst->numDestRegs();
         inst->clearDependents();
         squash_it--;
         instList.pop_back();
     }

     frontEnd->addFreeRegs(freed_regs);

     for (int i = 0; i < latency+1; ++i) {
         numInstsToWB.advance();
     }

     squashPending = false;

     // Probably want to make sure that this squash is the one that set the
     // thread into inSyscall mode.
     thread->inSyscall = false;

     // Tell front end to squash, reset PC to new one.
     frontEnd->squash(squash_num, next_PC);

     faultFromFetch = NULL;
 }

 template <class Impl>
 void
 InorderBackEnd<Impl>::squashFromXC()
 {
     // Record that I need to squash
     squashPending = true;

     thread->inSyscall = true;
 }

 template <class Impl>
 void
 InorderBackEnd<Impl>::setSquashInfoFromXC()
 {
     // Need to handle the case of the instList being empty.  In that case
     // probably any number works, except maybe with stores in the store buffer.
     squashSeqNum = instList.empty() ? 0 : instList.front()->seqNum - 1;

     squashNextPC = thread->PC;
 }

 template <class Impl>
 void
 InorderBackEnd<Impl>::fetchFault(Fault &fault)
 {
     faultFromFetch = fault;
 }

 template <class Impl>
 void
 InorderBackEnd<Impl>::dumpInsts()
 {
     int num = 0;
     int valid_num = 0;

     InstListIt inst_list_it = instList.begin();

     cprintf("Inst list size: %i\n", instList.size());

     while (inst_list_it != instList.end())
     {
         cprintf("Instruction:%i\n",
                 num);
         if (!(*inst_list_it)->isSquashed()) {
             if (!(*inst_list_it)->isIssued()) {
                 ++valid_num;
                 cprintf("Count:%i\n", valid_num);
             } else if ((*inst_list_it)->isMemRef() &&
                        !(*inst_list_it)->memOpDone) {
                 // Loads that have not been marked as executed still count
                 // towards the total instructions.
                 ++valid_num;
                 cprintf("Count:%i\n", valid_num);
             }
         }

         cprintf("PC:%#x\n[sn:%lli]\n[tid:%i]\n"
                 "Issued:%i\nSquashed:%i\n",
                 (*inst_list_it)->readPC(),
                 (*inst_list_it)->seqNum,
                 (*inst_list_it)->threadNumber,
                 (*inst_list_it)->isIssued(),
                 (*inst_list_it)->isSquashed());

         if ((*inst_list_it)->isMemRef()) {
             cprintf("MemOpDone:%i\n", (*inst_list_it)->memOpDone);
         }

         cprintf("\n");

         inst_list_it++;
         ++num;
     }
 }

 template <class Impl>
 InorderBackEnd<Impl>::DCacheCompletionEvent::DCacheCompletionEvent(
     InorderBackEnd *_be)
     : Event(&mainEventQueue, CPU_Tick_Pri), be(_be)
 {
 //    this->setFlags(Event::AutoDelete);
 }

 template <class Impl>
 void
 InorderBackEnd<Impl>::DCacheCompletionEvent::process()
 {
     inst->completeAcc();
     be->status = DcacheMissComplete;
 }

 template <class Impl>
 const char *
 InorderBackEnd<Impl>::DCacheCompletionEvent::description() const
 {
     return "DCache completion";
 }
	/*
	* Copyright (c) 2006 The Regents of The University of Michigan
	* All rights reserved.
	*
	* Redistribution and use in source and binary forms, with or without
	* modification, are permitted provided that the following conditions are
	* met: redistributions of source code must retain the above copyright
	* notice, this list of conditions and the following disclaimer;
	* redistributions in binary form must reproduce the above copyright
	* notice, this list of conditions and the following disclaimer in the
	* documentation and/or other materials provided with the distribution;
	* neither the name of the copyright holders nor the names of its
	* contributors may be used to endorse or promote products derived from
	* this software without specific prior written permission.
	*
	* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
	* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
	* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
	* A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
	* OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
	* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
	* LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
	* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
	* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
	* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
	* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
	*
	* Authors: Kevin Lim
	*/

	#include "arch/types.hh"
	#include "config/the_isa.hh"
	#include "cpu/ozone/inorder_back_end.hh"
	#include "cpu/ozone/thread_state.hh"
	#include "sim/faults.hh"

	template <class Impl>
	InorderBackEnd<Impl>::InorderBackEnd(Params *params)
	: squashPending(false),
	squashSeqNum(0),
	squashNextPC(0),
	faultFromFetch(NoFault),
	interruptBlocked(false),
	cacheCompletionEvent(this),
	dcacheInterface(params->dcacheInterface),
	width(params->backEndWidth),
	latency(params->backEndLatency),
	squashLatency(params->backEndSquashLatency),
	numInstsToWB(0, latency + 1)
	{
	instsAdded = numInstsToWB.getWire(latency);
	instsToExecute = numInstsToWB.getWire(0);

	memReq = new MemReq;
	memReq->data = new uint8_t[64];
	status = Running;
	}

	template <class Impl>
	std::string
	InorderBackEnd<Impl>::name() const
	{
	return cpu->name() + ".inorderbackend";
	}

	template <class Impl>
	void
	InorderBackEnd<Impl>::setXC(ExecContext *xc_ptr)
	{
	xc = xc_ptr;
	memReq->xc = xc;
	}

	template <class Impl>
	void
	InorderBackEnd<Impl>::setThreadState(OzoneThreadState<Impl> *thread_ptr)
	{
	thread = thread_ptr;
	thread->setFuncExeInst(0);
	}

	#if FULL_SYSTEM
	template <class Impl>
	void
	InorderBackEnd<Impl>::checkInterrupts()
	{
	//Check if there are any outstanding interrupts
	//Handle the interrupts
	int ipl = 0;
	int summary = 0;


	if (thread->readMiscRegNoEffect(IPR_ASTRR))
	panic("asynchronous traps not implemented\n");

	if (thread->readMiscRegNoEffect(IPR_SIRR)) {
	for (int i = INTLEVEL_SOFTWARE_MIN;
	i < INTLEVEL_SOFTWARE_MAX; i++) {
	if (thread->readMiscRegNoEffect(IPR_SIRR) & (ULL(1) << i)) {
	// See table 4-19 of the 21164 hardware reference
	ipl = (i - INTLEVEL_SOFTWARE_MIN) + 1;
	summary \|= (ULL(1) << i);
	}
	}
	}

	uint64_t interrupts = cpu->intr_status();

	if (interrupts) {
	for (int i = INTLEVEL_EXTERNAL_MIN;
	i < INTLEVEL_EXTERNAL_MAX; i++) {
	if (interrupts & (ULL(1) << i)) {
	// See table 4-19 of the 21164 hardware reference
	ipl = i;
	summary \|= (ULL(1) << i);
	}
	}
	}

	if (ipl && ipl > thread->readMiscRegNoEffect(IPR_IPLR)) {
	thread->inSyscall = true;

	thread->setMiscRegNoEffect(IPR_ISR, summary);
	thread->setMiscRegNoEffect(IPR_INTID, ipl);
	Fault(new InterruptFault)->invoke(xc);
	DPRINTF(Flow, "Interrupt! IPLR=%d ipl=%d summary=%x\n",
	thread->readMiscRegNoEffect(IPR_IPLR), ipl, summary);

	// May need to go 1 inst prior
	squashPending = true;

	thread->inSyscall = false;

	setSquashInfoFromXC();
	}
	}
	#endif

	template <class Impl>
	void
	InorderBackEnd<Impl>::tick()
	{
	// Squash due to an external source
	// Not sure if this or an interrupt has higher priority
	if (squashPending) {
	squash(squashSeqNum, squashNextPC);
	return;
	}

	// if (interrupt) then set thread PC, stall front end, record that
	// I'm waiting for it to drain. (for now just squash)
	#if FULL_SYSTEM
	if (interruptBlocked \|\| cpu->checkInterrupts(tc)) {
	if (!robEmpty()) {
	interruptBlocked = true;
	//AlphaDep
	} else if (robEmpty() && (PC & 0x3)) {
	// Will need to let the front end continue a bit until
	// we're out of pal mode. Hopefully we never get into an
	// infinite loop...
	interruptBlocked = false;
	} else {
	interruptBlocked = false;
	checkInterrupts();
	return;
	}
	}
	#endif

	if (status != DcacheMissLoadStall &&
	status != DcacheMissStoreStall) {
	for (int i = 0; i < width && (*instsAdded) < width; ++i) {
	DynInstPtr inst = frontEnd->getInst();

	if (!inst)
	break;

	instList.push_back(inst);

	(*instsAdded)++;
	}

	#if FULL_SYSTEM
	if (faultFromFetch && robEmpty() && frontEnd->isEmpty()) {
	handleFault();
	} else {
	executeInsts();
	}
	#else
	executeInsts();
	#endif
	}
	}

	template <class Impl>
	void
	InorderBackEnd<Impl>::executeInsts()
	{
	bool completed_last_inst = true;
	int insts_to_execute = *instsToExecute;
	int freed_regs = 0;

	while (insts_to_execute > 0) {
	assert(!instList.empty());
	DynInstPtr inst = instList.front();

	commitPC = inst->readPC();

	thread->setPC(commitPC);
	thread->setNextPC(inst->readNextPC());

	#if FULL_SYSTEM
	int count = 0;
	Addr oldpc;
	do {
	if (count == 0)
	assert(!thread->inSyscall && !thread->trapPending);
	oldpc = thread->readPC();
	cpu->system->pcEventQueue.service(
	thread->getXCProxy());
	count++;
	} while (oldpc != thread->readPC());
	if (count > 1) {
	DPRINTF(IBE, "PC skip function event, stopping commit\n");
	completed_last_inst = false;
	squashPending = true;
	break;
	}
	#endif

	Fault inst_fault = NoFault;

	if (status == DcacheMissComplete) {
	DPRINTF(IBE, "Completing inst [sn:%lli]\n", inst->seqNum);
	status = Running;
	} else if (inst->isMemRef() && status != DcacheMissComplete &&
	(!inst->isDataPrefetch() && !inst->isInstPrefetch())) {
	DPRINTF(IBE, "Initiating mem op inst [sn:%lli] PC: %#x\n",
	inst->seqNum, inst->readPC());

	cacheCompletionEvent.inst = inst;
	inst_fault = inst->initiateAcc();
	if (inst_fault == NoFault &&
	status != DcacheMissLoadStall &&
	status != DcacheMissStoreStall) {
	inst_fault = inst->completeAcc();
	}
	++thread->funcExeInst;
	} else {
	DPRINTF(IBE, "Executing inst [sn:%lli] PC: %#x\n",
	inst->seqNum, inst->readPC());
	inst_fault = inst->execute();
	++thread->funcExeInst;
	}

	// Will need to be able to break this loop in case the load
	// misses. Split access/complete ops would be useful here
	// with writeback events.
	if (status == DcacheMissLoadStall) {
	*instsToExecute = insts_to_execute;

	completed_last_inst = false;
	break;
	} else if (status == DcacheMissStoreStall) {
	// Figure out how to fix this hack. Probably have DcacheMissLoad
	// vs DcacheMissStore.
	*instsToExecute = insts_to_execute;
	completed_last_inst = false;
	/*
	instList.pop_front();
	--insts_to_execute;
	if (inst->traceData) {
	inst->traceData->finalize();
	}
	*/

	// Don't really need to stop for a store stall as long as
	// the memory system is able to handle store forwarding
	// and such. Breaking out might help avoid the cache
	// interface becoming blocked.
	break;
	}

	inst->setExecuted();
	inst->setResultReady();
	inst->setCanCommit();

	instList.pop_front();

	--insts_to_execute;
	--(*instsToExecute);

	if (inst->traceData) {
	inst->traceData->finalize();
	inst->traceData = NULL;
	}

	if (inst_fault != NoFault) {
	#if FULL_SYSTEM
	DPRINTF(IBE, "Inst [sn:%lli] PC %#x has a fault\n",
	inst->seqNum, inst->readPC());

	assert(!thread->inSyscall);

	thread->inSyscall = true;

	// Consider holding onto the trap and waiting until the trap event
	// happens for this to be executed.
	inst_fault->invoke(xc);

	// Exit state update mode to avoid accidental updating.
	thread->inSyscall = false;

	squashPending = true;

	// Generate trap squash event.
	// generateTrapEvent(tid);
	completed_last_inst = false;
	break;
	#else // !FULL_SYSTEM
	panic("fault (%d) detected @ PC %08p", inst_fault,
	inst->PC);
	#endif // FULL_SYSTEM
	}

	for (int i = 0; i < inst->numDestRegs(); ++i) {
	renameTable[inst->destRegIdx(i)] = inst;
	thread->renameTable[inst->destRegIdx(i)] = inst;
	++freed_regs;
	}

	inst->clearDependents();

	comm->access(0)->doneSeqNum = inst->seqNum;

	if (inst->mispredicted()) {
	squash(inst->seqNum, inst->readNextPC());

	thread->setNextPC(inst->readNextPC());

	break;
	} else if (squashPending) {
	// Something external happened that caused the CPU to squash.
	// Break out of commit and handle the squash next cycle.
	break;
	}
	// If it didn't mispredict, then it executed fine. Send back its
	// registers and BP info? What about insts that may still have
	// latency, like loads? Probably can send back the information after
	// it is completed.

	// keep an instruction count
	cpu->numInst++;
	thread->numInsts++;
	}

	frontEnd->addFreeRegs(freed_regs);

	assert(insts_to_execute >= 0);

	// Should only advance this if I have executed all instructions.
	if (insts_to_execute == 0) {
	numInstsToWB.advance();
	}

	// Should I set the PC to the next PC here? What do I set next PC to?
	if (completed_last_inst) {
	thread->setPC(thread->readNextPC());
	thread->setNextPC(thread->readPC() + sizeof(MachInst));
	}

	if (squashPending) {
	setSquashInfoFromXC();
	}
	}

	template <class Impl>
	void
	InorderBackEnd<Impl>::handleFault()
	{
	DPRINTF(Commit, "Handling fault from fetch\n");

	assert(!thread->inSyscall);

	thread->inSyscall = true;

	// Consider holding onto the trap and waiting until the trap event
	// happens for this to be executed.
	faultFromFetch->invoke(xc);

	// Exit state update mode to avoid accidental updating.
	thread->inSyscall = false;

	squashPending = true;

	setSquashInfoFromXC();
	}

	template <class Impl>
	void
	InorderBackEnd<Impl>::squash(const InstSeqNum &squash_num, const Addr &next_PC)
	{
	DPRINTF(IBE, "Squashing from [sn:%lli], setting PC to %#x\n",
	squash_num, next_PC);

	InstListIt squash_it = --(instList.end());

	int freed_regs = 0;

	while (!instList.empty() && (*squash_it)->seqNum > squash_num) {
	DynInstPtr inst = *squash_it;

	DPRINTF(IBE, "Squashing instruction PC %#x, [sn:%lli].\n",
	inst->readPC(),
	inst->seqNum);

	// May cause problems with misc regs
	freed_regs+= inst->numDestRegs();
	inst->clearDependents();
	squash_it--;
	instList.pop_back();
	}

	frontEnd->addFreeRegs(freed_regs);

	for (int i = 0; i < latency+1; ++i) {
	numInstsToWB.advance();
	}

	squashPending = false;

	// Probably want to make sure that this squash is the one that set the
	// thread into inSyscall mode.
	thread->inSyscall = false;

	// Tell front end to squash, reset PC to new one.
	frontEnd->squash(squash_num, next_PC);

	faultFromFetch = NULL;
	}

	template <class Impl>
	void
	InorderBackEnd<Impl>::squashFromXC()
	{
	// Record that I need to squash
	squashPending = true;

	thread->inSyscall = true;
	}

	template <class Impl>
	void
	InorderBackEnd<Impl>::setSquashInfoFromXC()
	{
	// Need to handle the case of the instList being empty. In that case
	// probably any number works, except maybe with stores in the store buffer.
	squashSeqNum = instList.empty() ? 0 : instList.front()->seqNum - 1;

	squashNextPC = thread->PC;
	}

	template <class Impl>
	void
	InorderBackEnd<Impl>::fetchFault(Fault &fault)
	{
	faultFromFetch = fault;
	}

	template <class Impl>
	void
	InorderBackEnd<Impl>::dumpInsts()
	{
	int num = 0;
	int valid_num = 0;

	InstListIt inst_list_it = instList.begin();

	cprintf("Inst list size: %i\n", instList.size());

	while (inst_list_it != instList.end())
	{
	cprintf("Instruction:%i\n",
	num);
	if (!(*inst_list_it)->isSquashed()) {
	if (!(*inst_list_it)->isIssued()) {
	++valid_num;
	cprintf("Count:%i\n", valid_num);
	} else if ((*inst_list_it)->isMemRef() &&
	!(*inst_list_it)->memOpDone) {
	// Loads that have not been marked as executed still count
	// towards the total instructions.
	++valid_num;
	cprintf("Count:%i\n", valid_num);
	}
	}

	cprintf("PC:%#x\n[sn:%lli]\n[tid:%i]\n"
	"Issued:%i\nSquashed:%i\n",
	(*inst_list_it)->readPC(),
	(*inst_list_it)->seqNum,
	(*inst_list_it)->threadNumber,
	(*inst_list_it)->isIssued(),
	(*inst_list_it)->isSquashed());

	if ((*inst_list_it)->isMemRef()) {
	cprintf("MemOpDone:%i\n", (*inst_list_it)->memOpDone);
	}

	cprintf("\n");

	inst_list_it++;
	++num;
	}
	}

	template <class Impl>
	InorderBackEnd<Impl>::DCacheCompletionEvent::DCacheCompletionEvent(
	InorderBackEnd *_be)
	: Event(&mainEventQueue, CPU_Tick_Pri), be(_be)
	{
	// this->setFlags(Event::AutoDelete);
	}

	template <class Impl>
	void
	InorderBackEnd<Impl>::DCacheCompletionEvent::process()
	{
	inst->completeAcc();
	be->status = DcacheMissComplete;
	}

	template <class Impl>
	const char *
	InorderBackEnd<Impl>::DCacheCompletionEvent::description() const
	{
	return "DCache completion";
	}