summaryrefslogtreecommitdiff
path: root/src/cpu/o3/fetch_impl.hh
diff options
context:
space:
mode:
authorKevin Lim <ktlim@umich.edu>2006-05-31 11:34:42 -0400
committerKevin Lim <ktlim@umich.edu>2006-05-31 11:34:42 -0400
commitd4b73086b6b0856c28433b55c8dd5c7b56a1b6df (patch)
treeb54cb10579c6c5788fc09e7abd5d3a0ab1dd533c /src/cpu/o3/fetch_impl.hh
parentd77d39daee5c3ba8483d58911a1d5b12c4707040 (diff)
parent4a5b51b516853c9fcaabc44caacdd7e8e93dc0ef (diff)
downloadgem5-d4b73086b6b0856c28433b55c8dd5c7b56a1b6df.tar.xz
Merge ktlim@zizzer:/bk/newmem
into zamp.eecs.umich.edu:/z/ktlim2/clean/newmem --HG-- extra : convert_revision : 3d951bbeee0178de47e1bdbe704808544bfe732e
Diffstat (limited to 'src/cpu/o3/fetch_impl.hh')
-rw-r--r--src/cpu/o3/fetch_impl.hh1142
1 files changed, 872 insertions, 270 deletions
diff --git a/src/cpu/o3/fetch_impl.hh b/src/cpu/o3/fetch_impl.hh
index 8029fc732..1c5e508f6 100644
--- a/src/cpu/o3/fetch_impl.hh
+++ b/src/cpu/o3/fetch_impl.hh
@@ -1,5 +1,5 @@
/*
- * Copyright (c) 2004-2005 The Regents of The University of Michigan
+ * Copyright (c) 2004-2006 The Regents of The University of Michigan
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
@@ -26,66 +26,100 @@
* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
-// Remove this later; used only for debugging.
-#define OPCODE(X) (X >> 26) & 0x3f
-
#include "arch/isa_traits.hh"
-#include "sim/byteswap.hh"
#include "cpu/exetrace.hh"
+#include "cpu/o3/fetch.hh"
#include "mem/base_mem.hh"
#include "mem/mem_interface.hh"
#include "mem/mem_req.hh"
-#include "cpu/o3/fetch.hh"
-
+#include "sim/byteswap.hh"
#include "sim/root.hh"
+#if FULL_SYSTEM
+#include "arch/tlb.hh"
+#include "arch/vtophys.hh"
+#include "base/remote_gdb.hh"
+#include "mem/functional/memory_control.hh"
+#include "mem/functional/physical.hh"
+#include "sim/system.hh"
+#else // !FULL_SYSTEM
+#include "mem/functional/functional.hh"
+#endif // FULL_SYSTEM
+
+#include <algorithm>
+
+using namespace std;
+
template<class Impl>
-SimpleFetch<Impl>::CacheCompletionEvent
-::CacheCompletionEvent(SimpleFetch *_fetch)
- : Event(&mainEventQueue),
+DefaultFetch<Impl>::CacheCompletionEvent::CacheCompletionEvent(MemReqPtr &_req,
+ DefaultFetch *_fetch)
+ : Event(&mainEventQueue, Delayed_Writeback_Pri),
+ req(_req),
fetch(_fetch)
{
+ this->setFlags(Event::AutoDelete);
}
template<class Impl>
void
-SimpleFetch<Impl>::CacheCompletionEvent::process()
+DefaultFetch<Impl>::CacheCompletionEvent::process()
{
- fetch->processCacheCompletion();
+ fetch->processCacheCompletion(req);
}
template<class Impl>
const char *
-SimpleFetch<Impl>::CacheCompletionEvent::description()
+DefaultFetch<Impl>::CacheCompletionEvent::description()
{
- return "SimpleFetch cache completion event";
+ return "DefaultFetch cache completion event";
}
template<class Impl>
-SimpleFetch<Impl>::SimpleFetch(Params &params)
- : icacheInterface(params.icacheInterface),
+DefaultFetch<Impl>::DefaultFetch(Params *params)
+ : icacheInterface(params->icacheInterface),
branchPred(params),
- decodeToFetchDelay(params.decodeToFetchDelay),
- renameToFetchDelay(params.renameToFetchDelay),
- iewToFetchDelay(params.iewToFetchDelay),
- commitToFetchDelay(params.commitToFetchDelay),
- fetchWidth(params.fetchWidth)
+ decodeToFetchDelay(params->decodeToFetchDelay),
+ renameToFetchDelay(params->renameToFetchDelay),
+ iewToFetchDelay(params->iewToFetchDelay),
+ commitToFetchDelay(params->commitToFetchDelay),
+ fetchWidth(params->fetchWidth),
+ numThreads(params->numberOfThreads),
+ numFetchingThreads(params->smtNumFetchingThreads),
+ interruptPending(false)
{
- DPRINTF(Fetch, "Fetch: Fetch constructor called\n");
-
- // Set status to idle.
- _status = Idle;
-
- // Create a new memory request.
- memReq = new MemReq();
- // Not sure of this parameter. I think it should be based on the
- // thread number.
-#if !FULL_SYSTEM
- memReq->asid = 0;
-#else
- memReq->asid = 0;
-#endif // FULL_SYSTEM
- memReq->data = new uint8_t[64];
+ if (numThreads > Impl::MaxThreads)
+ fatal("numThreads is not a valid value\n");
+
+ DPRINTF(Fetch, "Fetch constructor called\n");
+
+ // Set fetch stage's status to inactive.
+ _status = Inactive;
+
+ string policy = params->smtFetchPolicy;
+
+ // Convert string to lowercase
+ std::transform(policy.begin(), policy.end(), policy.begin(),
+ (int(*)(int)) tolower);
+
+ // Figure out fetch policy
+ if (policy == "singlethread") {
+ fetchPolicy = SingleThread;
+ } else if (policy == "roundrobin") {
+ fetchPolicy = RoundRobin;
+ DPRINTF(Fetch, "Fetch policy set to Round Robin\n");
+ } else if (policy == "branch") {
+ fetchPolicy = Branch;
+ DPRINTF(Fetch, "Fetch policy set to Branch Count\n");
+ } else if (policy == "iqcount") {
+ fetchPolicy = IQ;
+ DPRINTF(Fetch, "Fetch policy set to IQ count\n");
+ } else if (policy == "lsqcount") {
+ fetchPolicy = LSQ;
+ DPRINTF(Fetch, "Fetch policy set to LSQ count\n");
+ } else {
+ fatal("Invalid Fetch Policy. Options Are: {SingleThread,"
+ " RoundRobin,LSQcount,IQcount}\n");
+ }
// Size of cache block.
cacheBlkSize = icacheInterface ? icacheInterface->getBlockSize() : 64;
@@ -93,75 +127,142 @@ SimpleFetch<Impl>::SimpleFetch(Params &params)
// Create mask to get rid of offset bits.
cacheBlkMask = (cacheBlkSize - 1);
+ for (int tid=0; tid < numThreads; tid++) {
+
+ fetchStatus[tid] = Running;
+
+ priorityList.push_back(tid);
+
+ // Create a new memory request.
+ memReq[tid] = NULL;
+
+ // Create space to store a cache line.
+ cacheData[tid] = new uint8_t[cacheBlkSize];
+
+ stalls[tid].decode = 0;
+ stalls[tid].rename = 0;
+ stalls[tid].iew = 0;
+ stalls[tid].commit = 0;
+ }
+
// Get the size of an instruction.
instSize = sizeof(MachInst);
+}
- // Create space to store a cache line.
- cacheData = new uint8_t[cacheBlkSize];
+template <class Impl>
+std::string
+DefaultFetch<Impl>::name() const
+{
+ return cpu->name() + ".fetch";
}
template <class Impl>
void
-SimpleFetch<Impl>::regStats()
+DefaultFetch<Impl>::regStats()
{
icacheStallCycles
- .name(name() + ".icacheStallCycles")
+ .name(name() + ".FETCH:icacheStallCycles")
.desc("Number of cycles fetch is stalled on an Icache miss")
.prereq(icacheStallCycles);
fetchedInsts
- .name(name() + ".fetchedInsts")
+ .name(name() + ".FETCH:Insts")
.desc("Number of instructions fetch has processed")
.prereq(fetchedInsts);
+
+ fetchedBranches
+ .name(name() + ".FETCH:Branches")
+ .desc("Number of branches that fetch encountered")
+ .prereq(fetchedBranches);
+
predictedBranches
- .name(name() + ".predictedBranches")
+ .name(name() + ".FETCH:predictedBranches")
.desc("Number of branches that fetch has predicted taken")
.prereq(predictedBranches);
+
fetchCycles
- .name(name() + ".fetchCycles")
+ .name(name() + ".FETCH:Cycles")
.desc("Number of cycles fetch has run and was not squashing or"
" blocked")
.prereq(fetchCycles);
+
fetchSquashCycles
- .name(name() + ".fetchSquashCycles")
+ .name(name() + ".FETCH:SquashCycles")
.desc("Number of cycles fetch has spent squashing")
.prereq(fetchSquashCycles);
+
+ fetchIdleCycles
+ .name(name() + ".FETCH:IdleCycles")
+ .desc("Number of cycles fetch was idle")
+ .prereq(fetchIdleCycles);
+
fetchBlockedCycles
- .name(name() + ".fetchBlockedCycles")
+ .name(name() + ".FETCH:BlockedCycles")
.desc("Number of cycles fetch has spent blocked")
.prereq(fetchBlockedCycles);
+
fetchedCacheLines
- .name(name() + ".fetchedCacheLines")
+ .name(name() + ".FETCH:CacheLines")
.desc("Number of cache lines fetched")
.prereq(fetchedCacheLines);
- fetch_nisn_dist
+ fetchMiscStallCycles
+ .name(name() + ".FETCH:MiscStallCycles")
+ .desc("Number of cycles fetch has spent waiting on interrupts, or "
+ "bad addresses, or out of MSHRs")
+ .prereq(fetchMiscStallCycles);
+
+ fetchIcacheSquashes
+ .name(name() + ".FETCH:IcacheSquashes")
+ .desc("Number of outstanding Icache misses that were squashed")
+ .prereq(fetchIcacheSquashes);
+
+ fetchNisnDist
.init(/* base value */ 0,
/* last value */ fetchWidth,
/* bucket size */ 1)
- .name(name() + ".FETCH:rate_dist")
+ .name(name() + ".FETCH:rateDist")
.desc("Number of instructions fetched each cycle (Total)")
- .flags(Stats::pdf)
- ;
+ .flags(Stats::pdf);
+
+ idleRate
+ .name(name() + ".FETCH:idleRate")
+ .desc("Percent of cycles fetch was idle")
+ .prereq(idleRate);
+ idleRate = fetchIdleCycles * 100 / cpu->numCycles;
+
+ branchRate
+ .name(name() + ".FETCH:branchRate")
+ .desc("Number of branch fetches per cycle")
+ .flags(Stats::total);
+ branchRate = predictedBranches / cpu->numCycles;
+
+ fetchRate
+ .name(name() + ".FETCH:rate")
+ .desc("Number of inst fetches per cycle")
+ .flags(Stats::total);
+ fetchRate = fetchedInsts / cpu->numCycles;
branchPred.regStats();
}
template<class Impl>
void
-SimpleFetch<Impl>::setCPU(FullCPU *cpu_ptr)
+DefaultFetch<Impl>::setCPU(FullCPU *cpu_ptr)
{
- DPRINTF(Fetch, "Fetch: Setting the CPU pointer.\n");
+ DPRINTF(Fetch, "Setting the CPU pointer.\n");
cpu = cpu_ptr;
- // This line will be removed eventually.
- memReq->xc = cpu->xcBase();
+
+ // Fetch needs to start fetching instructions at the very beginning,
+ // so it must start up in active state.
+ switchToActive();
}
template<class Impl>
void
-SimpleFetch<Impl>::setTimeBuffer(TimeBuffer<TimeStruct> *time_buffer)
+DefaultFetch<Impl>::setTimeBuffer(TimeBuffer<TimeStruct> *time_buffer)
{
- DPRINTF(Fetch, "Fetch: Setting the time buffer pointer.\n");
+ DPRINTF(Fetch, "Setting the time buffer pointer.\n");
timeBuffer = time_buffer;
// Create wires to get information from proper places in time buffer.
@@ -173,32 +274,160 @@ SimpleFetch<Impl>::setTimeBuffer(TimeBuffer<TimeStruct> *time_buffer)
template<class Impl>
void
-SimpleFetch<Impl>::setFetchQueue(TimeBuffer<FetchStruct> *fq_ptr)
+DefaultFetch<Impl>::setActiveThreads(list<unsigned> *at_ptr)
+{
+ DPRINTF(Fetch, "Setting active threads list pointer.\n");
+ activeThreads = at_ptr;
+}
+
+template<class Impl>
+void
+DefaultFetch<Impl>::setFetchQueue(TimeBuffer<FetchStruct> *fq_ptr)
{
- DPRINTF(Fetch, "Fetch: Setting the fetch queue pointer.\n");
+ DPRINTF(Fetch, "Setting the fetch queue pointer.\n");
fetchQueue = fq_ptr;
// Create wire to write information to proper place in fetch queue.
toDecode = fetchQueue->getWire(0);
}
+#if 0
+template<class Impl>
+void
+DefaultFetch<Impl>::setPageTable(PageTable *pt_ptr)
+{
+ DPRINTF(Fetch, "Setting the page table pointer.\n");
+#if !FULL_SYSTEM
+ pTable = pt_ptr;
+#endif
+}
+#endif
+
+template<class Impl>
+void
+DefaultFetch<Impl>::initStage()
+{
+ for (int tid = 0; tid < numThreads; tid++) {
+ PC[tid] = cpu->readPC(tid);
+ nextPC[tid] = cpu->readNextPC(tid);
+ }
+}
+
template<class Impl>
void
-SimpleFetch<Impl>::processCacheCompletion()
+DefaultFetch<Impl>::processCacheCompletion(MemReqPtr &req)
{
- DPRINTF(Fetch, "Fetch: Waking up from cache miss.\n");
+ unsigned tid = req->thread_num;
+
+ DPRINTF(Fetch, "[tid:%u] Waking up from cache miss.\n",tid);
// Only change the status if it's still waiting on the icache access
// to return.
// Can keep track of how many cache accesses go unused due to
// misspeculation here.
- if (_status == IcacheMissStall)
- _status = IcacheMissComplete;
+ if (fetchStatus[tid] != IcacheMissStall ||
+ req != memReq[tid] ||
+ isSwitchedOut()) {
+ ++fetchIcacheSquashes;
+ return;
+ }
+
+ // Wake up the CPU (if it went to sleep and was waiting on this completion
+ // event).
+ cpu->wakeCPU();
+
+ DPRINTF(Activity, "[tid:%u] Activating fetch due to cache completion\n",
+ tid);
+
+ switchToActive();
+
+ // Only switch to IcacheMissComplete if we're not stalled as well.
+ if (checkStall(tid)) {
+ fetchStatus[tid] = Blocked;
+ } else {
+ fetchStatus[tid] = IcacheMissComplete;
+ }
+
+// memcpy(cacheData[tid], memReq[tid]->data, memReq[tid]->size);
+
+ // Reset the mem req to NULL.
+ memReq[tid] = NULL;
+}
+
+template <class Impl>
+void
+DefaultFetch<Impl>::switchOut()
+{
+ switchedOut = true;
+ cpu->signalSwitched();
+}
+
+template <class Impl>
+void
+DefaultFetch<Impl>::doSwitchOut()
+{
+ branchPred.switchOut();
+}
+
+template <class Impl>
+void
+DefaultFetch<Impl>::takeOverFrom()
+{
+ // Reset all state
+ for (int i = 0; i < Impl::MaxThreads; ++i) {
+ stalls[i].decode = 0;
+ stalls[i].rename = 0;
+ stalls[i].iew = 0;
+ stalls[i].commit = 0;
+ PC[i] = cpu->readPC(i);
+ nextPC[i] = cpu->readNextPC(i);
+ fetchStatus[i] = Running;
+ }
+ numInst = 0;
+ wroteToTimeBuffer = false;
+ _status = Inactive;
+ switchedOut = false;
+ branchPred.takeOverFrom();
+}
+
+template <class Impl>
+void
+DefaultFetch<Impl>::wakeFromQuiesce()
+{
+ DPRINTF(Fetch, "Waking up from quiesce\n");
+ // Hopefully this is safe
+ fetchStatus[0] = Running;
+}
+
+template <class Impl>
+inline void
+DefaultFetch<Impl>::switchToActive()
+{
+ if (_status == Inactive) {
+ DPRINTF(Activity, "Activating stage.\n");
+
+ cpu->activateStage(FullCPU::FetchIdx);
+
+ _status = Active;
+ }
+}
+
+template <class Impl>
+inline void
+DefaultFetch<Impl>::switchToInactive()
+{
+ if (_status == Active) {
+ DPRINTF(Activity, "Deactivating stage.\n");
+
+ cpu->deactivateStage(FullCPU::FetchIdx);
+
+ _status = Inactive;
+ }
}
template <class Impl>
bool
-SimpleFetch<Impl>::lookupAndUpdateNextPC(DynInstPtr &inst, Addr &next_PC)
+DefaultFetch<Impl>::lookupAndUpdateNextPC(DynInstPtr &inst, Addr &next_PC)
{
// Do branch prediction check here.
// A bit of a misnomer...next_PC is actually the current PC until
@@ -211,7 +440,9 @@ SimpleFetch<Impl>::lookupAndUpdateNextPC(DynInstPtr &inst, Addr &next_PC)
return false;
}
- predict_taken = branchPred.predict(inst, next_PC);
+ predict_taken = branchPred.predict(inst, next_PC, inst->threadNumber);
+
+ ++fetchedBranches;
if (predict_taken) {
++predictedBranches;
@@ -221,251 +452,429 @@ SimpleFetch<Impl>::lookupAndUpdateNextPC(DynInstPtr &inst, Addr &next_PC)
}
template <class Impl>
-Fault
-SimpleFetch<Impl>::fetchCacheLine(Addr fetch_PC)
+bool
+DefaultFetch<Impl>::fetchCacheLine(Addr fetch_PC, Fault &ret_fault, unsigned tid)
{
- // Check if the instruction exists within the cache.
- // If it does, then proceed on to read the instruction and the rest
- // of the instructions in the cache line until either the end of the
- // cache line or a predicted taken branch is encountered.
+ Fault fault = NoFault;
#if FULL_SYSTEM
// Flag to say whether or not address is physical addr.
- unsigned flags = cpu->inPalMode() ? PHYSICAL : 0;
+ unsigned flags = cpu->inPalMode(fetch_PC) ? PHYSICAL : 0;
#else
unsigned flags = 0;
#endif // FULL_SYSTEM
- Fault fault = NoFault;
+ if (interruptPending && flags == 0 || switchedOut) {
+ // Hold off fetch from getting new instructions while an interrupt
+ // is pending.
+ return false;
+ }
// Align the fetch PC so it's at the start of a cache block.
fetch_PC = icacheBlockAlignPC(fetch_PC);
- // Setup the memReq to do a read of the first isntruction's address.
+ // Setup the memReq to do a read of the first instruction's address.
// Set the appropriate read size and flags as well.
- memReq->cmd = Read;
- memReq->reset(fetch_PC, cacheBlkSize, flags);
+ memReq[tid] = new MemReq();
- // Translate the instruction request.
- // Should this function be
- // in the CPU class ? Probably...ITB/DTB should exist within the
- // CPU.
+ memReq[tid]->asid = tid;
+ memReq[tid]->thread_num = tid;
+ memReq[tid]->data = new uint8_t[64];
+ memReq[tid]->xc = cpu->xcBase(tid);
+ memReq[tid]->cmd = Read;
+ memReq[tid]->reset(fetch_PC, cacheBlkSize, flags);
- fault = cpu->translateInstReq(memReq);
+ // Translate the instruction request.
+//#if FULL_SYSTEM
+ fault = cpu->translateInstReq(memReq[tid]);
+//#else
+// fault = pTable->translate(memReq[tid]);
+//#endif
// In the case of faults, the fetch stage may need to stall and wait
- // on what caused the fetch (ITB or Icache miss).
+ // for the ITB miss to be handled.
// If translation was successful, attempt to read the first
// instruction.
if (fault == NoFault) {
+#if FULL_SYSTEM
+ if (cpu->system->memctrl->badaddr(memReq[tid]->paddr) ||
+ memReq[tid]->flags & UNCACHEABLE) {
+ DPRINTF(Fetch, "Fetch: Bad address %#x (hopefully on a "
+ "misspeculating path)!",
+ memReq[tid]->paddr);
+ ret_fault = TheISA::genMachineCheckFault();
+ return false;
+ }
+#endif
+
DPRINTF(Fetch, "Fetch: Doing instruction read.\n");
- fault = cpu->mem->read(memReq, cacheData);
+ fault = cpu->mem->read(memReq[tid], cacheData[tid]);
// This read may change when the mem interface changes.
- fetchedCacheLines++;
- }
+ // Now do the timing access to see whether or not the instruction
+ // exists within the cache.
+ if (icacheInterface && !icacheInterface->isBlocked()) {
+ DPRINTF(Fetch, "Doing cache access.\n");
- // Now do the timing access to see whether or not the instruction
- // exists within the cache.
- if (icacheInterface && fault == NoFault) {
- DPRINTF(Fetch, "Fetch: Doing timing memory access.\n");
- memReq->completionEvent = NULL;
+ memReq[tid]->completionEvent = NULL;
- memReq->time = curTick;
+ memReq[tid]->time = curTick;
- MemAccessResult result = icacheInterface->access(memReq);
+ MemAccessResult result = icacheInterface->access(memReq[tid]);
- // If the cache missed (in this model functional and timing
- // memories are different), then schedule an event to wake
- // up this stage once the cache miss completes.
- if (result != MA_HIT && icacheInterface->doEvents()) {
- memReq->completionEvent = new CacheCompletionEvent(this);
+ fetchedCacheLines++;
- // How does current model work as far as individual
- // stages scheduling/unscheduling?
- // Perhaps have only the main CPU scheduled/unscheduled,
- // and have it choose what stages to run appropriately.
+ // If the cache missed, then schedule an event to wake
+ // up this stage once the cache miss completes.
+ // @todo: Possibly allow for longer than 1 cycle cache hits.
+ if (result != MA_HIT && icacheInterface->doEvents()) {
- DPRINTF(Fetch, "Fetch: Stalling due to icache miss.\n");
- _status = IcacheMissStall;
+ memReq[tid]->completionEvent =
+ new CacheCompletionEvent(memReq[tid], this);
+
+ lastIcacheStall[tid] = curTick;
+
+ DPRINTF(Activity, "[tid:%i]: Activity: Stalling due to I-cache "
+ "miss.\n", tid);
+
+ fetchStatus[tid] = IcacheMissStall;
+ } else {
+ DPRINTF(Fetch, "[tid:%i]: I-Cache hit. Doing Instruction "
+ "read.\n", tid);
+
+// memcpy(cacheData[tid], memReq[tid]->data, memReq[tid]->size);
+ }
+ } else {
+ DPRINTF(Fetch, "[tid:%i] Out of MSHRs!\n", tid);
+ ret_fault = NoFault;
+ return false;
}
}
- return fault;
+ ret_fault = fault;
+ return true;
}
template <class Impl>
inline void
-SimpleFetch<Impl>::doSquash(const Addr &new_PC)
+DefaultFetch<Impl>::doSquash(const Addr &new_PC, unsigned tid)
{
- DPRINTF(Fetch, "Fetch: Squashing, setting PC to: %#x.\n", new_PC);
+ DPRINTF(Fetch, "[tid:%i]: Squashing, setting PC to: %#x.\n",
+ tid, new_PC);
- cpu->setNextPC(new_PC + instSize);
- cpu->setPC(new_PC);
+ PC[tid] = new_PC;
+ nextPC[tid] = new_PC + instSize;
// Clear the icache miss if it's outstanding.
- if (_status == IcacheMissStall && icacheInterface) {
- DPRINTF(Fetch, "Fetch: Squashing outstanding Icache miss.\n");
- // @todo: Use an actual thread number here.
- icacheInterface->squash(0);
+ if (fetchStatus[tid] == IcacheMissStall && icacheInterface) {
+ DPRINTF(Fetch, "[tid:%i]: Squashing outstanding Icache miss.\n",
+ tid);
+ memReq[tid] = NULL;
}
- _status = Squashing;
+ fetchStatus[tid] = Squashing;
++fetchSquashCycles;
}
template<class Impl>
void
-SimpleFetch<Impl>::squashFromDecode(const Addr &new_PC,
- const InstSeqNum &seq_num)
+DefaultFetch<Impl>::squashFromDecode(const Addr &new_PC,
+ const InstSeqNum &seq_num,
+ unsigned tid)
{
- DPRINTF(Fetch, "Fetch: Squashing from decode.\n");
+ DPRINTF(Fetch, "[tid:%i]: Squashing from decode.\n",tid);
- doSquash(new_PC);
+ doSquash(new_PC, tid);
// Tell the CPU to remove any instructions that are in flight between
// fetch and decode.
- cpu->removeInstsUntil(seq_num);
+ cpu->removeInstsUntil(seq_num, tid);
+}
+
+template<class Impl>
+bool
+DefaultFetch<Impl>::checkStall(unsigned tid) const
+{
+ bool ret_val = false;
+
+ if (cpu->contextSwitch) {
+ DPRINTF(Fetch,"[tid:%i]: Stalling for a context switch.\n",tid);
+ ret_val = true;
+ } else if (stalls[tid].decode) {
+ DPRINTF(Fetch,"[tid:%i]: Stall from Decode stage detected.\n",tid);
+ ret_val = true;
+ } else if (stalls[tid].rename) {
+ DPRINTF(Fetch,"[tid:%i]: Stall from Rename stage detected.\n",tid);
+ ret_val = true;
+ } else if (stalls[tid].iew) {
+ DPRINTF(Fetch,"[tid:%i]: Stall from IEW stage detected.\n",tid);
+ ret_val = true;
+ } else if (stalls[tid].commit) {
+ DPRINTF(Fetch,"[tid:%i]: Stall from Commit stage detected.\n",tid);
+ ret_val = true;
+ }
+
+ return ret_val;
+}
+
+template<class Impl>
+typename DefaultFetch<Impl>::FetchStatus
+DefaultFetch<Impl>::updateFetchStatus()
+{
+ //Check Running
+ list<unsigned>::iterator threads = (*activeThreads).begin();
+
+ while (threads != (*activeThreads).end()) {
+
+ unsigned tid = *threads++;
+
+ if (fetchStatus[tid] == Running ||
+ fetchStatus[tid] == Squashing ||
+ fetchStatus[tid] == IcacheMissComplete) {
+
+ if (_status == Inactive) {
+ DPRINTF(Activity, "[tid:%i]: Activating stage.\n",tid);
+
+ if (fetchStatus[tid] == IcacheMissComplete) {
+ DPRINTF(Activity, "[tid:%i]: Activating fetch due to cache"
+ "completion\n",tid);
+ }
+
+ cpu->activateStage(FullCPU::FetchIdx);
+ }
+
+ return Active;
+ }
+ }
+
+ // Stage is switching from active to inactive, notify CPU of it.
+ if (_status == Active) {
+ DPRINTF(Activity, "Deactivating stage.\n");
+
+ cpu->deactivateStage(FullCPU::FetchIdx);
+ }
+
+ return Inactive;
}
template <class Impl>
void
-SimpleFetch<Impl>::squash(const Addr &new_PC)
+DefaultFetch<Impl>::squash(const Addr &new_PC, unsigned tid)
{
- DPRINTF(Fetch, "Fetch: Squash from commit.\n");
+ DPRINTF(Fetch, "[tid:%u]: Squash from commit.\n",tid);
- doSquash(new_PC);
+ doSquash(new_PC, tid);
// Tell the CPU to remove any instructions that are not in the ROB.
- cpu->removeInstsNotInROB();
+ cpu->removeInstsNotInROB(tid);
}
-template<class Impl>
+template <class Impl>
void
-SimpleFetch<Impl>::tick()
+DefaultFetch<Impl>::tick()
{
+ list<unsigned>::iterator threads = (*activeThreads).begin();
+ bool status_change = false;
+
+ wroteToTimeBuffer = false;
+
+ while (threads != (*activeThreads).end()) {
+ unsigned tid = *threads++;
+
+ // Check the signals for each thread to determine the proper status
+ // for each thread.
+ bool updated_status = checkSignalsAndUpdate(tid);
+ status_change = status_change || updated_status;
+ }
+
+ DPRINTF(Fetch, "Running stage.\n");
+
+ // Reset the number of the instruction we're fetching.
+ numInst = 0;
+
+ if (fromCommit->commitInfo[0].interruptPending) {
+ interruptPending = true;
+ }
+ if (fromCommit->commitInfo[0].clearInterrupt) {
+ interruptPending = false;
+ }
+
+ for (threadFetched = 0; threadFetched < numFetchingThreads;
+ threadFetched++) {
+ // Fetch each of the actively fetching threads.
+ fetch(status_change);
+ }
+
+ // Record number of instructions fetched this cycle for distribution.
+ fetchNisnDist.sample(numInst);
+
+ if (status_change) {
+ // Change the fetch stage status if there was a status change.
+ _status = updateFetchStatus();
+ }
+
+ // If there was activity this cycle, inform the CPU of it.
+ if (wroteToTimeBuffer || cpu->contextSwitch) {
+ DPRINTF(Activity, "Activity this cycle.\n");
+
+ cpu->activityThisCycle();
+ }
+}
+
+template <class Impl>
+bool
+DefaultFetch<Impl>::checkSignalsAndUpdate(unsigned tid)
+{
+ // Update the per thread stall statuses.
+ if (fromDecode->decodeBlock[tid]) {
+ stalls[tid].decode = true;
+ }
+
+ if (fromDecode->decodeUnblock[tid]) {
+ assert(stalls[tid].decode);
+ assert(!fromDecode->decodeBlock[tid]);
+ stalls[tid].decode = false;
+ }
+
+ if (fromRename->renameBlock[tid]) {
+ stalls[tid].rename = true;
+ }
+
+ if (fromRename->renameUnblock[tid]) {
+ assert(stalls[tid].rename);
+ assert(!fromRename->renameBlock[tid]);
+ stalls[tid].rename = false;
+ }
+
+ if (fromIEW->iewBlock[tid]) {
+ stalls[tid].iew = true;
+ }
+
+ if (fromIEW->iewUnblock[tid]) {
+ assert(stalls[tid].iew);
+ assert(!fromIEW->iewBlock[tid]);
+ stalls[tid].iew = false;
+ }
+
+ if (fromCommit->commitBlock[tid]) {
+ stalls[tid].commit = true;
+ }
+
+ if (fromCommit->commitUnblock[tid]) {
+ assert(stalls[tid].commit);
+ assert(!fromCommit->commitBlock[tid]);
+ stalls[tid].commit = false;
+ }
+
// Check squash signals from commit.
- if (fromCommit->commitInfo.squash) {
- DPRINTF(Fetch, "Fetch: Squashing instructions due to squash "
- "from commit.\n");
+ if (fromCommit->commitInfo[tid].squash) {
+
+ DPRINTF(Fetch, "[tid:%u]: Squashing instructions due to squash "
+ "from commit.\n",tid);
// In any case, squash.
- squash(fromCommit->commitInfo.nextPC);
+ squash(fromCommit->commitInfo[tid].nextPC,tid);
// Also check if there's a mispredict that happened.
- if (fromCommit->commitInfo.branchMispredict) {
- branchPred.squash(fromCommit->commitInfo.doneSeqNum,
- fromCommit->commitInfo.nextPC,
- fromCommit->commitInfo.branchTaken);
+ if (fromCommit->commitInfo[tid].branchMispredict) {
+ branchPred.squash(fromCommit->commitInfo[tid].doneSeqNum,
+ fromCommit->commitInfo[tid].nextPC,
+ fromCommit->commitInfo[tid].branchTaken,
+ tid);
} else {
- branchPred.squash(fromCommit->commitInfo.doneSeqNum);
+ branchPred.squash(fromCommit->commitInfo[tid].doneSeqNum,
+ tid);
}
- return;
- } else if (fromCommit->commitInfo.doneSeqNum) {
+ return true;
+ } else if (fromCommit->commitInfo[tid].doneSeqNum) {
// Update the branch predictor if it wasn't a squashed instruction
- // that was braodcasted.
- branchPred.update(fromCommit->commitInfo.doneSeqNum);
+ // that was broadcasted.
+ branchPred.update(fromCommit->commitInfo[tid].doneSeqNum, tid);
}
// Check ROB squash signals from commit.
- if (fromCommit->commitInfo.robSquashing) {
- DPRINTF(Fetch, "Fetch: ROB is still squashing.\n");
+ if (fromCommit->commitInfo[tid].robSquashing) {
+ DPRINTF(Fetch, "[tid:%u]: ROB is still squashing Thread %u.\n", tid);
// Continue to squash.
- _status = Squashing;
+ fetchStatus[tid] = Squashing;
- ++fetchSquashCycles;
- return;
+ return true;
}
// Check squash signals from decode.
- if (fromDecode->decodeInfo.squash) {
- DPRINTF(Fetch, "Fetch: Squashing instructions due to squash "
- "from decode.\n");
+ if (fromDecode->decodeInfo[tid].squash) {
+ DPRINTF(Fetch, "[tid:%u]: Squashing instructions due to squash "
+ "from decode.\n",tid);
// Update the branch predictor.
- if (fromDecode->decodeInfo.branchMispredict) {
- branchPred.squash(fromDecode->decodeInfo.doneSeqNum,
- fromDecode->decodeInfo.nextPC,
- fromDecode->decodeInfo.branchTaken);
+ if (fromDecode->decodeInfo[tid].branchMispredict) {
+ branchPred.squash(fromDecode->decodeInfo[tid].doneSeqNum,
+ fromDecode->decodeInfo[tid].nextPC,
+ fromDecode->decodeInfo[tid].branchTaken,
+ tid);
} else {
- branchPred.squash(fromDecode->decodeInfo.doneSeqNum);
+ branchPred.squash(fromDecode->decodeInfo[tid].doneSeqNum,
+ tid);
}
- if (_status != Squashing) {
- // Squash unless we're already squashing?
- squashFromDecode(fromDecode->decodeInfo.nextPC,
- fromDecode->decodeInfo.doneSeqNum);
- return;
+ if (fetchStatus[tid] != Squashing) {
+ // Squash unless we're already squashing
+ squashFromDecode(fromDecode->decodeInfo[tid].nextPC,
+ fromDecode->decodeInfo[tid].doneSeqNum,
+ tid);
+
+ return true;
}
}
- // Check if any of the stall signals are high.
- if (fromDecode->decodeInfo.stall ||
- fromRename->renameInfo.stall ||
- fromIEW->iewInfo.stall ||
- fromCommit->commitInfo.stall)
- {
- // Block stage, regardless of current status.
+ if (checkStall(tid) && fetchStatus[tid] != IcacheMissStall) {
+ DPRINTF(Fetch, "[tid:%i]: Setting to blocked\n",tid);
- DPRINTF(Fetch, "Fetch: Stalling stage.\n");
- DPRINTF(Fetch, "Fetch: Statuses: Decode: %i Rename: %i IEW: %i "
- "Commit: %i\n",
- fromDecode->decodeInfo.stall,
- fromRename->renameInfo.stall,
- fromIEW->iewInfo.stall,
- fromCommit->commitInfo.stall);
+ fetchStatus[tid] = Blocked;
- _status = Blocked;
-
- ++fetchBlockedCycles;
- return;
- } else if (_status == Blocked) {
- // Unblock stage if status is currently blocked and none of the
- // stall signals are being held high.
- _status = Running;
-
- ++fetchBlockedCycles;
- return;
+ return true;
}
- // If fetch has reached this point, then there are no squash signals
- // still being held high. Check if fetch is in the squashing state;
- // if so, fetch can switch to running.
- // Similarly, there are no blocked signals still being held high.
- // Check if fetch is in the blocked state; if so, fetch can switch to
- // running.
- if (_status == Squashing) {
- DPRINTF(Fetch, "Fetch: Done squashing, switching to running.\n");
-
- // Switch status to running
- _status = Running;
+ if (fetchStatus[tid] == Blocked ||
+ fetchStatus[tid] == Squashing) {
+ // Switch status to running if fetch isn't being told to block or
+ // squash this cycle.
+ DPRINTF(Fetch, "[tid:%i]: Done squashing, switching to running.\n",
+ tid);
- ++fetchCycles;
+ fetchStatus[tid] = Running;
- fetch();
- } else if (_status != IcacheMissStall) {
- DPRINTF(Fetch, "Fetch: Running stage.\n");
-
- ++fetchCycles;
-
- fetch();
+ return true;
}
+
+ // If we've reached this point, we have not gotten any signals that
+ // cause fetch to change its status. Fetch remains the same as before.
+ return false;
}
template<class Impl>
void
-SimpleFetch<Impl>::fetch()
+DefaultFetch<Impl>::fetch(bool &status_change)
{
//////////////////////////////////////////
// Start actual fetch
//////////////////////////////////////////
+ int tid = getFetchingThread(fetchPolicy);
+
+ if (tid == -1) {
+ DPRINTF(Fetch,"There are no more threads available to fetch from.\n");
+
+ // Breaks looping condition in tick()
+ threadFetched = numFetchingThreads;
+ return;
+ }
// The current PC.
- Addr fetch_PC = cpu->readPC();
+ Addr &fetch_PC = PC[tid];
// Fault code for memory access.
Fault fault = NoFault;
@@ -473,60 +882,71 @@ SimpleFetch<Impl>::fetch()
// If returning from the delay of a cache miss, then update the status
// to running, otherwise do the cache access. Possibly move this up
// to tick() function.
- if (_status == IcacheMissComplete) {
- DPRINTF(Fetch, "Fetch: Icache miss is complete.\n");
-
- // Reset the completion event to NULL.
- memReq->completionEvent = NULL;
-
- _status = Running;
+ if (fetchStatus[tid] == IcacheMissComplete) {
+ DPRINTF(Fetch, "[tid:%i]: Icache miss is complete.\n",
+ tid);
+
+ fetchStatus[tid] = Running;
+ status_change = true;
+ } else if (fetchStatus[tid] == Running) {
+ DPRINTF(Fetch, "[tid:%i]: Attempting to translate and read "
+ "instruction, starting at PC %08p.\n",
+ tid, fetch_PC);
+
+ bool fetch_success = fetchCacheLine(fetch_PC, fault, tid);
+ if (!fetch_success) {
+ ++fetchMiscStallCycles;
+ return;
+ }
} else {
- DPRINTF(Fetch, "Fetch: Attempting to translate and read "
- "instruction, starting at PC %08p.\n",
- fetch_PC);
+ if (fetchStatus[tid] == Idle) {
+ ++fetchIdleCycles;
+ } else if (fetchStatus[tid] == Blocked) {
+ ++fetchBlockedCycles;
+ } else if (fetchStatus[tid] == Squashing) {
+ ++fetchSquashCycles;
+ } else if (fetchStatus[tid] == IcacheMissStall) {
+ ++icacheStallCycles;
+ }
- fault = fetchCacheLine(fetch_PC);
+ // Status is Idle, Squashing, Blocked, or IcacheMissStall, so
+ // fetch should do nothing.
+ return;
}
- // If we had a stall due to an icache miss, then return. It'd
- // be nicer if this were handled through the kind of fault that
- // is returned by the function.
- if (_status == IcacheMissStall) {
+ ++fetchCycles;
+
+ // If we had a stall due to an icache miss, then return.
+ if (fetchStatus[tid] == IcacheMissStall) {
+ ++icacheStallCycles;
+ status_change = true;
return;
}
- // As far as timing goes, the CPU will need to send an event through
- // the MemReq in order to be woken up once the memory access completes.
- // Probably have a status on a per thread basis so each thread can
- // block independently and be woken up independently.
-
Addr next_PC = fetch_PC;
InstSeqNum inst_seq;
MachInst inst;
- unsigned offset = fetch_PC & cacheBlkMask;
- unsigned fetched;
+ ExtMachInst ext_inst;
+ // @todo: Fix this hack.
+ unsigned offset = (fetch_PC & cacheBlkMask) & ~3;
if (fault == NoFault) {
// If the read of the first instruction was successful, then grab the
// instructions from the rest of the cache line and put them into the
// queue heading to decode.
- DPRINTF(Fetch, "Fetch: Adding instructions to queue to decode.\n");
-
- //////////////////////////
- // Fetch first instruction
- //////////////////////////
+ DPRINTF(Fetch, "[tid:%i]: Adding instructions to queue to "
+ "decode.\n",tid);
// Need to keep track of whether or not a predicted branch
// ended this fetch block.
bool predicted_branch = false;
- for (fetched = 0;
+ for (;
offset < cacheBlkSize &&
- fetched < fetchWidth &&
+ numInst < fetchWidth &&
!predicted_branch;
- ++fetched)
- {
+ ++numInst) {
// Get a sequence number.
inst_seq = cpu->getAndIncrementInstSeq();
@@ -536,31 +956,40 @@ SimpleFetch<Impl>::fetch()
// Get the instruction from the array of the cache line.
inst = gtoh(*reinterpret_cast<MachInst *>
- (&cacheData[offset]));
+ (&cacheData[tid][offset]));
+
+ ext_inst = TheISA::makeExtMI(inst, fetch_PC);
// Create a new DynInst from the instruction fetched.
- DynInstPtr instruction = new DynInst(inst, fetch_PC, next_PC,
+ DynInstPtr instruction = new DynInst(ext_inst, fetch_PC,
+ next_PC,
inst_seq, cpu);
+ instruction->setThread(tid);
+
+ instruction->setASID(tid);
- DPRINTF(Fetch, "Fetch: Instruction %i created, with PC %#x\n",
- inst_seq, instruction->readPC());
+ instruction->setState(cpu->thread[tid]);
- DPRINTF(Fetch, "Fetch: Instruction opcode is: %03p\n",
- OPCODE(inst));
+ DPRINTF(Fetch, "[tid:%i]: Instruction PC %#x created "
+ "[sn:%lli]\n",
+ tid, instruction->readPC(), inst_seq);
+
+ DPRINTF(Fetch, "[tid:%i]: Instruction is: %s\n",
+ tid, instruction->staticInst->disassemble(fetch_PC));
instruction->traceData =
- Trace::getInstRecord(curTick, cpu->xcBase(), cpu,
+ Trace::getInstRecord(curTick, cpu->xcBase(tid), cpu,
instruction->staticInst,
- instruction->readPC(), 0);
+ instruction->readPC(),tid);
predicted_branch = lookupAndUpdateNextPC(instruction, next_PC);
// Add instruction to the CPU's list of instructions.
- cpu->addInst(instruction);
+ instruction->setInstListIt(cpu->addInst(instruction));
// Write the instruction to the first slot in the queue
// that heads to decode.
- toDecode->insts[fetched] = instruction;
+ toDecode->insts[numInst] = instruction;
toDecode->size++;
@@ -570,48 +999,221 @@ SimpleFetch<Impl>::fetch()
// Move to the next instruction, unless we have a branch.
fetch_PC = next_PC;
+ if (instruction->isQuiesce()) {
+ warn("%lli: Quiesce instruction encountered, halting fetch!",
+ curTick);
+ fetchStatus[tid] = QuiescePending;
+ ++numInst;
+ status_change = true;
+ break;
+ }
+
offset+= instSize;
}
+ }
- fetch_nisn_dist.sample(fetched);
+ if (numInst > 0) {
+ wroteToTimeBuffer = true;
}
// Now that fetching is completed, update the PC to signify what the next
- // cycle will be. Might want to move this to the beginning of this
- // function so that the PC updates at the beginning of everything.
- // Or might want to leave setting the PC to the main CPU, with fetch
- // only changing the nextPC (will require correct determination of
- // next PC).
+ // cycle will be.
if (fault == NoFault) {
- DPRINTF(Fetch, "Fetch: Setting PC to %08p.\n", next_PC);
- cpu->setPC(next_PC);
- cpu->setNextPC(next_PC + instSize);
+ DPRINTF(Fetch, "[tid:%i]: Setting PC to %08p.\n",tid, next_PC);
+
+ PC[tid] = next_PC;
+ nextPC[tid] = next_PC + instSize;
} else {
- // If the issue was an icache miss, then we can just return and
- // wait until it is handled.
- if (_status == IcacheMissStall) {
- return;
+ // We shouldn't be in an icache miss and also have a fault (an ITB
+ // miss)
+ if (fetchStatus[tid] == IcacheMissStall) {
+ panic("Fetch should have exited prior to this!");
}
- // Handle the fault.
- // This stage will not be able to continue until all the ROB
- // slots are empty, at which point the fault can be handled.
- // The only other way it can wake up is if a squash comes along
- // and changes the PC. Not sure how to handle that case...perhaps
- // have it handled by the upper level CPU class which peeks into the
- // time buffer and sees if a squash comes along, in which case it
- // changes the status.
+ // Send the fault to commit. This thread will not do anything
+ // until commit handles the fault. The only other way it can
+ // wake up is if a squash comes along and changes the PC.
+#if FULL_SYSTEM
+ assert(numInst != fetchWidth);
+ // Get a sequence number.
+ inst_seq = cpu->getAndIncrementInstSeq();
+ // We will use a nop in order to carry the fault.
+ ext_inst = TheISA::NoopMachInst;
- DPRINTF(Fetch, "Fetch: Blocked, need to handle the trap.\n");
+ // Create a new DynInst from the dummy nop.
+ DynInstPtr instruction = new DynInst(ext_inst, fetch_PC,
+ next_PC,
+ inst_seq, cpu);
+ instruction->setPredTarg(next_PC + instSize);
+ instruction->setThread(tid);
- _status = Blocked;
-#if FULL_SYSTEM
-// cpu->trap(fault);
- // Send a signal to the ROB indicating that there's a trap from the
- // fetch stage that needs to be handled. Need to indicate that
- // there's a fault, and the fault type.
+ instruction->setASID(tid);
+
+ instruction->setState(cpu->thread[tid]);
+
+ instruction->traceData = NULL;
+
+ instruction->setInstListIt(cpu->addInst(instruction));
+
+ instruction->fault = fault;
+
+ toDecode->insts[numInst] = instruction;
+ toDecode->size++;
+
+ DPRINTF(Fetch, "[tid:%i]: Blocked, need to handle the trap.\n",tid);
+
+ fetchStatus[tid] = TrapPending;
+ status_change = true;
+
+ warn("%lli fault (%d) detected @ PC %08p", curTick, fault, PC[tid]);
#else // !FULL_SYSTEM
- fatal("fault (%d) detected @ PC %08p", fault, cpu->readPC());
+ fatal("fault (%d) detected @ PC %08p", fault, PC[tid]);
#endif // FULL_SYSTEM
}
}
+
+
+///////////////////////////////////////
+// //
+// SMT FETCH POLICY MAINTAINED HERE //
+// //
+///////////////////////////////////////
+template<class Impl>
+int
+DefaultFetch<Impl>::getFetchingThread(FetchPriority &fetch_priority)
+{
+ if (numThreads > 1) {
+ switch (fetch_priority) {
+
+ case SingleThread:
+ return 0;
+
+ case RoundRobin:
+ return roundRobin();
+
+ case IQ:
+ return iqCount();
+
+ case LSQ:
+ return lsqCount();
+
+ case Branch:
+ return branchCount();
+
+ default:
+ return -1;
+ }
+ } else {
+ int tid = *((*activeThreads).begin());
+
+ if (fetchStatus[tid] == Running ||
+ fetchStatus[tid] == IcacheMissComplete ||
+ fetchStatus[tid] == Idle) {
+ return tid;
+ } else {
+ return -1;
+ }
+ }
+
+}
+
+
+template<class Impl>
+int
+DefaultFetch<Impl>::roundRobin()
+{
+ list<unsigned>::iterator pri_iter = priorityList.begin();
+ list<unsigned>::iterator end = priorityList.end();
+
+ int high_pri;
+
+ while (pri_iter != end) {
+ high_pri = *pri_iter;
+
+ assert(high_pri <= numThreads);
+
+ if (fetchStatus[high_pri] == Running ||
+ fetchStatus[high_pri] == IcacheMissComplete ||
+ fetchStatus[high_pri] == Idle) {
+
+ priorityList.erase(pri_iter);
+ priorityList.push_back(high_pri);
+
+ return high_pri;
+ }
+
+ pri_iter++;
+ }
+
+ return -1;
+}
+
+template<class Impl>
+int
+DefaultFetch<Impl>::iqCount()
+{
+ priority_queue<unsigned> PQ;
+
+ list<unsigned>::iterator threads = (*activeThreads).begin();
+
+ while (threads != (*activeThreads).end()) {
+ unsigned tid = *threads++;
+
+ PQ.push(fromIEW->iewInfo[tid].iqCount);
+ }
+
+ while (!PQ.empty()) {
+
+ unsigned high_pri = PQ.top();
+
+ if (fetchStatus[high_pri] == Running ||
+ fetchStatus[high_pri] == IcacheMissComplete ||
+ fetchStatus[high_pri] == Idle)
+ return high_pri;
+ else
+ PQ.pop();
+
+ }
+
+ return -1;
+}
+
+template<class Impl>
+int
+DefaultFetch<Impl>::lsqCount()
+{
+ priority_queue<unsigned> PQ;
+
+
+ list<unsigned>::iterator threads = (*activeThreads).begin();
+
+ while (threads != (*activeThreads).end()) {
+ unsigned tid = *threads++;
+
+ PQ.push(fromIEW->iewInfo[tid].ldstqCount);
+ }
+
+ while (!PQ.empty()) {
+
+ unsigned high_pri = PQ.top();
+
+ if (fetchStatus[high_pri] == Running ||
+ fetchStatus[high_pri] == IcacheMissComplete ||
+ fetchStatus[high_pri] == Idle)
+ return high_pri;
+ else
+ PQ.pop();
+
+ }
+
+ return -1;
+}
+
+template<class Impl>
+int
+DefaultFetch<Impl>::branchCount()
+{
+ list<unsigned>::iterator threads = (*activeThreads).begin();
+
+ return *threads;
+}