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#include <map>
#include "cpu/beta_cpu/mem_dep_unit.hh"
// Hack: dependence predictor sizes are hardcoded.
template <class MemDepPred, class Impl>
MemDepUnit<MemDepPred, Impl>::MemDepUnit(Params ¶ms)
: depPred(4028, 128)
{
DPRINTF(MemDepUnit, "MemDepUnit: Creating MemDepUnit object.\n");
}
template <class MemDepPred, class Impl>
void
MemDepUnit<MemDepPred, Impl>::insert(DynInstPtr &inst)
{
InstSeqNum inst_seq_num = inst->seqNum;
InstSeqNum producing_store = depPred.checkInst(inst->readPC());
if (producing_store == 0 ||
dependencies.find(producing_store) == dependencies.end()) {
readyInsts.insert(inst_seq_num);
} else {
// If it's not already ready, then add it to the renamed
// list and the dependencies.
renamedInsts.insert(inst_seq_num);
dependencies[producing_store].push_back(inst_seq_num);
}
if (inst->isStore()) {
depPred.insertStore(inst->readPC(), inst_seq_num);
// Make sure this store isn't already in this list.
assert(dependencies.find(inst_seq_num) == dependencies.end());
// Put a dependency entry in at the store's sequence number.
// Uh, not sure how this works...I want to create an entry but
// I don't have anything to put into the value yet.
dependencies[inst_seq_num];
} else if (!inst->isLoad()) {
panic("MemDepUnit: Unknown type! (most likely a barrier).");
}
}
template <class MemDepPred, class Impl>
bool
MemDepUnit<MemDepPred, Impl>::readyToIssue(DynInstPtr &inst)
{
InstSeqNum inst_seq_num = inst->seqNum;
if (readyInsts.find(inst_seq_num) == readyInsts.end()) {
return false;
} else {
return true;
}
}
template <class MemDepPred, class Impl>
void
MemDepUnit<MemDepPred, Impl>::issue(DynInstPtr &inst)
{
assert(readyInsts.find(inst->seqNum) != readyInsts.end());
// Remove the instruction from the ready list.
readyInsts.erase(inst->seqNum);
}
template <class MemDepPred, class Impl>
void
MemDepUnit<MemDepPred, Impl>::wakeDependents(DynInstPtr &inst)
{
// Wake any dependencies.
dep_it_t dep_it = dependencies.find(inst);
// If there's no entry, then return. Really there should only be
// no entry if the instruction is a load.
if (dep_it == dependencies.end()) {
return;
}
assert(inst->isStore());
for(int i = 0; i < (*dep_it).second.size(); ++i ) {
InstSeqNum woken_inst = (*dep_it).second[i];
// Should we have reached instructions that are actually squashed,
// there will be no more useful instructions in this dependency
// list. Break out early.
if (renamedInsts.find(woken_inst) == renamedInsts.end()) {
DPRINTF(MemDepUnit, "MemDepUnit: Dependents on inst PC %#x "
"are squashed, starting at SN %i. Breaking early.\n",
inst->readPC(), woken_inst);
break;
}
// Remove it from the renamed instructions.
renamedInsts.erase(woken_inst);
// Add it to the ready list.
readyInsts.insert(woken_inst);
}
dependencies.erase(dep_it);
}
template <class MemDepPred, class Impl>
void
MemDepUnit<MemDepPred, Impl>::squash(const InstSeqNum &squashed_num)
{
if (!renamedInsts.empty()) {
sn_it_t renamed_it = renamedInsts.end();
--renamed_it;
// Remove entries from the renamed list as long as we haven't reached
// the end and the entries continue to be younger than the squashed.
while (!renamedInsts.empty() &&
(*renamed_it) > squashed_num)
{
renamedInsts.erase(renamed_it--);
}
}
if (!readyInsts.empty()) {
sn_it_t ready_it = readyInsts.end();
--ready_it;
// Same for the ready list.
while (!readyInsts.empty() &&
(*ready_it) > squashed_num)
{
readyInsts.erase(ready_it--);
}
}
if (!dependencies.empty()) {
dep_it_t dep_it = dependencies.end();
--dep_it;
// Same for the dependencies list.
while (!dependencies.empty() &&
(*dep_it).first > squashed_num)
{
dependencies.erase(dep_it--);
}
}
// Tell the dependency predictor to squash as well.
depPred.squash(squashed_num);
}
template <class MemDepPred, class Impl>
void
MemDepUnit<MemDepPred, Impl>::violation(DynInstPtr &store_inst,
DynInstPtr &violating_load)
{
// Tell the memory dependence unit of the violation.
depPred.violation(violating_load->readPC(), store_inst->readPC());
}
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