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