| /* |
| * Copyright (c) 2004-2005 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. |
| */ |
| |
| #include <list> |
| |
| #include "config/full_system.hh" |
| #include "cpu/o3/rename.hh" |
| |
| template <class Impl> |
| SimpleRename<Impl>::SimpleRename(Params ¶ms) |
| : iewToRenameDelay(params.iewToRenameDelay), |
| decodeToRenameDelay(params.decodeToRenameDelay), |
| commitToRenameDelay(params.commitToRenameDelay), |
| renameWidth(params.renameWidth), |
| commitWidth(params.commitWidth), |
| numInst(0) |
| { |
| _status = Idle; |
| } |
| |
| template <class Impl> |
| void |
| SimpleRename<Impl>::regStats() |
| { |
| renameSquashCycles |
| .name(name() + ".renameSquashCycles") |
| .desc("Number of cycles rename is squashing") |
| .prereq(renameSquashCycles); |
| renameIdleCycles |
| .name(name() + ".renameIdleCycles") |
| .desc("Number of cycles rename is idle") |
| .prereq(renameIdleCycles); |
| renameBlockCycles |
| .name(name() + ".renameBlockCycles") |
| .desc("Number of cycles rename is blocking") |
| .prereq(renameBlockCycles); |
| renameUnblockCycles |
| .name(name() + ".renameUnblockCycles") |
| .desc("Number of cycles rename is unblocking") |
| .prereq(renameUnblockCycles); |
| renameRenamedInsts |
| .name(name() + ".renameRenamedInsts") |
| .desc("Number of instructions processed by rename") |
| .prereq(renameRenamedInsts); |
| renameSquashedInsts |
| .name(name() + ".renameSquashedInsts") |
| .desc("Number of squashed instructions processed by rename") |
| .prereq(renameSquashedInsts); |
| renameROBFullEvents |
| .name(name() + ".renameROBFullEvents") |
| .desc("Number of times rename has considered the ROB 'full'") |
| .prereq(renameROBFullEvents); |
| renameIQFullEvents |
| .name(name() + ".renameIQFullEvents") |
| .desc("Number of times rename has considered the IQ 'full'") |
| .prereq(renameIQFullEvents); |
| renameFullRegistersEvents |
| .name(name() + ".renameFullRegisterEvents") |
| .desc("Number of times there has been no free registers") |
| .prereq(renameFullRegistersEvents); |
| renameRenamedOperands |
| .name(name() + ".renameRenamedOperands") |
| .desc("Number of destination operands rename has renamed") |
| .prereq(renameRenamedOperands); |
| renameRenameLookups |
| .name(name() + ".renameRenameLookups") |
| .desc("Number of register rename lookups that rename has made") |
| .prereq(renameRenameLookups); |
| renameHBPlaceHolders |
| .name(name() + ".renameHBPlaceHolders") |
| .desc("Number of place holders added to the history buffer") |
| .prereq(renameHBPlaceHolders); |
| renameCommittedMaps |
| .name(name() + ".renameCommittedMaps") |
| .desc("Number of HB maps that are committed") |
| .prereq(renameCommittedMaps); |
| renameUndoneMaps |
| .name(name() + ".renameUndoneMaps") |
| .desc("Number of HB maps that are undone due to squashing") |
| .prereq(renameUndoneMaps); |
| renameValidUndoneMaps |
| .name(name() + ".renameValidUndoneMaps") |
| .desc("Number of HB maps that are undone, and are not place holders") |
| .prereq(renameValidUndoneMaps); |
| } |
| |
| template <class Impl> |
| void |
| SimpleRename<Impl>::setCPU(FullCPU *cpu_ptr) |
| { |
| DPRINTF(Rename, "Rename: Setting CPU pointer.\n"); |
| cpu = cpu_ptr; |
| } |
| |
| template <class Impl> |
| void |
| SimpleRename<Impl>::setTimeBuffer(TimeBuffer<TimeStruct> *tb_ptr) |
| { |
| DPRINTF(Rename, "Rename: Setting time buffer pointer.\n"); |
| timeBuffer = tb_ptr; |
| |
| // Setup wire to read information from time buffer, from IEW stage. |
| fromIEW = timeBuffer->getWire(-iewToRenameDelay); |
| |
| // Setup wire to read infromation from time buffer, from commit stage. |
| fromCommit = timeBuffer->getWire(-commitToRenameDelay); |
| |
| // Setup wire to write information to previous stages. |
| toDecode = timeBuffer->getWire(0); |
| } |
| |
| template <class Impl> |
| void |
| SimpleRename<Impl>::setRenameQueue(TimeBuffer<RenameStruct> *rq_ptr) |
| { |
| DPRINTF(Rename, "Rename: Setting rename queue pointer.\n"); |
| renameQueue = rq_ptr; |
| |
| // Setup wire to write information to future stages. |
| toIEW = renameQueue->getWire(0); |
| } |
| |
| template <class Impl> |
| void |
| SimpleRename<Impl>::setDecodeQueue(TimeBuffer<DecodeStruct> *dq_ptr) |
| { |
| DPRINTF(Rename, "Rename: Setting decode queue pointer.\n"); |
| decodeQueue = dq_ptr; |
| |
| // Setup wire to get information from decode. |
| fromDecode = decodeQueue->getWire(-decodeToRenameDelay); |
| } |
| |
| template <class Impl> |
| void |
| SimpleRename<Impl>::setRenameMap(RenameMap *rm_ptr) |
| { |
| DPRINTF(Rename, "Rename: Setting rename map pointer.\n"); |
| renameMap = rm_ptr; |
| } |
| |
| template <class Impl> |
| void |
| SimpleRename<Impl>::setFreeList(FreeList *fl_ptr) |
| { |
| DPRINTF(Rename, "Rename: Setting free list pointer.\n"); |
| freeList = fl_ptr; |
| } |
| |
| template <class Impl> |
| void |
| SimpleRename<Impl>::dumpHistory() |
| { |
| typename list<RenameHistory>::iterator buf_it = historyBuffer.begin(); |
| |
| while (buf_it != historyBuffer.end()) |
| { |
| cprintf("Seq num: %i\nArch reg: %i New phys reg: %i Old phys " |
| "reg: %i\n", (*buf_it).instSeqNum, (int)(*buf_it).archReg, |
| (int)(*buf_it).newPhysReg, (int)(*buf_it).prevPhysReg); |
| |
| buf_it++; |
| } |
| } |
| |
| template <class Impl> |
| void |
| SimpleRename<Impl>::block() |
| { |
| DPRINTF(Rename, "Rename: Blocking.\n"); |
| // Set status to Blocked. |
| _status = Blocked; |
| |
| // Add the current inputs onto the skid buffer, so they can be |
| // reprocessed when this stage unblocks. |
| skidBuffer.push(*fromDecode); |
| |
| // Note that this stage only signals previous stages to stall when |
| // it is the cause of the stall originates at this stage. Otherwise |
| // the previous stages are expected to check all possible stall signals. |
| } |
| |
| template <class Impl> |
| inline void |
| SimpleRename<Impl>::unblock() |
| { |
| DPRINTF(Rename, "Rename: Read instructions out of skid buffer this " |
| "cycle.\n"); |
| // Remove the now processed instructions from the skid buffer. |
| skidBuffer.pop(); |
| |
| // If there's still information in the skid buffer, then |
| // continue to tell previous stages to stall. They will be |
| // able to restart once the skid buffer is empty. |
| if (!skidBuffer.empty()) { |
| toDecode->renameInfo.stall = true; |
| } else { |
| DPRINTF(Rename, "Rename: Done unblocking.\n"); |
| _status = Running; |
| } |
| } |
| |
| template <class Impl> |
| void |
| SimpleRename<Impl>::doSquash() |
| { |
| typename list<RenameHistory>::iterator hb_it = historyBuffer.begin(); |
| |
| InstSeqNum squashed_seq_num = fromCommit->commitInfo.doneSeqNum; |
| |
| #if FULL_SYSTEM |
| assert(!historyBuffer.empty()); |
| #else |
| // After a syscall squashes everything, the history buffer may be empty |
| // but the ROB may still be squashing instructions. |
| if (historyBuffer.empty()) { |
| return; |
| } |
| #endif // FULL_SYSTEM |
| |
| // Go through the most recent instructions, undoing the mappings |
| // they did and freeing up the registers. |
| while ((*hb_it).instSeqNum > squashed_seq_num) |
| { |
| assert(hb_it != historyBuffer.end()); |
| |
| DPRINTF(Rename, "Rename: Removing history entry with sequence " |
| "number %i.\n", (*hb_it).instSeqNum); |
| |
| // If it's not simply a place holder, then add the registers. |
| if (!(*hb_it).placeHolder) { |
| // Tell the rename map to set the architected register to the |
| // previous physical register that it was renamed to. |
| renameMap->setEntry(hb_it->archReg, hb_it->prevPhysReg); |
| |
| // Put the renamed physical register back on the free list. |
| freeList->addReg(hb_it->newPhysReg); |
| |
| ++renameValidUndoneMaps; |
| } |
| |
| historyBuffer.erase(hb_it++); |
| |
| ++renameUndoneMaps; |
| } |
| } |
| |
| template <class Impl> |
| void |
| SimpleRename<Impl>::squash() |
| { |
| DPRINTF(Rename, "Rename: Squashing instructions.\n"); |
| // Set the status to Squashing. |
| _status = Squashing; |
| |
| numInst = 0; |
| |
| // Clear the skid buffer in case it has any data in it. |
| while (!skidBuffer.empty()) |
| { |
| skidBuffer.pop(); |
| } |
| |
| doSquash(); |
| } |
| |
| template<class Impl> |
| void |
| SimpleRename<Impl>::removeFromHistory(InstSeqNum inst_seq_num) |
| { |
| DPRINTF(Rename, "Rename: Removing a committed instruction from the " |
| "history buffer, until sequence number %lli.\n", inst_seq_num); |
| typename list<RenameHistory>::iterator hb_it = historyBuffer.end(); |
| |
| --hb_it; |
| |
| if (hb_it->instSeqNum > inst_seq_num) { |
| DPRINTF(Rename, "Rename: Old sequence number encountered. Ensure " |
| "that a syscall happened recently.\n"); |
| return; |
| } |
| |
| while ((*hb_it).instSeqNum != inst_seq_num) |
| { |
| // Make sure we haven't gone off the end of the list. |
| assert(hb_it != historyBuffer.end()); |
| |
| // In theory instructions at the end of the history buffer |
| // should be older than the instruction being removed, which |
| // means they will have a lower sequence number. Also the |
| // instruction being removed from the history really should |
| // be the last instruction in the list, as it is the instruction |
| // that was just committed that is being removed. |
| assert(hb_it->instSeqNum < inst_seq_num); |
| DPRINTF(Rename, "Rename: Freeing up older rename of reg %i, sequence" |
| " number %i.\n", |
| (*hb_it).prevPhysReg, (*hb_it).instSeqNum); |
| |
| if (!(*hb_it).placeHolder) { |
| freeList->addReg((*hb_it).prevPhysReg); |
| ++renameCommittedMaps; |
| } |
| |
| historyBuffer.erase(hb_it--); |
| } |
| |
| // Finally free up the previous register of the finished instruction |
| // itself. |
| if (!(*hb_it).placeHolder) { |
| freeList->addReg(hb_it->prevPhysReg); |
| ++renameCommittedMaps; |
| } |
| |
| historyBuffer.erase(hb_it); |
| } |
| |
| template <class Impl> |
| inline void |
| SimpleRename<Impl>::renameSrcRegs(DynInstPtr &inst) |
| { |
| unsigned num_src_regs = inst->numSrcRegs(); |
| |
| // Get the architectual register numbers from the source and |
| // destination operands, and redirect them to the right register. |
| // Will need to mark dependencies though. |
| for (int src_idx = 0; src_idx < num_src_regs; src_idx++) |
| { |
| RegIndex src_reg = inst->srcRegIdx(src_idx); |
| |
| // Look up the source registers to get the phys. register they've |
| // been renamed to, and set the sources to those registers. |
| PhysRegIndex renamed_reg = renameMap->lookup(src_reg); |
| |
| DPRINTF(Rename, "Rename: Looking up arch reg %i, got " |
| "physical reg %i.\n", (int)src_reg, (int)renamed_reg); |
| |
| inst->renameSrcReg(src_idx, renamed_reg); |
| |
| // Either incorporate it into the info passed back, |
| // or make another function call to see if that register is |
| // ready or not. |
| if (renameMap->isReady(renamed_reg)) { |
| DPRINTF(Rename, "Rename: Register is ready.\n"); |
| |
| inst->markSrcRegReady(src_idx); |
| } |
| |
| ++renameRenameLookups; |
| } |
| } |
| |
| template <class Impl> |
| inline void |
| SimpleRename<Impl>::renameDestRegs(DynInstPtr &inst) |
| { |
| typename SimpleRenameMap::RenameInfo rename_result; |
| |
| unsigned num_dest_regs = inst->numDestRegs(); |
| |
| // If it's an instruction with no destination registers, then put |
| // a placeholder within the history buffer. It might be better |
| // to not put it in the history buffer at all (other than branches, |
| // which always need at least a place holder), and differentiate |
| // between instructions with and without destination registers |
| // when getting from commit the instructions that committed. |
| if (num_dest_regs == 0) { |
| RenameHistory hb_entry(inst->seqNum); |
| |
| historyBuffer.push_front(hb_entry); |
| |
| DPRINTF(Rename, "Rename: Adding placeholder instruction to " |
| "history buffer, sequence number %lli.\n", |
| inst->seqNum); |
| |
| ++renameHBPlaceHolders; |
| } else { |
| |
| // Rename the destination registers. |
| for (int dest_idx = 0; dest_idx < num_dest_regs; dest_idx++) |
| { |
| RegIndex dest_reg = inst->destRegIdx(dest_idx); |
| |
| // Get the physical register that the destination will be |
| // renamed to. |
| rename_result = renameMap->rename(dest_reg); |
| |
| DPRINTF(Rename, "Rename: Renaming arch reg %i to physical " |
| "reg %i.\n", (int)dest_reg, |
| (int)rename_result.first); |
| |
| // Record the rename information so that a history can be kept. |
| RenameHistory hb_entry(inst->seqNum, dest_reg, |
| rename_result.first, |
| rename_result.second); |
| |
| historyBuffer.push_front(hb_entry); |
| |
| DPRINTF(Rename, "Rename: Adding instruction to history buffer, " |
| "sequence number %lli.\n", |
| (*historyBuffer.begin()).instSeqNum); |
| |
| // Tell the instruction to rename the appropriate destination |
| // register (dest_idx) to the new physical register |
| // (rename_result.first), and record the previous physical |
| // register that the same logical register was renamed to |
| // (rename_result.second). |
| inst->renameDestReg(dest_idx, |
| rename_result.first, |
| rename_result.second); |
| |
| ++renameRenamedOperands; |
| } |
| } |
| } |
| |
| template <class Impl> |
| inline int |
| SimpleRename<Impl>::calcFreeROBEntries() |
| { |
| return fromCommit->commitInfo.freeROBEntries - |
| renameWidth * iewToRenameDelay; |
| } |
| |
| template <class Impl> |
| inline int |
| SimpleRename<Impl>::calcFreeIQEntries() |
| { |
| return fromIEW->iewInfo.freeIQEntries - renameWidth * iewToRenameDelay; |
| } |
| |
| template<class Impl> |
| void |
| SimpleRename<Impl>::tick() |
| { |
| // Rename will need to try to rename as many instructions as it |
| // has bandwidth, unless it is blocked. |
| |
| // Check if _status is BarrierStall. If so, then check if the number |
| // of free ROB entries is equal to the number of total ROB entries. |
| // Once equal then wake this stage up. Set status to unblocking maybe. |
| |
| if (_status != Blocked && _status != Squashing) { |
| DPRINTF(Rename, "Rename: Status is not blocked, will attempt to " |
| "run stage.\n"); |
| // Make sure that the skid buffer has something in it if the |
| // status is unblocking. |
| assert(_status == Unblocking ? !skidBuffer.empty() : 1); |
| |
| rename(); |
| |
| // If the status was unblocking, then instructions from the skid |
| // buffer were used. Remove those instructions and handle |
| // the rest of unblocking. |
| if (_status == Unblocking) { |
| ++renameUnblockCycles; |
| |
| if (fromDecode->size > 0) { |
| // Add the current inputs onto the skid buffer, so they can be |
| // reprocessed when this stage unblocks. |
| skidBuffer.push(*fromDecode); |
| } |
| |
| unblock(); |
| } |
| } else if (_status == Blocked) { |
| ++renameBlockCycles; |
| |
| // If stage is blocked and still receiving valid instructions, |
| // make sure to store them in the skid buffer. |
| if (fromDecode->size > 0) { |
| |
| block(); |
| |
| // Continue to tell previous stage to stall. |
| toDecode->renameInfo.stall = true; |
| } |
| |
| if (!fromIEW->iewInfo.stall && |
| !fromCommit->commitInfo.stall && |
| calcFreeROBEntries() > 0 && |
| calcFreeIQEntries() > 0 && |
| renameMap->numFreeEntries() > 0) { |
| |
| // Need to be sure to check all blocking conditions above. |
| // If they have cleared, then start unblocking. |
| DPRINTF(Rename, "Rename: Stall signals cleared, going to " |
| "unblock.\n"); |
| _status = Unblocking; |
| |
| // Continue to tell previous stage to block until this stage |
| // is done unblocking. |
| toDecode->renameInfo.stall = true; |
| } else { |
| // Otherwise no conditions have changed. Tell previous |
| // stage to continue blocking. |
| toDecode->renameInfo.stall = true; |
| } |
| |
| if (fromCommit->commitInfo.squash || |
| fromCommit->commitInfo.robSquashing) { |
| squash(); |
| return; |
| } |
| } else if (_status == Squashing) { |
| ++renameSquashCycles; |
| |
| if (fromCommit->commitInfo.squash) { |
| squash(); |
| } else if (!fromCommit->commitInfo.squash && |
| !fromCommit->commitInfo.robSquashing) { |
| |
| DPRINTF(Rename, "Rename: Done squashing, going to running.\n"); |
| _status = Running; |
| rename(); |
| } else { |
| doSquash(); |
| } |
| } |
| |
| // Ugly code, revamp all of the tick() functions eventually. |
| if (fromCommit->commitInfo.doneSeqNum != 0 && _status != Squashing) { |
| #if !FULL_SYSTEM |
| if (!fromCommit->commitInfo.squash) { |
| removeFromHistory(fromCommit->commitInfo.doneSeqNum); |
| } |
| #else |
| removeFromHistory(fromCommit->commitInfo.doneSeqNum); |
| #endif |
| } |
| |
| } |
| |
| template<class Impl> |
| void |
| SimpleRename<Impl>::rename() |
| { |
| // Check if any of the stages ahead of rename are telling rename |
| // to squash. The squash() function will also take care of fixing up |
| // the rename map and the free list. |
| if (fromCommit->commitInfo.squash || |
| fromCommit->commitInfo.robSquashing) { |
| DPRINTF(Rename, "Rename: Receiving signal from Commit to squash.\n"); |
| squash(); |
| return; |
| } |
| |
| // Check if time buffer is telling this stage to stall. |
| if (fromIEW->iewInfo.stall || |
| fromCommit->commitInfo.stall) { |
| DPRINTF(Rename, "Rename: Receiving signal from IEW/Commit to " |
| "stall.\n"); |
| block(); |
| return; |
| } |
| |
| // Check if the current status is squashing. If so, set its status |
| // to running and resume execution the next cycle. |
| if (_status == Squashing) { |
| DPRINTF(Rename, "Rename: Done squashing.\n"); |
| _status = Running; |
| return; |
| } |
| |
| // Check the decode queue to see if instructions are available. |
| // If there are no available instructions to rename, then do nothing. |
| // Or, if the stage is currently unblocking, then go ahead and run it. |
| if (fromDecode->size == 0 && _status != Unblocking) { |
| DPRINTF(Rename, "Rename: Nothing to do, breaking out early.\n"); |
| // Should I change status to idle? |
| return; |
| } |
| |
| //////////////////////////////////// |
| // Actual rename part. |
| //////////////////////////////////// |
| |
| DynInstPtr inst; |
| |
| // If we're unblocking, then we may be in the middle of an instruction |
| // group. Subtract off numInst to get the proper number of instructions |
| // left. |
| int insts_available = _status == Unblocking ? |
| skidBuffer.front().size - numInst : |
| fromDecode->size; |
| |
| bool block_this_cycle = false; |
| |
| // Will have to do a different calculation for the number of free |
| // entries. Number of free entries recorded on this cycle - |
| // renameWidth * renameToDecodeDelay |
| int free_rob_entries = calcFreeROBEntries(); |
| int free_iq_entries = calcFreeIQEntries(); |
| int min_iq_rob = min(free_rob_entries, free_iq_entries); |
| |
| unsigned to_iew_index = 0; |
| |
| // Check if there's any space left. |
| if (min_iq_rob <= 0) { |
| DPRINTF(Rename, "Rename: Blocking due to no free ROB or IQ " |
| "entries.\n" |
| "Rename: ROB has %d free entries.\n" |
| "Rename: IQ has %d free entries.\n", |
| free_rob_entries, |
| free_iq_entries); |
| block(); |
| // Tell previous stage to stall. |
| toDecode->renameInfo.stall = true; |
| |
| if (free_rob_entries <= 0) { |
| ++renameROBFullEvents; |
| } else { |
| ++renameIQFullEvents; |
| } |
| |
| return; |
| } else if (min_iq_rob < insts_available) { |
| DPRINTF(Rename, "Rename: Will have to block this cycle. Only " |
| "%i insts can be renamed due to IQ/ROB limits.\n", |
| min_iq_rob); |
| |
| insts_available = min_iq_rob; |
| |
| block_this_cycle = true; |
| |
| if (free_rob_entries < free_iq_entries) { |
| ++renameROBFullEvents; |
| } else { |
| ++renameIQFullEvents; |
| } |
| } |
| |
| while (insts_available > 0) { |
| DPRINTF(Rename, "Rename: Sending instructions to iew.\n"); |
| |
| // Get the next instruction either from the skid buffer or the |
| // decode queue. |
| inst = _status == Unblocking ? skidBuffer.front().insts[numInst] : |
| fromDecode->insts[numInst]; |
| |
| if (inst->isSquashed()) { |
| DPRINTF(Rename, "Rename: instruction %i with PC %#x is " |
| "squashed, skipping.\n", |
| inst->seqNum, inst->readPC()); |
| |
| // Go to the next instruction. |
| ++numInst; |
| |
| ++renameSquashedInsts; |
| |
| // Decrement how many instructions are available. |
| --insts_available; |
| |
| continue; |
| } |
| |
| DPRINTF(Rename, "Rename: Processing instruction %i with PC %#x.\n", |
| inst->seqNum, inst->readPC()); |
| |
| // If it's a trap instruction, then it needs to wait here within |
| // rename until the ROB is empty. Needs a way to detect that the |
| // ROB is empty. Maybe an event? |
| // Would be nice if it could be avoided putting this into a |
| // specific stage and instead just put it into the AlphaFullCPU. |
| // Might not really be feasible though... |
| // (EXCB, TRAPB) |
| if (inst->isSerializing()) { |
| panic("Rename: Serializing instruction encountered.\n"); |
| DPRINTF(Rename, "Rename: Serializing instruction " |
| "encountered.\n"); |
| |
| // Change status over to BarrierStall so that other stages know |
| // what this is blocked on. |
| _status = BarrierStall; |
| |
| block_this_cycle = true; |
| |
| break; |
| } |
| |
| // Check here to make sure there are enough destination registers |
| // to rename to. Otherwise block. |
| if (renameMap->numFreeEntries() < inst->numDestRegs()) |
| { |
| DPRINTF(Rename, "Rename: Blocking due to lack of free " |
| "physical registers to rename to.\n"); |
| // Need some sort of event based on a register being freed. |
| |
| block_this_cycle = true; |
| |
| ++renameFullRegistersEvents; |
| |
| break; |
| } |
| |
| renameSrcRegs(inst); |
| |
| renameDestRegs(inst); |
| |
| // Put instruction in rename queue. |
| toIEW->insts[to_iew_index] = inst; |
| ++(toIEW->size); |
| |
| // Decrease the number of free ROB and IQ entries. |
| --free_rob_entries; |
| --free_iq_entries; |
| |
| // Increment which instruction we're on. |
| ++to_iew_index; |
| ++numInst; |
| |
| ++renameRenamedInsts; |
| |
| // Decrement how many instructions are available. |
| --insts_available; |
| } |
| |
| // Check if there's any instructions left that haven't yet been renamed. |
| // If so then block. |
| if (block_this_cycle) { |
| block(); |
| |
| toDecode->renameInfo.stall = true; |
| } else { |
| // If we had a successful rename and didn't have to exit early, then |
| // reset numInst so it will refer to the correct instruction on next |
| // run. |
| numInst = 0; |
| } |
| } |
