src/mem/ruby/protocol/MOESI_CMP_directory-L1cache.sm

/*
 * Copyright (c) 2019 ARM Limited
 * All rights reserved
 *
 * The license below extends only to copyright in the software and shall
 * not be construed as granting a license to any other intellectual
 * property including but not limited to intellectual property relating
 * to a hardware implementation of the functionality of the software
 * licensed hereunder.  You may use the software subject to the license
 * terms below provided that you ensure that this notice is replicated
 * unmodified and in its entirety in all distributions of the software,
 * modified or unmodified, in source code or in binary form.
 *
 * Copyright (c) 1999-2013 Mark D. Hill and David A. Wood
 * 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.
 */

machine(MachineType:L1Cache, "L1 cache protocol")
 : Sequencer * sequencer;
   CacheMemory * L1Icache;
   CacheMemory * L1Dcache;
   Cycles request_latency := 1;
   Cycles response_latency := 1;
   Cycles use_timeout_latency := 50;
   bool send_evictions;

   // Message Queues
   // From this node's L1 cache TO the network
   // a local L1 -> this L2 bank, currently ordered with directory forwarded requests
   MessageBuffer * requestFromL1Cache, network="To", virtual_network="0",
        vnet_type="request";
   // a local L1 -> this L2 bank
   MessageBuffer * responseFromL1Cache, network="To", virtual_network="2",
        vnet_type="response";

   // To this node's L1 cache FROM the network
   // a L2 bank -> this L1
   MessageBuffer * requestToL1Cache, network="From", virtual_network="0",
        vnet_type="request";
   // a L2 bank -> this L1
   MessageBuffer * responseToL1Cache, network="From", virtual_network="2",
        vnet_type="response";

   MessageBuffer * triggerQueue;

   MessageBuffer * mandatoryQueue;
{
  // STATES
  state_declaration(State, desc="Cache states", default="L1Cache_State_I") {
    // Base states
    I, AccessPermission:Invalid, desc="Idle";
    S, AccessPermission:Read_Only, desc="Shared";
    O, AccessPermission:Read_Only, desc="Owned";
    M, AccessPermission:Read_Only, desc="Modified (dirty)";
    M_W, AccessPermission:Read_Only, desc="Modified (dirty)";
    MM, AccessPermission:Read_Write, desc="Modified (dirty and locally modified)";
    MM_W, AccessPermission:Read_Write, desc="Modified (dirty and locally modified)";

    // Transient States
    IM, AccessPermission:Busy, "IM", desc="Issued GetX";
    SM, AccessPermission:Read_Only, "SM", desc="Issued GetX, we still have an old copy of the line";
    OM, AccessPermission:Read_Only, "SM", desc="Issued GetX, received data";
    IS, AccessPermission:Busy, "IS", desc="Issued GetS";
    SI, AccessPermission:Busy, "OI", desc="Issued PutS, waiting for ack";
    OI, AccessPermission:Busy, "OI", desc="Issued PutO, waiting for ack";
    MI, AccessPermission:Busy, "MI", desc="Issued PutX, waiting for ack";
    II, AccessPermission:Busy, "II", desc="Issued PutX/O, saw Fwd_GETS or Fwd_GETX, waiting for ack";
  }

  // EVENTS
  enumeration(Event, desc="Cache events") {
    Load,            desc="Load request from the processor";
    Ifetch,          desc="I-fetch request from the processor";
    Store,           desc="Store request from the processor";
    L1_Replacement,  desc="Replacement";

    // Requests
    Own_GETX,      desc="We observe our own GetX forwarded back to us";
    Fwd_GETX,      desc="A GetX from another processor";
    Fwd_GETS,      desc="A GetS from another processor";
    Fwd_DMA,      desc="A GetS from another processor";
    Inv,           desc="Invalidations from the directory";

    // Responses
    Ack,             desc="Received an ack message";
    Data,            desc="Received a data message, responder has a shared copy";
    Exclusive_Data,  desc="Received a data message";

    Writeback_Ack,   desc="Writeback O.K. from directory";
    Writeback_Ack_Data,   desc="Writeback O.K. from directory";
    Writeback_Nack,  desc="Writeback not O.K. from directory";

    // Triggers
    All_acks,                  desc="Received all required data and message acks";

    // Timeouts
    Use_Timeout, desc="lockout period ended";
  }

  // TYPES

  // CacheEntry
  structure(Entry, desc="...", interface="AbstractCacheEntry") {
    State CacheState,        desc="cache state";
    bool Dirty,              desc="Is the data dirty (different than memory)?";
    DataBlock DataBlk,       desc="data for the block";
  }

  // TBE fields
  structure(TBE, desc="...") {
    Addr addr,         desc="Physical address for this TBE";
    State TBEState,          desc="Transient state";
    DataBlock DataBlk,       desc="data for the block, required for concurrent writebacks";
    bool Dirty,              desc="Is the data dirty (different than memory)?";
    int NumPendingMsgs, default="0",     desc="Number of acks/data messages that this processor is waiting for";
  }

  structure(TBETable, external ="yes") {
    TBE lookup(Addr);
    void allocate(Addr);
    void deallocate(Addr);
    bool isPresent(Addr);
  }

  Tick clockEdge();
  Tick cyclesToTicks(Cycles c);
  void set_cache_entry(AbstractCacheEntry b);
  void unset_cache_entry();
  void set_tbe(TBE b);
  void unset_tbe();
  MachineID mapAddressToMachine(Addr addr, MachineType mtype);

  TBETable TBEs, template="<L1Cache_TBE>", constructor="m_number_of_TBEs";
  TimerTable useTimerTable;

  Entry getCacheEntry(Addr addr), return_by_pointer="yes" {
    Entry L1Dcache_entry := static_cast(Entry, "pointer", L1Dcache.lookup(addr));
    if(is_valid(L1Dcache_entry)) {
      return L1Dcache_entry;
    }

    Entry L1Icache_entry := static_cast(Entry, "pointer", L1Icache.lookup(addr));
    return L1Icache_entry;
  }

  Entry getL1DCacheEntry(Addr addr), return_by_pointer="yes" {
    return static_cast(Entry, "pointer", L1Dcache.lookup(addr));
  }

  Entry getL1ICacheEntry(Addr addr), return_by_pointer="yes" {
    return static_cast(Entry, "pointer", L1Icache.lookup(addr));
  }

  State getState(TBE tbe, Entry cache_entry, Addr addr) {
    if(is_valid(tbe)) {
      return tbe.TBEState;
    } else if (is_valid(cache_entry)) {
      return cache_entry.CacheState;
    }
    return State:I;
  }

  // L1 hit latency
  Cycles mandatoryQueueLatency(RubyRequestType type) {
    if (type == RubyRequestType:IFETCH) {
      return L1Icache.getTagLatency();
    } else {
      return L1Dcache.getTagLatency();
    }
  }

  // Latency for responses that fetch data from cache
  Cycles cacheResponseLatency() {
    if (L1Dcache.getTagLatency() > response_latency) {
      return L1Dcache.getTagLatency();
    } else {
      return response_latency;
    }
  }

  void setState(TBE tbe, Entry cache_entry, Addr addr, State state) {
    assert((L1Dcache.isTagPresent(addr) && L1Icache.isTagPresent(addr)) == false);

    if (is_valid(tbe)) {
      tbe.TBEState := state;
    }

    if (is_valid(cache_entry)) {
      if ( ((cache_entry.CacheState != State:M) && (state == State:M)) ||
         ((cache_entry.CacheState != State:MM) && (state == State:MM)) ||
         ((cache_entry.CacheState != State:S) && (state == State:S)) ||
         ((cache_entry.CacheState != State:O) && (state == State:O)) ) {

        cache_entry.CacheState := state;
        sequencer.checkCoherence(addr);
      }
      else {
        cache_entry.CacheState := state;
      }
    }
  }

  AccessPermission getAccessPermission(Addr addr) {
    TBE tbe := TBEs[addr];
    if(is_valid(tbe)) {
      DPRINTF(RubySlicc, "%s\n", L1Cache_State_to_permission(tbe.TBEState));
      return L1Cache_State_to_permission(tbe.TBEState);
    }

    Entry cache_entry := getCacheEntry(addr);
    if(is_valid(cache_entry)) {
      DPRINTF(RubySlicc, "%s\n", L1Cache_State_to_permission(cache_entry.CacheState));
      return L1Cache_State_to_permission(cache_entry.CacheState);
    }

    DPRINTF(RubySlicc, "AccessPermission_NotPresent\n");
    return AccessPermission:NotPresent;
  }

  void setAccessPermission(Entry cache_entry, Addr addr, State state) {
    if (is_valid(cache_entry)) {
      cache_entry.changePermission(L1Cache_State_to_permission(state));
    }
  }

  void functionalRead(Addr addr, Packet *pkt) {
    Entry cache_entry := getCacheEntry(addr);
    if(is_valid(cache_entry)) {
      testAndRead(addr, cache_entry.DataBlk, pkt);
    } else {
      TBE tbe := TBEs[addr];
      if(is_valid(tbe)) {
        testAndRead(addr, tbe.DataBlk, pkt);
      } else {
        error("Data block missing!");
      }
    }
  }

  int functionalWrite(Addr addr, Packet *pkt) {
    int num_functional_writes := 0;

    Entry cache_entry := getCacheEntry(addr);
    if(is_valid(cache_entry)) {
      num_functional_writes := num_functional_writes +
        testAndWrite(addr, cache_entry.DataBlk, pkt);
      return num_functional_writes;
    }

    TBE tbe := TBEs[addr];
    num_functional_writes := num_functional_writes +
        testAndWrite(addr, tbe.DataBlk, pkt);
    return num_functional_writes;
  }

  Event mandatory_request_type_to_event(RubyRequestType type) {
    if (type == RubyRequestType:LD) {
      return Event:Load;
    } else if (type == RubyRequestType:IFETCH) {
      return Event:Ifetch;
    } else if ((type == RubyRequestType:ST) || (type == RubyRequestType:ATOMIC)) {
      return Event:Store;
    } else {
      error("Invalid RubyRequestType");
    }
  }

  // ** OUT_PORTS **

  out_port(requestNetwork_out, RequestMsg, requestFromL1Cache);
  out_port(responseNetwork_out, ResponseMsg, responseFromL1Cache);
  out_port(triggerQueue_out, TriggerMsg, triggerQueue);

  // ** IN_PORTS **

  // Use Timer
  in_port(useTimerTable_in, Addr, useTimerTable, rank=4) {
    if (useTimerTable_in.isReady(clockEdge())) {
        Addr readyAddress := useTimerTable.nextAddress();
        trigger(Event:Use_Timeout, readyAddress, getCacheEntry(readyAddress),
                TBEs.lookup(readyAddress));
    }
  }

  // Trigger Queue
  in_port(triggerQueue_in, TriggerMsg, triggerQueue, rank=3) {
    if (triggerQueue_in.isReady(clockEdge())) {
      peek(triggerQueue_in, TriggerMsg) {
        if (in_msg.Type == TriggerType:ALL_ACKS) {
          trigger(Event:All_acks, in_msg.addr,
                  getCacheEntry(in_msg.addr), TBEs[in_msg.addr]);
        } else {
          error("Unexpected message");
        }
      }
    }
  }

  // Response Network
  in_port(responseToL1Cache_in, ResponseMsg, responseToL1Cache, rank=2) {
    if (responseToL1Cache_in.isReady(clockEdge())) {
      peek(responseToL1Cache_in, ResponseMsg, block_on="addr") {
        if (in_msg.Type == CoherenceResponseType:ACK) {
          trigger(Event:Ack, in_msg.addr,
                  getCacheEntry(in_msg.addr), TBEs[in_msg.addr]);
        } else if (in_msg.Type == CoherenceResponseType:DATA) {
          trigger(Event:Data, in_msg.addr,
                  getCacheEntry(in_msg.addr), TBEs[in_msg.addr]);
        } else if (in_msg.Type == CoherenceResponseType:DATA_EXCLUSIVE) {
          trigger(Event:Exclusive_Data, in_msg.addr,
                  getCacheEntry(in_msg.addr), TBEs[in_msg.addr]);
        } else if (in_msg.Type == CoherenceResponseType:WB_ACK) {
          trigger(Event:Writeback_Ack, in_msg.addr,
                  getCacheEntry(in_msg.addr), TBEs[in_msg.addr]);
        } else if (in_msg.Type == CoherenceResponseType:WB_ACK_DATA) {
          trigger(Event:Writeback_Ack_Data, in_msg.addr,
                  getCacheEntry(in_msg.addr), TBEs[in_msg.addr]);
        } else if (in_msg.Type == CoherenceResponseType:WB_NACK) {
          trigger(Event:Writeback_Nack, in_msg.addr,
                  getCacheEntry(in_msg.addr), TBEs[in_msg.addr]);
        } else {
          error("Unexpected message");
        }
      }
    }
  }


  // Request Network
  in_port(requestNetwork_in, RequestMsg, requestToL1Cache, rank=1) {
    if (requestNetwork_in.isReady(clockEdge())) {
      peek(requestNetwork_in, RequestMsg, block_on="addr") {
        assert(in_msg.Destination.isElement(machineID));
        DPRINTF(RubySlicc, "L1 received: %s\n", in_msg.Type);

        if (in_msg.Type == CoherenceRequestType:GETX || in_msg.Type == CoherenceRequestType:DMA_WRITE) {
          if (in_msg.Requestor == machineID && in_msg.RequestorMachine == MachineType:L1Cache) {
            trigger(Event:Own_GETX, in_msg.addr,
                    getCacheEntry(in_msg.addr), TBEs[in_msg.addr]);
          } else {
            trigger(Event:Fwd_GETX, in_msg.addr,
                    getCacheEntry(in_msg.addr), TBEs[in_msg.addr]);
          }
        } else if (in_msg.Type == CoherenceRequestType:GETS) {
          trigger(Event:Fwd_GETS, in_msg.addr,
                  getCacheEntry(in_msg.addr), TBEs[in_msg.addr]);
        } else if (in_msg.Type == CoherenceRequestType:DMA_READ) {
          trigger(Event:Fwd_DMA, in_msg.addr,
                  getCacheEntry(in_msg.addr), TBEs[in_msg.addr]);
        } else if (in_msg.Type == CoherenceRequestType:INV) {
          trigger(Event:Inv, in_msg.addr,
                  getCacheEntry(in_msg.addr), TBEs[in_msg.addr]);
        } else {
          error("Unexpected message");
        }
      }
    }
  }

  // Mandatory Queue betweens Node's CPU and it's L1 caches
  in_port(mandatoryQueue_in, RubyRequest, mandatoryQueue, rank=0) {
    if (mandatoryQueue_in.isReady(clockEdge())) {
      peek(mandatoryQueue_in, RubyRequest, block_on="LineAddress") {

        // Check for data access to blocks in I-cache and ifetchs to blocks in D-cache

        if (in_msg.Type == RubyRequestType:IFETCH) {
          // ** INSTRUCTION ACCESS ***

          Entry L1Icache_entry := getL1ICacheEntry(in_msg.LineAddress);
          if (is_valid(L1Icache_entry)) {
            // The tag matches for the L1, so the L1 asks the L2 for it.
            trigger(mandatory_request_type_to_event(in_msg.Type),
                    in_msg.LineAddress, L1Icache_entry,
                    TBEs[in_msg.LineAddress]);
          } else {

            Entry L1Dcache_entry := getL1DCacheEntry(in_msg.LineAddress);
            // Check to see if it is in the OTHER L1
            if (is_valid(L1Dcache_entry)) {
              // The block is in the wrong L1, put the request on the queue to the shared L2
              trigger(Event:L1_Replacement, in_msg.LineAddress, L1Dcache_entry,
                      TBEs[in_msg.LineAddress]);
            }
            if (L1Icache.cacheAvail(in_msg.LineAddress)) {
              // L1 does't have the line, but we have space for it in the L1 so let's see if the L2 has it
              trigger(mandatory_request_type_to_event(in_msg.Type),
                      in_msg.LineAddress, L1Icache_entry,
                      TBEs[in_msg.LineAddress]);
            } else {
              // No room in the L1, so we need to make room in the L1
              // Check if the line we want to evict is not locked
              Addr addr := L1Icache.cacheProbe(in_msg.LineAddress);
              check_on_cache_probe(mandatoryQueue_in, addr);
              trigger(Event:L1_Replacement,
                      addr,
                      getL1ICacheEntry(addr),
                      TBEs[addr]);
            }
          }
        } else {
          // *** DATA ACCESS ***

          Entry L1Dcache_entry := getL1DCacheEntry(in_msg.LineAddress);
          if (is_valid(L1Dcache_entry)) {
            // The tag matches for the L1, so the L1 ask the L2 for it
            trigger(mandatory_request_type_to_event(in_msg.Type),
                    in_msg.LineAddress, L1Dcache_entry,
                    TBEs[in_msg.LineAddress]);
          } else {

            Entry L1Icache_entry := getL1ICacheEntry(in_msg.LineAddress);
            // Check to see if it is in the OTHER L1
            if (is_valid(L1Icache_entry)) {
              // The block is in the wrong L1, put the request on the queue to the shared L2
              trigger(Event:L1_Replacement, in_msg.LineAddress,
                      L1Icache_entry, TBEs[in_msg.LineAddress]);
            }
            if (L1Dcache.cacheAvail(in_msg.LineAddress)) {
              // L1 does't have the line, but we have space for it in the L1 let's see if the L2 has it
              trigger(mandatory_request_type_to_event(in_msg.Type),
                      in_msg.LineAddress, L1Dcache_entry,
                      TBEs[in_msg.LineAddress]);
            } else {
              // No room in the L1, so we need to make room in the L1
              // Check if the line we want to evict is not locked
              Addr addr := L1Dcache.cacheProbe(in_msg.LineAddress);
              check_on_cache_probe(mandatoryQueue_in, addr);
              trigger(Event:L1_Replacement,
                      addr,
                      getL1DCacheEntry(addr),
                      TBEs[addr]);
            }
          }
        }
      }
    }
  }


  // ACTIONS

  action(a_issueGETS, "a", desc="Issue GETS") {
    peek(mandatoryQueue_in, RubyRequest) {
      enqueue(requestNetwork_out, RequestMsg,  request_latency) {
        out_msg.addr := address;
        out_msg.Type := CoherenceRequestType:GETS;
        out_msg.Requestor := machineID;
        out_msg.RequestorMachine := MachineType:L1Cache;
        out_msg.Destination.add(mapAddressToMachine(address,
                                                    MachineType:L2Cache));
        out_msg.MessageSize := MessageSizeType:Request_Control;
        out_msg.AccessMode := in_msg.AccessMode;
        out_msg.Prefetch := in_msg.Prefetch;
      }
    }
  }

  action(b_issueGETX, "b", desc="Issue GETX") {
    peek(mandatoryQueue_in, RubyRequest) {
      enqueue(requestNetwork_out, RequestMsg, request_latency) {
        out_msg.addr := address;
        out_msg.Type := CoherenceRequestType:GETX;
        out_msg.Requestor := machineID;
        out_msg.RequestorMachine := MachineType:L1Cache;
        out_msg.Destination.add(mapAddressToMachine(address,
                                                    MachineType:L2Cache));
        out_msg.MessageSize := MessageSizeType:Request_Control;
        out_msg.AccessMode := in_msg.AccessMode;
        out_msg.Prefetch := in_msg.Prefetch;
      }
    }
  }

  action(d_issuePUTX, "d", desc="Issue PUTX") {
    enqueue(requestNetwork_out, RequestMsg, request_latency) {
      out_msg.addr := address;
      out_msg.Type := CoherenceRequestType:PUTX;
      out_msg.Requestor := machineID;
      out_msg.RequestorMachine := MachineType:L1Cache;
      out_msg.Destination.add(mapAddressToMachine(address,
                                                  MachineType:L2Cache));
      out_msg.MessageSize := MessageSizeType:Writeback_Control;
    }
  }

  action(dd_issuePUTO, "\d", desc="Issue PUTO") {
    enqueue(requestNetwork_out, RequestMsg, request_latency) {
      out_msg.addr := address;
      out_msg.Type := CoherenceRequestType:PUTO;
      out_msg.Requestor := machineID;
      out_msg.RequestorMachine := MachineType:L1Cache;
      out_msg.Destination.add(mapAddressToMachine(address,
                                                  MachineType:L2Cache));
      out_msg.MessageSize := MessageSizeType:Writeback_Control;
    }
  }

  action(dd_issuePUTS, "\ds", desc="Issue PUTS") {
    enqueue(requestNetwork_out, RequestMsg, request_latency) {
      out_msg.addr := address;
      out_msg.Type := CoherenceRequestType:PUTS;
      out_msg.Requestor := machineID;
      out_msg.RequestorMachine := MachineType:L1Cache;
      out_msg.Destination.add(mapAddressToMachine(address,
                                                  MachineType:L2Cache));
      out_msg.MessageSize := MessageSizeType:Writeback_Control;
    }
  }

  action(e_sendData, "e", desc="Send data from cache to requestor") {
    peek(requestNetwork_in, RequestMsg) {
      assert(is_valid(cache_entry));
      if (in_msg.RequestorMachine == MachineType:L2Cache) {
        enqueue(responseNetwork_out, ResponseMsg, cacheResponseLatency()) {
          out_msg.addr := address;
          out_msg.Type := CoherenceResponseType:DATA;
          out_msg.Sender := machineID;
          out_msg.SenderMachine := MachineType:L1Cache;
          out_msg.Destination.add(mapAddressToMachine(address,
                                                      MachineType:L2Cache));
          out_msg.DataBlk := cache_entry.DataBlk;
          // out_msg.Dirty := cache_entry.Dirty;
          out_msg.Dirty := false;
          out_msg.Acks := in_msg.Acks;
          out_msg.MessageSize := MessageSizeType:Response_Data;
        }
        DPRINTF(RubySlicc, "Sending data to L2: %#x\n", in_msg.addr);
      }
      else {
        enqueue(responseNetwork_out, ResponseMsg, cacheResponseLatency()) {
          out_msg.addr := address;
          out_msg.Type := CoherenceResponseType:DATA;
          out_msg.Sender := machineID;
          out_msg.SenderMachine := MachineType:L1Cache;
          out_msg.Destination.add(in_msg.Requestor);
          out_msg.DataBlk := cache_entry.DataBlk;
          // out_msg.Dirty := cache_entry.Dirty;
          out_msg.Dirty := false;
          out_msg.Acks := in_msg.Acks;
          out_msg.MessageSize := MessageSizeType:ResponseLocal_Data;
        }
        DPRINTF(RubySlicc, "Sending data to L1\n");
      }
    }
  }

  action(ee_sendDataExclusive, "\e", desc="Send data from cache to requestor, don't keep a shared copy") {
    peek(requestNetwork_in, RequestMsg) {
      assert(is_valid(cache_entry));
      if (in_msg.RequestorMachine == MachineType:L2Cache) {
        enqueue(responseNetwork_out, ResponseMsg, cacheResponseLatency()) {
          out_msg.addr := address;
          out_msg.Type := CoherenceResponseType:DATA_EXCLUSIVE;
          out_msg.Sender := machineID;
          out_msg.SenderMachine := MachineType:L1Cache;
          out_msg.Destination.add(mapAddressToMachine(address,
                                                      MachineType:L2Cache));
          out_msg.DataBlk := cache_entry.DataBlk;
          out_msg.Dirty := cache_entry.Dirty;
          out_msg.Acks := in_msg.Acks;
          out_msg.MessageSize := MessageSizeType:Response_Data;
        }
        DPRINTF(RubySlicc, "Sending exclusive data to L2\n");
      }
      else {
        enqueue(responseNetwork_out, ResponseMsg, cacheResponseLatency()) {
          out_msg.addr := address;
          out_msg.Type := CoherenceResponseType:DATA_EXCLUSIVE;
          out_msg.Sender := machineID;
          out_msg.SenderMachine := MachineType:L1Cache;
          out_msg.Destination.add(in_msg.Requestor);
          out_msg.DataBlk := cache_entry.DataBlk;
          out_msg.Dirty := cache_entry.Dirty;
          out_msg.Acks := in_msg.Acks;
          out_msg.MessageSize := MessageSizeType:ResponseLocal_Data;
        }
        DPRINTF(RubySlicc, "Sending exclusive data to L1\n");
      }
    }
  }

  action(f_sendAck, "f", desc="Send ack from cache to requestor") {
    peek(requestNetwork_in, RequestMsg) {
      if (in_msg.RequestorMachine == MachineType:L1Cache) {
        enqueue(responseNetwork_out, ResponseMsg, response_latency) {
          out_msg.addr := address;
          out_msg.Type := CoherenceResponseType:ACK;
          out_msg.Sender := machineID;
          out_msg.SenderMachine := MachineType:L1Cache;
          out_msg.Destination.add(in_msg.Requestor);
          out_msg.Acks := 0 - 1; // -1
          out_msg.MessageSize := MessageSizeType:Response_Control;
        }
      }
      else {
        enqueue(responseNetwork_out, ResponseMsg, response_latency) {
          out_msg.addr := address;
          out_msg.Type := CoherenceResponseType:ACK;
          out_msg.Sender := machineID;
          out_msg.SenderMachine := MachineType:L1Cache;
          out_msg.Destination.add(mapAddressToMachine(address,
                                                      MachineType:L2Cache));
          out_msg.Acks := 0 - 1; // -1
          out_msg.MessageSize := MessageSizeType:Response_Control;
        }
      }
    }
  }

  action(g_sendUnblock, "g", desc="Send unblock to memory") {
    enqueue(responseNetwork_out, ResponseMsg, response_latency) {
      out_msg.addr := address;
      out_msg.Type := CoherenceResponseType:UNBLOCK;
      out_msg.Sender := machineID;
      out_msg.SenderMachine := MachineType:L1Cache;
      out_msg.Destination.add(mapAddressToMachine(address,
                                                  MachineType:L2Cache));
      out_msg.MessageSize := MessageSizeType:Unblock_Control;
    }
  }

  action(gg_sendUnblockExclusive, "\g", desc="Send unblock exclusive to memory") {
    enqueue(responseNetwork_out, ResponseMsg, response_latency) {
      out_msg.addr := address;
      out_msg.Type := CoherenceResponseType:UNBLOCK_EXCLUSIVE;
      out_msg.Sender := machineID;
      out_msg.SenderMachine := MachineType:L1Cache;
      out_msg.Destination.add(mapAddressToMachine(address,
                                                  MachineType:L2Cache));
      out_msg.MessageSize := MessageSizeType:Unblock_Control;
    }
  }

  action(h_load_hit, "hd", desc="Notify sequencer the load completed.") {
    assert(is_valid(cache_entry));
    DPRINTF(RubySlicc, "%s\n", cache_entry.DataBlk);
    L1Dcache.setMRU(cache_entry);
    sequencer.readCallback(address, cache_entry.DataBlk);
  }

  action(h_ifetch_hit, "hi", desc="Notify the sequencer about ifetch completion.") {
    assert(is_valid(cache_entry));
    DPRINTF(RubySlicc, "%s\n", cache_entry.DataBlk);
    L1Icache.setMRU(cache_entry);
    sequencer.readCallback(address, cache_entry.DataBlk);
  }

  action(hx_load_hit, "hx", desc="Notify sequencer the load completed.") {
    assert(is_valid(cache_entry));
    DPRINTF(RubySlicc, "%s\n", cache_entry.DataBlk);
    L1Icache.setMRU(address);
    L1Dcache.setMRU(address);
    sequencer.readCallback(address, cache_entry.DataBlk, true);
  }

  action(hh_store_hit, "\h", desc="Notify sequencer that store completed.") {
    assert(is_valid(cache_entry));
    DPRINTF(RubySlicc, "%s\n", cache_entry.DataBlk);
    L1Dcache.setMRU(cache_entry);
    sequencer.writeCallback(address, cache_entry.DataBlk);
    cache_entry.Dirty := true;
  }

  action(xx_store_hit, "\xx", desc="Notify sequencer that store completed.") {
    assert(is_valid(cache_entry));
    DPRINTF(RubySlicc, "%s\n", cache_entry.DataBlk);
    L1Icache.setMRU(address);
    L1Dcache.setMRU(address);
    sequencer.writeCallback(address, cache_entry.DataBlk, true);
    cache_entry.Dirty := true;
  }

  action(i_allocateTBE, "i", desc="Allocate TBE") {
    check_allocate(TBEs);
    TBEs.allocate(address);
    set_tbe(TBEs[address]);
    assert(is_valid(cache_entry));
    tbe.DataBlk := cache_entry.DataBlk; // Data only used for writebacks
    tbe.Dirty := cache_entry.Dirty;
  }

  action(j_popTriggerQueue, "j", desc="Pop trigger queue.") {
    triggerQueue_in.dequeue(clockEdge());
  }

  action(jj_unsetUseTimer, "\jj", desc="Unset use timer.") {
    useTimerTable.unset(address);
  }

  action(k_popMandatoryQueue, "k", desc="Pop mandatory queue.") {
    mandatoryQueue_in.dequeue(clockEdge());
  }

  action(l_popForwardQueue, "l", desc="Pop forwarded request queue.") {
    requestNetwork_in.dequeue(clockEdge());
  }

  action(m_decrementNumberOfMessages, "m", desc="Decrement the number of messages for which we're waiting") {
    peek(responseToL1Cache_in, ResponseMsg) {
      assert(is_valid(tbe));
      DPRINTF(RubySlicc, "L1 decrementNumberOfMessages: %d\n", in_msg.Acks);
      tbe.NumPendingMsgs := tbe.NumPendingMsgs - in_msg.Acks;
    }
  }

  action(mm_decrementNumberOfMessages, "\m", desc="Decrement the number of messages for which we're waiting") {
    peek(requestNetwork_in, RequestMsg) {
      assert(is_valid(tbe));
      tbe.NumPendingMsgs := tbe.NumPendingMsgs - in_msg.Acks;
    }
  }

  action(n_popResponseQueue, "n", desc="Pop response queue") {
    responseToL1Cache_in.dequeue(clockEdge());
  }

  action(o_checkForCompletion, "o", desc="Check if we have received all the messages required for completion") {
    assert(is_valid(tbe));
    if (tbe.NumPendingMsgs == 0) {
      enqueue(triggerQueue_out, TriggerMsg) {
        out_msg.addr := address;
        out_msg.Type := TriggerType:ALL_ACKS;
      }
    }
  }

  action(o_scheduleUseTimeout, "oo", desc="Schedule a use timeout.") {
    useTimerTable.set(address,
                      clockEdge() + cyclesToTicks(use_timeout_latency));
  }

  action(ub_dmaUnblockL2Cache, "ub", desc="Send dma ack to l2 cache") {
    peek(requestNetwork_in, RequestMsg) {
      enqueue(responseNetwork_out, ResponseMsg, response_latency) {
        out_msg.addr := address;
        out_msg.Type := CoherenceResponseType:DMA_ACK;
        out_msg.Sender := machineID;
        out_msg.SenderMachine := MachineType:L1Cache;
        out_msg.Destination.add(mapAddressToMachine(address,
                                                    MachineType:L2Cache));
        out_msg.Dirty := false;
        out_msg.Acks := 1;
        out_msg.MessageSize := MessageSizeType:Response_Control;
      }
    }
  }

  action(q_sendDataFromTBEToCache, "q", desc="Send data from TBE to cache") {
    peek(requestNetwork_in, RequestMsg) {
      assert(is_valid(tbe));
      if (in_msg.RequestorMachine == MachineType:L1Cache ||
          in_msg.RequestorMachine == MachineType:DMA) {
        enqueue(responseNetwork_out, ResponseMsg, response_latency) {
          out_msg.addr := address;
          out_msg.Type := CoherenceResponseType:DATA;
          out_msg.Sender := machineID;
          out_msg.SenderMachine := MachineType:L1Cache;
          out_msg.Destination.add(in_msg.Requestor);
          out_msg.DataBlk := tbe.DataBlk;
          // out_msg.Dirty := tbe.Dirty;
          out_msg.Dirty := false;
          out_msg.Acks := in_msg.Acks;
          out_msg.MessageSize := MessageSizeType:ResponseLocal_Data;
        }
      }
      else {
        enqueue(responseNetwork_out, ResponseMsg, response_latency) {
          out_msg.addr := address;
          out_msg.Type := CoherenceResponseType:DATA;
          out_msg.Sender := machineID;
          out_msg.SenderMachine := MachineType:L1Cache;
          out_msg.Destination.add(mapAddressToMachine(address,
                                                      MachineType:L2Cache));
          out_msg.DataBlk := tbe.DataBlk;
          // out_msg.Dirty := tbe.Dirty;
          out_msg.Dirty := false;
          out_msg.Acks := in_msg.Acks;
          out_msg.MessageSize := MessageSizeType:Response_Data;
        }
      }
    }
  }

  action(q_sendExclusiveDataFromTBEToCache, "qq", desc="Send data from TBE to cache") {
    peek(requestNetwork_in, RequestMsg) {
      assert(is_valid(tbe));
      if (in_msg.RequestorMachine == MachineType:L1Cache) {
        enqueue(responseNetwork_out, ResponseMsg, response_latency) {
          out_msg.addr := address;
          out_msg.Type := CoherenceResponseType:DATA_EXCLUSIVE;
          out_msg.Sender := machineID;
          out_msg.SenderMachine := MachineType:L1Cache;
          out_msg.Destination.add(in_msg.Requestor);
          out_msg.DataBlk := tbe.DataBlk;
          out_msg.Dirty := tbe.Dirty;
          out_msg.Acks := in_msg.Acks;
          out_msg.MessageSize := MessageSizeType:ResponseLocal_Data;
        }
      }
      else {
        enqueue(responseNetwork_out, ResponseMsg, response_latency) {
          out_msg.addr := address;
          out_msg.Type := CoherenceResponseType:DATA_EXCLUSIVE;
          out_msg.Sender := machineID;
          out_msg.SenderMachine := MachineType:L1Cache;
          out_msg.Destination.add(mapAddressToMachine(address,
                                                      MachineType:L2Cache));
          out_msg.DataBlk := tbe.DataBlk;
          out_msg.Dirty := tbe.Dirty;
          out_msg.Acks := in_msg.Acks;
          out_msg.MessageSize := MessageSizeType:Response_Data;
        }
      }
    }
  }

  // L2 will usually request data for a writeback
  action(qq_sendWBDataFromTBEToL2, "\q", desc="Send data from TBE to L2") {
    enqueue(requestNetwork_out, RequestMsg, request_latency) {
      assert(is_valid(tbe));
      out_msg.addr := address;
      out_msg.Requestor := machineID;
      out_msg.RequestorMachine := MachineType:L1Cache;
      out_msg.Destination.add(mapAddressToMachine(address,
                                                  MachineType:L2Cache));
      if (tbe.Dirty) {
        out_msg.Type := CoherenceRequestType:WRITEBACK_DIRTY_DATA;
      } else {
        out_msg.Type := CoherenceRequestType:WRITEBACK_CLEAN_DATA;
      }
      out_msg.DataBlk := tbe.DataBlk;
      out_msg.MessageSize := MessageSizeType:Writeback_Data;
    }
  }

  action(s_deallocateTBE, "s", desc="Deallocate TBE") {
    TBEs.deallocate(address);
    unset_tbe();
  }

  action(u_writeDataToCache, "u", desc="Write data to cache") {
    peek(responseToL1Cache_in, ResponseMsg) {
      assert(is_valid(cache_entry));
      cache_entry.DataBlk := in_msg.DataBlk;
      cache_entry.Dirty := in_msg.Dirty;

      if (in_msg.Type == CoherenceResponseType:DATA) {
        //assert(in_msg.Dirty == false);
      }
    }
  }

  action(kk_deallocateL1CacheBlock, "\k", desc="Deallocate cache block.  Sets the cache to invalid, allowing a replacement in parallel with a fetch.") {
    if (L1Dcache.isTagPresent(address)) {
      L1Dcache.deallocate(address);
    } else {
      L1Icache.deallocate(address);
    }
    unset_cache_entry();
  }

  action(ii_allocateL1DCacheBlock, "\i", desc="Set L1 D-cache tag equal to tag of block B.") {
    if ((is_invalid(cache_entry))) {
      set_cache_entry(L1Dcache.allocate(address, new Entry));
    }
  }

  action(jj_allocateL1ICacheBlock, "\j", desc="Set L1 I-cache tag equal to tag of block B.") {
    if ((is_invalid(cache_entry))) {
      set_cache_entry(L1Icache.allocate(address, new Entry));
    }
  }

  action(forward_eviction_to_cpu, "\cc", desc="sends eviction information to the processor") {
    if (send_evictions) {
      DPRINTF(RubySlicc, "Sending invalidation for %#x to the CPU\n", address);
      sequencer.evictionCallback(address);
    }
  }

  action(uu_profileInstMiss, "\uim", desc="Profile the demand miss") {
      ++L1Icache.demand_misses;
  }

  action(uu_profileInstHit, "\uih", desc="Profile the demand hit") {
      ++L1Icache.demand_hits;
  }

  action(uu_profileDataMiss, "\udm", desc="Profile the demand miss") {
      ++L1Dcache.demand_misses;
  }

  action(uu_profileDataHit, "\udh", desc="Profile the demand hit") {
      ++L1Dcache.demand_hits;
  }

  action(z_recycleRequestQueue, "z", desc="Send the head of the mandatory queue to the back of the queue.") {
    requestNetwork_in.recycle(clockEdge(), cyclesToTicks(recycle_latency));
  }

  action(zz_recycleMandatoryQueue, "\z", desc="Send the head of the mandatory queue to the back of the queue.") {
    mandatoryQueue_in.recycle(clockEdge(), cyclesToTicks(recycle_latency));
  }

  //*****************************************************
  // TRANSITIONS
  //*****************************************************

  // Transitions for Load/Store/L2_Replacement from transient states
  transition({IM, SM, OM, IS, OI, SI, MI, II}, {Store, L1_Replacement}) {
    zz_recycleMandatoryQueue;
  }

  transition({M_W, MM_W}, L1_Replacement) {
    zz_recycleMandatoryQueue;
  }

  transition({M_W, MM_W}, {Fwd_GETS, Fwd_DMA, Fwd_GETX, Own_GETX, Inv}) {
    z_recycleRequestQueue;
  }

  transition({IM, IS, OI, MI, SI, II}, {Load, Ifetch}) {
    zz_recycleMandatoryQueue;
  }

  // Transitions from Idle
  transition(I, Load, IS) {
    ii_allocateL1DCacheBlock;
    i_allocateTBE;
    a_issueGETS;
    uu_profileDataMiss;
    k_popMandatoryQueue;
  }

  transition(I, Ifetch, IS) {
    jj_allocateL1ICacheBlock;
    i_allocateTBE;
    a_issueGETS;
    uu_profileInstMiss;
    k_popMandatoryQueue;
  }

  transition(I, Store, IM) {
    ii_allocateL1DCacheBlock;
    i_allocateTBE;
    b_issueGETX;
    uu_profileDataMiss;
    k_popMandatoryQueue;
  }

  transition(I, L1_Replacement) {
    kk_deallocateL1CacheBlock;
  }

  transition(I, Inv) {
    f_sendAck;
    l_popForwardQueue;
  }

  transition({S, SM, O, OM, MM, MM_W, M, M_W}, Load) {
    h_load_hit;
    uu_profileDataHit;
    k_popMandatoryQueue;
  }

  transition({S, SM, O, OM, MM, MM_W, M, M_W}, Ifetch) {
    h_ifetch_hit;
    uu_profileInstHit;
    k_popMandatoryQueue;
  }

  // Transitions from Shared
  transition(S, Store, SM) {
    i_allocateTBE;
    b_issueGETX;
    uu_profileDataMiss;
    k_popMandatoryQueue;
  }

  transition(S, L1_Replacement, SI) {
    i_allocateTBE;
    dd_issuePUTS;
    forward_eviction_to_cpu;
    kk_deallocateL1CacheBlock;
  }

  transition(S, Inv, I) {
    f_sendAck;
    forward_eviction_to_cpu;
    l_popForwardQueue;
  }

  transition(S, Fwd_GETS) {
    e_sendData;
    l_popForwardQueue;
  }

  transition(S, Fwd_DMA) {
    e_sendData;
    ub_dmaUnblockL2Cache;
    l_popForwardQueue;
  }

  // Transitions from Owned
  transition(O, Store, OM) {
    i_allocateTBE;
    b_issueGETX;
    uu_profileDataMiss;
    k_popMandatoryQueue;
  }

  transition(O, L1_Replacement, OI) {
    i_allocateTBE;
    dd_issuePUTO;
    forward_eviction_to_cpu;
    kk_deallocateL1CacheBlock;
  }

  transition(O, Fwd_GETX, I) {
    ee_sendDataExclusive;
    forward_eviction_to_cpu;
    l_popForwardQueue;
  }

  transition(O, Fwd_GETS) {
    e_sendData;
    l_popForwardQueue;
  }

  transition(O, Fwd_DMA) {
    e_sendData;
    ub_dmaUnblockL2Cache;
    l_popForwardQueue;
  }

  // Transitions from MM
  transition({MM, MM_W}, Store) {
    hh_store_hit;
    uu_profileDataHit;
    k_popMandatoryQueue;
  }

  transition(MM, L1_Replacement, MI) {
    i_allocateTBE;
    d_issuePUTX;
    forward_eviction_to_cpu;
    kk_deallocateL1CacheBlock;
  }

  transition(MM, Fwd_GETX, I) {
    ee_sendDataExclusive;
    forward_eviction_to_cpu;
    l_popForwardQueue;
  }

  transition(MM, Fwd_GETS, I) {
    ee_sendDataExclusive;
    forward_eviction_to_cpu;
    l_popForwardQueue;
  }

  transition(MM, Fwd_DMA, MM) {
    e_sendData;
    ub_dmaUnblockL2Cache;
    l_popForwardQueue;
  }

  // Transitions from M
  transition(M, Store, MM) {
    hh_store_hit;
    uu_profileDataHit;
    k_popMandatoryQueue;
  }

  transition(M_W, Store, MM_W) {
    hh_store_hit;
    uu_profileDataHit;
    k_popMandatoryQueue;
  }

  transition(M, L1_Replacement, MI) {
    i_allocateTBE;
    d_issuePUTX;
    forward_eviction_to_cpu;
    kk_deallocateL1CacheBlock;
  }

  transition(M, Fwd_GETX, I) {
    // e_sendData;
    ee_sendDataExclusive;
    forward_eviction_to_cpu;
    l_popForwardQueue;
  }

  transition(M, Fwd_GETS, O) {
    e_sendData;
    l_popForwardQueue;
  }

  transition(M, Fwd_DMA) {
    e_sendData;
    ub_dmaUnblockL2Cache;
    l_popForwardQueue;
  }

  // Transitions from IM

  transition(IM, Inv) {
    f_sendAck;
    l_popForwardQueue;
  }

  transition(IM, Ack) {
    m_decrementNumberOfMessages;
    o_checkForCompletion;
    n_popResponseQueue;
  }

  transition(IM, {Exclusive_Data, Data}, OM) {
    u_writeDataToCache;
    m_decrementNumberOfMessages;
    o_checkForCompletion;
    n_popResponseQueue;
  }

  // Transitions from SM
  transition(SM, Inv, IM) {
    f_sendAck;
    forward_eviction_to_cpu;
    l_popForwardQueue;
  }

  transition(SM, Ack) {
    m_decrementNumberOfMessages;
    o_checkForCompletion;
    n_popResponseQueue;
  }

  transition(SM, {Data, Exclusive_Data}, OM) {
    // v_writeDataToCacheVerify;
    m_decrementNumberOfMessages;
    o_checkForCompletion;
    n_popResponseQueue;
  }

  transition(SM, Fwd_GETS) {
    e_sendData;
    l_popForwardQueue;
  }

  transition(SM, Fwd_DMA) {
    e_sendData;
    ub_dmaUnblockL2Cache;
    l_popForwardQueue;
  }

  // Transitions from OM
  transition(OM, Own_GETX) {
    mm_decrementNumberOfMessages;
    o_checkForCompletion;
    l_popForwardQueue;
  }


  // transition(OM, Fwd_GETX, OMF) {
  transition(OM, Fwd_GETX, IM) {
    ee_sendDataExclusive;
    l_popForwardQueue;
  }

  transition(OM, Fwd_GETS) {
    e_sendData;
    l_popForwardQueue;
  }

  transition(OM, Fwd_DMA) {
    e_sendData;
    ub_dmaUnblockL2Cache;
    l_popForwardQueue;
  }

  //transition({OM, OMF}, Ack) {
  transition(OM, Ack) {
    m_decrementNumberOfMessages;
    o_checkForCompletion;
    n_popResponseQueue;
  }

  transition(OM, All_acks, MM_W) {
    xx_store_hit;
    gg_sendUnblockExclusive;
    s_deallocateTBE;
    o_scheduleUseTimeout;
    j_popTriggerQueue;
  }

  transition(MM_W, Use_Timeout, MM) {
    jj_unsetUseTimer;
  }

  // Transitions from IS

  transition(IS, Inv) {
    f_sendAck;
    l_popForwardQueue;
  }

  transition(IS, Data, S) {
    u_writeDataToCache;
    m_decrementNumberOfMessages;
    hx_load_hit;
    g_sendUnblock;
    s_deallocateTBE;
    n_popResponseQueue;
  }

  transition(IS, Exclusive_Data, M_W) {
    u_writeDataToCache;
    m_decrementNumberOfMessages;
    hx_load_hit;
    gg_sendUnblockExclusive;
    o_scheduleUseTimeout;
    s_deallocateTBE;
    n_popResponseQueue;
  }

  transition(M_W, Use_Timeout, M) {
    jj_unsetUseTimer;
  }

  // Transitions from OI/MI

  transition(MI, Fwd_GETS, OI) {
    q_sendDataFromTBEToCache;
    l_popForwardQueue;
  }

  transition(MI, Fwd_DMA) {
    q_sendDataFromTBEToCache;
    ub_dmaUnblockL2Cache;
    l_popForwardQueue;
  }

  transition(MI, Fwd_GETX, II) {
    q_sendExclusiveDataFromTBEToCache;
    l_popForwardQueue;
  }

  transition({SI, OI}, Fwd_GETS) {
    q_sendDataFromTBEToCache;
    l_popForwardQueue;
  }

  transition({SI, OI}, Fwd_DMA) {
    q_sendDataFromTBEToCache;
    ub_dmaUnblockL2Cache;
    l_popForwardQueue;
  }

  transition(OI, Fwd_GETX, II) {
    q_sendExclusiveDataFromTBEToCache;
    l_popForwardQueue;
  }

  transition({SI, OI, MI}, Writeback_Ack_Data, I) {
    qq_sendWBDataFromTBEToL2;  // always send data
    s_deallocateTBE;
    n_popResponseQueue;
  }

  transition({SI, OI, MI}, Writeback_Ack, I) {
    g_sendUnblock;
    s_deallocateTBE;
    n_popResponseQueue;
  }

  transition({MI, OI}, Writeback_Nack, OI) {
    // FIXME: This might cause deadlock by re-using the writeback
    // channel, we should handle this case differently.
    dd_issuePUTO;
    n_popResponseQueue;
  }

  // Transitions from II
  transition(II, {Writeback_Ack, Writeback_Ack_Data}, I) {
    g_sendUnblock;
    s_deallocateTBE;
    n_popResponseQueue;
  }

  // transition({II, SI}, Writeback_Nack, I) {
  transition(II, Writeback_Nack, I) {
    s_deallocateTBE;
    n_popResponseQueue;
  }

  transition(SI, Writeback_Nack) {
    dd_issuePUTS;
    n_popResponseQueue;
  }

  transition(II, Inv) {
    f_sendAck;
    l_popForwardQueue;
  }

  transition(SI, Inv, II) {
    f_sendAck;
    l_popForwardQueue;
  }
}