path: root/src/mem/protocol/MOSI_SMP_directory_1level-cache.sm

/*
 * Copyright (c) 1999-2005 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.
 */

/*
 * $Id: MOSI_directory_1level-cache.sm 1.18 04/09/07 13:52:52-05:00 mikem@maya.cs.wisc.edu $
 *
 */

machine(L1Cache, "MOSI Directory Optimized") {

  MessageBuffer requestFromCache, network="To", virtual_network="0", ordered="false";
  MessageBuffer responseFromCache, network="To", virtual_network="2", ordered="false";

  MessageBuffer forwardedRequestToCache, network="From", virtual_network="1", ordered="true";
  MessageBuffer responseToCache, network="From", virtual_network="2", ordered="false";

  // STATES
  enumeration(State, desc="Cache states", default="L1Cache_State_I") {
    // Base states
    I, desc="Idle";
    S, desc="Shared";
    O, desc="Owned";
    M, desc="Modified", format="!b";

    // Transient States
    MI,  desc="modified, issued PUTX, have not seen response yet";
    OI, desc="owned, issued PUTX, have not seen response yet";

    IS, desc="idle, issued GETS, have not seen response yet";
    ISI, desc="idle, issued GETS, saw INV, have not seen data for GETS yet", format="!b";

    IM, desc="idle, issued GETX, have not seen response yet";
    IMI, desc="idle, issued GETX, saw forwarded GETX";
    IMO, desc="idle, issued GETX, saw forwarded GETS";
    IMOI, desc="idle, issued GETX, saw forwarded GETS, saw forwarded GETX";

    // Note: OM is a strange state, because it is waiting for the line
    // to be stolen away, or look like it has been stolen away.  The
    // common case is that we see a forward from the directory that is
    // really from us, we forwarded the data to our dataqueue, and
    // everythings works fine.

    OM, desc="owned, issued GETX, have not seen response yet";
  }

  // EVENTS
  enumeration(Event, desc="Cache events") {
    Load,            desc="Load request from the processor";
    Load_prefetch,   desc="Load prefetch request from the processor";
    Ifetch,          desc="I-fetch request from the processor";
    Store_prefetch,  desc="Store prefetch request from the processor";
    Store,           desc="Store request from the processor";
    Replacement,     desc="Replacement", format="!r";

    Forwarded_GETS, "Forwarded GETS", desc="Directory forwards GETS to us";
    Forwarded_GETX, "Forwarded GETX", desc="Directory forwards GETX to us";
    INV, "INV", desc="Invalidation", format="!r";

    Proc_ack, "Proc ack", desc="Ack from proc";
    Proc_last_ack, "Proc last ack", desc="Last ack", format="!r";

    Data_ack_0, "Data ack 0", desc="Data with ack count = 0";
    Data_ack_not_0, "Data ack not 0", desc="Data with ack count != 0 (but haven't seen all acks first";
    Data_ack_not_0_last, "Data ack not 0 last", desc="Data with ack count != 0 after having received all acks";

    Dir_WB_ack, "WB ack", desc="Writeback ack from dir";
  }

  // TYPES

  // CacheEntry
  structure(Entry, desc="...", interface="AbstractCacheEntry") {
    State CacheState,        desc="cache state";
    DataBlock DataBlk,       desc="data for the block";
  }

  // TBE fields
  structure(TBE, desc="...") {
    Address Address,              desc="Physical address for this TBE";
    State TBEState,        desc="Transient state";
    DataBlock DataBlk,                desc="Buffer for the data block";
    int NumPendingAcks,      desc="Number of acks that this processor is waiting for";
    NetDest ForwardGetS_IDs,                       desc="Set of the processors to forward the block";
    MachineID ForwardGetX_ID,            desc="ID of the processor to forward the block";
    int ForwardGetX_AckCount,        desc="Number of acks the GetX we are forwarded needs";
    bool isPrefetch,       desc="Set if this was caused by a prefetch";
  }

  external_type(CacheMemory) {
    bool cacheAvail(Address);
    Address cacheProbe(Address);
    void allocate(Address);
    void deallocate(Address);
    Entry lookup(Address);
    void changePermission(Address, AccessPermission);
    bool isTagPresent(Address);
  }

  external_type(TBETable) {
    TBE lookup(Address);
    void allocate(Address);
    void deallocate(Address);
    bool isPresent(Address);
  }

  MessageBuffer mandatoryQueue, ordered="false", abstract_chip_ptr="true";
  MessageBuffer optionalQueue, ordered="false", abstract_chip_ptr="true";
  Sequencer sequencer, abstract_chip_ptr="true", constructor_hack="i";
  StoreBuffer storeBuffer, abstract_chip_ptr="true", constructor_hack="i";

  TBETable TBEs, template_hack="<L1Cache_TBE>";
  CacheMemory cacheMemory, template_hack="<L1Cache_Entry>", constructor_hack='L1_CACHE_NUM_SETS_BITS,L1_CACHE_ASSOC,MachineType_L1Cache,int_to_string(i)+"_unified L1"', abstract_chip_ptr="true";

  State getState(Address addr) {
    if(TBEs.isPresent(addr)) {
      return TBEs[addr].TBEState;
    } else if (cacheMemory.isTagPresent(addr)) {
      return cacheMemory[addr].CacheState;
    }
    return State:I;
  }

  void setState(Address addr, State state) {
    if (TBEs.isPresent(addr)) {
      TBEs[addr].TBEState := state;
    }
    if (cacheMemory.isTagPresent(addr)) {
      cacheMemory[addr].CacheState := state;

      // Set permission
      if ((state == State:I) || (state == State:MI) || (state == State:OI)) {
        cacheMemory.changePermission(addr, AccessPermission:Invalid);
      } else if (state == State:S || state == State:O) {
        cacheMemory.changePermission(addr, AccessPermission:Read_Only);
      } else if (state == State:M) {
        cacheMemory.changePermission(addr, AccessPermission:Read_Write);
      } else {
        cacheMemory.changePermission(addr, AccessPermission:Busy);
      }
    }
  }

  // ** OUT_PORTS **

  out_port(requestNetwork_out, RequestMsg, requestFromCache);
  out_port(responseNetwork_out, ResponseMsg, responseFromCache);

  // ** IN_PORTS **

  // Response Network
  in_port(responseNetwork_in, ResponseMsg, responseToCache) {
    if (responseNetwork_in.isReady()) {
      peek(responseNetwork_in, ResponseMsg) {
        if(in_msg.Type == CoherenceResponseType:DATA) {
          if(in_msg.NumPendingAcks == 0) {
            trigger(Event:Data_ack_0, in_msg.Address);
          } else {
            if(in_msg.NumPendingAcks + TBEs[in_msg.Address].NumPendingAcks != 0) {
              trigger(Event:Data_ack_not_0, in_msg.Address);
            } else {
              trigger(Event:Data_ack_not_0_last, in_msg.Address);
            }
          }
        } else if(in_msg.Type == CoherenceResponseType:ACK) {
          if(TBEs[in_msg.Address].NumPendingAcks != 1){
            trigger(Event:Proc_ack, in_msg.Address);
          } else {
            trigger(Event:Proc_last_ack, in_msg.Address);
          }
        }
      }
    }
  }

  // Forwarded Request network
  in_port(forwardedRequestNetwork_in, RequestMsg, forwardedRequestToCache) {
    if(forwardedRequestNetwork_in.isReady()) {
      peek(forwardedRequestNetwork_in, RequestMsg) {
        if(in_msg.Type == CoherenceRequestType:GETS) {
          trigger(Event:Forwarded_GETS, in_msg.Address);
        } else if (in_msg.Type == CoherenceRequestType:GETX) {
          trigger(Event:Forwarded_GETX, in_msg.Address);
        } else if (in_msg.Type == CoherenceRequestType:INV) {
          trigger(Event:INV, in_msg.Address);
        } else if (in_msg.Type == CoherenceRequestType:WB_ACK) {
          trigger(Event:Dir_WB_ack, in_msg.Address);
        } else {
          error("Invalid forwarded request type");
        }
      }
    }
  }

  // Mandatory Queue
  in_port(mandatoryQueue_in, CacheMsg, mandatoryQueue, desc="...") {
    if (mandatoryQueue_in.isReady()) {
      peek(mandatoryQueue_in, CacheMsg) {
        if (cacheMemory.cacheAvail(in_msg.Address) == false) {
          trigger(Event:Replacement, cacheMemory.cacheProbe(in_msg.Address));
        } else {
          if (in_msg.Type == CacheRequestType:LD) {
            trigger(Event:Load, in_msg.Address);
          } else if (in_msg.Type == CacheRequestType:IFETCH) {
            trigger(Event:Ifetch, in_msg.Address);
          } else if ((in_msg.Type == CacheRequestType:ST) || (in_msg.Type == CacheRequestType:ATOMIC)) {
            trigger(Event:Store, in_msg.Address);
          } else {
            error("Invalid CacheRequestType");
          }
        }
      }
    }
  }

  // Optional Queue
  in_port(optionalQueue_in, CacheMsg, optionalQueue, desc="...") {
    if (optionalQueue_in.isReady()) {
      peek(optionalQueue_in, CacheMsg) {
        if (cacheMemory.cacheAvail(in_msg.Address) == false) {
          trigger(Event:Replacement, cacheMemory.cacheProbe(in_msg.Address));
        } else {
          if (in_msg.Type == CacheRequestType:LD) {
            trigger(Event:Load_prefetch, in_msg.Address);
          } else if (in_msg.Type == CacheRequestType:IFETCH) {
            trigger(Event:Load_prefetch, in_msg.Address);
          } else if ((in_msg.Type == CacheRequestType:ST) || (in_msg.Type == CacheRequestType:ATOMIC)) {
            trigger(Event:Store_prefetch, in_msg.Address);
          } else {
            error("Invalid CacheRequestType");
          }
        }
      }
    }
  }

  // ACTIONS

  action(a_issueGETS, "a", desc="Issue GETS") {
    enqueue(requestNetwork_out, RequestMsg, latency="ISSUE_LATENCY") {
      out_msg.Address := address;
      out_msg.Type := CoherenceRequestType:GETS;
      out_msg.Requestor := machineID;
      out_msg.Destination.add(map_Address_to_Directory(address));
      out_msg.MessageSize := MessageSizeType:Control;
    }
  }

  action(b_issueGETX, "b", desc="Issue GETX") {
    enqueue(requestNetwork_out, RequestMsg, latency="ISSUE_LATENCY") {
      out_msg.Address := address;
      out_msg.Type := CoherenceRequestType:GETX;
      out_msg.Requestor := machineID;
      out_msg.Destination.add(map_Address_to_Directory(address));
      out_msg.MessageSize := MessageSizeType:Control;
    }
  }

  action(d_issuePUTX, "d", desc="Issue PUTX") {
    enqueue(requestNetwork_out, RequestMsg, latency="ISSUE_LATENCY") {
      out_msg.Address := address;
      out_msg.Type := CoherenceRequestType:PUTX;
      out_msg.Requestor := machineID;
      out_msg.Destination.add(map_Address_to_Directory(address));
      out_msg.DataBlk := cacheMemory[address].DataBlk;
      out_msg.MessageSize := MessageSizeType:Data;
    }
  }

  action(e_dataFromCacheToRequestor, "e", desc="Send data from cache to requestor") {
    peek(forwardedRequestNetwork_in, RequestMsg) {
      enqueue(responseNetwork_out, ResponseMsg, latency="CACHE_RESPONSE_LATENCY") {
        out_msg.Address := address;
        out_msg.Type := CoherenceResponseType:DATA;
        out_msg.Sender := machineID;
        out_msg.SenderMachine := MachineType:L1Cache;
        out_msg.NumPendingAcks := in_msg.NumPendingAcks; // Needed when in state O and we see a GetX
        out_msg.Destination.add(in_msg.Requestor);
        out_msg.DestMachine := MachineType:L1Cache;
        DEBUG_EXPR(out_msg.Destination);
        out_msg.DataBlk := cacheMemory[address].DataBlk;
        out_msg.MessageSize := MessageSizeType:Data;
      }
    }
  }

  action(g_allocateCacheBlock, "g", desc="Allocate cache block") {
    if (cacheMemory.isTagPresent(address) == false) {
      cacheMemory.allocate(address);
    }
  }

  action(h_load_hit, "h", desc="If not prefetch, notify sequencer the load completed.") {
    DEBUG_EXPR(cacheMemory[address].DataBlk);
    if((TBEs.isPresent(address) == false) || (TBEs[address].isPrefetch == false)) {
      // Non-prefetch
      sequencer.readCallback(address, cacheMemory[address].DataBlk);
    } else {
      // Prefetch - don't call back
    }
  }

  action(hh_store_hit, "\h", desc="If not prefetch, notify sequencer that store completed.") {
    DEBUG_EXPR(cacheMemory[address].DataBlk);
    if((TBEs.isPresent(address) == false) || (TBEs[address].isPrefetch == false)) {
      // Non-prefetch
      sequencer.writeCallback(address, cacheMemory[address].DataBlk);
    } else {
      // Prefetch - don't call back
    }
  }

  action(i_allocateTBE, "i", desc="Allocate TBE (isPrefetch=0, number of invalidates=0)") {
    check_allocate(TBEs);
    TBEs.allocate(address);
    TBEs[address].NumPendingAcks := 0;  // default value
    TBEs[address].isPrefetch := false;
    TBEs[address].ForwardGetS_IDs.clear();
  }

  action(j_setPrefetchBit, "j", desc="Set prefetch bit") {
    TBEs[address].isPrefetch := true;
  }

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

  action(l_popForwardedRequestQueue, "l", desc="Pop incoming forwarded request queue") {
    forwardedRequestNetwork_in.dequeue();
  }

  action(m_popOptionalQueue, "m", desc="Pop optional queue") {
    optionalQueue_in.dequeue();
  }

  action(o_popIncomingResponseQueue, "o", desc="Pop Incoming Response queue") {
    responseNetwork_in.dequeue();
  }

  action(p_addNumberOfPendingAcks, "p", desc="Add number of pending acks to TBE") {
    peek(responseNetwork_in, ResponseMsg) {
      DEBUG_EXPR(TBEs[address].NumPendingAcks);
      TBEs[address].NumPendingAcks := TBEs[address].NumPendingAcks + in_msg.NumPendingAcks;
      DEBUG_EXPR(in_msg.NumPendingAcks);
      DEBUG_EXPR(TBEs[address].NumPendingAcks);
    }
  }

  action(q_decrementNumberOfPendingAcks, "q", desc="Decrement number of pending invalidations by one") {
    DEBUG_EXPR(TBEs[address].NumPendingAcks);
    TBEs[address].NumPendingAcks := TBEs[address].NumPendingAcks - 1;
    DEBUG_EXPR(TBEs[address].NumPendingAcks);
  }

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

  action(t_sendAckToInvalidator, "t", desc="Send ack to invalidator") {
    peek(forwardedRequestNetwork_in, RequestMsg) {
      enqueue(responseNetwork_out, ResponseMsg, latency="NULL_LATENCY") {
        out_msg.Address := address;
        out_msg.Type := CoherenceResponseType:ACK;
        out_msg.Sender := machineID;
        out_msg.SenderMachine := MachineType:L1Cache;
        out_msg.Destination.add(in_msg.Requestor);
        out_msg.DestMachine := MachineType:L1Cache;
        DEBUG_EXPR(out_msg.Destination);
        out_msg.NumPendingAcks := 0;
        out_msg.MessageSize := MessageSizeType:Control;
      }
    }
  }

  action(u_writeDataToCache, "u", desc="Write data to cache") {
    peek(responseNetwork_in, ResponseMsg) {
      cacheMemory[address].DataBlk := in_msg.DataBlk;
    }
  }

  action(x_copyDataFromCacheToTBE, "x", desc="Copy data from cache to TBE") {
    TBEs[address].DataBlk := cacheMemory[address].DataBlk;
  }

  action(y_dataFromTBEToRequestor, "y", desc="Send data from TBE to requestor") {
    peek(forwardedRequestNetwork_in, RequestMsg) {
      enqueue(responseNetwork_out, ResponseMsg, latency="NULL_LATENCY") {
        out_msg.Address := address;
        out_msg.Type := CoherenceResponseType:DATA;
        out_msg.Sender := machineID;
        out_msg.SenderMachine := MachineType:L1Cache;
        out_msg.NumPendingAcks := in_msg.NumPendingAcks; // Needed when in state MS and we see a GetX
        out_msg.Destination.add(in_msg.Requestor);
        out_msg.DestMachine := MachineType:L1Cache;
        DEBUG_EXPR(out_msg.Destination);
        out_msg.DataBlk := TBEs[address].DataBlk;
        out_msg.MessageSize := MessageSizeType:Data;
      }
    }
  }

  action(z_stall, "z", desc="Stall") {
  }

  action(dd_recordGetSForwardID, "\d", desc="Record forwarded GetS for future forwarding") {
    peek(forwardedRequestNetwork_in, RequestMsg) {
      TBEs[address].ForwardGetS_IDs.add(in_msg.Requestor);
    }
  }

  action(ee_dataFromCacheToGetSForwardIDs, "\e", desc="Send data from cache to GetS ForwardIDs") {
    // FIXME - In some cases this should be from the TBE, not the cache.
    enqueue(responseNetwork_out, ResponseMsg, latency="NULL_LATENCY") {
      out_msg.Address := address;
      out_msg.Type := CoherenceResponseType:DATA;
      out_msg.Sender := machineID;
      out_msg.SenderMachine := MachineType:L1Cache;
      out_msg.Destination := TBEs[address].ForwardGetS_IDs;
      out_msg.DestMachine := MachineType:L1Cache;
      DEBUG_EXPR(out_msg.Destination);
      out_msg.DataBlk := cacheMemory[address].DataBlk;
      out_msg.NumPendingAcks := 0;
      out_msg.MessageSize := MessageSizeType:Data;
    }
  }

  action(ff_deallocateCacheBlock, "\f", desc="Deallocate cache block.  Sets the cache to invalid, allowing a replacement in parallel with a fetch.") {
    cacheMemory.deallocate(address);
  }

  action(gg_dataFromCacheToGetXForwardID, "\g", desc="Send data from cache to GetX ForwardID") {
    // FIXME - In some cases this should be from the TBE, not the cache.
    enqueue(responseNetwork_out, ResponseMsg, latency="NULL_LATENCY") {
      out_msg.Address := address;
      out_msg.Type := CoherenceResponseType:DATA;
      out_msg.Sender := machineID;
      out_msg.SenderMachine := MachineType:L1Cache;
      out_msg.Destination.add(TBEs[address].ForwardGetX_ID);
      out_msg.DestMachine := MachineType:L1Cache;
      DEBUG_EXPR(out_msg.Destination);
      out_msg.DataBlk := cacheMemory[address].DataBlk;
      out_msg.NumPendingAcks := TBEs[address].ForwardGetX_AckCount;
      out_msg.MessageSize := MessageSizeType:Data;
    }
  }

  action(ii_recordGetXForwardID, "\i", desc="Record forwarded GetX and ack count for future forwarding") {
    peek(forwardedRequestNetwork_in, RequestMsg) {
      TBEs[address].ForwardGetX_ID := in_msg.Requestor;
      TBEs[address].ForwardGetX_AckCount := in_msg.NumPendingAcks;
    }
  }

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

  // Transitions for Load/Store/Prefetch/Replacement from transient states
  transition({OM, OI, IS, ISI, IM, IMO, IMOI, IMI, MI}, {Load, Load_prefetch, Ifetch, Store, Store_prefetch, Replacement}) {
    z_stall;
  }

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

  transition(I, {Load_prefetch}, IS) {
    g_allocateCacheBlock;
    i_allocateTBE;
    j_setPrefetchBit;
    a_issueGETS;
    m_popOptionalQueue;
  }

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

  transition(I, Store_prefetch, IM) {
    g_allocateCacheBlock;
    i_allocateTBE;
    j_setPrefetchBit;
    b_issueGETX;
    m_popOptionalQueue;
  }

  transition(I, Replacement) {
    ff_deallocateCacheBlock;
  }

  transition(I, INV) {
    t_sendAckToInvalidator;
    l_popForwardedRequestQueue;
  }

  // Transitions from Shared
  transition({S, O}, {Load,Ifetch}) {
    h_load_hit;
    k_popMandatoryQueue;
  }

  transition({S, O, M}, Load_prefetch) {
    m_popOptionalQueue;
  }

  transition(S, Store, IM) {
    i_allocateTBE;
    b_issueGETX;
    k_popMandatoryQueue;
  }

  transition(S, Store_prefetch, IM) {
    i_allocateTBE;
    j_setPrefetchBit;
    b_issueGETX;
    m_popOptionalQueue;
  }

  transition(S, Replacement, I) {
    ff_deallocateCacheBlock;
  }

  transition(S, INV, I) {
    t_sendAckToInvalidator;
    l_popForwardedRequestQueue;
  }

  // Transitions from Modified
  transition(M, {Load, Ifetch}) {
    h_load_hit;
    k_popMandatoryQueue;
  }

  transition(M, Store) {
    hh_store_hit;
    k_popMandatoryQueue;
  }

  transition(M, Store_prefetch) {
    m_popOptionalQueue;
  }

  transition(M, Replacement, MI) {
    i_allocateTBE;
    d_issuePUTX;
    x_copyDataFromCacheToTBE;
    ff_deallocateCacheBlock;
  }

  transition(M, Forwarded_GETS, O) {
    e_dataFromCacheToRequestor;
    l_popForwardedRequestQueue;
  }

  transition(M, Forwarded_GETX, I) {
    e_dataFromCacheToRequestor;
    l_popForwardedRequestQueue;
  }

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

  transition(O, Store_prefetch, OM) {
    i_allocateTBE;
    j_setPrefetchBit;
    b_issueGETX;
    m_popOptionalQueue;
  }

  transition(O, Replacement, OI){
    i_allocateTBE;
    d_issuePUTX;
    x_copyDataFromCacheToTBE;
    ff_deallocateCacheBlock;
  }

  transition(O, Forwarded_GETS) {
    e_dataFromCacheToRequestor;
    l_popForwardedRequestQueue;
  }

  transition(O, Forwarded_GETX, I) {
    e_dataFromCacheToRequestor;
    l_popForwardedRequestQueue;
  }

  // transitions from OI

  transition(OI, Forwarded_GETS) {
    y_dataFromTBEToRequestor;
    l_popForwardedRequestQueue;
  }

  transition(OI, Forwarded_GETX) {
    y_dataFromTBEToRequestor;
    l_popForwardedRequestQueue;
  }

  transition(OI, Dir_WB_ack, I) {
    s_deallocateTBE;
    l_popForwardedRequestQueue;
  }

  // Transitions from IS

  transition(IS, INV, ISI) {
    t_sendAckToInvalidator;
    l_popForwardedRequestQueue;
  }

  transition(IS, Data_ack_0, S) {
    u_writeDataToCache;
    h_load_hit;
    s_deallocateTBE;
    o_popIncomingResponseQueue;
  }

  // transitions from ISI

  // in ISI, could get data from the Proc whose GETX caused INV to go from IS to ISI
  // or, could get data from Dir if Dir's data lost race to Dir's INV
  // or, could get data from Dir, if my GETS took forever to get to Dir, and the GETX
  // processor already wrote it back

  transition(ISI, Data_ack_0, I) {
    u_writeDataToCache;
    h_load_hit;
    s_deallocateTBE;
    o_popIncomingResponseQueue;
  }

  transition(ISI, INV) {
    t_sendAckToInvalidator;
    l_popForwardedRequestQueue;
  }

  // Transitions from IM

  transition(IM, INV) {       // do not need to go to IMI, since INV is for earlier epoch
    t_sendAckToInvalidator;
    l_popForwardedRequestQueue;
  }

  transition({IM, IMO}, Forwarded_GETS, IMO) {
    dd_recordGetSForwardID;
    l_popForwardedRequestQueue;
  }

  transition(IM, Forwarded_GETX, IMI) {
    ii_recordGetXForwardID;
    l_popForwardedRequestQueue;
  }

  transition(IM, {Data_ack_0, Data_ack_not_0_last}, M) {
    u_writeDataToCache;
    hh_store_hit;
    s_deallocateTBE;
    o_popIncomingResponseQueue;
  }

  transition(IM, Data_ack_not_0) {
    u_writeDataToCache;
    p_addNumberOfPendingAcks;
    o_popIncomingResponseQueue;
  }

  transition(IM, Proc_ack) {
    q_decrementNumberOfPendingAcks;
    o_popIncomingResponseQueue;
  }

  transition(IM, Proc_last_ack, M) {
    hh_store_hit;
    s_deallocateTBE;
    o_popIncomingResponseQueue;
  }

  // transitions from IMO

  transition(IMO, Forwarded_GETX, IMOI) {
    ii_recordGetXForwardID;
    l_popForwardedRequestQueue;
  }

  transition(IMO, {Data_ack_0, Data_ack_not_0_last}, O) {
    u_writeDataToCache;
    hh_store_hit;
    ee_dataFromCacheToGetSForwardIDs;
    s_deallocateTBE;
    o_popIncomingResponseQueue;
  }

  transition(IMO, Data_ack_not_0) {
    u_writeDataToCache;
    p_addNumberOfPendingAcks;
    o_popIncomingResponseQueue;
  }

  transition(IMO, Proc_ack) {
    q_decrementNumberOfPendingAcks;
    o_popIncomingResponseQueue;
  }

  transition(IMO, Proc_last_ack, O) {
    hh_store_hit;
    ee_dataFromCacheToGetSForwardIDs;
    s_deallocateTBE;
    o_popIncomingResponseQueue;
  }

  // transitions from IMI

  transition(IMI, {Data_ack_0, Data_ack_not_0_last}, I) {
    u_writeDataToCache;
    hh_store_hit;
    gg_dataFromCacheToGetXForwardID;
    s_deallocateTBE;
    o_popIncomingResponseQueue;
  }

  transition(IMI, Data_ack_not_0) {
    u_writeDataToCache;
    p_addNumberOfPendingAcks;
    o_popIncomingResponseQueue;
  }

  transition(IMI, Proc_ack) {
    q_decrementNumberOfPendingAcks;
    o_popIncomingResponseQueue;
  }

  transition(IMI, Proc_last_ack, I) {
    hh_store_hit;
    gg_dataFromCacheToGetXForwardID;
    s_deallocateTBE;
    o_popIncomingResponseQueue;
  }

  // transitions from IMOI

  transition(IMOI, {Data_ack_0, Data_ack_not_0_last}, I) {
    u_writeDataToCache;
    hh_store_hit;
    ee_dataFromCacheToGetSForwardIDs;
    gg_dataFromCacheToGetXForwardID;
    s_deallocateTBE;
    o_popIncomingResponseQueue;
  }

  transition(IMOI, Data_ack_not_0) {
    u_writeDataToCache;
    p_addNumberOfPendingAcks;
    o_popIncomingResponseQueue;
  }

  transition(IMOI, Proc_ack) {
    q_decrementNumberOfPendingAcks;
    o_popIncomingResponseQueue;
  }

  transition(IMOI, Proc_last_ack, I) {
    hh_store_hit;
    ee_dataFromCacheToGetSForwardIDs;
    gg_dataFromCacheToGetXForwardID;
    s_deallocateTBE;
    o_popIncomingResponseQueue;
  }

  // Transitions from OM
  transition(OM, Proc_ack) {
    q_decrementNumberOfPendingAcks;
    o_popIncomingResponseQueue;
  }

  transition(OM, Forwarded_GETS) {
    e_dataFromCacheToRequestor;
    l_popForwardedRequestQueue;
  }

  transition(OM, Forwarded_GETX, IM) {
    e_dataFromCacheToRequestor;
    l_popForwardedRequestQueue;
  }

  // Transitions from MI

  transition(MI, Forwarded_GETS) {
    y_dataFromTBEToRequestor;
    l_popForwardedRequestQueue;
  }

  transition(MI, Forwarded_GETX) {
    y_dataFromTBEToRequestor;
    l_popForwardedRequestQueue;
  }

  transition(MI, Dir_WB_ack, I) {
    s_deallocateTBE;
    l_popForwardedRequestQueue;
  }
}