text: /*
   * Copyright (c) 2012-2013 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) 2006 The Regents of The University of Michigan
   * Copyright (c) 2010 Advanced Micro Devices, Inc.
   * 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.
   *
   * Authors: Ron Dreslinski
   *          Steve Reinhardt
   *          Ali Saidi
   *          Andreas Hansson
   */
  
  /**
   * @file
   * Declaration of the Packet class.
   */
  
  #ifndef __MEM_PACKET_HH__
  #define __MEM_PACKET_HH__
  
  #include <bitset>
  #include <cassert>
  #include <list>
  
  #include "base/cast.hh"
  #include "base/compiler.hh"
  #include "base/flags.hh"
  #include "base/misc.hh"
  #include "base/printable.hh"
  #include "base/types.hh"
  #include "mem/request.hh"
  #include "sim/core.hh"
  
  class Packet;
  typedef Packet *PacketPtr;
  typedef uint8_t* PacketDataPtr;
  typedef std::list<PacketPtr> PacketList;
  
  class MemCmd
  {
      friend class Packet;
  
    public:
      /**
       * List of all commands associated with a packet.
       */
      enum Command
      {
          InvalidCmd,
          ReadReq,
          ReadResp,
          ReadRespWithInvalidate,
          WriteReq,
          WriteResp,
          Writeback,
          SoftPFReq,
          HardPFReq,
          SoftPFResp,
          HardPFResp,
          // WriteInvalidateReq transactions used to be generated by the
          // DMA ports when writing full blocks to memory, however, it
          // is not used anymore since we put the I/O cache in place to
          // deal with partial block writes. Hence, WriteInvalidateReq
          // and WriteInvalidateResp are currently unused. The
          // implication is that the I/O cache does read-exclusive
          // operations on every full-cache-block DMA, and ultimately
          // this needs to be fixed.
          WriteInvalidateReq,
          WriteInvalidateResp,
          UpgradeReq,
          SCUpgradeReq,           // Special "weak" upgrade for StoreCond
          UpgradeResp,
          SCUpgradeFailReq,       // Failed SCUpgradeReq in MSHR (never sent)
          UpgradeFailResp,        // Valid for SCUpgradeReq only
          ReadExReq,
          ReadExResp,
          LoadLockedReq,
          StoreCondReq,
          StoreCondFailReq,       // Failed StoreCondReq in MSHR (never sent)
          StoreCondResp,
          SwapReq,
          SwapResp,
          MessageReq,
          MessageResp,
          // Error responses
          // @TODO these should be classified as responses rather than
          // requests; coding them as requests initially for backwards
          // compatibility
          InvalidDestError,  // packet dest field invalid
          BadAddressError,   // memory address invalid
          FunctionalReadError, // unable to fulfill functional read
          FunctionalWriteError, // unable to fulfill functional write
          // Fake simulator-only commands
          PrintReq,       // Print state matching address
          FlushReq,      //request for a cache flush
          InvalidationReq,   // request for address to be invalidated from lsq
          NUM_MEM_CMDS
      };
  
    private:
      /**
       * List of command attributes.
       */
      enum Attribute
      {
          IsRead,         //!< Data flows from responder to requester
          IsWrite,        //!< Data flows from requester to responder
          IsUpgrade,
          IsInvalidate,
          NeedsExclusive, //!< Requires exclusive copy to complete in-cache
          IsRequest,      //!< Issued by requester
          IsResponse,     //!< Issue by responder
          NeedsResponse,  //!< Requester needs response from target
          IsSWPrefetch,
          IsHWPrefetch,
          IsLlsc,         //!< Alpha/MIPS LL or SC access
          HasData,        //!< There is an associated payload
          IsError,        //!< Error response
          IsPrint,        //!< Print state matching address (for debugging)
          IsFlush,        //!< Flush the address from caches
          NUM_COMMAND_ATTRIBUTES
      };
  
      /**
       * Structure that defines attributes and other data associated
       * with a Command.
       */
      struct CommandInfo
      {
          /// Set of attribute flags.
          const std::bitset<NUM_COMMAND_ATTRIBUTES> attributes;
          /// Corresponding response for requests; InvalidCmd if no
          /// response is applicable.
          const Command response;
          /// String representation (for printing)
          const std::string str;
      };
  
      /// Array to map Command enum to associated info.
      static const CommandInfo commandInfo[];
  
    private:
  
      Command cmd;
  
      bool
      testCmdAttrib(MemCmd::Attribute attrib) const
      {
          return commandInfo[cmd].attributes[attrib] != 0;
      }
  
    public:
  
      bool isRead() const         { return testCmdAttrib(IsRead); }
      bool isWrite() const        { return testCmdAttrib(IsWrite); }
      bool isUpgrade() const      { return testCmdAttrib(IsUpgrade); }
      bool isRequest() const      { return testCmdAttrib(IsRequest); }
      bool isResponse() const     { return testCmdAttrib(IsResponse); }
      bool needsExclusive() const { return testCmdAttrib(NeedsExclusive); }
      bool needsResponse() const  { return testCmdAttrib(NeedsResponse); }
      bool isInvalidate() const   { return testCmdAttrib(IsInvalidate); }
      bool hasData() const        { return testCmdAttrib(HasData); }
      bool isReadWrite() const    { return isRead() && isWrite(); }
      bool isLLSC() const         { return testCmdAttrib(IsLlsc); }
      bool isError() const        { return testCmdAttrib(IsError); }
      bool isPrint() const        { return testCmdAttrib(IsPrint); }
      bool isFlush() const        { return testCmdAttrib(IsFlush); }
  
      const Command
      responseCommand() const
      {
          return commandInfo[cmd].response;
      }
  
      /// Return the string to a cmd given by idx.
      const std::string &toString() const { return commandInfo[cmd].str; }
      int toInt() const { return (int)cmd; }
  
      MemCmd(Command _cmd) : cmd(_cmd) { }
      MemCmd(int _cmd) : cmd((Command)_cmd) { }
      MemCmd() : cmd(InvalidCmd) { }
  
      bool operator==(MemCmd c2) const { return (cmd == c2.cmd); }
      bool operator!=(MemCmd c2) const { return (cmd != c2.cmd); }
  };
  
  /**
   * A Packet is used to encapsulate a transfer between two objects in
   * the memory system (e.g., the L1 and L2 cache).  (In contrast, a
   * single Request travels all the way from the requester to the
   * ultimate destination and back, possibly being conveyed by several
   * different Packets along the way.)
   */
  class Packet : public Printable
  {
    public:
      typedef uint32_t FlagsType;
      typedef ::Flags<FlagsType> Flags;
  
    private:
      static const FlagsType PUBLIC_FLAGS           = 0x00000000;
      static const FlagsType PRIVATE_FLAGS          = 0x00007F0F;
      static const FlagsType COPY_FLAGS             = 0x0000000F;
  
      static const FlagsType SHARED                 = 0x00000001;
      // Special control flags
      /// Special timing-mode atomic snoop for multi-level coherence.
      static const FlagsType EXPRESS_SNOOP          = 0x00000002;
      /// Does supplier have exclusive copy?
      /// Useful for multi-level coherence.
      static const FlagsType SUPPLY_EXCLUSIVE       = 0x00000004;
      // Snoop response flags
      static const FlagsType MEM_INHIBIT            = 0x00000008;
      /// Are the 'addr' and 'size' fields valid?
      static const FlagsType VALID_ADDR             = 0x00000100;
      static const FlagsType VALID_SIZE             = 0x00000200;
      /// Is the data pointer set to a value that shouldn't be freed
      /// when the packet is destroyed?
      static const FlagsType STATIC_DATA            = 0x00001000;
      /// The data pointer points to a value that should be freed when
      /// the packet is destroyed.
      static const FlagsType DYNAMIC_DATA           = 0x00002000;
      /// the data pointer points to an array (thus delete []) needs to
      /// be called on it rather than simply delete.
      static const FlagsType ARRAY_DATA             = 0x00004000;
      /// suppress the error if this packet encounters a functional
      /// access failure.
      static const FlagsType SUPPRESS_FUNC_ERROR    = 0x00008000;
  
      Flags flags;
  
    public:
      typedef MemCmd::Command Command;
  
      /// The command field of the packet.
      MemCmd cmd;
  
      /// A pointer to the original request.
      RequestPtr req;
  
    private:
     /**
      * A pointer to the data being transfered.  It can be differnt
      * sizes at each level of the heirarchy so it belongs in the
      * packet, not request. This may or may not be populated when a
      * responder recieves the packet. If not populated it memory should
      * be allocated.
      */
      PacketDataPtr data;
  
      /// The address of the request.  This address could be virtual or
      /// physical, depending on the system configuration.
      Addr addr;
  
      /// The size of the request or transfer.
      uint64_t size;
  
      /**
       * Source port identifier set on a request packet to enable
       * appropriate routing of the responses. The source port
       * identifier is set by any multiplexing component, e.g. a bus, as
       * the timing responses need this information to be routed back to
       * the appropriate port at a later point in time. The field can be
       * updated (over-written) as the request packet passes through
       * additional multiplexing components, and it is their
       * responsibility to remember the original source port identifier,
       * for example by using an appropriate sender state. The latter is
       * done in the cache and bridge.
       */
      PortID src;
  
      /**
       * Destination port identifier that is present on all response
       * packets that passed through a multiplexing component as a
       * request packet. The source port identifier is turned into a
       * destination port identifier when the packet is turned into a
       * response, and the destination is used, e.g. by the bus, to
       * select the appropriate path through the interconnect.
       */
      PortID dest;
  
      /**
       * The original value of the command field.  Only valid when the
       * current command field is an error condition; in that case, the
       * previous contents of the command field are copied here.  This
       * field is *not* set on non-error responses.
       */
      MemCmd origCmd;
  
      /**
       * These values specify the range of bytes found that satisfy a
       * functional read.
       */
      uint16_t bytesValidStart;
      uint16_t bytesValidEnd;
  
    public:
  
      /**
       * The extra delay from seeing the packet until the first word is
       * transmitted by the bus that provided it (if any). This delay is
       * used to communicate the bus waiting time to the neighbouring
       * object (e.g. a cache) that actually makes the packet wait. As
       * the delay is relative, a 32-bit unsigned should be sufficient.
       */
      uint32_t busFirstWordDelay;
  
      /**
       * The extra delay from seeing the packet until the last word is
       * transmitted by the bus that provided it (if any). Similar to
       * the first word time, this is used to make up for the fact that
       * the bus does not make the packet wait. As the delay is relative,
       * a 32-bit unsigned should be sufficient.
       */
      uint32_t busLastWordDelay;
  
      /**
       * A virtual base opaque structure used to hold state associated
       * with the packet (e.g., an MSHR), specific to a MemObject that
       * sees the packet. A pointer to this state is returned in the
       * packet's response so that the MemObject in question can quickly
       * look up the state needed to process it. A specific subclass
       * would be derived from this to carry state specific to a
       * particular sending device.
       *
       * As multiple MemObjects may add their SenderState throughout the
       * memory system, the SenderStates create a stack, where a
       * MemObject can add a new Senderstate, as long as the
       * predecessing SenderState is restored when the response comes
       * back. For this reason, the predecessor should always be
       * populated with the current SenderState of a packet before
       * modifying the senderState field in the request packet.
       */
      struct SenderState
      {
          SenderState* predecessor;
          SenderState() : predecessor(NULL) {}
          virtual ~SenderState() {}
      };
  
      /**
       * Object used to maintain state of a PrintReq.  The senderState
       * field of a PrintReq should always be of this type.
       */
      class PrintReqState : public SenderState
      {
        private:
          /**
           * An entry in the label stack.
           */
          struct LabelStackEntry
          {
              const std::string label;
              std::string *prefix;
              bool labelPrinted;
              LabelStackEntry(const std::string &_label, std::string *_prefix);
          };
  
          typedef std::list<LabelStackEntry> LabelStack;
          LabelStack labelStack;
  
          std::string *curPrefixPtr;
  
        public:
          std::ostream &os;
          const int verbosity;
  
          PrintReqState(std::ostream &os, int verbosity = 0);
          ~PrintReqState();
  
          /**
           * Returns the current line prefix.
           */
          const std::string &curPrefix() { return *curPrefixPtr; }
  
          /**
           * Push a label onto the label stack, and prepend the given
           * prefix string onto the current prefix.  Labels will only be
           * printed if an object within the label's scope is printed.
           */
          void pushLabel(const std::string &lbl,
                         const std::string &prefix = "  ");
  
          /**
           * Pop a label off the label stack.
           */
          void popLabel();
  
          /**
           * Print all of the pending unprinted labels on the
           * stack. Called by printObj(), so normally not called by
           * users unless bypassing printObj().
           */
          void printLabels();
  
          /**
           * Print a Printable object to os, because it matched the
           * address on a PrintReq.
           */
          void printObj(Printable *obj);
      };
  
      /**
       * This packet's sender state.  Devices should use dynamic_cast<>
       * to cast to the state appropriate to the sender.  The intent of
       * this variable is to allow a device to attach extra information
       * to a request. A response packet must return the sender state
       * that was attached to the original request (even if a new packet
       * is created).
       */
      SenderState *senderState;
  
      /**
       * Push a new sender state to the packet and make the current
       * sender state the predecessor of the new one. This should be
       * prefered over direct manipulation of the senderState member
       * variable.
       *
       * @param sender_state SenderState to push at the top of the stack
       */
      void pushSenderState(SenderState *sender_state);
  
      /**
       * Pop the top of the state stack and return a pointer to it. This
       * assumes the current sender state is not NULL. This should be
       * preferred over direct manipulation of the senderState member
       * variable.
       *
       * @return The current top of the stack
       */
      SenderState *popSenderState();
  
      /**
       * Go through the sender state stack and return the first instance
       * that is of type T (as determined by a dynamic_cast). If there
       * is no sender state of type T, NULL is returned.
       *
       * @return The topmost state of type T
       */
      template <typename T>
      T * findNextSenderState() const
      {
          T *t = NULL;
          SenderState* sender_state = senderState;
          while (t == NULL && sender_state != NULL) {
              t = dynamic_cast<T*>(sender_state);
              sender_state = sender_state->predecessor;
          }
          return t;
      }
  
      /// Return the string name of the cmd field (for debugging and
      /// tracing).
      const std::string &cmdString() const { return cmd.toString(); }
  
      /// Return the index of this command.
      inline int cmdToIndex() const { return cmd.toInt(); }
  
      bool isRead() const         { return cmd.isRead(); }
      bool isWrite() const        { return cmd.isWrite(); }
      bool isUpgrade()  const     { return cmd.isUpgrade(); }
      bool isRequest() const      { return cmd.isRequest(); }
      bool isResponse() const     { return cmd.isResponse(); }
      bool needsExclusive() const { return cmd.needsExclusive(); }
      bool needsResponse() const  { return cmd.needsResponse(); }
      bool isInvalidate() const   { return cmd.isInvalidate(); }
      bool hasData() const        { return cmd.hasData(); }
      bool isReadWrite() const    { return cmd.isReadWrite(); }
      bool isLLSC() const         { return cmd.isLLSC(); }
      bool isError() const        { return cmd.isError(); }
      bool isPrint() const        { return cmd.isPrint(); }
      bool isFlush() const        { return cmd.isFlush(); }
  
      // Snoop flags
      void assertMemInhibit()         { flags.set(MEM_INHIBIT); }
      bool memInhibitAsserted() const { return flags.isSet(MEM_INHIBIT); }
      void assertShared()             { flags.set(SHARED); }
      bool sharedAsserted() const     { return flags.isSet(SHARED); }
  
      // Special control flags
      void setExpressSnoop()          { flags.set(EXPRESS_SNOOP); }
      bool isExpressSnoop() const     { return flags.isSet(EXPRESS_SNOOP); }
      void setSupplyExclusive()       { flags.set(SUPPLY_EXCLUSIVE); }
      void clearSupplyExclusive()     { flags.clear(SUPPLY_EXCLUSIVE); }
      bool isSupplyExclusive() const  { return flags.isSet(SUPPLY_EXCLUSIVE); }
      void setSuppressFuncError()     { flags.set(SUPPRESS_FUNC_ERROR); }
      bool suppressFuncError() const  { return flags.isSet(SUPPRESS_FUNC_ERROR); }
  
      // Network error conditions... encapsulate them as methods since
      // their encoding keeps changing (from result field to command
      // field, etc.)
      void
      setBadAddress()
      {
          assert(isResponse());
          cmd = MemCmd::BadAddressError;
      }
  
      bool hadBadAddress() const { return cmd == MemCmd::BadAddressError; }
      void copyError(Packet *pkt) { assert(pkt->isError()); cmd = pkt->cmd; }
  
      bool isSrcValid() const { return src != InvalidPortID; }
      /// Accessor function to get the source index of the packet.
      PortID getSrc() const { assert(isSrcValid()); return src; }
      /// Accessor function to set the source index of the packet.
      void setSrc(PortID _src) { src = _src; }
      /// Reset source field, e.g. to retransmit packet on different bus.
      void clearSrc() { src = InvalidPortID; }
  
      bool isDestValid() const { return dest != InvalidPortID; }
      /// Accessor function for the destination index of the packet.
      PortID getDest() const { assert(isDestValid()); return dest; }
      /// Accessor function to set the destination index of the packet.
      void setDest(PortID _dest) { dest = _dest; }
      /// Reset destination field, e.g. to turn a response into a request again.
      void clearDest() { dest = InvalidPortID; }
  
      Addr getAddr() const { assert(flags.isSet(VALID_ADDR)); return addr; }
      /**
       * Update the address of this packet mid-transaction. This is used
       * by the address mapper to change an already set address to a new
       * one based on the system configuration. It is intended to remap
       * an existing address, so it asserts that the current address is
       * valid.
       */
      void setAddr(Addr _addr) { assert(flags.isSet(VALID_ADDR)); addr = _addr; }
  
      unsigned getSize() const  { assert(flags.isSet(VALID_SIZE)); return size; }
      Addr getOffset(int blkSize) const { return getAddr() & (Addr)(blkSize - 1); }
  
      /**
       * It has been determined that the SC packet should successfully update
       * memory.  Therefore, convert this SC packet to a normal write.
       */
      void
      convertScToWrite()
      {
          assert(isLLSC());
          assert(isWrite());
          cmd = MemCmd::WriteReq;
      }
  
      /**
       * When ruby is in use, Ruby will monitor the cache line and thus M5 
       * phys memory should treat LL ops as normal reads. 
       */
      void
      convertLlToRead()
      {
          assert(isLLSC());
          assert(isRead());
          cmd = MemCmd::ReadReq;
      }
  
      /**
       * Constructor.  Note that a Request object must be constructed
       * first, but the Requests's physical address and size fields need
       * not be valid. The command must be supplied.
       */
      Packet(Request *_req, MemCmd _cmd)
          :  cmd(_cmd), req(_req), data(NULL),
             src(InvalidPortID), dest(InvalidPortID),
             bytesValidStart(0), bytesValidEnd(0),
             busFirstWordDelay(0), busLastWordDelay(0),
             senderState(NULL)
      {
          if (req->hasPaddr()) {
              addr = req->getPaddr();
              flags.set(VALID_ADDR);
          }
          if (req->hasSize()) {
              size = req->getSize();
              flags.set(VALID_SIZE);
          }
      }
  
      /**
       * Alternate constructor if you are trying to create a packet with
       * a request that is for a whole block, not the address from the
       * req.  this allows for overriding the size/addr of the req.
       */
      Packet(Request *_req, MemCmd _cmd, int _blkSize)
          :  cmd(_cmd), req(_req), data(NULL),
             src(InvalidPortID), dest(InvalidPortID),
             bytesValidStart(0), bytesValidEnd(0),
             busFirstWordDelay(0), busLastWordDelay(0),
             senderState(NULL)
      {
          if (req->hasPaddr()) {
              addr = req->getPaddr() & ~(_blkSize - 1);
              flags.set(VALID_ADDR);
          }
          size = _blkSize;
          flags.set(VALID_SIZE);
      }
  
      /**
       * Alternate constructor for copying a packet.  Copy all fields
       * *except* if the original packet's data was dynamic, don't copy
       * that, as we can't guarantee that the new packet's lifetime is
       * less than that of the original packet.  In this case the new
       * packet should allocate its own data.
       */
      Packet(Packet *pkt, bool clearFlags = false)
          :  cmd(pkt->cmd), req(pkt->req),
             data(pkt->flags.isSet(STATIC_DATA) ? pkt->data : NULL),
             addr(pkt->addr), size(pkt->size), src(pkt->src), dest(pkt->dest),
             bytesValidStart(pkt->bytesValidStart),
             bytesValidEnd(pkt->bytesValidEnd),
             busFirstWordDelay(pkt->busFirstWordDelay),
             busLastWordDelay(pkt->busLastWordDelay),
             senderState(pkt->senderState)
      {
          if (!clearFlags)
              flags.set(pkt->flags & COPY_FLAGS);
  
          flags.set(pkt->flags & (VALID_ADDR|VALID_SIZE));
          flags.set(pkt->flags & STATIC_DATA);
  
      }
  
      /**
       * clean up packet variables
       */
      ~Packet()
      {
          // If this is a request packet for which there's no response,
          // delete the request object here, since the requester will
          // never get the chance.
          if (req && isRequest() && !needsResponse())
              delete req;
          deleteData();
      }
  
      /**
       * Reinitialize packet address and size from the associated
       * Request object, and reset other fields that may have been
       * modified by a previous transaction.  Typically called when a
       * statically allocated Request/Packet pair is reused for multiple
       * transactions.
       */
      void
      reinitFromRequest()
      {
          assert(req->hasPaddr());
          flags = 0;
          addr = req->getPaddr();
          size = req->getSize();
  
          src = InvalidPortID;
          dest = InvalidPortID;
          bytesValidStart = 0;
          bytesValidEnd = 0;
          busFirstWordDelay = 0;
          busLastWordDelay = 0;
  
          flags.set(VALID_ADDR|VALID_SIZE);
          deleteData();
      }
  
      /**
       * Take a request packet and modify it in place to be suitable for
       * returning as a response to that request. The source field is
       * turned into the destination, and subsequently cleared. Note
       * that the latter is not necessary for atomic requests, but
       * causes no harm as neither field is valid.
       */
      void
      makeResponse()
      {
          assert(needsResponse());
          assert(isRequest());
          origCmd = cmd;
          cmd = cmd.responseCommand();
  
          // responses are never express, even if the snoop that
          // triggered them was
          flags.clear(EXPRESS_SNOOP);
  
          dest = src;
          clearSrc();
      }
  
      void
      makeAtomicResponse()
      {
          makeResponse();
      }
  
      void
      makeTimingResponse()
      {
          makeResponse();
      }
  
      void
      setFunctionalResponseStatus(bool success)
      {
          if (!success) {
              if (isWrite()) {
                  cmd = MemCmd::FunctionalWriteError;
              } else {
                  cmd = MemCmd::FunctionalReadError;
              }
          }
      }
  
      void
      setSize(unsigned size)
      {
          assert(!flags.isSet(VALID_SIZE));
  
          this->size = size;
          flags.set(VALID_SIZE);
      }
  
  
      /**
       * Set the data pointer to the following value that should not be
       * freed.
       */
      template <typename T>
      void
      dataStatic(T *p)
      {
          assert(flags.noneSet(STATIC_DATA|DYNAMIC_DATA|ARRAY_DATA));
          data = (PacketDataPtr)p;
          flags.set(STATIC_DATA);
      }
  
      /**
       * Set the data pointer to a value that should have delete []
       * called on it.
       */
      template <typename T>
      void
      dataDynamicArray(T *p)
      {
          assert(flags.noneSet(STATIC_DATA|DYNAMIC_DATA|ARRAY_DATA));
          data = (PacketDataPtr)p;
          flags.set(DYNAMIC_DATA|ARRAY_DATA);
      }
  
      /**
       * set the data pointer to a value that should have delete called
       * on it.
       */
      template <typename T>
      void
      dataDynamic(T *p)
      {
          assert(flags.noneSet(STATIC_DATA|DYNAMIC_DATA|ARRAY_DATA));
          data = (PacketDataPtr)p;
          flags.set(DYNAMIC_DATA);
      }
  
      /**
       * get a pointer to the data ptr.
       */
      template <typename T>
      T*
      getPtr(bool null_ok = false)
      {
          assert(null_ok || flags.isSet(STATIC_DATA|DYNAMIC_DATA));
          return (T*)data;
      }
  
      /**
       * return the value of what is pointed to in the packet.
       */
      template <typename T>
      T get();
  
      /**
       * set the value in the data pointer to v.
       */
      template <typename T>
      void set(T v);
  
      /**
       * Copy data into the packet from the provided pointer.
       */
      void
      setData(uint8_t *p)
      {
          if (p != getPtr<uint8_t>())
              std::memcpy(getPtr<uint8_t>(), p, getSize());
      }
  
      /**
       * Copy data into the packet from the provided block pointer,
       * which is aligned to the given block size.
       */
      void
      setDataFromBlock(uint8_t *blk_data, int blkSize)
      {
          setData(blk_data + getOffset(blkSize));
      }
  
      /**
       * Copy data from the packet to the provided block pointer, which
       * is aligned to the given block size.
       */
      void
      writeData(uint8_t *p)
      {
          std::memcpy(p, getPtr<uint8_t>(), getSize());
      }
  
      /**
       * Copy data from the packet to the memory at the provided pointer.
       */
      void
      writeDataToBlock(uint8_t *blk_data, int blkSize)
      {
          writeData(blk_data + getOffset(blkSize));
      }
  
      /**
       * delete the data pointed to in the data pointer. Ok to call to
       * matter how data was allocted.
       */
      void
      deleteData()
      {
          if (flags.isSet(ARRAY_DATA))
              delete [] data;
          else if (flags.isSet(DYNAMIC_DATA))
              delete data;
  
          flags.clear(STATIC_DATA|DYNAMIC_DATA|ARRAY_DATA);
          data = NULL;
      }
  
      /** If there isn't data in the packet, allocate some. */
      void
      allocate()
      {
          if (data) {
              assert(flags.isSet(STATIC_DATA|DYNAMIC_DATA));
              return;
          }
  
          assert(flags.noneSet(STATIC_DATA|DYNAMIC_DATA));
          flags.set(DYNAMIC_DATA|ARRAY_DATA);
          data = new uint8_t[getSize()];
      }
  
      /**
       * Check a functional request against a memory value represented
       * by a base/size pair and an associated data array.  If the
       * functional request is a read, it may be satisfied by the memory
       * value.  If the functional request is a write, it may update the
       * memory value.
       */
      bool checkFunctional(Printable *obj, Addr base, int size, uint8_t *data);
  
      /**
       * Check a functional request against a memory value stored in
       * another packet (i.e. an in-transit request or response).
       */
      bool
      checkFunctional(PacketPtr other) 
      {
          uint8_t *data = other->hasData() ? other->getPtr<uint8_t>() : NULL;
          return checkFunctional(other, other->getAddr(), other->getSize(),
                                 data);
      }
  
      /**
       * Push label for PrintReq (safe to call unconditionally).
       */
      void
      pushLabel(const std::string &lbl)
      {
          if (isPrint())
              safe_cast<PrintReqState*>(senderState)->pushLabel(lbl);
      }
  
      /**
       * Pop label for PrintReq (safe to call unconditionally).
       */
      void
      popLabel()
      {
          if (isPrint())
              safe_cast<PrintReqState*>(senderState)->popLabel();
      }
  
      void print(std::ostream &o, int verbosity = 0,
                 const std::string &prefix = "") const;
  
      /**
       * A no-args wrapper of print(std::ostream...)
       * meant to be invoked from DPRINTFs
       * avoiding string overheads in fast mode
       * @return string with the request's type and start<->end addresses
       */
      std::string print() const;
  };
  
  #endif //__MEM_PACKET_HH
  