Get rid of Packet result field. Error responses are

now encoded in cmd field.

--HG--
extra : convert_revision : d67819b7e3ee4b9a5bf08541104de0a89485e90b

10 files changed, 128 insertions, 149 deletions

diff --git a/src/mem/bridge.cc b/src/mem/bridge.cc
index fb4574844..77178d518 100644
--- a/src/mem/bridge.cc
+++ b/src/mem/bridge.cc
@@ -121,14 +121,13 @@ Bridge::BridgePort::recvTiming(PacketPtr pkt)
                     otherPort->sendQueue.size(), otherPort->queuedRequests,
                     otherPort->outstandingResponses);
 
-    if (pkt->isRequest() && otherPort->reqQueueFull() && pkt->result !=
-            Packet::Nacked) {
+    if (pkt->isRequest() && otherPort->reqQueueFull() && !pkt->wasNacked()) {
         DPRINTF(BusBridge, "Remote queue full, nacking\n");
         nackRequest(pkt);
         return true;
     }
 
-    if (pkt->needsResponse() && pkt->result != Packet::Nacked)
+    if (pkt->needsResponse() && !pkt->wasNacked())
         if (respQueueFull()) {
             DPRINTF(BusBridge, "Local queue full, no space for response, nacking\n");
             DPRINTF(BusBridge, "queue size: %d outreq: %d outstanding resp: %d\n",
@@ -149,7 +148,7 @@ void
 Bridge::BridgePort::nackRequest(PacketPtr pkt)
 {
     // Nack the packet
-    pkt->result = Packet::Nacked;
+    pkt->setNacked();
     pkt->setDest(pkt->getSrc());
 
     //put it on the list to send
@@ -194,7 +193,7 @@ Bridge::BridgePort::nackRequest(PacketPtr pkt)
 void
 Bridge::BridgePort::queueForSendTiming(PacketPtr pkt)
 {
-    if (pkt->isResponse() || pkt->result == Packet::Nacked) {
+    if (pkt->isResponse() || pkt->wasNacked()) {
         // This is a response for a request we forwarded earlier.  The
         // corresponding PacketBuffer should be stored in the packet's
         // senderState field.
@@ -206,7 +205,7 @@ Bridge::BridgePort::queueForSendTiming(PacketPtr pkt)
 
         // Check if this packet was expecting a response and it's a nacked
         // packet, in which case we will never being seeing it
-        if (buf->expectResponse && pkt->result == Packet::Nacked)
+        if (buf->expectResponse && pkt->wasNacked())
             --outstandingResponses;
 
 
@@ -217,7 +216,7 @@ Bridge::BridgePort::queueForSendTiming(PacketPtr pkt)
     }
 
 
-    if (pkt->isRequest() && pkt->result != Packet::Nacked) {
+    if (pkt->isRequest() && !pkt->wasNacked()) {
         ++queuedRequests;
     }
 
@@ -251,7 +250,7 @@ Bridge::BridgePort::trySend()
 
     // Ugly! @todo When multilevel coherence works this will be removed
     if (pkt->cmd == MemCmd::WriteInvalidateReq && fixPartialWrite &&
-            pkt->result != Packet::Nacked) {
+            !pkt->wasNacked()) {
         PacketPtr funcPkt = new Packet(pkt->req, MemCmd::WriteReq,
                             Packet::Broadcast);
         funcPkt->dataStatic(pkt->getPtr<uint8_t>());
@@ -264,7 +263,7 @@ Bridge::BridgePort::trySend()
             buf->origSrc, pkt->getDest(), pkt->getAddr());
 
     bool wasReq = pkt->isRequest();
-    bool wasNacked = pkt->result == Packet::Nacked;
+    bool wasNacked = pkt->wasNacked();
 
     if (sendTiming(pkt)) {
         // send successful
diff --git a/src/mem/bridge.hh b/src/mem/bridge.hh
index 89d626611..7af764437 100644
--- a/src/mem/bridge.hh
+++ b/src/mem/bridge.hh
@@ -86,7 +86,7 @@ class Bridge : public MemObject
                   expectResponse(_pkt->needsResponse() && !nack)
 
             {
-                if (!pkt->isResponse() && !nack && pkt->result != Packet::Nacked)
+                if (!pkt->isResponse() && !nack && !pkt->wasNacked())
                     pkt->senderState = this;
             }
 
diff --git a/src/mem/bus.cc b/src/mem/bus.cc
index ffd5e25a7..83ce0f87d 100644
--- a/src/mem/bus.cc
+++ b/src/mem/bus.cc
@@ -173,9 +173,8 @@ bool
 Bus::recvTiming(PacketPtr pkt)
 {
     Port *port;
-    DPRINTF(Bus, "recvTiming: packet src %d dest %d addr 0x%x cmd %s result %d\n",
-            pkt->getSrc(), pkt->getDest(), pkt->getAddr(), pkt->cmdString(),
-            pkt->result);
+    DPRINTF(Bus, "recvTiming: packet src %d dest %d addr 0x%x cmd %s\n",
+            pkt->getSrc(), pkt->getDest(), pkt->getAddr(), pkt->cmdString());
 
     BusPort *pktPort;
     if (pkt->getSrc() == defaultId)
@@ -329,6 +328,8 @@ Bus::functionalSnoop(PacketPtr pkt, Port *responder)
     // id after each
     int src_id = pkt->getSrc();
 
+    assert(pkt->isRequest()); // hasn't already been satisfied
+
     for (SnoopIter s_iter = snoopPorts.begin();
          s_iter != snoopPorts.end();
          s_iter++) {
@@ -336,7 +337,7 @@ Bus::functionalSnoop(PacketPtr pkt, Port *responder)
         if (p != responder && p->getId() != src_id) {
             p->sendFunctional(pkt);
         }
-        if (pkt->result == Packet::Success) {
+        if (pkt->isResponse()) {
             break;
         }
         pkt->setSrc(src_id);
@@ -369,14 +370,15 @@ Bus::recvAtomic(PacketPtr pkt)
     DPRINTF(Bus, "recvAtomic: packet src %d dest %d addr 0x%x cmd %s\n",
             pkt->getSrc(), pkt->getDest(), pkt->getAddr(), pkt->cmdString());
     assert(pkt->getDest() == Packet::Broadcast);
+    assert(pkt->isRequest());
 
     // Variables for recording original command and snoop response (if
     // any)... if a snooper respondes, we will need to restore
     // original command so that additional snoops can take place
     // properly
     MemCmd orig_cmd = pkt->cmd;
-    Packet::Result response_result = Packet::Unknown;
     MemCmd response_cmd = MemCmd::InvalidCmd;
+    int orig_src = pkt->getSrc();
 
     Port *target_port = findPort(pkt->getAddr(), pkt->getSrc());
 
@@ -387,20 +389,18 @@ Bus::recvAtomic(PacketPtr pkt)
         assert(p != target_port);
         if (p->getId() != pkt->getSrc()) {
             p->sendAtomic(pkt);
-            if (pkt->result != Packet::Unknown) {
+            if (pkt->isResponse()) {
                 // response from snoop agent
                 assert(pkt->cmd != orig_cmd);
                 assert(pkt->memInhibitAsserted());
-                assert(pkt->isResponse());
                 // should only happen once
-                assert(response_result == Packet::Unknown);
                 assert(response_cmd == MemCmd::InvalidCmd);
                 // save response state
-                response_result = pkt->result;
                 response_cmd = pkt->cmd;
                 // restore original packet state for remaining snoopers
                 pkt->cmd = orig_cmd;
-                pkt->result = Packet::Unknown;
+                pkt->setSrc(orig_src);
+                pkt->setDest(Packet::Broadcast);
             }
         }
     }
@@ -408,13 +408,11 @@ Bus::recvAtomic(PacketPtr pkt)
     Tick response_time = target_port->sendAtomic(pkt);
 
     // if we got a response from a snooper, restore it here
-    if (response_result != Packet::Unknown) {
-        assert(response_cmd != MemCmd::InvalidCmd);
+    if (response_cmd != MemCmd::InvalidCmd) {
         // no one else should have responded
-        assert(pkt->result == Packet::Unknown);
+        assert(!pkt->isResponse());
         assert(pkt->cmd == orig_cmd);
         pkt->cmd = response_cmd;
-        pkt->result = response_result;
     }
 
     // why do we have this packet field and the return value both???
@@ -434,8 +432,8 @@ Bus::recvFunctional(PacketPtr pkt)
     Port* port = findPort(pkt->getAddr(), pkt->getSrc());
     functionalSnoop(pkt, port ? port : interfaces[pkt->getSrc()]);
 
-    // If the snooping found what we were looking for, we're done.
-    if (pkt->result != Packet::Success && port) {
+    // If the snooping hasn't found what we were looking for, keep going.
+    if (!pkt->isResponse() && port) {
         port->sendFunctional(pkt);
     }
 }
diff --git a/src/mem/cache/base_cache.cc b/src/mem/cache/base_cache.cc
index 5062d6e87..870658675 100644
--- a/src/mem/cache/base_cache.cc
+++ b/src/mem/cache/base_cache.cc
@@ -82,7 +82,7 @@ void
 BaseCache::CachePort::checkAndSendFunctional(PacketPtr pkt)
 {
     checkFunctional(pkt);
-    if (pkt->result != Packet::Success)
+    if (!pkt->isResponse())
         sendFunctional(pkt);
 }
 
diff --git a/src/mem/cache/cache_impl.hh b/src/mem/cache/cache_impl.hh
index b76d7e392..1823ea6b9 100644
--- a/src/mem/cache/cache_impl.hh
+++ b/src/mem/cache/cache_impl.hh
@@ -502,7 +502,6 @@ Cache<TagStore>::atomicAccess(PacketPtr pkt)
 
     if (pkt->needsResponse()) {
         pkt->makeAtomicResponse();
-        pkt->result = Packet::Success;
     }
 
     return lat;
@@ -648,14 +647,13 @@ Cache<TagStore>::handleResponse(PacketPtr pkt)
     MSHR *mshr = dynamic_cast<MSHR*>(pkt->senderState);
     assert(mshr);
 
-    if (pkt->result == Packet::Nacked) {
+    if (pkt->wasNacked()) {
         //pkt->reinitFromRequest();
         warn("NACKs from devices not connected to the same bus "
              "not implemented\n");
         return;
     }
-    assert(pkt->result != Packet::BadAddress);
-    assert(pkt->result == Packet::Success);
+    assert(!pkt->isError());
     DPRINTF(Cache, "Handling response to %x\n", pkt->getAddr());
 
     MSHRQueue *mq = mshr->queue;
@@ -1142,7 +1140,7 @@ void
 Cache<TagStore>::CpuSidePort::recvFunctional(PacketPtr pkt)
 {
     checkFunctional(pkt);
-    if (pkt->result != Packet::Success)
+    if (!pkt->isResponse())
         myCache()->functionalAccess(pkt, cache->memSidePort);
 }
 
@@ -1180,7 +1178,7 @@ Cache<TagStore>::MemSidePort::recvTiming(PacketPtr pkt)
     // this needs to be fixed so that the cache updates the mshr and sends the
     // packet back out on the link, but it probably won't happen so until this
     // gets fixed, just panic when it does
-    if (pkt->result == Packet::Nacked)
+    if (pkt->wasNacked())
         panic("Need to implement cache resending nacked packets!\n");
 
     if (pkt->isRequest() && blocked) {
@@ -1216,7 +1214,7 @@ void
 Cache<TagStore>::MemSidePort::recvFunctional(PacketPtr pkt)
 {
     checkFunctional(pkt);
-    if (pkt->result != Packet::Success)
+    if (!pkt->isResponse())
         myCache()->functionalAccess(pkt, cache->cpuSidePort);
 }
 
diff --git a/src/mem/packet.cc b/src/mem/packet.cc
index cd0ed8a2e..55fe13f3c 100644
--- a/src/mem/packet.cc
+++ b/src/mem/packet.cc
@@ -115,7 +115,13 @@ MemCmd::commandInfo[] =
         SwapResp, "SwapReq" },
     /* SwapResp -- for Swap ldstub type operations */
     { SET5(IsRead, IsWrite, NeedsExclusive, IsResponse, HasData),
-        InvalidCmd, "SwapResp" }
+            InvalidCmd, "SwapResp" },
+    /* NetworkNackError  -- nacked at network layer (not by protocol) */
+    { SET2(IsRequest, IsError), InvalidCmd, "NetworkNackError" },
+    /* InvalidDestError  -- packet dest field invalid */
+    { SET2(IsRequest, IsError), InvalidCmd, "InvalidDestError" },
+    /* BadAddressError   -- memory address invalid */
+    { SET2(IsRequest, IsError), InvalidCmd, "BadAddressError" }
 };
 
 
@@ -205,7 +211,7 @@ Packet::checkFunctional(Addr addr, int size, uint8_t *data)
         if (func_start >= val_start && func_end <= val_end) {
             allocate();
             std::memcpy(getPtr<uint8_t>(), data + offset, getSize());
-            result = Packet::Success;
+            makeResponse();
             return true;
         } else {
             // In this case the timing packet only partially satisfies
@@ -245,15 +251,6 @@ operator<<(std::ostream &o, const Packet &p)
     o <<  p.getAddr() + p.getSize() - 1 << "] ";
     o.unsetf(std::ios_base::hex| std::ios_base::showbase);
 
-    if (p.result == Packet::Success)
-        o << "Successful ";
-    if (p.result == Packet::BadAddress)
-        o << "BadAddress ";
-    if (p.result == Packet::Nacked)
-        o << "Nacked ";
-    if (p.result == Packet::Unknown)
-        o << "Inflight ";
-
     if (p.isRead())
         o << "Read ";
     if (p.isWrite())
diff --git a/src/mem/packet.hh b/src/mem/packet.hh
index fc1c283ed..10b9f490c 100644
--- a/src/mem/packet.hh
+++ b/src/mem/packet.hh
@@ -84,6 +84,13 @@ class MemCmd
         StoreCondResp,
         SwapReq,
         SwapResp,
+        // Error responses
+        // @TODO these should be classified as responses rather than
+        // requests; coding them as requests initially for backwards
+        // compatibility
+        NetworkNackError,  // nacked at network layer (not by protocol)
+        InvalidDestError,  // packet dest field invalid
+        BadAddressError,   // memory address invalid
         NUM_MEM_CMDS
     };
 
@@ -103,6 +110,7 @@ class MemCmd
         IsHWPrefetch,
         IsLocked,       //!< Alpha/MIPS LL or SC access
         HasData,        //!< There is an associated payload
+        IsError,        //!< Error response
         NUM_COMMAND_ATTRIBUTES
     };
 
@@ -135,12 +143,13 @@ class MemCmd
     bool isWrite()  const       { return testCmdAttrib(IsWrite); }
     bool isRequest() const      { return testCmdAttrib(IsRequest); }
     bool isResponse() const     { return testCmdAttrib(IsResponse); }
-    bool needsExclusive() const  { return testCmdAttrib(NeedsExclusive); }
+    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 isLocked() const       { return testCmdAttrib(IsLocked); }
+    bool isError() const        { return testCmdAttrib(IsError); }
 
     const Command responseCommand() const {
         return commandInfo[cmd].response;
@@ -184,6 +193,12 @@ class Packet : public FastAlloc
 
     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
@@ -223,19 +238,28 @@ class Packet : public FastAlloc
      *   (unlike * addr, size, and src). */
     short 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;
+
     /** Are the 'addr' and 'size' fields valid? */
     bool addrSizeValid;
     /** Is the 'src' field valid? */
     bool srcValid;
+    bool destValid;
 
-    enum SnoopFlag {
+    enum Flag {
+        // Snoop flags
         MemInhibit,
         Shared,
-        NUM_SNOOP_FLAGS
+        NUM_PACKET_FLAGS
     };
 
-    /** Coherence snoopFlags for snooping */
-    std::bitset<NUM_SNOOP_FLAGS> snoopFlags;
+    /** Status flags */
+    std::bitset<NUM_PACKET_FLAGS> flags;
 
   public:
 
@@ -252,22 +276,6 @@ class Packet : public FastAlloc
      *   should be routed based on its address. */
     static const short Broadcast = -1;
 
-    /** A pointer to the original request. */
-    RequestPtr req;
-
-    /** A virtual base opaque structure used to hold coherence-related
-     *    state.  A specific subclass would be derived from this to
-     *    carry state specific to a particular coherence protocol.  */
-    class CoherenceState : public FastAlloc {
-      public:
-        virtual ~CoherenceState() {}
-    };
-
-    /** This packet's coherence state.  Caches should use
-     *   dynamic_cast<> to cast to the state appropriate for the
-     *   system's coherence protocol.  */
-    CoherenceState *coherence;
-
     /** A virtual base opaque structure used to hold state associated
      *    with the packet but specific to the sending device (e.g., an
      *    MSHR).  A pointer to this state is returned in the packet's
@@ -284,11 +292,6 @@ class Packet : public FastAlloc
      *   to cast to the state appropriate to the sender. */
     SenderState *senderState;
 
-  public:
-
-    /** The command field of the packet. */
-    MemCmd cmd;
-
     /** Return the string name of the cmd field (for debugging and
      *   tracing). */
     const std::string &cmdString() const { return cmd.toString(); }
@@ -296,68 +299,59 @@ class Packet : public FastAlloc
     /** Return the index of this command. */
     inline int cmdToIndex() const { return cmd.toInt(); }
 
-  public:
-
     bool isRead() const         { return cmd.isRead(); }
     bool isWrite()  const       { return cmd.isWrite(); }
     bool isRequest() const      { return cmd.isRequest(); }
     bool isResponse() const     { return cmd.isResponse(); }
-    bool needsExclusive() const  { return cmd.needsExclusive(); }
+    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 isLocked() const       { return cmd.isLocked(); }
-
-    void assertMemInhibit()     { snoopFlags[MemInhibit] = true; }
-    void assertShared()         { snoopFlags[Shared] = true; }
-    bool memInhibitAsserted()   { return snoopFlags[MemInhibit]; }
-    bool sharedAsserted()       { return snoopFlags[Shared]; }
+    bool isError() const        { return cmd.isError(); }
+
+    // Snoop flags
+    void assertMemInhibit()     { flags[MemInhibit] = true; }
+    void assertShared()         { flags[Shared] = true; }
+    bool memInhibitAsserted()   { return flags[MemInhibit]; }
+    bool sharedAsserted()       { return flags[Shared]; }
+
+    // Network error conditions... encapsulate them as methods since
+    // their encoding keeps changing (from result field to command
+    // field, etc.)
+    void setNacked()     { origCmd = cmd; cmd = MemCmd::NetworkNackError; }
+    void setBadAddress() { origCmd = cmd; cmd = MemCmd::BadAddressError; }
+    bool wasNacked()     { return cmd == MemCmd::NetworkNackError; }
+    bool hadBadAddress() { return cmd == MemCmd::BadAddressError; }
 
     bool nic_pkt() { panic("Unimplemented"); M5_DUMMY_RETURN }
 
-    /** Possible results of a packet's request. */
-    enum Result
-    {
-        Success,
-        BadAddress,
-        Nacked,
-        Unknown
-    };
-
-    /** The result of this packet's request. */
-    Result result;
-
     /** Accessor function that returns the source index of the packet. */
-    short getSrc() const { assert(srcValid); return src; }
+    short getSrc() const    { assert(srcValid); return src; }
     void setSrc(short _src) { src = _src; srcValid = true; }
     /** Reset source field, e.g. to retransmit packet on different bus. */
     void clearSrc() { srcValid = false; }
 
     /** Accessor function that returns the destination index of
         the packet. */
-    short getDest() const { return dest; }
-    void setDest(short _dest) { dest = _dest; }
+    short getDest() const     { assert(destValid); return dest; }
+    void setDest(short _dest) { dest = _dest; destValid = true; }
 
     Addr getAddr() const { assert(addrSizeValid); return addr; }
-    int getSize() const { assert(addrSizeValid); return size; }
+    int getSize() const  { assert(addrSizeValid); return size; }
     Addr getOffset(int blkSize) const { return addr & (Addr)(blkSize - 1); }
 
-    void addrOverride(Addr newAddr) { assert(addrSizeValid); addr = newAddr; }
-    void cmdOverride(MemCmd newCmd) { cmd = newCmd; }
-
     /** 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 and destination addresses
      *   must be supplied.  */
     Packet(Request *_req, MemCmd _cmd, short _dest)
-        :  data(NULL), staticData(false), dynamicData(false), arrayData(false),
+        :  cmd(_cmd), req(_req),
+           data(NULL), staticData(false), dynamicData(false), arrayData(false),
            addr(_req->paddr), size(_req->size), dest(_dest),
-           addrSizeValid(_req->validPaddr), srcValid(false),
-           snoopFlags(0),
-           time(curTick),
-           req(_req), coherence(NULL), senderState(NULL), cmd(_cmd),
-           result(Unknown)
+           addrSizeValid(_req->validPaddr), srcValid(false), destValid(true),
+           flags(0), time(curTick), senderState(NULL)
     {
     }
 
@@ -365,13 +359,11 @@ class Packet : public FastAlloc
      *  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, short _dest, int _blkSize)
-        :  data(NULL), staticData(false), dynamicData(false), arrayData(false),
+        :  cmd(_cmd), req(_req),
+           data(NULL), staticData(false), dynamicData(false), arrayData(false),
            addr(_req->paddr & ~(_blkSize - 1)), size(_blkSize), dest(_dest),
-           addrSizeValid(_req->validPaddr), srcValid(false),
-           snoopFlags(0),
-           time(curTick),
-           req(_req), coherence(NULL), senderState(NULL), cmd(_cmd),
-           result(Unknown)
+           addrSizeValid(_req->validPaddr), srcValid(false), destValid(true),
+           flags(0), time(curTick), senderState(NULL)
     {
     }
 
@@ -382,15 +374,14 @@ class Packet : public FastAlloc
      * dynamic data, user must guarantee that the new packet's
      * lifetime is less than that of the original packet. */
     Packet(Packet *origPkt)
-        :  data(NULL), staticData(false), dynamicData(false), arrayData(false),
+        :  cmd(origPkt->cmd), req(origPkt->req),
+           data(NULL), staticData(false), dynamicData(false), arrayData(false),
            addr(origPkt->addr), size(origPkt->size),
            src(origPkt->src), dest(origPkt->dest),
-           addrSizeValid(origPkt->addrSizeValid), srcValid(origPkt->srcValid),
-           snoopFlags(origPkt->snoopFlags),
-           time(curTick),
-           req(origPkt->req), coherence(origPkt->coherence),
-           senderState(origPkt->senderState), cmd(origPkt->cmd),
-           result(origPkt->result)
+           addrSizeValid(origPkt->addrSizeValid),
+           srcValid(origPkt->srcValid), destValid(origPkt->destValid),
+           flags(origPkt->flags),
+           time(curTick), senderState(origPkt->senderState)
     {
     }
 
@@ -405,12 +396,11 @@ class Packet : public FastAlloc
      *   multiple transactions. */
     void reinitFromRequest() {
         assert(req->validPaddr);
-        snoopFlags = 0;
+        flags = 0;
         addr = req->paddr;
         size = req->size;
         time = req->time;
         addrSizeValid = true;
-        result = Unknown;
         if (dynamicData) {
             deleteData();
             dynamicData = false;
@@ -424,34 +414,24 @@ class Packet : public FastAlloc
      * destination fields are *not* modified, as is appropriate for
      * atomic accesses.
      */
-    void makeAtomicResponse()
+    void makeResponse()
     {
         assert(needsResponse());
         assert(isRequest());
-        assert(result == Unknown);
         cmd = cmd.responseCommand();
-        result = Success;
+        dest = src;
+        destValid = srcValid;
+        srcValid = false;
     }
 
-    /**
-     * Perform the additional work required for timing responses above
-     * and beyond atomic responses; i.e., change the destination to
-     * point back to the requester and clear the source field.
-     */
-    void convertAtomicToTimingResponse()
+    void makeAtomicResponse()
     {
-        dest = getSrc();
-        srcValid = false;
+        makeResponse();
     }
 
-    /**
-     * Take a request packet and modify it in place to be suitable for
-     * returning as a response to a timing request.
-     */
     void makeTimingResponse()
     {
-        makeAtomicResponse();
-        convertAtomicToTimingResponse();
+        makeResponse();
     }
 
     /**
@@ -462,9 +442,10 @@ class Packet : public FastAlloc
     void
     reinitNacked()
     {
-        assert(needsResponse() && result == Nacked);
-        dest =  Broadcast;
-        result = Unknown;
+        assert(wasNacked());
+        cmd = origCmd;
+        assert(needsResponse());
+        setDest(Broadcast);
     }
 
 
diff --git a/src/mem/physical.cc b/src/mem/physical.cc
index 93cba96c4..2742eca51 100644
--- a/src/mem/physical.cc
+++ b/src/mem/physical.cc
@@ -322,7 +322,7 @@ PhysicalMemory::doFunctionalAccess(PacketPtr pkt)
               pkt->cmdString());
     }
 
-    pkt->result = Packet::Success;
+    pkt->makeAtomicResponse();
 }
 
 
diff --git a/src/mem/port.cc b/src/mem/port.cc
index e6ea773f2..ba4f23668 100644
--- a/src/mem/port.cc
+++ b/src/mem/port.cc
@@ -58,12 +58,11 @@ void
 Port::blobHelper(Addr addr, uint8_t *p, int size, MemCmd cmd)
 {
     Request req;
-    Packet pkt(&req, cmd, Packet::Broadcast);
 
     for (ChunkGenerator gen(addr, size, peerBlockSize());
          !gen.done(); gen.next()) {
         req.setPhys(gen.addr(), gen.size(), 0);
-        pkt.reinitFromRequest();
+        Packet pkt(&req, cmd, Packet::Broadcast);
         pkt.dataStatic(p);
         sendFunctional(&pkt);
         p += gen.size();
diff --git a/src/mem/tport.cc b/src/mem/tport.cc
index 6c8c12ce2..d6ff64608 100644
--- a/src/mem/tport.cc
+++ b/src/mem/tport.cc
@@ -55,7 +55,7 @@ SimpleTimingPort::recvFunctional(PacketPtr pkt)
     checkFunctional(pkt);
 
     // Just do an atomic access and throw away the returned latency
-    if (pkt->result != Packet::Success)
+    if (!pkt->isResponse())
         recvAtomic(pkt);
 }
 
@@ -68,7 +68,6 @@ SimpleTimingPort::recvTiming(PacketPtr pkt)
     // correctly with the drain code, so that would need to be fixed
     // if we ever added it back.
     assert(pkt->isRequest());
-    assert(pkt->result == Packet::Unknown);
 
     if (pkt->memInhibitAsserted()) {
         // snooper will supply based on copy of packet
@@ -85,7 +84,6 @@ SimpleTimingPort::recvTiming(PacketPtr pkt)
         // recvAtomic() should already have turned packet into
         // atomic response
         assert(pkt->isResponse());
-        pkt->convertAtomicToTimingResponse();
         schedSendTiming(pkt, curTick + latency);
     } else {
         delete pkt->req;
@@ -138,12 +136,15 @@ void
 SimpleTimingPort::sendDeferredPacket()
 {
     assert(deferredPacketReady());
-    bool success = sendTiming(transmitList.front().pkt);
+    // take packet off list here; if recvTiming() on the other side
+    // calls sendTiming() back on us (like SimpleTimingCpu does), then
+    // we get confused by having a non-active packet on transmitList
+    DeferredPacket dp = transmitList.front();
+    transmitList.pop_front();
+    bool success = sendTiming(dp.pkt);
 
     if (success) {
-        //send successful, remove packet
-        transmitList.pop_front();
-        if (!transmitList.empty()) {
+        if (!transmitList.empty() && !sendEvent->scheduled()) {
             Tick time = transmitList.front().tick;
             sendEvent->schedule(time <= curTick ? curTick+1 : time);
         }
@@ -152,6 +153,12 @@ SimpleTimingPort::sendDeferredPacket()
             drainEvent->process();
             drainEvent = NULL;
         }
+    } else {
+        // Unsuccessful, need to put back on transmitList.  Callee
+        // should not have messed with it (since it didn't accept that
+        // packet), so we can just push it back on the front.
+        assert(!sendEvent->scheduled());
+        transmitList.push_front(dp);
     }
 
     waitingOnRetry = !success;