14 files changed, 478 insertions, 378 deletions

diff --git a/src/mem/bridge.cc b/src/mem/bridge.cc
index c4b137869..736e8dc81 100644
--- a/src/mem/bridge.cc
+++ b/src/mem/bridge.cc
@@ -31,209 +31,209 @@
  * @file Definition of a simple bus bridge without buffering.
  */
 
+#include <algorithm>
 
 #include "base/trace.hh"
 #include "mem/bridge.hh"
 #include "sim/builder.hh"
 
+Bridge::BridgePort::BridgePort(const std::string &_name,
+                               Bridge *_bridge, BridgePort *_otherPort,
+                               int _delay, int _queueLimit)
+    : Port(_name), bridge(_bridge), otherPort(_otherPort),
+      delay(_delay), outstandingResponses(0),
+      queueLimit(_queueLimit), sendEvent(this)
+{
+}
+
+Bridge::Bridge(const std::string &n, int qsa, int qsb,
+               Tick _delay, int write_ack)
+    : MemObject(n),
+      portA(n + "-portA", this, &portB, _delay, qsa),
+      portB(n + "-portB", this, &portA, _delay, qsa),
+      ackWrites(write_ack)
+{
+}
+
+Port *
+Bridge::getPort(const std::string &if_name)
+{
+    BridgePort *port;
+
+    if (if_name == "side_a")
+        port = &portA;
+    else if (if_name == "side_b")
+        port = &portB;
+    else
+        return NULL;
+
+    if (port->getPeer() != NULL)
+        panic("bridge side %s already connected to.", if_name);
+    return port;
+}
+
+
 void
 Bridge::init()
 {
     // Make sure that both sides are connected to.
-    if (sideA == NULL || sideB == NULL)
+    if (portA.getPeer() == NULL || portB.getPeer() == NULL)
         panic("Both ports of bus bridge are not connected to a bus.\n");
 }
 
 
-/** Function called by the port when the bus is recieving a Timing
+/** Function called by the port when the bus is receiving a Timing
  * transaction.*/
 bool
-Bridge::recvTiming(Packet *pkt, Side id)
+Bridge::BridgePort::recvTiming(Packet *pkt)
 {
-    if (blockedA && id == SideA)
-        return false;
-    if (blockedB && id == SideB)
-        return false;
-
-    if (delay) {
-        if (!sendEvent.scheduled())
-            sendEvent.schedule(curTick + delay);
-        if (id == SideA) {
-            inboundA.push_back(std::make_pair<Packet*, Tick>(pkt, curTick));
-            blockCheck(SideA);
-        } else {
-            inboundB.push_back(std::make_pair<Packet*, Tick>(pkt, curTick));
-            blockCheck(SideB);
-        }
-    } else {
-        if (id == SideB) {
-            sideA->sendPkt(pkt);
-            blockCheck(SideB);
-        } else {
-            sideB->sendPkt(pkt);
-            blockCheck(SideA);
-        }
+    DPRINTF(BusBridge, "recvTiming: src %d dest %d addr 0x%x\n",
+            pkt->getSrc(), pkt->getDest(), pkt->getAddr());
+
+    if (pkt->isResponse()) {
+        // This is a response for a request we forwarded earlier.  The
+        // corresponding PacketBuffer should be stored in the packet's
+        // senderState field.
+        PacketBuffer *buf = dynamic_cast<PacketBuffer*>(pkt->senderState);
+        assert(buf != NULL);
+        // set up new packet dest & senderState based on values saved
+        // from original request
+        buf->fixResponse(pkt);
+        DPRINTF(BusBridge, "  is response, new dest %d\n", pkt->getDest());
+        delete buf;
     }
-    return true;
 
+    return otherPort->queueForSendTiming(pkt);
 }
 
-void
-Bridge::blockCheck(Side id)
-{
-    /* Check that we still have buffer space available. */
-    if (id == SideB) {
-        if (sideA->numQueued() + inboundB.size() >= queueSizeA && !blockedB) {
-            sideB->sendStatusChange(Port::Blocked);
-            blockedB = true;
-        } else if (sideA->numQueued() + inboundB.size() < queueSizeA && blockedB) {
-            sideB->sendStatusChange(Port::Unblocked);
-            blockedB = false;
-        }
-    } else {
-        if (sideB->numQueued() + inboundA.size() >= queueSizeB && !blockedA) {
-            sideA->sendStatusChange(Port::Blocked);
-            blockedA = true;
-        } else if (sideB->numQueued() + inboundA.size() < queueSizeB && blockedA) {
-            sideA->sendStatusChange(Port::Unblocked);
-            blockedA = false;
-        }
-    }
-}
 
-void Bridge::timerEvent()
+bool
+Bridge::BridgePort::queueForSendTiming(Packet *pkt)
 {
-    Tick t = 0;
+    if (queueFull())
+        return false;
 
-    assert(inboundA.size() || inboundB.size());
-    if (inboundA.size()) {
-        while (inboundA.front().second <= curTick + delay){
-            sideB->sendPkt(inboundA.front());
-            inboundA.pop_front();
-        }
-        if (inboundA.size())
-            t = inboundA.front().second + delay;
-    }
-    if (inboundB.size()) {
-        while (inboundB.front().second <= curTick + delay){
-            sideB->sendPkt(inboundA.front());
-            inboundB.pop_front();
-        }
-        if (inboundB.size())
-            if (t == 0)
-               t = inboundB.front().second + delay;
-            else
-               t = std::min(t,inboundB.front().second + delay);
-    } else {
-        panic("timerEvent() called but nothing to do?");
+    Tick readyTime = curTick + delay;
+    PacketBuffer *buf = new PacketBuffer(pkt, readyTime);
+
+    // If we're about to put this packet at the head of the queue, we
+    // need to schedule an event to do the transmit.  Otherwise there
+    // should already be an event scheduled for sending the head
+    // packet.
+    if (sendQueue.empty()) {
+        sendEvent.schedule(readyTime);
     }
 
-    if (t != 0)
-        sendEvent.schedule(t);
+    sendQueue.push_back(buf);
+
+    // Did we just become blocked?  If yes, let other side know.
+    if (queueFull())
+        otherPort->sendStatusChange(Port::Blocked);
+
+    return true;
 }
 
 
 void
-Bridge::BridgePort::sendPkt(Packet *pkt)
+Bridge::BridgePort::finishSend(PacketBuffer *buf)
 {
-    if (!sendTiming(pkt))
-        outbound.push_back(std::make_pair<Packet*,Tick>(pkt, curTick));
+    if (buf->expectResponse) {
+        // Must wait for response.  We just need to count outstanding
+        // responses (in case we want to cap them); PacketBuffer
+        // pointer will be recovered on response.
+        ++outstandingResponses;
+        DPRINTF(BusBridge, "  successful: awaiting response (%d)\n",
+                outstandingResponses);
+    } else {
+        // no response expected... deallocate packet buffer now.
+        DPRINTF(BusBridge, "  successful: no response expected\n");
+        delete buf;
+    }
+
+    // If there are more packets to send, schedule event to try again.
+    if (!sendQueue.empty()) {
+        buf = sendQueue.front();
+        sendEvent.schedule(std::max(buf->ready, curTick + 1));
+    }
 }
 
+
 void
-Bridge::BridgePort::sendPkt(std::pair<Packet*, Tick> p)
+Bridge::BridgePort::trySend()
 {
-    if (!sendTiming(p.first))
-        outbound.push_back(p);
+    assert(!sendQueue.empty());
+
+    PacketBuffer *buf = sendQueue.front();
+
+    assert(buf->ready <= curTick);
+
+    Packet *pkt = buf->pkt;
+
+    DPRINTF(BusBridge, "trySend: origSrc %d dest %d addr 0x%x\n",
+            buf->origSrc, pkt->getDest(), pkt->getAddr());
+
+    if (sendTiming(pkt)) {
+        // send successful
+        sendQueue.pop_front();
+        buf->pkt = NULL; // we no longer own packet, so it's not safe to look at it
+        finishSend(buf);
+    } else {
+        DPRINTF(BusBridge, "  unsuccessful\n");
+    }
 }
 
 
 Packet *
 Bridge::BridgePort::recvRetry()
 {
-    Packet *pkt;
-    assert(outbound.size() > 0);
-    assert(outbound.front().second >= curTick + bridge->delay);
-    pkt = outbound.front().first;
-    outbound.pop_front();
-    bridge->blockCheck(side);
+    PacketBuffer *buf = sendQueue.front();
+    Packet *pkt = buf->pkt;
+    finishSend(buf);
     return pkt;
 }
 
-/** Function called by the port when the bus is recieving a Atomic
+/** Function called by the port when the bus is receiving a Atomic
  * transaction.*/
 Tick
-Bridge::recvAtomic(Packet *pkt, Side id)
+Bridge::BridgePort::recvAtomic(Packet *pkt)
 {
-    pkt->time += delay;
-
-    if (id == SideA)
-        return sideB->sendAtomic(pkt);
-    else
-        return sideA->sendAtomic(pkt);
+    return otherPort->sendAtomic(pkt) + delay;
 }
 
-/** Function called by the port when the bus is recieving a Functional
+/** Function called by the port when the bus is receiving a Functional
  * transaction.*/
 void
-Bridge::recvFunctional(Packet *pkt, Side id)
+Bridge::BridgePort::recvFunctional(Packet *pkt)
 {
-    pkt->time += delay;
-    std::list<std::pair<Packet*, Tick> >::iterator i;
+    std::list<PacketBuffer*>::iterator i;
     bool pktContinue = true;
 
-    for(i = inboundA.begin();  i != inboundA.end(); ++i) {
-        if (pkt->intersect(i->first)) {
-            pktContinue &= fixPacket(pkt, i->first);
-        }
-    }
-
-    for(i = inboundB.begin();  i != inboundB.end(); ++i) {
-        if (pkt->intersect(i->first)) {
-            pktContinue &= fixPacket(pkt, i->first);
-        }
-    }
-
-    for(i = sideA->outbound.begin();  i != sideA->outbound.end(); ++i) {
-        if (pkt->intersect(i->first)) {
-            pktContinue &= fixPacket(pkt, i->first);
-        }
-    }
-
-    for(i = sideB->outbound.begin();  i != sideB->outbound.end(); ++i) {
-        if (pkt->intersect(i->first)) {
-            pktContinue &= fixPacket(pkt, i->first);
+    for (i = sendQueue.begin();  i != sendQueue.end(); ++i) {
+        if (pkt->intersect((*i)->pkt)) {
+            pktContinue &= fixPacket(pkt, (*i)->pkt);
         }
     }
 
     if (pktContinue) {
-        if (id == SideA)
-            sideB->sendFunctional(pkt);
-        else
-            sideA->sendFunctional(pkt);
+        otherPort->sendFunctional(pkt);
     }
 }
 
-/** Function called by the port when the bus is recieving a status change.*/
+/** Function called by the port when the bus is receiving a status change.*/
 void
-Bridge::recvStatusChange(Port::Status status, Side id)
+Bridge::BridgePort::recvStatusChange(Port::Status status)
 {
     if (status == Port::Blocked || status == Port::Unblocked)
-        return ;
+        return;
 
-    if (id == SideA)
-        sideB->sendStatusChange(status);
-    else
-        sideA->sendStatusChange(status);
+    otherPort->sendStatusChange(status);
 }
 
 void
-Bridge::addressRanges(AddrRangeList &resp, AddrRangeList &snoop, Side id)
+Bridge::BridgePort::getDeviceAddressRanges(AddrRangeList &resp,
+                                           AddrRangeList &snoop)
 {
-    if (id == SideA)
-        sideB->getPeerAddressRanges(resp, snoop);
-    else
-        sideA->getPeerAddressRanges(resp, snoop);
+    otherPort->getPeerAddressRanges(resp, snoop);
 }
 
 BEGIN_DECLARE_SIM_OBJECT_PARAMS(Bridge)
diff --git a/src/mem/bridge.hh b/src/mem/bridge.hh
index 5f19ded40..8a5cbf92a 100644
--- a/src/mem/bridge.hh
+++ b/src/mem/bridge.hh
@@ -46,132 +46,127 @@
 
 class Bridge : public MemObject
 {
-  public:
-    enum Side
+  protected:
+    /** Decleration of the buses port type, one will be instantiated for each
+        of the interfaces connecting to the bus. */
+    class BridgePort : public Port
     {
-        SideA,
-        SideB
-    };
+        /** A pointer to the bridge to which this port belongs. */
+        Bridge *bridge;
 
-  protected:
-    /** Function called by the port when the bus is recieving a Timing
-        transaction.*/
-    bool recvTiming(Packet *pkt, Side id);
+        /**
+         * Pointer to the port on the other side of the bridge
+         * (connected to the other bus).
+         */
+        BridgePort *otherPort;
 
-    /** Function called by the port when the bus is recieving a Atomic
-        transaction.*/
-    Tick recvAtomic(Packet *pkt, Side id);
+        /** Minimum delay though this bridge. */
+        Tick delay;
 
-    /** Function called by the port when the bus is recieving a Functional
-        transaction.*/
-    void recvFunctional(Packet *pkt, Side id);
+        class PacketBuffer : public Packet::SenderState {
 
-    /** Function called by the port when the bus is recieving a status change.*/
-    void recvStatusChange(Port::Status status, Side id);
+          public:
+            Tick ready;
+            Packet *pkt;
+            Packet::SenderState *origSenderState;
+            short origSrc;
+            bool expectResponse;
 
-    /** Process address range request.
-     * @param resp addresses that we can respond to
-     * @param snoop addresses that we would like to snoop
-     * @param id ide of the busport that made the request.
-     */
-    void addressRanges(AddrRangeList &resp, AddrRangeList &snoop, Side id);
+            PacketBuffer(Packet *_pkt, Tick t)
+                : ready(t), pkt(_pkt),
+                  origSenderState(_pkt->senderState), origSrc(_pkt->getSrc()),
+                  expectResponse(_pkt->needsResponse())
+            {
+                pkt->senderState = this;
+            }
 
+            void fixResponse(Packet *pkt)
+            {
+                assert(pkt->senderState == this);
+                pkt->setDest(origSrc);
+                pkt->senderState = origSenderState;
+            }
+        };
 
-    /** Event that the SendEvent calls when it fires. This code must reschedule
-     * the send event as required. */
-    void timerEvent();
+        /**
+         * Outbound packet queue.  Packets are held in this queue for a
+         * specified delay to model the processing delay of the
+         * bridge.
+         */
+        std::list<PacketBuffer*> sendQueue;
 
-    /** Decleration of the buses port type, one will be instantiated for each
-        of the interfaces connecting to the bus. */
-    class BridgePort : public Port
-    {
-        /** A pointer to the bus to which this port belongs. */
-        Bridge *bridge;
+        int outstandingResponses;
+
+        /** Max queue size for outbound packets */
+        int queueLimit;
+
+        /**
+         * Is this side blocked from accepting outbound packets?
+         */
+        bool queueFull() { return (sendQueue.size() == queueLimit); }
+
+        bool queueForSendTiming(Packet *pkt);
+
+        void finishSend(PacketBuffer *buf);
+
+        /**
+         * Handle send event, scheduled when the packet at the head of
+         * the outbound queue is ready to transmit (for timing
+         * accesses only).
+         */
+        void trySend();
+
+        class SendEvent : public Event
+        {
+            BridgePort *port;
+
+          public:
+            SendEvent(BridgePort *p)
+                : Event(&mainEventQueue), port(p) {}
+
+            virtual void process() { port->trySend(); }
 
-        /** A id to keep track of the intercafe ID this port is connected to. */
-        Bridge::Side side;
+            virtual const char *description() { return "bridge send event"; }
+        };
+
+        SendEvent sendEvent;
 
       public:
 
         /** Constructor for the BusPort.*/
-        BridgePort(Bridge *_bridge, Side _side)
-            : bridge(_bridge), side(_side)
-        { }
-
-        int numQueued() { return outbound.size(); }
+        BridgePort(const std::string &_name,
+                   Bridge *_bridge, BridgePort *_otherPort,
+                   int _delay, int _queueLimit);
 
       protected:
-        /** Data this is waiting to be transmitted. */
-        std::list<std::pair<Packet*, Tick> > outbound;
-
-        void sendPkt(Packet *pkt);
-        void sendPkt(std::pair<Packet*, Tick> p);
 
-        /** When reciving a timing request from the peer port,
+        /** When receiving a timing request from the peer port,
             pass it to the bridge. */
-        virtual bool recvTiming(Packet *pkt)
-        { return bridge->recvTiming(pkt, side); }
+        virtual bool recvTiming(Packet *pkt);
 
-        /** When reciving a retry request from the peer port,
+        /** When receiving a retry request from the peer port,
             pass it to the bridge. */
         virtual Packet* recvRetry();
 
-        /** When reciving a Atomic requestfrom the peer port,
+        /** When receiving a Atomic requestfrom the peer port,
             pass it to the bridge. */
-        virtual Tick recvAtomic(Packet *pkt)
-        { return bridge->recvAtomic(pkt, side); }
+        virtual Tick recvAtomic(Packet *pkt);
 
-        /** When reciving a Functional request from the peer port,
+        /** When receiving a Functional request from the peer port,
             pass it to the bridge. */
-        virtual void recvFunctional(Packet *pkt)
-        { bridge->recvFunctional(pkt, side); }
+        virtual void recvFunctional(Packet *pkt);
 
-        /** When reciving a status changefrom the peer port,
+        /** When receiving a status changefrom the peer port,
             pass it to the bridge. */
-        virtual void recvStatusChange(Status status)
-        { bridge->recvStatusChange(status, side); }
+        virtual void recvStatusChange(Status status);
 
-        /** When reciving a address range request the peer port,
+        /** When receiving a address range request the peer port,
             pass it to the bridge. */
-        virtual void getDeviceAddressRanges(AddrRangeList &resp, AddrRangeList &snoop)
-        { bridge->addressRanges(resp, snoop, side); }
-
-        friend class Bridge;
-    };
-
-    class SendEvent : public Event
-    {
-        Bridge *bridge;
-
-        SendEvent(Bridge *b)
-            : Event(&mainEventQueue), bridge(b) {}
-
-        virtual void process() { bridge->timerEvent(); }
-
-        virtual const char *description() { return "bridge delay event"; }
-        friend class Bridge;
+        virtual void getDeviceAddressRanges(AddrRangeList &resp,
+                                            AddrRangeList &snoop);
     };
 
-    SendEvent sendEvent;
-
-    /** Sides of the bus bridges. */
-    BridgePort* sideA;
-    BridgePort* sideB;
-
-    /** inbound queues on both sides. */
-    std::list<std::pair<Packet*, Tick> > inboundA;
-    std::list<std::pair<Packet*, Tick> > inboundB;
-
-    /** The size of the queue for data coming into side a */
-    int queueSizeA;
-    int queueSizeB;
-
-    /* if the side is blocked or not. */
-    bool blockedA;
-    bool blockedB;
-
-    /** Miminum delay though this bridge. */
-    Tick delay;
+    BridgePort portA, portB;
 
     /** If this bridge should acknowledge writes. */
     bool ackWrites;
@@ -179,36 +174,11 @@ class Bridge : public MemObject
   public:
 
     /** A function used to return the port associated with this bus object. */
-    virtual Port *getPort(const std::string &if_name)
-    {
-        if (if_name == "side_a") {
-            if (sideA != NULL)
-                panic("bridge side a already connected to.");
-            sideA = new BridgePort(this, SideA);
-            return sideA;
-        } else if (if_name == "side_b") {
-            if (sideB != NULL)
-                panic("bridge side b already connected to.");
-            sideB = new BridgePort(this, SideB);
-            return sideB;
-        } else
-            return NULL;
-    }
+    virtual Port *getPort(const std::string &if_name);
 
     virtual void init();
 
-    Bridge(const std::string &n, int qsa, int qsb, Tick _delay, int write_ack)
-        : MemObject(n), sendEvent(this), sideA(NULL), sideB(NULL),
-          queueSizeA(qsa), queueSizeB(qsb), blockedA(false), blockedB(false),
-          delay(_delay), ackWrites(write_ack)
-          {}
-
-    /** Check if the port should block/unblock after recieving/sending a packet.
-     * */
-    void blockCheck(Side id);
-
-    friend class Bridge::SendEvent;
-
+    Bridge(const std::string &n, int qsa, int qsb, Tick _delay, int write_ack);
 };
 
 #endif //__MEM_BUS_HH__
diff --git a/src/mem/bus.cc b/src/mem/bus.cc
index f7c2b874a..cfc99a64f 100644
--- a/src/mem/bus.cc
+++ b/src/mem/bus.cc
@@ -35,6 +35,16 @@
 #include "mem/bus.hh"
 #include "sim/builder.hh"
 
+Port *
+Bus::getPort(const std::string &if_name)
+{
+    // if_name ignored?  forced to be empty?
+    int id = interfaces.size();
+    BusPort *bp = new BusPort(csprintf("%s-p%d", name(), id), this, id);
+    interfaces.push_back(bp);
+    return bp;
+}
+
 /** Get the ranges of anyone that we are connected to. */
 void
 Bus::init()
@@ -45,17 +55,22 @@ Bus::init()
 }
 
 
-/** Function called by the port when the bus is recieving a Timing
+/** Function called by the port when the bus is receiving a Timing
  * transaction.*/
 bool
 Bus::recvTiming(Packet *pkt)
 {
     Port *port;
-    if (pkt->dest == Packet::Broadcast) {
-        port = findPort(pkt->addr, pkt->src);
+    DPRINTF(Bus, "recvTiming: packet src %d dest %d addr 0x%x cmd %s\n",
+            pkt->getSrc(), pkt->getDest(), pkt->getAddr(), pkt->cmdString());
+
+    short dest = pkt->getDest();
+    if (dest == Packet::Broadcast) {
+        port = findPort(pkt->getAddr(), pkt->getSrc());
     } else {
-        assert(pkt->dest > 0 && pkt->dest < interfaces.size());
-        port = interfaces[pkt->dest];
+        assert(dest >= 0 && dest < interfaces.size());
+        assert(dest != pkt->getSrc()); // catch infinite loops
+        port = interfaces[dest];
     }
     return port->sendTiming(pkt);
 }
@@ -73,7 +88,7 @@ Bus::findPort(Addr addr, int id)
         if (portList[i].range == addr) {
             dest_id = portList[i].portId;
             found = true;
-            DPRINTF(Bus, "Found Addr: %llx on device %d\n", addr, dest_id);
+            DPRINTF(Bus, "  found addr 0x%llx on device %d\n", addr, dest_id);
         }
         i++;
     }
@@ -86,33 +101,37 @@ Bus::findPort(Addr addr, int id)
     return interfaces[dest_id];
 }
 
-/** Function called by the port when the bus is recieving a Atomic
+/** Function called by the port when the bus is receiving a Atomic
  * transaction.*/
 Tick
 Bus::recvAtomic(Packet *pkt)
 {
-    assert(pkt->dest == Packet::Broadcast);
-    return findPort(pkt->addr, pkt->src)->sendAtomic(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);
+    return findPort(pkt->getAddr(), pkt->getSrc())->sendAtomic(pkt);
 }
 
-/** Function called by the port when the bus is recieving a Functional
+/** Function called by the port when the bus is receiving a Functional
  * transaction.*/
 void
 Bus::recvFunctional(Packet *pkt)
 {
-    assert(pkt->dest == Packet::Broadcast);
-    findPort(pkt->addr, pkt->src)->sendFunctional(pkt);
+    DPRINTF(Bus, "recvFunctional: packet src %d dest %d addr 0x%x cmd %s\n",
+            pkt->getSrc(), pkt->getDest(), pkt->getAddr(), pkt->cmdString());
+    assert(pkt->getDest() == Packet::Broadcast);
+    findPort(pkt->getAddr(), pkt->getSrc())->sendFunctional(pkt);
 }
 
-/** Function called by the port when the bus is recieving a status change.*/
+/** Function called by the port when the bus is receiving a status change.*/
 void
 Bus::recvStatusChange(Port::Status status, int id)
 {
-    DPRINTF(Bus, "Bus %d recieved status change from device id %d\n",
-            busId, id);
     assert(status == Port::RangeChange &&
            "The other statuses need to be implemented.");
 
+    DPRINTF(BusAddrRanges, "received RangeChange from device id %d\n", id);
+
     assert(id < interfaces.size() && id >= 0);
     int x;
     Port *port = interfaces[id];
@@ -138,8 +157,8 @@ Bus::recvStatusChange(Port::Status status, int id)
         dm.portId = id;
         dm.range = *iter;
 
-        DPRINTF(MMU, "Adding range %llx - %llx for id %d\n", dm.range.start,
-                dm.range.end, id);
+        DPRINTF(BusAddrRanges, "Adding range %llx - %llx for id %d\n",
+                dm.range.start, dm.range.end, id);
         portList.push_back(dm);
     }
     DPRINTF(MMU, "port list has %d entries\n", portList.size());
@@ -159,13 +178,12 @@ Bus::addressRanges(AddrRangeList &resp, AddrRangeList &snoop, int id)
     resp.clear();
     snoop.clear();
 
-    DPRINTF(Bus, "Bus id %d recieved address range request returning\n",
-            busId);
+    DPRINTF(BusAddrRanges, "received address range request, returning:\n");
     for (portIter = portList.begin(); portIter != portList.end(); portIter++) {
         if (portIter->portId != id) {
             resp.push_back(portIter->range);
-            DPRINTF(Bus, "-- %#llX : %#llX\n", portIter->range.start,
-                    portIter->range.end);
+            DPRINTF(BusAddrRanges, "  -- %#llX : %#llX\n",
+                    portIter->range.start, portIter->range.end);
         }
     }
 }
diff --git a/src/mem/bus.hh b/src/mem/bus.hh
index 38573e514..5eeb07904 100644
--- a/src/mem/bus.hh
+++ b/src/mem/bus.hh
@@ -100,8 +100,8 @@ class Bus : public MemObject
       public:
 
         /** Constructor for the BusPort.*/
-        BusPort(Bus *_bus, int _id)
-            : bus(_bus), id(_id)
+        BusPort(const std::string &_name, Bus *_bus, int _id)
+            : Port(_name), bus(_bus), id(_id)
         { }
 
       protected:
@@ -109,17 +109,17 @@ class Bus : public MemObject
         /** When reciving a timing request from the peer port (at id),
             pass it to the bus. */
         virtual bool recvTiming(Packet *pkt)
-        { pkt->src = id; return bus->recvTiming(pkt); }
+        { pkt->setSrc(id); return bus->recvTiming(pkt); }
 
         /** When reciving a Atomic requestfrom the peer port (at id),
             pass it to the bus. */
         virtual Tick recvAtomic(Packet *pkt)
-        { pkt->src = id; return bus->recvAtomic(pkt); }
+        { pkt->setSrc(id); return bus->recvAtomic(pkt); }
 
         /** When reciving a Functional requestfrom the peer port (at id),
             pass it to the bus. */
         virtual void recvFunctional(Packet *pkt)
-        { pkt->src = id; bus->recvFunctional(pkt); }
+        { pkt->setSrc(id); bus->recvFunctional(pkt); }
 
         /** When reciving a status changefrom the peer port (at id),
             pass it to the bus. */
@@ -146,13 +146,7 @@ class Bus : public MemObject
   public:
 
     /** A function used to return the port associated with this bus object. */
-    virtual Port *getPort(const std::string &if_name)
-    {
-        // if_name ignored?  forced to be empty?
-        int id = interfaces.size();
-        interfaces.push_back(new BusPort(this, id));
-        return interfaces.back();
-    }
+    virtual Port *getPort(const std::string &if_name);
 
     virtual void init();
 
diff --git a/src/mem/packet.cc b/src/mem/packet.cc
index a9be7ac51..3b415d77f 100644
--- a/src/mem/packet.cc
+++ b/src/mem/packet.cc
@@ -34,11 +34,31 @@
 #include "base/misc.hh"
 #include "mem/packet.hh"
 
+static const std::string ReadReqString("ReadReq");
+static const std::string WriteReqString("WriteReq");
+static const std::string WriteReqNoAckString("WriteReqNoAck");
+static const std::string ReadRespString("ReadResp");
+static const std::string WriteRespString("WriteResp");
+static const std::string OtherCmdString("<other>");
+
+const std::string &
+Packet::cmdString() const
+{
+    switch (cmd) {
+      case ReadReq:         return ReadReqString;
+      case WriteReq:        return WriteReqString;
+      case WriteReqNoAck:   return WriteReqNoAckString;
+      case ReadResp:        return ReadRespString;
+      case WriteResp:       return WriteRespString;
+      default:              return OtherCmdString;
+    }
+}
 
 /** delete the data pointed to in the data pointer. Ok to call to matter how
  * data was allocted. */
 void
-Packet::deleteData() {
+Packet::deleteData()
+{
     assert(staticData || dynamicData);
     if (staticData)
         return;
@@ -51,22 +71,24 @@ Packet::deleteData() {
 
 /** If there isn't data in the packet, allocate some. */
 void
-Packet::allocate() {
+Packet::allocate()
+{
     if (data)
         return;
     assert(!staticData);
     dynamicData = true;
     arrayData = true;
-    data = new uint8_t[size];
+    data = new uint8_t[getSize()];
 }
 
 /** Do the packet modify the same addresses. */
 bool
-Packet::intersect(Packet *p) {
-    Addr s1 = addr;
-    Addr e1 = addr + size;
-    Addr s2 = p->addr;
-    Addr e2 = p->addr + p->size;
+Packet::intersect(Packet *p)
+{
+    Addr s1 = getAddr();
+    Addr e1 = getAddr() + getSize();
+    Addr s2 = p->getAddr();
+    Addr e2 = p->getAddr() + p->getSize();
 
     if (s1 >= s2 && s1 < e2)
         return true;
@@ -77,7 +99,8 @@ Packet::intersect(Packet *p) {
 
 /** Minimally reset a packet so something like simple cpu can reuse it. */
 void
-Packet::reset() {
+Packet::reset()
+{
     result = Unknown;
     if (dynamicData) {
        deleteData();
@@ -88,7 +111,8 @@ Packet::reset() {
 }
 
 
-
-
-bool fixPacket(Packet *func, Packet *timing)
-{ panic("Need to implement!"); }
+bool
+fixPacket(Packet *func, Packet *timing)
+{
+    panic("Need to implement!");
+}
diff --git a/src/mem/packet.hh b/src/mem/packet.hh
index e8a7b0c73..83f52ede5 100644
--- a/src/mem/packet.hh
+++ b/src/mem/packet.hh
@@ -43,24 +43,6 @@ struct Packet;
 typedef Packet* PacketPtr;
 typedef uint8_t* PacketDataPtr;
 
-/** List of all commands associated with a packet. */
-enum Command
-{
-    Read,
-    Write
-};
-
-/** The result of a particular pakets request. */
-enum PacketResult
-{
-    Success,
-    BadAddress,
-    Unknown
-};
-
-class SenderState{};
-class Coherence{};
-
 /**
  * A Packet is the structure to handle requests between two levels
  * of the memory system.  The Request is a global object that trancends
@@ -74,7 +56,7 @@ class Coherence{};
  * Packets are assumed to be returned in the case of a single response.  If
  * the transaction has no response, then the consumer will delete the packet.
  */
-struct Packet
+class Packet
 {
   private:
    /** A pointer to the data being transfered.  It can be differnt sizes
@@ -95,57 +77,132 @@ struct Packet
     bool arrayData;
 
 
-  public:
     /** The address of the request, could be virtual or physical (depending on
         cache configurations). */
     Addr addr;
 
-    /** Flag structure to hold flags for this particular packet */
-    uint64_t flags;
+     /** Indicates the size of the request. */
+    int size;
+
+    /** A index of the source of the transaction. */
+    short src;
+
+    /** A index to the destination of the transaction. */
+    short dest;
+
+    bool addrValid;
+    bool sizeValid;
+    bool srcValid;
+
+  public:
+
+    static const short Broadcast = -1;
 
     /** A pointer to the overall request. */
     RequestPtr req;
 
+    class CoherenceState {
+      public:
+        virtual ~CoherenceState() {}
+    };
+
     /** A virtual base opaque structure used to hold
         coherence status messages. */
-    Coherence *coherence;  // virtual base opaque,
+    CoherenceState *coherence;  // virtual base opaque,
                            // assert(dynamic_cast<Foo>) etc.
 
-    /** A virtual base opaque structure used to hold the senders state. */
-    void *senderState; // virtual base opaque,
-                           // assert(dynamic_cast<Foo>) etc.
-
-     /** Indicates the size of the request. */
-    int size;
+    class SenderState {
+      public:
+        virtual ~SenderState() {}
+    };
 
-    /** A index of the source of the transaction. */
-    short src;
+    /** A virtual base opaque structure used to hold the senders state. */
+    SenderState *senderState; // virtual base opaque,
+    // assert(dynamic_cast<Foo>) etc.
 
-    static const short Broadcast = -1;
+  private:
+    /** List of command attributes. */
+    enum CommandAttribute
+    {
+        IsRead		= 1 << 0,
+        IsWrite		= 1 << 1,
+        IsPrefetch	= 1 << 2,
+        IsInvalidate	= 1 << 3,
+        IsRequest	= 1 << 4,
+        IsResponse 	= 1 << 5,
+        NeedsResponse	= 1 << 6,
+    };
 
-    /** A index to the destination of the transaction. */
-    short dest;
+  public:
+    /** List of all commands associated with a packet. */
+    enum Command
+    {
+        ReadReq		= IsRead  | IsRequest | NeedsResponse,
+        WriteReq	= IsWrite | IsRequest | NeedsResponse,
+        WriteReqNoAck	= IsWrite | IsRequest,
+        ReadResp	= IsRead  | IsResponse,
+        WriteResp	= IsWrite | IsResponse
+    };
+
+    const std::string &cmdString() const;
 
     /** The command of the transaction. */
     Command cmd;
 
+    bool isRead() 	 { return (cmd & IsRead)  != 0; }
+    bool isRequest()	 { return (cmd & IsRequest)  != 0; }
+    bool isResponse()	 { return (cmd & IsResponse) != 0; }
+    bool needsResponse() { return (cmd & NeedsResponse) != 0; }
+
+    void makeTimingResponse() {
+        assert(needsResponse());
+        int icmd = (int)cmd;
+        icmd &= ~(IsRequest | NeedsResponse);
+        icmd |= IsResponse;
+        cmd = (Command)icmd;
+        dest = src;
+        srcValid = false;
+    }
+
     /** The time this request was responded to. Used to calculate latencies. */
     Tick time;
 
+    /** The result of a particular packets request. */
+    enum Result
+    {
+        Success,
+        BadAddress,
+        Unknown
+    };
+
     /** The result of the packet transaction. */
-    PacketResult result;
+    Result result;
 
     /** Accessor function that returns the source index of the packet. */
-    short getSrc() const { return src; }
+    short getSrc() const { assert(srcValid); return src; }
+    void setSrc(short _src) { src = _src; srcValid = true; }
 
     /** Accessor function that returns the destination index of
         the packet. */
     short getDest() const { return dest; }
+    void setDest(short _dest) { dest = _dest; }
+
+    Addr getAddr() const { assert(addrValid); return addr; }
+    void setAddr(Addr _addr) { addr = _addr; addrValid = true; }
+
+    int getSize() const { assert(sizeValid); return size; }
+    void setSize(int _size) { size = _size; sizeValid = true; }
 
-    Packet()
+
+    Packet(Request *_req, Command _cmd, short _dest)
         :  data(NULL), staticData(false), dynamicData(false), arrayData(false),
+           addr(_req->paddr), size(_req->size), dest(_dest),
+           addrValid(_req->validPaddr), sizeValid(_req->validSize),
+           srcValid(false),
+           req(_req), coherence(NULL), senderState(NULL), cmd(_cmd),
            time(curTick), result(Unknown)
-        {}
+    {
+    }
 
     ~Packet()
     { deleteData(); }
@@ -154,6 +211,11 @@ struct Packet
     /** Minimally reset a packet so something like simple cpu can reuse it. */
     void reset();
 
+    void reinitFromRequest() {
+        if (req->validPaddr) setAddr(req->paddr);
+        if (req->validSize)  setSize(req->size);
+    }
+
     /** Set the data pointer to the following value that should not be freed. */
     template <typename T>
     void dataStatic(T *p);
diff --git a/src/mem/physical.cc b/src/mem/physical.cc
index bc2500678..26dbef0cd 100644
--- a/src/mem/physical.cc
+++ b/src/mem/physical.cc
@@ -127,7 +127,8 @@ PhysicalMemory::doTimingAccess (Packet *pkt, MemoryPort* memoryPort)
 {
     doFunctionalAccess(pkt);
 
-    pkt->dest = pkt->src;
+    // turn packet around to go back to requester
+    pkt->makeTimingResponse();
     MemResponseEvent* response = new MemResponseEvent(pkt, memoryPort);
     response->schedule(curTick + lat);
 
@@ -145,16 +146,18 @@ PhysicalMemory::doAtomicAccess(Packet *pkt)
 void
 PhysicalMemory::doFunctionalAccess(Packet *pkt)
 {
-    assert(pkt->addr + pkt->size < pmem_size);
+    assert(pkt->getAddr() + pkt->getSize() < pmem_size);
 
     switch (pkt->cmd) {
-      case Read:
-        memcpy(pkt->getPtr<uint8_t>(), pmem_addr + pkt->addr - base_addr,
-                pkt->size);
+      case Packet::ReadReq:
+        memcpy(pkt->getPtr<uint8_t>(),
+               pmem_addr + pkt->getAddr() - base_addr,
+               pkt->getSize());
         break;
-      case Write:
-        memcpy(pmem_addr + pkt->addr - base_addr, pkt->getPtr<uint8_t>(),
-                pkt->size);
+      case Packet::WriteReq:
+        memcpy(pmem_addr + pkt->getAddr() - base_addr,
+               pkt->getPtr<uint8_t>(),
+               pkt->getSize());
         // temporary hack: will need to add real LL/SC implementation
         // for cacheless systems later.
         if (pkt->req->getFlags() & LOCKED) {
@@ -165,7 +168,7 @@ PhysicalMemory::doFunctionalAccess(Packet *pkt)
         panic("unimplemented");
     }
 
-    pkt->result = Success;
+    pkt->result = Packet::Success;
 }
 
 Port *
@@ -174,11 +177,11 @@ PhysicalMemory::getPort(const std::string &if_name)
     if (if_name == "") {
         if (port != NULL)
            panic("PhysicalMemory::getPort: additional port requested to memory!");
-        port = new MemoryPort(this);
+        port = new MemoryPort(name() + "-port", this);
         return port;
     } else if (if_name == "functional") {
         /* special port for functional writes at startup. */
-        return new MemoryPort(this);
+        return new MemoryPort(name() + "-funcport", this);
     } else {
         panic("PhysicalMemory::getPort: unknown port %s requested", if_name);
     }
@@ -189,8 +192,9 @@ PhysicalMemory::recvStatusChange(Port::Status status)
 {
 }
 
-PhysicalMemory::MemoryPort::MemoryPort(PhysicalMemory *_memory)
-    : memory(_memory)
+PhysicalMemory::MemoryPort::MemoryPort(const std::string &_name,
+                                       PhysicalMemory *_memory)
+    : Port(_name), memory(_memory)
 { }
 
 void
diff --git a/src/mem/physical.hh b/src/mem/physical.hh
index 1cf5444ab..2ced79045 100644
--- a/src/mem/physical.hh
+++ b/src/mem/physical.hh
@@ -51,7 +51,7 @@ class PhysicalMemory : public MemObject
 
       public:
 
-        MemoryPort(PhysicalMemory *_memory);
+        MemoryPort(const std::string &_name, PhysicalMemory *_memory);
 
       protected:
 
diff --git a/src/mem/port.cc b/src/mem/port.cc
index fb3103ed1..651cb739a 100644
--- a/src/mem/port.cc
+++ b/src/mem/port.cc
@@ -31,22 +31,28 @@
  */
 
 #include "base/chunk_generator.hh"
+#include "base/trace.hh"
 #include "mem/packet_impl.hh"
 #include "mem/port.hh"
 
 void
-Port::blobHelper(Addr addr, uint8_t *p, int size, Command cmd)
+Port::setPeer(Port *port)
+{
+    DPRINTF(Config, "setting peer to %s\n", port->name());
+    peer = port;
+}
+
+void
+Port::blobHelper(Addr addr, uint8_t *p, int size, Packet::Command cmd)
 {
     Request req(false);
-    Packet pkt;
-    pkt.req = &req;
-    pkt.cmd = cmd;
-    pkt.dest = Packet::Broadcast;
+    Packet pkt(&req, cmd, Packet::Broadcast);
 
     for (ChunkGenerator gen(addr, size, peerBlockSize());
          !gen.done(); gen.next()) {
-        req.setPaddr(pkt.addr = gen.addr());
-        req.setSize(pkt.size = gen.size());
+        req.setPaddr(gen.addr());
+        req.setSize(gen.size());
+        pkt.reinitFromRequest();
         pkt.dataStatic(p);
         sendFunctional(&pkt);
         p += gen.size();
@@ -56,13 +62,13 @@ Port::blobHelper(Addr addr, uint8_t *p, int size, Command cmd)
 void
 Port::writeBlob(Addr addr, uint8_t *p, int size)
 {
-    blobHelper(addr, p, size, Write);
+    blobHelper(addr, p, size, Packet::WriteReq);
 }
 
 void
 Port::readBlob(Addr addr, uint8_t *p, int size)
 {
-    blobHelper(addr, p, size, Read);
+    blobHelper(addr, p, size, Packet::ReadReq);
 }
 
 void
@@ -72,7 +78,7 @@ Port::memsetBlob(Addr addr, uint8_t val, int size)
     uint8_t *buf = new uint8_t[size];
 
     memset(buf, val, size);
-    blobHelper(addr, buf, size, Write);
+    blobHelper(addr, buf, size, Packet::WriteReq);
 
     delete [] buf;
 }
diff --git a/src/mem/port.hh b/src/mem/port.hh
index 1b1920c03..f9103865e 100644
--- a/src/mem/port.hh
+++ b/src/mem/port.hh
@@ -69,9 +69,28 @@ typedef std::list<Range<Addr> >::iterator AddrRangeIter;
  */
 class Port
 {
+  private:
+
+    /** Descriptive name (for DPRINTF output) */
+    const std::string portName;
+
   public:
 
+    /**
+     * Constructor.
+     *
+     * @param _name Port name for DPRINTF output.  Should include name
+     * of memory system object to which the port belongs.
+     */
+    Port(const std::string &_name)
+        : portName(_name)
+    { }
+
+    /** Return port name (for DPRINTF). */
+    const std::string &name() const { return portName; }
+
     virtual ~Port() {};
+
     // mey be better to use subclasses & RTTI?
     /** Holds the ports status.  Keeps track if it is blocked, or has
         calculated a range change. */
@@ -93,9 +112,9 @@ class Port
     /** Function to set the pointer for the peer port.
         @todo should be called by the configuration stuff (python).
     */
-    void setPeer(Port *port) { peer = port; }
+    void setPeer(Port *port);
 
-        /** Function to set the pointer for the peer port.
+    /** Function to set the pointer for the peer port.
         @todo should be called by the configuration stuff (python).
     */
     Port *getPeer() { return peer; }
@@ -213,7 +232,7 @@ class Port
 
     /** Internal helper function for read/writeBlob().
      */
-    void blobHelper(Addr addr, uint8_t *p, int size, Command cmd);
+    void blobHelper(Addr addr, uint8_t *p, int size, Packet::Command cmd);
 };
 
 /** A simple functional port that is only meant for one way communication to
@@ -224,6 +243,10 @@ class Port
 class FunctionalPort : public Port
 {
   public:
+    FunctionalPort(const std::string &_name)
+        : Port(_name)
+    {}
+
     virtual bool recvTiming(Packet *pkt) { panic("FuncPort is UniDir"); }
     virtual Tick recvAtomic(Packet *pkt) { panic("FuncPort is UniDir"); }
     virtual void recvFunctional(Packet *pkt) { panic("FuncPort is UniDir"); }
diff --git a/src/mem/request.hh b/src/mem/request.hh
index 2db7b7779..10550e859 100644
--- a/src/mem/request.hh
+++ b/src/mem/request.hh
@@ -195,6 +195,7 @@ class Request
     /** Accesor function for pc.*/
     void setPC(Addr _pc);
 
+    friend class Packet;
 };
 
 #endif // __MEM_REQUEST_HH__
diff --git a/src/mem/translating_port.cc b/src/mem/translating_port.cc
index 5dfeaff31..ee4d277b6 100644
--- a/src/mem/translating_port.cc
+++ b/src/mem/translating_port.cc
@@ -34,8 +34,9 @@
 
 using namespace TheISA;
 
-TranslatingPort::TranslatingPort(PageTable *p_table, bool alloc)
-    : pTable(p_table), allocating(alloc)
+TranslatingPort::TranslatingPort(const std::string &_name,
+                                 PageTable *p_table, bool alloc)
+    : FunctionalPort(_name), pTable(p_table), allocating(alloc)
 { }
 
 TranslatingPort::~TranslatingPort()
diff --git a/src/mem/translating_port.hh b/src/mem/translating_port.hh
index 7611ac3c7..d078158a3 100644
--- a/src/mem/translating_port.hh
+++ b/src/mem/translating_port.hh
@@ -39,14 +39,11 @@ class TranslatingPort : public FunctionalPort
     PageTable *pTable;
     bool allocating;
 
-    TranslatingPort(const TranslatingPort &specmem);
-    const TranslatingPort &operator=(const TranslatingPort &specmem);
-
   public:
-    TranslatingPort(PageTable *p_table, bool alloc = false);
+    TranslatingPort(const std::string &_name,
+                    PageTable *p_table, bool alloc = false);
     virtual ~TranslatingPort();
 
-  public:
     bool tryReadBlob(Addr addr, uint8_t *p, int size);
     bool tryWriteBlob(Addr addr, uint8_t *p, int size);
     bool tryMemsetBlob(Addr addr, uint8_t val, int size);
@@ -56,9 +53,9 @@ class TranslatingPort : public FunctionalPort
     virtual void readBlob(Addr addr, uint8_t *p, int size);
     virtual void writeBlob(Addr addr, uint8_t *p, int size);
     virtual void memsetBlob(Addr addr, uint8_t val, int size);
+
     void writeString(Addr addr, const char *str);
     void readString(std::string &str, Addr addr);
-
 };
 
 #endif
diff --git a/src/mem/vport.hh b/src/mem/vport.hh
index fbc230ba3..0f3b1f09e 100644
--- a/src/mem/vport.hh
+++ b/src/mem/vport.hh
@@ -53,8 +53,8 @@ class VirtualPort  : public FunctionalPort
     ExecContext *xc;
 
   public:
-    VirtualPort(ExecContext *_xc = NULL)
-        : xc(_xc)
+    VirtualPort(const std::string &_name, ExecContext *_xc = NULL)
+        : FunctionalPort(_name), xc(_xc)
     {}
 
     /** Return true if we have an exec context. This is used to prevent someone