Get rid of Packet result field. Error responses are

now encoded in cmd field.

--HG--
extra : convert_revision : d67819b7e3ee4b9a5bf08541104de0a89485e90b

35 files changed, 199 insertions, 341 deletions

diff --git a/src/arch/sparc/tlb.cc b/src/arch/sparc/tlb.cc
index 09266fd6e..68df19618 100644
--- a/src/arch/sparc/tlb.cc
+++ b/src/arch/sparc/tlb.cc
@@ -1023,7 +1023,7 @@ doMmuReadError:
         panic("need to impl DTB::doMmuRegRead() got asi=%#x, va=%#x\n",
             (uint32_t)asi, va);
     }
-    pkt->result = Packet::Success;
+    pkt->makeAtomicResponse();
     return tc->getCpuPtr()->cycles(1);
 }
 
@@ -1268,7 +1268,7 @@ doMmuWriteError:
         panic("need to impl DTB::doMmuRegWrite() got asi=%#x, va=%#x d=%#x\n",
             (uint32_t)pkt->req->getAsi(), pkt->getAddr(), data);
     }
-    pkt->result = Packet::Success;
+    pkt->makeAtomicResponse();
     return tc->getCpuPtr()->cycles(1);
 }
 
diff --git a/src/cpu/o3/fetch_impl.hh b/src/cpu/o3/fetch_impl.hh
index 01e9b5b31..aa0c69ac4 100644
--- a/src/cpu/o3/fetch_impl.hh
+++ b/src/cpu/o3/fetch_impl.hh
@@ -628,12 +628,6 @@ DefaultFetch<Impl>::fetchCacheLine(Addr fetch_PC, Fault &ret_fault, unsigned tid
         // Now do the timing access to see whether or not the instruction
         // exists within the cache.
         if (!icachePort->sendTiming(data_pkt)) {
-            if (data_pkt->result == Packet::BadAddress) {
-                fault = TheISA::genMachineCheckFault();
-                delete mem_req;
-                memReq[tid] = NULL;
-                warn("Bad address!\n");
-            }
             assert(retryPkt == NULL);
             assert(retryTid == -1);
             DPRINTF(Fetch, "[tid:%i] Out of MSHRs!\n", tid);
diff --git a/src/cpu/o3/lsq_unit.hh b/src/cpu/o3/lsq_unit.hh
index cc33e025d..d964b9f9f 100644
--- a/src/cpu/o3/lsq_unit.hh
+++ b/src/cpu/o3/lsq_unit.hh
@@ -653,8 +653,6 @@ LSQUnit<Impl>::read(Request *req, T &data, int load_idx)
         data_pkt->senderState = state;
 
         if (!dcachePort->sendTiming(data_pkt)) {
-            Packet::Result result = data_pkt->result;
-
             // Delete state and data packet because a load retry
             // initiates a pipeline restart; it does not retry.
             delete state;
@@ -663,10 +661,6 @@ LSQUnit<Impl>::read(Request *req, T &data, int load_idx)
 
             req = NULL;
 
-            if (result == Packet::BadAddress) {
-                return TheISA::genMachineCheckFault();
-            }
-
             // If the access didn't succeed, tell the LSQ by setting
             // the retry thread id.
             lsq->setRetryTid(lsqID);
diff --git a/src/cpu/o3/lsq_unit_impl.hh b/src/cpu/o3/lsq_unit_impl.hh
index bde4f8079..91e616589 100644
--- a/src/cpu/o3/lsq_unit_impl.hh
+++ b/src/cpu/o3/lsq_unit_impl.hh
@@ -690,9 +690,6 @@ LSQUnit<Impl>::writebackStores()
         }
 
         if (!dcachePort->sendTiming(data_pkt)) {
-            if (data_pkt->result == Packet::BadAddress) {
-                panic("LSQ sent out a bad address for a completed store!");
-            }
             // Need to handle becoming blocked on a store.
             DPRINTF(IEW, "D-Cache became blocked when writing [sn:%lli], will"
                     "retry later\n",
@@ -844,26 +841,6 @@ LSQUnit<Impl>::storePostSend(PacketPtr pkt)
 #endif
     }
 
-    if (pkt->result != Packet::Success) {
-        DPRINTF(LSQUnit,"D-Cache Write Miss on idx:%i!\n",
-                storeWBIdx);
-
-        DPRINTF(Activity, "Active st accessing mem miss [sn:%lli]\n",
-                storeQueue[storeWBIdx].inst->seqNum);
-
-        //mshrSeqNums.push_back(storeQueue[storeWBIdx].inst->seqNum);
-
-        //DPRINTF(LSQUnit, "Added MSHR. count = %i\n",mshrSeqNums.size());
-
-        // @todo: Increment stat here.
-    } else {
-        DPRINTF(LSQUnit,"D-Cache: Write Hit on idx:%i !\n",
-                storeWBIdx);
-
-        DPRINTF(Activity, "Active st accessing mem hit [sn:%lli]\n",
-                storeQueue[storeWBIdx].inst->seqNum);
-    }
-
     incrStIdx(storeWBIdx);
 }
 
@@ -952,9 +929,6 @@ LSQUnit<Impl>::recvRetry()
         assert(retryPkt != NULL);
 
         if (dcachePort->sendTiming(retryPkt)) {
-            if (retryPkt->result == Packet::BadAddress) {
-                panic("LSQ sent out a bad address for a completed store!");
-            }
             storePostSend(retryPkt);
             retryPkt = NULL;
             isStoreBlocked = false;
diff --git a/src/cpu/ozone/lw_lsq.hh b/src/cpu/ozone/lw_lsq.hh
index 2048ad6bb..d9e0d04ac 100644
--- a/src/cpu/ozone/lw_lsq.hh
+++ b/src/cpu/ozone/lw_lsq.hh
@@ -661,16 +661,6 @@ OzoneLWLSQ<Impl>::read(RequestPtr req, T &data, int load_idx)
         cpu->lockFlag = true;
     }
 
-    if (data_pkt->result != Packet::Success) {
-        DPRINTF(OzoneLSQ, "OzoneLSQ: D-cache miss!\n");
-        DPRINTF(Activity, "Activity: ld accessing mem miss [sn:%lli]\n",
-                inst->seqNum);
-    } else {
-        DPRINTF(OzoneLSQ, "OzoneLSQ: D-cache hit!\n");
-        DPRINTF(Activity, "Activity: ld accessing mem hit [sn:%lli]\n",
-                inst->seqNum);
-    }
-
     return NoFault;
 }
 
diff --git a/src/cpu/ozone/lw_lsq_impl.hh b/src/cpu/ozone/lw_lsq_impl.hh
index f26b06453..eefc0df83 100644
--- a/src/cpu/ozone/lw_lsq_impl.hh
+++ b/src/cpu/ozone/lw_lsq_impl.hh
@@ -853,24 +853,6 @@ OzoneLWLSQ<Impl>::storePostSend(PacketPtr pkt, DynInstPtr &inst)
         }
 #endif
     }
-
-    if (pkt->result != Packet::Success) {
-        DPRINTF(OzoneLSQ,"D-Cache Write Miss!\n");
-
-        DPRINTF(Activity, "Active st accessing mem miss [sn:%lli]\n",
-                inst->seqNum);
-
-        //mshrSeqNums.push_back(storeQueue[storeWBIdx].inst->seqNum);
-
-        //DPRINTF(OzoneLWLSQ, "Added MSHR. count = %i\n",mshrSeqNums.size());
-
-        // @todo: Increment stat here.
-    } else {
-        DPRINTF(OzoneLSQ,"D-Cache: Write Hit!\n");
-
-        DPRINTF(Activity, "Active st accessing mem hit [sn:%lli]\n",
-                inst->seqNum);
-    }
 }
 
 template <class Impl>
diff --git a/src/cpu/simple/atomic.cc b/src/cpu/simple/atomic.cc
index 03ff1282b..bcd6662c8 100644
--- a/src/cpu/simple/atomic.cc
+++ b/src/cpu/simple/atomic.cc
@@ -148,23 +148,9 @@ AtomicSimpleCPU::AtomicSimpleCPU(Params *p)
     icachePort.snoopRangeSent = false;
     dcachePort.snoopRangeSent = false;
 
-    ifetch_req = new Request();
-    ifetch_req->setThreadContext(p->cpu_id, 0); // Add thread ID if we add MT
-    ifetch_pkt = new Packet(ifetch_req, MemCmd::ReadReq, Packet::Broadcast);
-    ifetch_pkt->dataStatic(&inst);
-
-    data_read_req = new Request();
-    data_read_req->setThreadContext(p->cpu_id, 0); // Add thread ID here too
-    data_read_pkt = new Packet(data_read_req, MemCmd::ReadReq,
-                               Packet::Broadcast);
-    data_read_pkt->dataStatic(&dataReg);
-
-    data_write_req = new Request();
-    data_write_req->setThreadContext(p->cpu_id, 0); // Add thread ID here too
-    data_write_pkt = new Packet(data_write_req, MemCmd::WriteReq,
-                                Packet::Broadcast);
-    data_swap_pkt = new Packet(data_write_req, MemCmd::SwapReq,
-                                Packet::Broadcast);
+    ifetch_req.setThreadContext(p->cpu_id, 0); // Add thread ID if we add MT
+    data_read_req.setThreadContext(p->cpu_id, 0); // Add thread ID here too
+    data_write_req.setThreadContext(p->cpu_id, 0); // Add thread ID here too
 }
 
 
@@ -282,9 +268,7 @@ Fault
 AtomicSimpleCPU::read(Addr addr, T &data, unsigned flags)
 {
     // use the CPU's statically allocated read request and packet objects
-    Request *req = data_read_req;
-    PacketPtr pkt = data_read_pkt;
-
+    Request *req = &data_read_req;
     req->setVirt(0, addr, sizeof(T), flags, thread->readPC());
 
     if (traceData) {
@@ -296,19 +280,15 @@ AtomicSimpleCPU::read(Addr addr, T &data, unsigned flags)
 
     // Now do the access.
     if (fault == NoFault) {
-        pkt->reinitFromRequest();
+        Packet pkt = Packet(req, MemCmd::ReadReq, Packet::Broadcast);
+        pkt.dataStatic(&data);
 
         if (req->isMmapedIpr())
-            dcache_latency = TheISA::handleIprRead(thread->getTC(),pkt);
+            dcache_latency = TheISA::handleIprRead(thread->getTC(), &pkt);
         else
-            dcache_latency = dcachePort.sendAtomic(pkt);
+            dcache_latency = dcachePort.sendAtomic(&pkt);
         dcache_access = true;
-#if !defined(NDEBUG)
-        if (pkt->result != Packet::Success)
-            panic("Unable to find responder for address pa = %#X va = %#X\n",
-                    pkt->req->getPaddr(), pkt->req->getVaddr());
-#endif
-        data = pkt->get<T>();
+        assert(!pkt.isError());
 
         if (req->isLocked()) {
             TheISA::handleLockedRead(thread, req);
@@ -378,16 +358,9 @@ Fault
 AtomicSimpleCPU::write(T data, Addr addr, unsigned flags, uint64_t *res)
 {
     // use the CPU's statically allocated write request and packet objects
-    Request *req = data_write_req;
-    PacketPtr pkt;
-
+    Request *req = &data_write_req;
     req->setVirt(0, addr, sizeof(T), flags, thread->readPC());
 
-    if (req->isSwap())
-        pkt = data_swap_pkt;
-    else
-        pkt = data_write_pkt;
-
     if (traceData) {
         traceData->setAddr(addr);
     }
@@ -397,6 +370,11 @@ AtomicSimpleCPU::write(T data, Addr addr, unsigned flags, uint64_t *res)
 
     // Now do the access.
     if (fault == NoFault) {
+        Packet pkt =
+            Packet(req, req->isSwap() ? MemCmd::SwapReq : MemCmd::WriteReq,
+                   Packet::Broadcast);
+        pkt.dataStatic(&data);
+
         bool do_access = true;  // flag to suppress cache access
 
         if (req->isLocked()) {
@@ -409,27 +387,19 @@ AtomicSimpleCPU::write(T data, Addr addr, unsigned flags, uint64_t *res)
 
 
         if (do_access) {
-            pkt->reinitFromRequest();
-            pkt->dataStatic(&data);
-
             if (req->isMmapedIpr()) {
-                dcache_latency = TheISA::handleIprWrite(thread->getTC(), pkt);
+                dcache_latency = TheISA::handleIprWrite(thread->getTC(), &pkt);
             } else {
                 data = htog(data);
-                dcache_latency = dcachePort.sendAtomic(pkt);
+                dcache_latency = dcachePort.sendAtomic(&pkt);
             }
             dcache_access = true;
-
-#if !defined(NDEBUG)
-            if (pkt->result != Packet::Success)
-                panic("Unable to find responder for address pa = %#X va = %#X\n",
-                        pkt->req->getPaddr(), pkt->req->getVaddr());
-#endif
+            assert(!pkt.isError());
         }
 
         if (req->isSwap()) {
             assert(res);
-            *res = pkt->get<T>();
+            *res = pkt.get<T>();
         } else if (res) {
             *res = req->getExtraData();
         }
@@ -513,7 +483,7 @@ AtomicSimpleCPU::tick()
         if (!curStaticInst || !curStaticInst->isDelayedCommit())
             checkForInterrupts();
 
-        Fault fault = setupFetchRequest(ifetch_req);
+        Fault fault = setupFetchRequest(&ifetch_req);
 
         if (fault == NoFault) {
             Tick icache_latency = 0;
@@ -524,9 +494,11 @@ AtomicSimpleCPU::tick()
             //if(predecoder.needMoreBytes())
             //{
                 icache_access = true;
-                ifetch_pkt->reinitFromRequest();
+                Packet ifetch_pkt = Packet(&ifetch_req, MemCmd::ReadReq,
+                                           Packet::Broadcast);
+                ifetch_pkt.dataStatic(&inst);
 
-                icache_latency = icachePort.sendAtomic(ifetch_pkt);
+                icache_latency = icachePort.sendAtomic(&ifetch_pkt);
                 // ifetch_req is initialized to read the instruction directly
                 // into the CPU object's inst field.
             //}
diff --git a/src/cpu/simple/atomic.hh b/src/cpu/simple/atomic.hh
index b127e3791..28e883b24 100644
--- a/src/cpu/simple/atomic.hh
+++ b/src/cpu/simple/atomic.hh
@@ -121,13 +121,9 @@ class AtomicSimpleCPU : public BaseSimpleCPU
     };
     DcachePort dcachePort;
 
-    Request  *ifetch_req;
-    PacketPtr ifetch_pkt;
-    Request  *data_read_req;
-    PacketPtr data_read_pkt;
-    Request  *data_write_req;
-    PacketPtr data_write_pkt;
-    PacketPtr data_swap_pkt;
+    Request ifetch_req;
+    Request data_read_req;
+    Request data_write_req;
 
     bool dcache_access;
     Tick dcache_latency;
diff --git a/src/cpu/simple/base.hh b/src/cpu/simple/base.hh
index 243167db0..0550aa036 100644
--- a/src/cpu/simple/base.hh
+++ b/src/cpu/simple/base.hh
@@ -131,9 +131,6 @@ class BaseSimpleCPU : public BaseCPU
     // The predecoder
     TheISA::Predecoder predecoder;
 
-    // Static data storage
-    TheISA::LargestRead dataReg;
-
     StaticInstPtr curStaticInst;
     StaticInstPtr curMacroStaticInst;
 
diff --git a/src/cpu/simple/timing.cc b/src/cpu/simple/timing.cc
index 7698a588d..b4e4a4433 100644
--- a/src/cpu/simple/timing.cc
+++ b/src/cpu/simple/timing.cc
@@ -501,7 +501,7 @@ TimingSimpleCPU::completeIfetch(PacketPtr pkt)
 {
     // received a response from the icache: execute the received
     // instruction
-    assert(pkt->result == Packet::Success);
+    assert(!pkt->isError());
     assert(_status == IcacheWaitResponse);
 
     _status = Running;
@@ -569,7 +569,7 @@ TimingSimpleCPU::IcachePort::recvTiming(PacketPtr pkt)
 
         return true;
     }
-    else if (pkt->result == Packet::Nacked) {
+    else if (pkt->wasNacked()) {
         assert(cpu->_status == IcacheWaitResponse);
         pkt->reinitNacked();
         if (!sendTiming(pkt)) {
@@ -600,7 +600,7 @@ TimingSimpleCPU::completeDataAccess(PacketPtr pkt)
 {
     // received a response from the dcache: complete the load or store
     // instruction
-    assert(pkt->result == Packet::Success);
+    assert(!pkt->isError());
     assert(_status == DcacheWaitResponse);
     _status = Running;
 
@@ -663,7 +663,7 @@ TimingSimpleCPU::DcachePort::recvTiming(PacketPtr pkt)
 
         return true;
     }
-    else if (pkt->result == Packet::Nacked) {
+    else if (pkt->wasNacked()) {
         assert(cpu->_status == DcacheWaitResponse);
         pkt->reinitNacked();
         if (!sendTiming(pkt)) {
diff --git a/src/dev/alpha/console.cc b/src/dev/alpha/console.cc
index 443f376a5..55549a154 100644
--- a/src/dev/alpha/console.cc
+++ b/src/dev/alpha/console.cc
@@ -102,7 +102,6 @@ AlphaConsole::read(PacketPtr pkt)
      * machine dependent address swizzle is required?
      */
 
-    assert(pkt->result == Packet::Unknown);
     assert(pkt->getAddr() >= pioAddr && pkt->getAddr() < pioAddr + pioSize);
 
     Addr daddr = pkt->getAddr() - pioAddr;
@@ -130,7 +129,7 @@ AlphaConsole::read(PacketPtr pkt)
                     /* Old console code read in everyting as a 32bit int
                      * we now break that for better error checking.
                      */
-                  pkt->result = Packet::BadAddress;
+                  pkt->setBadAddress();
             }
             DPRINTF(AlphaConsole, "read: offset=%#x val=%#x\n", daddr,
                     pkt->get<uint32_t>());
@@ -187,17 +186,15 @@ AlphaConsole::read(PacketPtr pkt)
                     pkt->get<uint64_t>());
             break;
         default:
-          pkt->result = Packet::BadAddress;
+          pkt->setBadAddress();
     }
-    if (pkt->result == Packet::Unknown)
-        pkt->result = Packet::Success;
+    pkt->makeAtomicResponse();
     return pioDelay;
 }
 
 Tick
 AlphaConsole::write(PacketPtr pkt)
 {
-    assert(pkt->result == Packet::Unknown);
     assert(pkt->getAddr() >= pioAddr && pkt->getAddr() < pioAddr + pioSize);
     Addr daddr = pkt->getAddr() - pioAddr;
 
@@ -245,7 +242,7 @@ AlphaConsole::write(PacketPtr pkt)
             panic("Unknown 64bit access, %#x\n", daddr);
     }
 
-    pkt->result = Packet::Success;
+    pkt->makeAtomicResponse();
 
     return pioDelay;
 }
diff --git a/src/dev/alpha/tsunami_cchip.cc b/src/dev/alpha/tsunami_cchip.cc
index 118160adf..a7175d90c 100644
--- a/src/dev/alpha/tsunami_cchip.cc
+++ b/src/dev/alpha/tsunami_cchip.cc
@@ -78,7 +78,6 @@ TsunamiCChip::read(PacketPtr pkt)
 {
     DPRINTF(Tsunami, "read  va=%#x size=%d\n", pkt->getAddr(), pkt->getSize());
 
-    assert(pkt->result == Packet::Unknown);
     assert(pkt->getAddr() >= pioAddr && pkt->getAddr() < pioAddr + pioSize);
 
     Addr regnum = (pkt->getAddr() - pioAddr) >> 6;
@@ -181,7 +180,7 @@ TsunamiCChip::read(PacketPtr pkt)
     DPRINTF(Tsunami, "Tsunami CChip: read  regnum=%#x size=%d data=%lld\n",
             regnum, pkt->getSize(), pkt->get<uint64_t>());
 
-    pkt->result = Packet::Success;
+    pkt->makeAtomicResponse();
     return pioDelay;
 }
 
@@ -365,7 +364,7 @@ TsunamiCChip::write(PacketPtr pkt)
               panic("default in cchip read reached, accessing 0x%x\n");
         }  // swtich(regnum)
     } // not BIG_TSUNAMI write
-    pkt->result = Packet::Success;
+    pkt->makeAtomicResponse();
     return pioDelay;
 }
 
diff --git a/src/dev/alpha/tsunami_io.cc b/src/dev/alpha/tsunami_io.cc
index 58933428c..f59a06fba 100644
--- a/src/dev/alpha/tsunami_io.cc
+++ b/src/dev/alpha/tsunami_io.cc
@@ -461,7 +461,6 @@ TsunamiIO::frequency() const
 Tick
 TsunamiIO::read(PacketPtr pkt)
 {
-    assert(pkt->result == Packet::Unknown);
     assert(pkt->getAddr() >= pioAddr && pkt->getAddr() < pioAddr + pioSize);
 
     Addr daddr = pkt->getAddr() - pioAddr;
@@ -520,14 +519,13 @@ TsunamiIO::read(PacketPtr pkt)
     } else {
        panic("I/O Read - invalid size - va %#x size %d\n", pkt->getAddr(), pkt->getSize());
     }
-    pkt->result = Packet::Success;
+    pkt->makeAtomicResponse();
     return pioDelay;
 }
 
 Tick
 TsunamiIO::write(PacketPtr pkt)
 {
-    assert(pkt->result == Packet::Unknown);
     assert(pkt->getAddr() >= pioAddr && pkt->getAddr() < pioAddr + pioSize);
     Addr daddr = pkt->getAddr() - pioAddr;
 
@@ -600,7 +598,7 @@ TsunamiIO::write(PacketPtr pkt)
         panic("I/O Write - va%#x size %d data %#x\n", pkt->getAddr(), pkt->getSize(), pkt->get<uint8_t>());
     }
 
-    pkt->result = Packet::Success;
+    pkt->makeAtomicResponse();
     return pioDelay;
 }
 
diff --git a/src/dev/alpha/tsunami_pchip.cc b/src/dev/alpha/tsunami_pchip.cc
index f30199337..be164e5b9 100644
--- a/src/dev/alpha/tsunami_pchip.cc
+++ b/src/dev/alpha/tsunami_pchip.cc
@@ -71,7 +71,6 @@ TsunamiPChip::TsunamiPChip(Params *p)
 Tick
 TsunamiPChip::read(PacketPtr pkt)
 {
-    assert(pkt->result == Packet::Unknown);
     assert(pkt->getAddr() >= pioAddr && pkt->getAddr() < pioAddr + pioSize);
 
     pkt->allocate();
@@ -145,7 +144,7 @@ TsunamiPChip::read(PacketPtr pkt)
       default:
           panic("Default in PChip Read reached reading 0x%x\n", daddr);
     }
-    pkt->result = Packet::Success;
+    pkt->makeAtomicResponse();
     return pioDelay;
 
 }
@@ -153,7 +152,6 @@ TsunamiPChip::read(PacketPtr pkt)
 Tick
 TsunamiPChip::write(PacketPtr pkt)
 {
-    assert(pkt->result == Packet::Unknown);
     assert(pkt->getAddr() >= pioAddr && pkt->getAddr() < pioAddr + pioSize);
     Addr daddr = (pkt->getAddr() - pioAddr) >> 6;
 
@@ -224,7 +222,7 @@ TsunamiPChip::write(PacketPtr pkt)
 
     } // uint64_t
 
-    pkt->result = Packet::Success;
+    pkt->makeAtomicResponse();
     return pioDelay;
 }
 
diff --git a/src/dev/i8254xGBe.cc b/src/dev/i8254xGBe.cc
index baf13c49a..7ea4c704b 100644
--- a/src/dev/i8254xGBe.cc
+++ b/src/dev/i8254xGBe.cc
@@ -271,7 +271,7 @@ IGbE::read(PacketPtr pkt)
             pkt->set<uint32_t>(0);
     };
 
-    pkt->result = Packet::Success;
+    pkt->makeAtomicResponse();
     return pioDelay;
 }
 
@@ -543,7 +543,7 @@ IGbE::write(PacketPtr pkt)
            panic("Write request to unknown register number: %#x\n", daddr);
     };
 
-    pkt->result = Packet::Success;
+    pkt->makeAtomicResponse();
     return pioDelay;
 }
 
diff --git a/src/dev/ide_ctrl.cc b/src/dev/ide_ctrl.cc
index 921ba1cd0..01243ae73 100644
--- a/src/dev/ide_ctrl.cc
+++ b/src/dev/ide_ctrl.cc
@@ -295,7 +295,7 @@ IdeController::readConfig(PacketPtr pkt)
       default:
         panic("invalid access size(?) for PCI configspace!\n");
     }
-    pkt->result = Packet::Success;
+    pkt->makeAtomicResponse();
     return configDelay;
 
 }
@@ -403,7 +403,7 @@ IdeController::writeConfig(PacketPtr pkt)
             bm_enabled = false;
         break;
     }
-    pkt->result = Packet::Success;
+    pkt->makeAtomicResponse();
     return configDelay;
 }
 
@@ -423,7 +423,7 @@ IdeController::read(PacketPtr pkt)
     parseAddr(pkt->getAddr(), offset, channel, reg_type);
 
     if (!io_enabled) {
-        pkt->result = Packet::Success;
+        pkt->makeAtomicResponse();
         return pioDelay;
     }
 
@@ -490,7 +490,7 @@ IdeController::read(PacketPtr pkt)
     DPRINTF(IdeCtrl, "read from offset: %#x size: %#x data: %#x\n",
             offset, pkt->getSize(), pkt->get<uint32_t>());
 
-    pkt->result = Packet::Success;
+    pkt->makeAtomicResponse();
     return pioDelay;
 }
 
@@ -506,7 +506,7 @@ IdeController::write(PacketPtr pkt)
     parseAddr(pkt->getAddr(), offset, channel, reg_type);
 
     if (!io_enabled) {
-        pkt->result = Packet::Success;
+        pkt->makeAtomicResponse();
         DPRINTF(IdeCtrl, "io not enabled\n");
         return pioDelay;
     }
@@ -514,7 +514,7 @@ IdeController::write(PacketPtr pkt)
     switch (reg_type) {
       case BMI_BLOCK:
         if (!bm_enabled) {
-            pkt->result = Packet::Success;
+            pkt->makeAtomicResponse();
             return pioDelay;
         }
 
@@ -673,7 +673,7 @@ IdeController::write(PacketPtr pkt)
             offset, pkt->getSize(), pkt->get<uint32_t>());
 
 
-    pkt->result = Packet::Success;
+    pkt->makeAtomicResponse();
     return pioDelay;
 }
 
diff --git a/src/dev/io_device.cc b/src/dev/io_device.cc
index ecbb391ef..806d13d07 100644
--- a/src/dev/io_device.cc
+++ b/src/dev/io_device.cc
@@ -100,9 +100,7 @@ DmaPort::DmaPort(DmaDevice *dev, System *s)
 bool
 DmaPort::recvTiming(PacketPtr pkt)
 {
-
-
-    if (pkt->result == Packet::Nacked) {
+    if (pkt->wasNacked()) {
         DPRINTF(DMA, "Received nacked Pkt %#x with State: %#x Addr: %#x\n",
                pkt, pkt->senderState, pkt->getAddr());
 
diff --git a/src/dev/isa_fake.cc b/src/dev/isa_fake.cc
index c36ddeb83..5cd0afb36 100644
--- a/src/dev/isa_fake.cc
+++ b/src/dev/isa_fake.cc
@@ -56,7 +56,6 @@ IsaFake::IsaFake(Params *p)
 Tick
 IsaFake::read(PacketPtr pkt)
 {
-    assert(pkt->result == Packet::Unknown);
 
     if (params()->warnAccess != "")
         warn("Device %s accessed by read to address %#x size=%d\n",
@@ -64,7 +63,7 @@ IsaFake::read(PacketPtr pkt)
     if (params()->retBadAddr) {
         DPRINTF(Tsunami, "read to bad address va=%#x size=%d\n",
                 pkt->getAddr(), pkt->getSize());
-        pkt->result = Packet::BadAddress;
+        pkt->setBadAddress();
     } else {
         assert(pkt->getAddr() >= pioAddr && pkt->getAddr() < pioAddr + pioSize);
         DPRINTF(Tsunami, "read  va=%#x size=%d\n",
@@ -85,7 +84,7 @@ IsaFake::read(PacketPtr pkt)
           default:
             panic("invalid access size!\n");
         }
-        pkt->result = Packet::Success;
+        pkt->makeAtomicResponse();
     }
     return pioDelay;
 }
@@ -117,7 +116,7 @@ IsaFake::write(PacketPtr pkt)
     if (params()->retBadAddr) {
         DPRINTF(Tsunami, "write to bad address va=%#x size=%d \n",
                 pkt->getAddr(), pkt->getSize());
-        pkt->result = Packet::BadAddress;
+        pkt->setBadAddress();
     } else {
         DPRINTF(Tsunami, "write - va=%#x size=%d \n",
                 pkt->getAddr(), pkt->getSize());
@@ -140,7 +139,7 @@ IsaFake::write(PacketPtr pkt)
                 panic("invalid access size!\n");
             }
         }
-        pkt->result = Packet::Success;
+        pkt->makeAtomicResponse();
     }
     return pioDelay;
 }
diff --git a/src/dev/ns_gige.cc b/src/dev/ns_gige.cc
index e9d9c419d..86f664238 100644
--- a/src/dev/ns_gige.cc
+++ b/src/dev/ns_gige.cc
@@ -487,7 +487,7 @@ NSGigE::writeConfig(PacketPtr pkt)
             ioEnable = false;
         break;
     }
-    pkt->result = Packet::Success;
+    pkt->makeAtomicResponse();
     return configDelay;
 }
 
@@ -519,7 +519,7 @@ NSGigE::read(PacketPtr pkt)
         // doesn't actually DEPEND upon their values
         // MIB are just hardware stats keepers
         pkt->set<uint32_t>(0);
-        pkt->result = Packet::Success;
+        pkt->makeAtomicResponse();
         return pioDelay;
     } else if (daddr > 0x3FC)
         panic("Something is messed up!\n");
@@ -715,7 +715,7 @@ NSGigE::read(PacketPtr pkt)
         DPRINTF(EthernetPIO, "read from %#x: data=%d data=%#x\n",
                 daddr, reg, reg);
 
-    pkt->result = Packet::Success;
+    pkt->makeAtomicResponse();
     return pioDelay;
 }
 
@@ -1122,7 +1122,7 @@ NSGigE::write(PacketPtr pkt)
     } else {
         panic("Invalid Request Size");
     }
-    pkt->result = Packet::Success;
+    pkt->makeAtomicResponse();
     return pioDelay;
 }
 
diff --git a/src/dev/pciconfigall.cc b/src/dev/pciconfigall.cc
index bd1855847..b07ee1a49 100644
--- a/src/dev/pciconfigall.cc
+++ b/src/dev/pciconfigall.cc
@@ -54,7 +54,6 @@ PciConfigAll::PciConfigAll(Params *p)
 Tick
 PciConfigAll::read(PacketPtr pkt)
 {
-    assert(pkt->result == Packet::Unknown);
 
     pkt->allocate();
 
@@ -74,14 +73,13 @@ PciConfigAll::read(PacketPtr pkt)
       default:
         panic("invalid access size(?) for PCI configspace!\n");
     }
-    pkt->result = Packet::Success;
+    pkt->makeAtomicResponse();
     return params()->pio_delay;
 }
 
 Tick
 PciConfigAll::write(PacketPtr pkt)
 {
-    assert(pkt->result == Packet::Unknown);
     panic("Attempting to write to config space on non-existant device\n");
     M5_DUMMY_RETURN
 }
diff --git a/src/dev/pcidev.cc b/src/dev/pcidev.cc
index c2a2bc02d..85337c841 100644
--- a/src/dev/pcidev.cc
+++ b/src/dev/pcidev.cc
@@ -68,7 +68,6 @@ PciDev::PciConfigPort::PciConfigPort(PciDev *dev, int busid, int devid,
 Tick
 PciDev::PciConfigPort::recvAtomic(PacketPtr pkt)
 {
-    assert(pkt->result == Packet::Unknown);
     assert(pkt->getAddr() >= configAddr &&
            pkt->getAddr() < configAddr + PCI_CONFIG_SIZE);
     return pkt->isRead() ? device->readConfig(pkt) : device->writeConfig(pkt);
@@ -156,7 +155,7 @@ PciDev::readConfig(PacketPtr pkt)
       default:
         panic("invalid access size(?) for PCI configspace!\n");
     }
-    pkt->result = Packet::Success;
+    pkt->makeAtomicResponse();
     return configDelay;
 
 }
@@ -283,7 +282,7 @@ PciDev::writeConfig(PacketPtr pkt)
       default:
         panic("invalid access size(?) for PCI configspace!\n");
     }
-    pkt->result = Packet::Success;
+    pkt->makeAtomicResponse();
     return configDelay;
 
 }
diff --git a/src/dev/sparc/dtod.cc b/src/dev/sparc/dtod.cc
index 42275c60a..22df873b6 100644
--- a/src/dev/sparc/dtod.cc
+++ b/src/dev/sparc/dtod.cc
@@ -74,7 +74,6 @@ DumbTOD::DumbTOD(Params *p)
 Tick
 DumbTOD::read(PacketPtr pkt)
 {
-    assert(pkt->result == Packet::Unknown);
     assert(pkt->getAddr() >= pioAddr && pkt->getAddr() < pioAddr + pioSize);
     assert(pkt->getSize() == 8);
 
@@ -82,7 +81,7 @@ DumbTOD::read(PacketPtr pkt)
     pkt->set(todTime);
     todTime += 1000;
 
-    pkt->result = Packet::Success;
+    pkt->makeAtomicResponse();
     return pioDelay;
 }
 
diff --git a/src/dev/sparc/iob.cc b/src/dev/sparc/iob.cc
index e686e51f7..b27f45eba 100644
--- a/src/dev/sparc/iob.cc
+++ b/src/dev/sparc/iob.cc
@@ -72,7 +72,6 @@ Iob::Iob(Params *p)
 Tick
 Iob::read(PacketPtr pkt)
 {
-    assert(pkt->result == Packet::Unknown);
 
     if (pkt->getAddr() >= iobManAddr && pkt->getAddr() < iobManAddr + iobManSize)
         readIob(pkt);
@@ -81,7 +80,7 @@ Iob::read(PacketPtr pkt)
     else
         panic("Invalid address reached Iob\n");
 
-    pkt->result = Packet::Success;
+    pkt->makeAtomicResponse();
     return pioDelay;
 }
 
@@ -176,7 +175,7 @@ Iob::write(PacketPtr pkt)
         panic("Invalid address reached Iob\n");
 
 
-    pkt->result = Packet::Success;
+    pkt->makeAtomicResponse();
     return pioDelay;
 }
 
diff --git a/src/dev/sparc/mm_disk.cc b/src/dev/sparc/mm_disk.cc
index 81c5c589a..bbb773c48 100644
--- a/src/dev/sparc/mm_disk.cc
+++ b/src/dev/sparc/mm_disk.cc
@@ -61,7 +61,6 @@ MmDisk::read(PacketPtr pkt)
     uint32_t d32;
     uint64_t d64;
 
-    assert(pkt->result == Packet::Unknown);
     assert(pkt->getAddr() >= pioAddr && pkt->getAddr() < pioAddr + pioSize);
     accessAddr = pkt->getAddr() - pioAddr;
 
@@ -101,7 +100,7 @@ MmDisk::read(PacketPtr pkt)
         panic("Invalid access size\n");
     }
 
-    pkt->result = Packet::Success;
+    pkt->makeAtomicResponse();
     return pioDelay;
 }
 
@@ -115,7 +114,6 @@ MmDisk::write(PacketPtr pkt)
     uint32_t d32;
     uint64_t d64;
 
-    assert(pkt->result == Packet::Unknown);
     assert(pkt->getAddr() >= pioAddr && pkt->getAddr() < pioAddr + pioSize);
     accessAddr = pkt->getAddr() - pioAddr;
 
@@ -157,7 +155,7 @@ MmDisk::write(PacketPtr pkt)
         panic("Invalid access size\n");
     }
 
-    pkt->result = Packet::Success;
+    pkt->makeAtomicResponse();
     return pioDelay;
 }
 
diff --git a/src/dev/uart8250.cc b/src/dev/uart8250.cc
index 50307aad4..0ad80e077 100644
--- a/src/dev/uart8250.cc
+++ b/src/dev/uart8250.cc
@@ -111,7 +111,6 @@ Uart8250::Uart8250(Params *p)
 Tick
 Uart8250::read(PacketPtr pkt)
 {
-    assert(pkt->result == Packet::Unknown);
     assert(pkt->getAddr() >= pioAddr && pkt->getAddr() < pioAddr + pioSize);
     assert(pkt->getSize() == 1);
 
@@ -186,7 +185,7 @@ Uart8250::read(PacketPtr pkt)
 /*    uint32_t d32 = *data;
     DPRINTF(Uart, "Register read to register %#x returned %#x\n", daddr, d32);
 */
-    pkt->result = Packet::Success;
+    pkt->makeAtomicResponse();
     return pioDelay;
 }
 
@@ -194,7 +193,6 @@ Tick
 Uart8250::write(PacketPtr pkt)
 {
 
-    assert(pkt->result == Packet::Unknown);
     assert(pkt->getAddr() >= pioAddr && pkt->getAddr() < pioAddr + pioSize);
     assert(pkt->getSize() == 1);
 
@@ -272,7 +270,7 @@ Uart8250::write(PacketPtr pkt)
             panic("Tried to access a UART port that doesn't exist\n");
             break;
     }
-    pkt->result = Packet::Success;
+    pkt->makeAtomicResponse();
     return pioDelay;
 }
 
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;