diff -r 049a08351e7d -r 93d82aae1592 src/base/types.hh
--- a/src/base/types.hh	Thu Jul 26 08:26:12 2012 +0100
+++ b/src/base/types.hh	Thu Jul 26 14:52:16 2012 +0100
@@ -51,13 +51,11 @@
 typedef int64_t Counter;
 
 /**
- * Clock cycle count type.
- * @note using an unsigned breaks the cache.
+ * Tick count type.
  */
-typedef int64_t Tick;
-typedef uint64_t UTick;
+typedef uint64_t Tick;
 
-const Tick MaxTick = LL(0x7fffffffffffffff);
+const Tick MaxTick = ULL(0xffffffffffffffff);
 
 /**
  * Address type
diff -r 049a08351e7d -r 93d82aae1592 src/cpu/o3/cpu.cc
--- a/src/cpu/o3/cpu.cc	Thu Jul 26 08:26:12 2012 +0100
+++ b/src/cpu/o3/cpu.cc	Thu Jul 26 14:52:16 2012 +0100
@@ -388,7 +388,7 @@
 
     lastRunningCycle = curTick();
 
-    lastActivatedCycle = -1;
+    lastActivatedCycle = 0;
 #if 0
     // Give renameMap & rename stage access to the freeList;
     for (ThreadID tid = 0; tid < numThreads; tid++)
@@ -752,7 +752,9 @@
         activateThread(tid);
     }
 
-    if (lastActivatedCycle < curTick()) {
+    // If we are time 0 or if the last activation time is in the past,
+    // schedule the next tick and wake up the fetch unit
+    if (lastActivatedCycle == 0 || lastActivatedCycle < curTick()) {
         scheduleTickEvent(delay);
 
         // Be sure to signal that there's some activity so the CPU doesn't
diff -r 049a08351e7d -r 93d82aae1592 src/sim/eventq.hh
--- a/src/sim/eventq.hh	Thu Jul 26 08:26:12 2012 +0100
+++ b/src/sim/eventq.hh	Thu Jul 26 14:52:16 2012 +0100
@@ -481,9 +481,7 @@
 inline void
 EventQueue::schedule(Event *event, Tick when)
 {
-    // Typecasting Tick->Utick here since gcc
-    // complains about signed overflow
-    assert((UTick)when >= (UTick)curTick());
+    assert(when >= curTick());
     assert(!event->scheduled());
     assert(event->initialized());
 
@@ -520,9 +518,7 @@
 inline void
 EventQueue::reschedule(Event *event, Tick when, bool always)
 {
-    // Typecasting Tick->Utick here since gcc
-    // complains about signed overflow
-    assert((UTick)when >= (UTick)curTick());
+    assert(when >= curTick());
     assert(always || event->scheduled());
     assert(event->initialized());