diff --git a/src/sim/simulate.cc b/src/sim/simulate.cc
--- a/src/sim/simulate.cc
+++ b/src/sim/simulate.cc
@@ -51,10 +51,10 @@
 
     if (num_cycles < 0)
         fatal("simulate: num_cycles must be >= 0 (was %d)\n", num_cycles);
-    else if (curTick() + num_cycles < 0)  //Overflow
+    else if (num cycles < MaxTick - curTick())
+        num_cycles = curTick() + num_cycles;
+    else //counter would roll over or, be set to MaxTick anyhow
         num_cycles = MaxTick;
-    else
-        num_cycles = curTick() + num_cycles;
 
     Event *limit_event =
         new SimLoopExitEvent("simulate() limit reached", 0);