diff -rup a/time-warp-test.c b/time-warp-test.c
--- a/time-warp-test.c	2010-04-15 16:30:13.955981607 -1000
+++ b/time-warp-test.c	2010-04-15 16:35:37.777982377 -1000
@@ -91,7 +91,7 @@ static inline unsigned long long __rdtsc
 {
 	DECLARE_ARGS(val, low, high);
 
-	asm volatile("cpuid; rdtsc" : EAX_EDX_RET(val, low, high));
+	asm volatile("cpuid; rdtsc" : EAX_EDX_RET(val, low, high) :: "ebx", "ecx");
 
 	return EAX_EDX_VAL(val, low, high);
 }