diff --git a/library/timing.c b/library/timing.c
index 94c36d1..523dbe1 100644
--- a/library/timing.c
+++ b/library/timing.c
@@ -70,9 +70,9 @@
 
 unsigned long hardclock( void )
 {
-    unsigned long tsc;
-    asm( "rdtsc" : "=a" (tsc) );
-    return( tsc );
+    unsigned long lo, hi;
+    asm( "rdtsc" : "=a" (lo), "=d" (hi) );
+    return( lo );
 }
 
 #else