Added missing spin hint procedure

git-svn-id: https://svn.inf.ethz.ch/svn/lecturers/a2/trunk@8686 8c9fc860-2736-0410-a75d-ab315db34111

source/Unix.Machine.Mod

@@ -424,6 +424,17 @@ CODE
 #END
 END AtomicCAS;
 
+(** This procedure should be called in all spin loops as a hint to the processor (e.g. Pentium 4). *)
+PROCEDURE  -SpinHint*;
+CODE
+#IF I386 THEN
+	PAUSE
+#ELSIF AMD64 THEN
+	PAUSE
+#ELSE
+	unimplemented
+#END
+END SpinHint;
 
 (* Return current instruction pointer *)
 PROCEDURE  CurrentPC* (): ADDRESS;