Add check that PIT ISR is firing

src/hulk/time.d

@@ -23,7 +23,7 @@ struct Time
      */
     public static @property ulong uptime()
     {
-        return s_uptime;
+        return volatileLoad(&s_uptime);
     }
 
     /**
@@ -35,7 +35,7 @@ struct Time
     public static void msleep(ulong count)
     {
         ulong wait_for = s_uptime + count + 1;
-        while (volatileLoad(&s_uptime) < wait_for)
+        while (uptime() < wait_for)
         {
         }
     }