if (!SimpleRCHeader.isGreyOrGreen(object)) { SimpleRCHeader.makeGrey(object);
if (!SimpleRCBaseHeader.isGrey(object)) { SimpleRCBaseHeader.makeGrey(object);
  public final void markGrey(VM_Address object)    throws VM_PragmaInline {    while (!object.isZero()) {      if (!SimpleRCHeader.isGreyOrGreen(object)) {	SimpleRCHeader.makeGrey(object);	ScanObject.scan(object);      }      object = workQueue.pop();    }  }