VM_Interface._assert(workDequeue.pop().isZero());
VM_Interface._assert(workDeque.pop().isZero());
  private final boolean markGrey(VM_Address object, long timeCap)    throws VM_PragmaInline {    boolean abort = false;    if (VM_Interface.VerifyAssertions)      VM_Interface._assert(workDequeue.pop().isZero());    while (!object.isZero()) {      if (VM_Interface.VerifyAssertions)	VM_Interface._assert(!RCBaseHeader.isGreen(object));      visitCount++;      if (visitCount % GREY_VISIT_GRAIN == 0 && VM_Interface.cycles() > timeCap) {	abort = true;      }            if (!abort && !RCBaseHeader.isGrey(object)) {	RCBaseHeader.makeGrey(object);	ScanObject.enumeratePointers(object, greyEnum);      }      object = workDequeue.pop();    }    return !abort;  }