VTG_BOTTOM_FIELD_EVENT
(event != VTG_BOTTOM_FIELD_EVENT)) {
case VTG_BOTTOM_FIELD_EVENT:
if ((evt != VTG_TOP_FIELD_EVENT) && (evt != VTG_BOTTOM_FIELD_EVENT)) {
VTG_TOP_FIELD_EVENT : VTG_BOTTOM_FIELD_EVENT;