FDCFLG_WAITING
fdc->c_flags |= FDCFLG_WAITING;
while (fdc->c_flags & FDCFLG_WAITING) {
if (fdc->c_flags & FDCFLG_WAITING) {
fdc->c_flags ^= FDCFLG_WAITING;
if (fdc->c_flags & FDCFLG_WAITING) {
fdc->c_flags ^= FDCFLG_WAITING;
fdc->c_flags |= FDCFLG_WAITING;
fdc->c_flags |= FDCFLG_WAITING;