BD_DONE
bd->mode.status |= BD_DONE;
bd->mode.status = BD_DONE | BD_EXTD | BD_CONT | BD_INTR;
bd0->mode.status = BD_DONE | BD_INTR | BD_WRAP | BD_EXTD;
bd0->mode.status = BD_DONE | BD_INTR | BD_WRAP | BD_EXTD;