zx_draw
volatile struct zx_draw *sc_zd_ss0;
sizeof(struct zx_draw), BUS_SPACE_MAP_LINEAR, 0, &bh) != 0) {
sc->sc_zd_ss0 = (struct zx_draw *)bus_space_vaddr(bt, bh);
volatile struct zx_draw *zd;
volatile struct zx_draw *zd;
volatile struct zx_draw *zd;
volatile struct zx_draw *zd;
volatile struct zx_draw *zd;