prom_read
ret.bits = prom_read(sc->sc_fd, reqcnt, addr, bn + pp->p_offset);
ret.bits = prom_read(fd, bbinfop->bsize, cp,
ret.bits = prom_read(sc->sc_fd, reqcnt, addr, bn);
ret.bits = prom_read(netfd, 0, hate, 0);
ret.bits = prom_read(netfd, sizeof hate, hate, 0);