prom_open
ret.bits = prom_open((u_int64_t)devname, devlen);
ret.bits = prom_open((u_int64_t)devname, devlen);
ret.bits = prom_open((u_int64_t)devname, devlen);
ret.bits = prom_open((u_int64_t)devname, devlen + 1);