add_sat
rs->total = add_sat(rs->total, entropybits);
add_sat(rs->time_delta.insamples, 1);
add_sat(rs->value_delta.insamples, 1);
add_sat(rc->rc_entropybits, entropybits));
add_sat(rc->rc_timesamples, 1));
add_sat(rc->rc_datasamples, 1));
urse->dt_samples = add_sat(urse->dt_samples,
urse->dv_samples = add_sat(urse->dv_samples,