RNG_FIFO_WORDS
uint64_t sc_sample[RNG_FIFO_WORDS];
octrnm_delay(ENT_DELAY_CLOCK*RNG_FIFO_WORDS);
CTASSERT(__arraycount(sc->sc_sample) == RNG_FIFO_WORDS);
octrnm_iobdma(sc, samplepos, RNG_FIFO_WORDS / 4);
samplepos += RNG_FIFO_WORDS / 4;