NBITS
x += NBITS;
printf("NBITS %lu\n", (unsigned long)NBITS);
KASSERT (up->len <= NBITS,
up->len, NBITS, line));
if (uf->len >= NBITS)
if ((up->len + l) > NBITS)
bit_nclear(ub->map, 0, NBITS - 1);
if (uf->len + us->len > NBITS)