NBBW
nsip->si_mapsize = P2ROUNDUP(pages, NBBW) / NBBY;
#define TESTBIT(map, i) (((map)[(i) >> MAPSHIFT] & (1 << (i) % NBBW)))
end = P2ROUNDUP(pages, NBBW);
#define SETBIT(map, i) (((map)[(i) >> MAPSHIFT] |= (1 << (i) % NBBW)))
#define CLEARBIT(map, i) (((map)[(i) >> MAPSHIFT] &= ~(1 << (i) % NBBW)))
for (boff = (sip->si_hint % NBBW); boff < NBBW; boff++) {
for (boff = 0; boff < (sip->si_hint % NBBW); boff++) {