BITMAP_SHIFT
KASSERT(spc->spc_bitmap[spc->spc_maxpriority >> BITMAP_SHIFT]);
i = (PRI_COUNT >> BITMAP_SHIFT) - 1;
i = eprio >> BITMAP_SHIFT;
KASSERT(spc->spc_bitmap[eprio >> BITMAP_SHIFT] != 0);
i = eprio >> BITMAP_SHIFT;
(i << BITMAP_SHIFT) + (BITMAP_BITS - q);