BN_MASK2h
dh = (d & BN_MASK2h) >> BN_BITS4;
if ((t & BN_MASK2h) || ((tl) <= ((t << BN_BITS4) | ((l & BN_MASK2h) >> BN_BITS4))))
tl = (tl << BN_BITS4) & BN_MASK2h;
#define bn_cp_32_naked(to, n, from, m) (((n) & 1) ? (to[(n) / 2] |= ((m) & 1) ? (from[(m) / 2] & BN_MASK2h) : (from[(m) / 2] << 32)) \