_WORD_LOWPART
((w.val[_WORD_HIGHPART] == 0) && (w.val[_WORD_LOWPART] == 0))
(w).val[_WORD_HIGHPART] = (w).val[_WORD_LOWPART] = 0
(w2).val[_WORD_LOWPART] = (w1).val[_WORD_LOWPART]; \
(i) = (((u_int32_t)ntohs((w).val[_WORD_HIGHPART])) << 16) | ntohs((w).val[_WORD_LOWPART])
(w).val[_WORD_LOWPART] = htons((u_int16_t) (i & 0xffff)); \