cmask_word_op2
return cmask_word_op2(&a_bits[lo_word - a_word_off],
if (cmask_word_op2(&a_bits[lo_word - a_word_off],
if (cmask_word_op2(&a_bits[w - a_word_off],
return cmask_word_op2(&a_bits[hi_word - a_word_off],