static void vli_modInv_update(uECC_word_t *uv,
                              const uECC_word_t *mod,
                              wordcount_t num_words) {
    uECC_word_t carry = 0;
    if (!EVEN(uv)) {
        carry = uECC_vli_add(uv, uv, mod, num_words);
    }
    uECC_vli_rshift1(uv, num_words);
    if (carry) {
        uv[num_words - 1] |= HIGH_BIT_SET;
    }
}