nn_modinv_2exp
ATTRIBUTE_WARN_UNUSED_RET int nn_modinv_2exp(nn_t out, nn_src_t in, bitcnt_t exp, int *in_isodd);
GENERIC_TEST_NN(nn_modinv_2exp, NN_MODINV_2EXP, "(^-1%)(2exp)", nn_modinv_2exp, "nnus", "oiio",
ret = nn_modinv_2exp(&tmp_nn1, &p, WORD_BITS, &isodd); EG(ret, err);