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/**
* @cond internal
* @file f_arithmetic.c
* @copyright
* Copyright (c) 2014 Cryptography Research, Inc. \n
* Released under the MIT License. See LICENSE.txt for license information.
* @author Mike Hamburg
* @brief Field-specific arithmetic.
*/
#include "field.h"
mask_t gf_isr (
gf a,
const gf x
) {
gf L0, L1, L2;
gf_sqr (L1, x );
gf_mul (L2, x, L1 );
gf_sqr (L1, L2 );
gf_mul (L2, x, L1 );
gf_sqrn (L1, L2, 3 );
gf_mul (L0, L2, L1 );
gf_sqrn (L1, L0, 3 );
gf_mul (L0, L2, L1 );
gf_sqrn (L2, L0, 9 );
gf_mul (L1, L0, L2 );
gf_sqr (L0, L1 );
gf_mul (L2, x, L0 );
gf_sqrn (L0, L2, 18 );
gf_mul (L2, L1, L0 );
gf_sqrn (L0, L2, 37 );
gf_mul (L1, L2, L0 );
gf_sqrn (L0, L1, 37 );
gf_mul (L1, L2, L0 );
gf_sqrn (L0, L1, 111 );
gf_mul (L2, L1, L0 );
gf_sqr (L0, L2 );
gf_mul (L1, x, L0 );
gf_sqrn (L0, L1, 223 );
gf_mul (L1, L2, L0 );
gf_sqr (L2, L1);
gf_mul (L0, L2, x);
gf_copy(a,L1);
return gf_eq(L0,ONE);
}
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