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