33 lines
656 B
C
33 lines
656 B
C
#include "tommath_private.h"
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#ifdef BN_MP_REDUCE_2K_SETUP_C
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/* LibTomMath, multiple-precision integer library -- Tom St Denis */
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/* SPDX-License-Identifier: Unlicense */
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/* determines the setup value */
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mp_err mp_reduce_2k_setup(const mp_int *a, mp_digit *d)
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{
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mp_err err;
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mp_int tmp;
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int p;
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if ((err = mp_init(&tmp)) != MP_OKAY) {
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return err;
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}
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p = mp_count_bits(a);
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if ((err = mp_2expt(&tmp, p)) != MP_OKAY) {
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mp_clear(&tmp);
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return err;
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}
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if ((err = s_mp_sub(&tmp, a, &tmp)) != MP_OKAY) {
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mp_clear(&tmp);
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return err;
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}
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*d = tmp.dp[0];
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mp_clear(&tmp);
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return MP_OKAY;
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}
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#endif
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