35 lines
801 B
C
35 lines
801 B
C
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#include "tommath_private.h"
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#ifdef MP_REDUCE_IS_2K_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 if mp_reduce_2k can be used */
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bool mp_reduce_is_2k(const mp_int *a)
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{
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if (mp_iszero(a)) {
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return false;
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} else if (a->used == 1) {
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return true;
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} else if (a->used > 1) {
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int ix, iy = mp_count_bits(a), iw = 1;
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mp_digit iz = 1;
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/* Test every bit from the second digit up, must be 1 */
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for (ix = MP_DIGIT_BIT; ix < iy; ix++) {
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if ((a->dp[iw] & iz) == 0u) {
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return false;
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}
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iz <<= 1;
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if (iz > MP_DIGIT_MAX) {
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++iw;
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iz = 1;
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}
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}
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return true;
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} else {
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return true;
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}
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}
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#endif
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