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annotate libtommath/bn_mp_clamp.c @ 1689:d2d3b5ba6c64

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update travis to Ubuntu focal to provide chacha20
author Matt Johnston <matt@ucc.asn.au>
date Tue, 26 May 2020 23:13:48 +0800
parents f52919ffd3b1
children 1051e4eea25a
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f52919ffd3b1 update ltm to 1.1.0 and enable FIPS 186.4 compliant key-generation (#79)
Steffen Jaeckel <s_jaeckel@gmx.de>
parents: 1470
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1 #include "tommath_private.h"
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2 #ifdef BN_MP_CLAMP_C
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3 /* LibTomMath, multiple-precision integer library -- Tom St Denis
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4 *
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5 * LibTomMath is a library that provides multiple-precision
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6 * integer arithmetic as well as number theoretic functionality.
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7 *
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8 * The library was designed directly after the MPI library by
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9 * Michael Fromberger but has been written from scratch with
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10 * additional optimizations in place.
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11 *
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f52919ffd3b1 update ltm to 1.1.0 and enable FIPS 186.4 compliant key-generation (#79)
Steffen Jaeckel <s_jaeckel@gmx.de>
parents: 1470
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12 * SPDX-License-Identifier: Unlicense
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13 */
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14
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parents: 1470
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15 /* trim unused digits
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16 *
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17 * This is used to ensure that leading zero digits are
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18 * trimed and the leading "used" digit will be non-zero
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19 * Typically very fast. Also fixes the sign if there
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20 * are no more leading digits
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21 */
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22 void mp_clamp(mp_int *a)
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23 {
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24 /* decrease used while the most significant digit is
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parents: 1470
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25 * zero.
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parents: 1470
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26 */
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parents: 1470
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27 while ((a->used > 0) && (a->dp[a->used - 1] == 0u)) {
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28 --(a->used);
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parents: 1470
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29 }
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parents: 1470
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31 /* reset the sign flag if used == 0 */
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parents: 1470
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32 if (a->used == 0) {
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parents: 1470
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33 a->sign = MP_ZPOS;
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parents: 1470
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34 }
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35 }
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36 #endif
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37
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parents: 1470
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38 /* ref: HEAD -> master, tag: v1.1.0 */
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39 /* git commit: 08549ad6bc8b0cede0b357a9c341c5c6473a9c55 */
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40 /* commit time: 2019-01-28 20:32:32 +0100 */