annotate bn_mp_cmp_mag.c @ 163:8e94663164c6 libtommath LTM_DB_0.44

make pointers volatile so that memory zeroing won't get optimised away
author Matt Johnston <matt@ucc.asn.au>
date Sun, 02 Jan 2005 17:09:26 +0000
parents d29b64170cf0
children
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1 #include <tommath.h>
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2 #ifdef BN_MP_CMP_MAG_C
2
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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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12 * The library is free for all purposes without any express
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13 * guarantee it works.
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14 *
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15 * Tom St Denis, [email protected], http://math.libtomcrypt.org
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16 */
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17
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18 /* compare maginitude of two ints (unsigned) */
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19 int mp_cmp_mag (mp_int * a, mp_int * b)
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20 {
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21 int n;
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22 mp_digit *tmpa, *tmpb;
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23
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24 /* compare based on # of non-zero digits */
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25 if (a->used > b->used) {
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26 return MP_GT;
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27 }
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28
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29 if (a->used < b->used) {
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30 return MP_LT;
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31 }
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32
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33 /* alias for a */
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34 tmpa = a->dp + (a->used - 1);
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35
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36 /* alias for b */
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37 tmpb = b->dp + (a->used - 1);
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38
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39 /* compare based on digits */
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40 for (n = 0; n < a->used; ++n, --tmpa, --tmpb) {
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41 if (*tmpa > *tmpb) {
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42 return MP_GT;
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43 }
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44
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45 if (*tmpa < *tmpb) {
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46 return MP_LT;
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47 }
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48 }
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49 return MP_EQ;
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50 }
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51 #endif