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annotate bn_mp_xor.c @ 2:86e0b50a9b58 libtommath-orig ltm-0.30-orig

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ltm 0.30 orig import
author Matt Johnston <matt@ucc.asn.au>
date Mon, 31 May 2004 18:25:22 +0000
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children d29b64170cf0
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1 /* LibTomMath, multiple-precision integer library -- Tom St Denis
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2 *
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3 * LibTomMath is a library that provides multiple-precision
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4 * integer arithmetic as well as number theoretic functionality.
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5 *
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6 * The library was designed directly after the MPI library by
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7 * Michael Fromberger but has been written from scratch with
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8 * additional optimizations in place.
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9 *
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10 * The library is free for all purposes without any express
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11 * guarantee it works.
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12 *
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13 * Tom St Denis, [email protected], http://math.libtomcrypt.org
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14 */
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15 #include <tommath.h>
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16
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17 /* XOR two ints together */
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18 int
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19 mp_xor (mp_int * a, mp_int * b, mp_int * c)
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20 {
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21 int res, ix, px;
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22 mp_int t, *x;
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23
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24 if (a->used > b->used) {
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25 if ((res = mp_init_copy (&t, a)) != MP_OKAY) {
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26 return res;
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27 }
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28 px = b->used;
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29 x = b;
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30 } else {
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31 if ((res = mp_init_copy (&t, b)) != MP_OKAY) {
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32 return res;
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33 }
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34 px = a->used;
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35 x = a;
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36 }
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37
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38 for (ix = 0; ix < px; ix++) {
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39 t.dp[ix] ^= x->dp[ix];
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40 }
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41 mp_clamp (&t);
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42 mp_exch (c, &t);
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43 mp_clear (&t);
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44 return MP_OKAY;
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45 }