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comparison bn_mp_xor.c @ 1:22d5cf7d4b1a libtommath

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Renaming branch
author Matt Johnston <matt@ucc.asn.au>
date Mon, 31 May 2004 18:23:46 +0000
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-1:000000000000 1:22d5cf7d4b1a
1 /* LibTomMath, multiple-precision integer library -- Tom St Denis
2 *
3 * LibTomMath is a library that provides multiple-precision
4 * integer arithmetic as well as number theoretic functionality.
5 *
6 * The library was designed directly after the MPI library by
7 * Michael Fromberger but has been written from scratch with
8 * additional optimizations in place.
9 *
10 * The library is free for all purposes without any express
11 * guarantee it works.
12 *
13 * Tom St Denis, [email protected], http://math.libtomcrypt.org
14 */
15 #include <tommath.h>
16
17 /* XOR two ints together */
18 int
19 mp_xor (mp_int * a, mp_int * b, mp_int * c)
20 {
21 int res, ix, px;
22 mp_int t, *x;
23
24 if (a->used > b->used) {
25 if ((res = mp_init_copy (&t, a)) != MP_OKAY) {
26 return res;
27 }
28 px = b->used;
29 x = b;
30 } else {
31 if ((res = mp_init_copy (&t, b)) != MP_OKAY) {
32 return res;
33 }
34 px = a->used;
35 x = a;
36 }
37
38 for (ix = 0; ix < px; ix++) {
39 t.dp[ix] ^= x->dp[ix];
40 }
41 mp_clamp (&t);
42 mp_exch (c, &t);
43 mp_clear (&t);
44 return MP_OKAY;
45 }