annotate bn_mp_xor.c @ 1:22d5cf7d4b1a libtommath

Renaming branch
author Matt Johnston <matt@ucc.asn.au>
date Mon, 31 May 2004 18:23:46 +0000
parents
children d29b64170cf0
Ignore whitespace changes - Everywhere: Within whitespace: At end of lines:
rev   line source
1
22d5cf7d4b1a Renaming branch
Matt Johnston <matt@ucc.asn.au>
parents:
diff changeset
1 /* LibTomMath, multiple-precision integer library -- Tom St Denis
22d5cf7d4b1a Renaming branch
Matt Johnston <matt@ucc.asn.au>
parents:
diff changeset
2 *
22d5cf7d4b1a Renaming branch
Matt Johnston <matt@ucc.asn.au>
parents:
diff changeset
3 * LibTomMath is a library that provides multiple-precision
22d5cf7d4b1a Renaming branch
Matt Johnston <matt@ucc.asn.au>
parents:
diff changeset
4 * integer arithmetic as well as number theoretic functionality.
22d5cf7d4b1a Renaming branch
Matt Johnston <matt@ucc.asn.au>
parents:
diff changeset
5 *
22d5cf7d4b1a Renaming branch
Matt Johnston <matt@ucc.asn.au>
parents:
diff changeset
6 * The library was designed directly after the MPI library by
22d5cf7d4b1a Renaming branch
Matt Johnston <matt@ucc.asn.au>
parents:
diff changeset
7 * Michael Fromberger but has been written from scratch with
22d5cf7d4b1a Renaming branch
Matt Johnston <matt@ucc.asn.au>
parents:
diff changeset
8 * additional optimizations in place.
22d5cf7d4b1a Renaming branch
Matt Johnston <matt@ucc.asn.au>
parents:
diff changeset
9 *
22d5cf7d4b1a Renaming branch
Matt Johnston <matt@ucc.asn.au>
parents:
diff changeset
10 * The library is free for all purposes without any express
22d5cf7d4b1a Renaming branch
Matt Johnston <matt@ucc.asn.au>
parents:
diff changeset
11 * guarantee it works.
22d5cf7d4b1a Renaming branch
Matt Johnston <matt@ucc.asn.au>
parents:
diff changeset
12 *
22d5cf7d4b1a Renaming branch
Matt Johnston <matt@ucc.asn.au>
parents:
diff changeset
13 * Tom St Denis, [email protected], http://math.libtomcrypt.org
22d5cf7d4b1a Renaming branch
Matt Johnston <matt@ucc.asn.au>
parents:
diff changeset
14 */
22d5cf7d4b1a Renaming branch
Matt Johnston <matt@ucc.asn.au>
parents:
diff changeset
15 #include <tommath.h>
22d5cf7d4b1a Renaming branch
Matt Johnston <matt@ucc.asn.au>
parents:
diff changeset
16
22d5cf7d4b1a Renaming branch
Matt Johnston <matt@ucc.asn.au>
parents:
diff changeset
17 /* XOR two ints together */
22d5cf7d4b1a Renaming branch
Matt Johnston <matt@ucc.asn.au>
parents:
diff changeset
18 int
22d5cf7d4b1a Renaming branch
Matt Johnston <matt@ucc.asn.au>
parents:
diff changeset
19 mp_xor (mp_int * a, mp_int * b, mp_int * c)
22d5cf7d4b1a Renaming branch
Matt Johnston <matt@ucc.asn.au>
parents:
diff changeset
20 {
22d5cf7d4b1a Renaming branch
Matt Johnston <matt@ucc.asn.au>
parents:
diff changeset
21 int res, ix, px;
22d5cf7d4b1a Renaming branch
Matt Johnston <matt@ucc.asn.au>
parents:
diff changeset
22 mp_int t, *x;
22d5cf7d4b1a Renaming branch
Matt Johnston <matt@ucc.asn.au>
parents:
diff changeset
23
22d5cf7d4b1a Renaming branch
Matt Johnston <matt@ucc.asn.au>
parents:
diff changeset
24 if (a->used > b->used) {
22d5cf7d4b1a Renaming branch
Matt Johnston <matt@ucc.asn.au>
parents:
diff changeset
25 if ((res = mp_init_copy (&t, a)) != MP_OKAY) {
22d5cf7d4b1a Renaming branch
Matt Johnston <matt@ucc.asn.au>
parents:
diff changeset
26 return res;
22d5cf7d4b1a Renaming branch
Matt Johnston <matt@ucc.asn.au>
parents:
diff changeset
27 }
22d5cf7d4b1a Renaming branch
Matt Johnston <matt@ucc.asn.au>
parents:
diff changeset
28 px = b->used;
22d5cf7d4b1a Renaming branch
Matt Johnston <matt@ucc.asn.au>
parents:
diff changeset
29 x = b;
22d5cf7d4b1a Renaming branch
Matt Johnston <matt@ucc.asn.au>
parents:
diff changeset
30 } else {
22d5cf7d4b1a Renaming branch
Matt Johnston <matt@ucc.asn.au>
parents:
diff changeset
31 if ((res = mp_init_copy (&t, b)) != MP_OKAY) {
22d5cf7d4b1a Renaming branch
Matt Johnston <matt@ucc.asn.au>
parents:
diff changeset
32 return res;
22d5cf7d4b1a Renaming branch
Matt Johnston <matt@ucc.asn.au>
parents:
diff changeset
33 }
22d5cf7d4b1a Renaming branch
Matt Johnston <matt@ucc.asn.au>
parents:
diff changeset
34 px = a->used;
22d5cf7d4b1a Renaming branch
Matt Johnston <matt@ucc.asn.au>
parents:
diff changeset
35 x = a;
22d5cf7d4b1a Renaming branch
Matt Johnston <matt@ucc.asn.au>
parents:
diff changeset
36 }
22d5cf7d4b1a Renaming branch
Matt Johnston <matt@ucc.asn.au>
parents:
diff changeset
37
22d5cf7d4b1a Renaming branch
Matt Johnston <matt@ucc.asn.au>
parents:
diff changeset
38 for (ix = 0; ix < px; ix++) {
22d5cf7d4b1a Renaming branch
Matt Johnston <matt@ucc.asn.au>
parents:
diff changeset
39 t.dp[ix] ^= x->dp[ix];
22d5cf7d4b1a Renaming branch
Matt Johnston <matt@ucc.asn.au>
parents:
diff changeset
40 }
22d5cf7d4b1a Renaming branch
Matt Johnston <matt@ucc.asn.au>
parents:
diff changeset
41 mp_clamp (&t);
22d5cf7d4b1a Renaming branch
Matt Johnston <matt@ucc.asn.au>
parents:
diff changeset
42 mp_exch (c, &t);
22d5cf7d4b1a Renaming branch
Matt Johnston <matt@ucc.asn.au>
parents:
diff changeset
43 mp_clear (&t);
22d5cf7d4b1a Renaming branch
Matt Johnston <matt@ucc.asn.au>
parents:
diff changeset
44 return MP_OKAY;
22d5cf7d4b1a Renaming branch
Matt Johnston <matt@ucc.asn.au>
parents:
diff changeset
45 }