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comparison libtommath/bn_mp_set_int.c @ 330:5488db2e9e4e

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merge of 332f709a4cb39cde4cedab7c3be89e05f3023067 and ca4ca78b82c5d430c69ce01bf794e8886ce81431
author Matt Johnston <matt@ucc.asn.au>
date Sat, 10 Jun 2006 16:39:40 +0000
parents eed26cff980b
children 5ff8218bcee9
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329:8ed0dce45126 330:5488db2e9e4e
1 #include <tommath.h>
2 #ifdef BN_MP_SET_INT_C
3 /* LibTomMath, multiple-precision integer library -- Tom St Denis
4 *
5 * LibTomMath is a library that provides multiple-precision
6 * integer arithmetic as well as number theoretic functionality.
7 *
8 * The library was designed directly after the MPI library by
9 * Michael Fromberger but has been written from scratch with
10 * additional optimizations in place.
11 *
12 * The library is free for all purposes without any express
13 * guarantee it works.
14 *
15 * Tom St Denis, [email protected], http://math.libtomcrypt.org
16 */
17
18 /* set a 32-bit const */
19 int mp_set_int (mp_int * a, unsigned long b)
20 {
21 int x, res;
22
23 mp_zero (a);
24
25 /* set four bits at a time */
26 for (x = 0; x < 8; x++) {
27 /* shift the number up four bits */
28 if ((res = mp_mul_2d (a, 4, a)) != MP_OKAY) {
29 return res;
30 }
31
32 /* OR in the top four bits of the source */
33 a->dp[0] |= (b >> 28) & 15;
34
35 /* shift the source up to the next four bits */
36 b <<= 4;
37
38 /* ensure that digits are not clamped off */
39 a->used += 1;
40 }
41 mp_clamp (a);
42 return MP_OKAY;
43 }
44 #endif