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comparison libtommath/bn_mp_2expt.c @ 1436:60fc6476e044

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Update to libtommath v1.0
author Matt Johnston <matt@ucc.asn.au>
date Sat, 24 Jun 2017 22:37:14 +0800
parents 5ff8218bcee9
children 8bba51a55704
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1435:f849a5ca2efc 1436:60fc6476e044
1 #include <tommath.h> 1 #include <tommath_private.h>
2 #ifdef BN_MP_2EXPT_C 2 #ifdef BN_MP_2EXPT_C
3 /* LibTomMath, multiple-precision integer library -- Tom St Denis 3 /* LibTomMath, multiple-precision integer library -- Tom St Denis
4 * 4 *
5 * LibTomMath is a library that provides multiple-precision 5 * LibTomMath is a library that provides multiple-precision
6 * integer arithmetic as well as number theoretic functionality. 6 * integer arithmetic as well as number theoretic functionality.
10 * additional optimizations in place. 10 * additional optimizations in place.
11 * 11 *
12 * The library is free for all purposes without any express 12 * The library is free for all purposes without any express
13 * guarantee it works. 13 * guarantee it works.
14 * 14 *
15 * Tom St Denis, [email protected], http://math.libtomcrypt.com 15 * Tom St Denis, [email protected], http://libtom.org
16 */ 16 */
17 17
18 /* computes a = 2**b 18 /* computes a = 2**b
19 * 19 *
20 * Simple algorithm which zeroes the int, grows it then just sets one bit 20 * Simple algorithm which zeroes the int, grows it then just sets one bit
27 27
28 /* zero a as per default */ 28 /* zero a as per default */
29 mp_zero (a); 29 mp_zero (a);
30 30
31 /* grow a to accomodate the single bit */ 31 /* grow a to accomodate the single bit */
32 if ((res = mp_grow (a, b / DIGIT_BIT + 1)) != MP_OKAY) { 32 if ((res = mp_grow (a, (b / DIGIT_BIT) + 1)) != MP_OKAY) {
33 return res; 33 return res;
34 } 34 }
35 35
36 /* set the used count of where the bit will go */ 36 /* set the used count of where the bit will go */
37 a->used = b / DIGIT_BIT + 1; 37 a->used = (b / DIGIT_BIT) + 1;
38 38
39 /* put the single bit in its place */ 39 /* put the single bit in its place */
40 a->dp[b / DIGIT_BIT] = ((mp_digit)1) << (b % DIGIT_BIT); 40 a->dp[b / DIGIT_BIT] = ((mp_digit)1) << (b % DIGIT_BIT);
41 41
42 return MP_OKAY; 42 return MP_OKAY;
43 } 43 }
44 #endif 44 #endif
45 45
46 /* $Source: /cvs/libtom/libtommath/bn_mp_2expt.c,v $ */ 46 /* $Source$ */
47 /* $Revision: 1.3 $ */ 47 /* $Revision$ */
48 /* $Date: 2006/03/31 14:18:44 $ */ 48 /* $Date$ */