Mercurial > dropbear
comparison libtommath/bn_mp_2expt.c @ 1439:8d24733026c5 coverity
merge
author | Matt Johnston <matt@ucc.asn.au> |
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date | Sat, 24 Jun 2017 23:33:16 +0800 |
parents | 60fc6476e044 |
children | 8bba51a55704 |
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1400:238a439670f5 | 1439:8d24733026c5 |
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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 /* $Date$ */ |