Mercurial > dropbear
comparison libtomcrypt/src/encauth/ocb3/ocb3_int_ntz.c @ 1471:6dba84798cd5
Update to libtomcrypt 1.18.1, merged with Dropbear changes
author | Matt Johnston <matt@ucc.asn.au> |
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date | Fri, 09 Feb 2018 21:44:05 +0800 |
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1470:8bba51a55704 | 1471:6dba84798cd5 |
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1 /* LibTomCrypt, modular cryptographic library -- Tom St Denis | |
2 * | |
3 * LibTomCrypt is a library that provides various cryptographic | |
4 * algorithms in a highly modular and flexible manner. | |
5 * | |
6 * The library is free for all purposes without any express | |
7 * guarantee it works. | |
8 */ | |
9 | |
10 /** | |
11 @file ocb3_int_ntz.c | |
12 OCB implementation, INTERNAL ONLY helper, by Tom St Denis | |
13 */ | |
14 #include "tomcrypt.h" | |
15 | |
16 #ifdef LTC_OCB3_MODE | |
17 | |
18 /** | |
19 Returns the number of leading zero bits [from lsb up] (internal function) | |
20 @param x The 32-bit value to observe | |
21 @return The number of bits [from the lsb up] that are zero | |
22 */ | |
23 int ocb3_int_ntz(unsigned long x) | |
24 { | |
25 int c; | |
26 x &= 0xFFFFFFFFUL; | |
27 c = 0; | |
28 while ((x & 1) == 0) { | |
29 ++c; | |
30 x >>= 1; | |
31 } | |
32 return c; | |
33 } | |
34 | |
35 #endif | |
36 | |
37 /* ref: $Format:%D$ */ | |
38 /* git commit: $Format:%H$ */ | |
39 /* commit time: $Format:%ai$ */ |