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comparison libtomcrypt/src/encauth/ocb/ocb_ntz.c @ 285:1b9e69c058d2

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propagate from branch 'au.asn.ucc.matt.ltc.dropbear' (head 20dccfc09627970a312d77fb41dc2970b62689c3) to branch 'au.asn.ucc.matt.dropbear' (head fdf4a7a3b97ae5046139915de7e40399cceb2c01)
author Matt Johnston <matt@ucc.asn.au>
date Wed, 08 Mar 2006 13:23:58 +0000
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281:997e6f7dc01e 285:1b9e69c058d2
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 * Tom St Denis, [email protected], http://libtomcrypt.org
10 */
11
12 /**
13 @file ocb_ntz.c
14 OCB implementation, internal function, by Tom St Denis
15 */
16
17 #include "tomcrypt.h"
18
19 #ifdef OCB_MODE
20
21 /**
22 Returns the number of leading zero bits [from lsb up]
23 @param x The 32-bit value to observe
24 @return The number of bits [from the lsb up] that are zero
25 */
26 int ocb_ntz(unsigned long x)
27 {
28 int c;
29 x &= 0xFFFFFFFFUL;
30 c = 0;
31 while ((x & 1) == 0) {
32 ++c;
33 x >>= 1;
34 }
35 return c;
36 }
37
38 #endif
39
40 /* $Source: /cvs/libtom/libtomcrypt/src/encauth/ocb/ocb_ntz.c,v $ */
41 /* $Revision: 1.3 $ */
42 /* $Date: 2005/05/05 14:35:58 $ */