Mercurial > dropbear
comparison src/encauth/ocb/ocb_ntz.c @ 192:9cc34777b479 libtomcrypt
propagate from branch 'au.asn.ucc.matt.ltc-orig' (head 9ba8f01f44320e9cb9f19881105ae84f84a43ea9)
to branch 'au.asn.ucc.matt.dropbear.ltc' (head dbf51c569bc34956ad948e4cc87a0eeb2170b768)
author | Matt Johnston <matt@ucc.asn.au> |
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date | Sun, 08 May 2005 06:36:47 +0000 |
parents | 1c15b283127b |
children | 39d5d58461d6 |
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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 * 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 |