view libtomcrypt/src/encauth/ocb/ocb_ntz.c @ 561:541ebf5bf0f6

propagate from branch 'au.asn.ucc.matt.dropbear.cli-agent' (head eb0dae4b62e243ba37a897beb7ba81a4f637d8b3) to branch 'au.asn.ucc.matt.dropbear' (head ff0abce7b29e61630e3b09e5fc5820ae6e192808)
author Matt Johnston <matt@ucc.asn.au>
date Thu, 30 Jul 2009 15:15:12 +0000
parents 0cbe8f6dbf9e
children f849a5ca2efc
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/* LibTomCrypt, modular cryptographic library -- Tom St Denis
 *
 * LibTomCrypt is a library that provides various cryptographic
 * algorithms in a highly modular and flexible manner.
 *
 * The library is free for all purposes without any express
 * guarantee it works.
 *
 * Tom St Denis, [email protected], http://libtomcrypt.com
 */

/**
   @file ocb_ntz.c
   OCB implementation, internal function, by Tom St Denis
*/

#include "tomcrypt.h"

#ifdef OCB_MODE

/**
   Returns the number of leading zero bits [from lsb up]
   @param x  The 32-bit value to observe
   @return   The number of bits [from the lsb up] that are zero
*/
int ocb_ntz(unsigned long x)
{
   int c;
   x &= 0xFFFFFFFFUL;
   c = 0;
   while ((x & 1) == 0) {
      ++c;
      x >>= 1;
   }
   return c;
}

#endif

/* $Source: /cvs/libtom/libtomcrypt/src/encauth/ocb/ocb_ntz.c,v $ */
/* $Revision: 1.4 $ */
/* $Date: 2006/03/31 14:15:35 $ */