view bn_mp_clamp.c @ 145:a96ff234ff19 libtommath

propagate of fc94c38452d9fd684a8e1eb9e3a73120aac0d38f and 3e4de4cbef3d9035a7b2f0c25e9f86e297f9f6d1 from branch 'au.asn.ucc.matt.ltm-orig' to 'au.asn.ucc.matt.ltm-db'
author Matt Johnston <matt@ucc.asn.au>
date Sun, 19 Dec 2004 15:57:19 +0000
parents d29b64170cf0
children
line wrap: on
line source

#include <tommath.h>
#ifdef BN_MP_CLAMP_C
/* LibTomMath, multiple-precision integer library -- Tom St Denis
 *
 * LibTomMath is a library that provides multiple-precision
 * integer arithmetic as well as number theoretic functionality.
 *
 * The library was designed directly after the MPI library by
 * Michael Fromberger but has been written from scratch with
 * additional optimizations in place.
 *
 * The library is free for all purposes without any express
 * guarantee it works.
 *
 * Tom St Denis, [email protected], http://math.libtomcrypt.org
 */

/* trim unused digits 
 *
 * This is used to ensure that leading zero digits are
 * trimed and the leading "used" digit will be non-zero
 * Typically very fast.  Also fixes the sign if there
 * are no more leading digits
 */
void
mp_clamp (mp_int * a)
{
  /* decrease used while the most significant digit is
   * zero.
   */
  while (a->used > 0 && a->dp[a->used - 1] == 0) {
    --(a->used);
  }

  /* reset the sign flag if used == 0 */
  if (a->used == 0) {
    a->sign = MP_ZPOS;
  }
}
#endif