view bn_mp_clear.c @ 163:8e94663164c6 libtommath LTM_DB_0.44

make pointers volatile so that memory zeroing won't get optimised away
author Matt Johnston <matt@ucc.asn.au>
date Sun, 02 Jan 2005 17:09:26 +0000
parents d29b64170cf0
children
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line source
#include <tommath.h>
#ifdef BN_MP_CLEAR_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
 */

/* clear one (frees)  */
void
mp_clear (mp_int * a)
{
  volatile mp_digit *p;
  int len;

  /* only do anything if a hasn't been freed previously */
  if (a->dp != NULL) {
    /* first zero the digits */
	len = a->alloc;
	p = a->dp;
	while (len--) {
		*p++ = 0;
	}

    /* free ram */
    XFREE(a->dp);

    /* reset members to make debugging easier */
    a->dp    = NULL;
    a->alloc = a->used = 0;
    a->sign  = MP_ZPOS;
  }
}
#endif