Donatien Garnier / MiniTLS-GPL

A super trimmed down TLS stack, GPL licensed

Dependents:   MiniTLS-HTTPS-Example

MiniTLS - A super trimmed down TLS/SSL Library for embedded devices Author: Donatien Garnier Copyright (C) 2013-2014 AppNearMe Ltd

This program is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation; either version 2 of the License, or (at your option) any later version.

This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details.

You should have received a copy of the GNU General Public License along with this program; if not, write to the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.

math/mul/fp_mul_2d.c

Committer:
MiniTLS
Date:
2014-06-10
Revision:
4:cbaf466d717d
Parent:
0:35aa5be3b78d

File content as of revision 4:cbaf466d717d:

/* TomsFastMath, a fast ISO C bignum library.
 * 
 * This project is meant to fill in where LibTomMath
 * falls short.  That is speed ;-)
 *
 * This project is public domain and free for all purposes.
 * 
 * Tom St Denis, tomstdenis@gmail.com
 */
#include <tfm.h>

/* c = a * 2**d */
void fp_mul_2d(fp_int *a, int b, fp_int *c)
{
   fp_digit carry, carrytmp, shift;
   int x;

   /* copy it */
   fp_copy(a, c);

   /* handle whole digits */
   if (b >= DIGIT_BIT) {
      fp_lshd(c, b/DIGIT_BIT);
   }
   b %= DIGIT_BIT;

   /* shift the digits */
   if (b != 0) {
      carry = 0;   
      shift = DIGIT_BIT - b;
      for (x = 0; x < c->used; x++) {
          carrytmp = c->dp[x] >> shift;
          c->dp[x] = (c->dp[x] << b) + carry;
          carry = carrytmp;
      }
      /* store last carry if room */
      if (carry && x < FP_SIZE) {
         c->dp[c->used++] = carry;
      }
   }
   fp_clamp(c);
}


/* $Source: /cvs/libtom/tomsfastmath/src/mul/fp_mul_2d.c,v $ */
/* $Revision: 1.1 $ */
/* $Date: 2006/12/31 21:25:53 $ */