release/src/router/nettle/cnd-copy.c

   1 /* cnd-copy.c */
   2
   3 /* nettle, low-level cryptographics library
   4  *
   5  * Copyright (C) 2013 Niels Möller
   6  *
   7  * The nettle library is free software; you can redistribute it and/or modify
   8  * it under the terms of the GNU Lesser General Public License as published by
   9  * the Free Software Foundation; either version 2.1 of the License, or (at your
  10  * option) any later version.
  11  *
  12  * The nettle library is distributed in the hope that it will be useful, but
  13  * WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
  14  * or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU Lesser General Public
  15  * License for more details.
  16  *
  17  * You should have received a copy of the GNU Lesser General Public License
  18  * along with the nettle library; see the file COPYING.LIB.  If not, write to
  19  * the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston,
  20  * MA 02111-1301, USA.
  21  */
  22
  23 /* Development of Nettle's ECC support was funded by the .SE Internet Fund. */
  24
  25 #if HAVE_CONFIG_H
  26 # include "config.h"
  27 #endif
  28
  29 #include "ecc-internal.h"
  30
  31 void
  32 cnd_copy (int cnd, mp_limb_t *rp, const mp_limb_t *ap, mp_size_t n)
  33 {
  34   mp_limb_t mask, keep;
  35   mp_size_t i;
  36
  37   mask = -(mp_limb_t) (cnd !=0);
  38   keep = ~mask;
  39
  40   for (i = 0; i < n; i++)
  41     rp[i] = (rp[i] & keep) + (ap[i] & mask);
  42 }