view libtommath/bn_mp_set_int.c @ 1663:c795520269f9

Fallback for key gen without hard link support (#89) Add a non-atomic fallback for key generation on platforms where link() is not permitted (such as most stock Android installs) or on filesystems without hard link support (such as FAT).
author Matt Robinson <git@nerdoftheherd.com>
date Sat, 14 Mar 2020 14:37:35 +0000
parents f52919ffd3b1
children
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#include "tommath_private.h"
#ifdef BN_MP_SET_INT_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.
 *
 * SPDX-License-Identifier: Unlicense
 */

/* set a 32-bit const */
int mp_set_int(mp_int *a, unsigned long b)
{
   int     x, res;

   mp_zero(a);

   /* set four bits at a time */
   for (x = 0; x < 8; x++) {
      /* shift the number up four bits */
      if ((res = mp_mul_2d(a, 4, a)) != MP_OKAY) {
         return res;
      }

      /* OR in the top four bits of the source */
      a->dp[0] |= (mp_digit)(b >> 28) & 15uL;

      /* shift the source up to the next four bits */
      b <<= 4;

      /* ensure that digits are not clamped off */
      a->used += 1;
   }
   mp_clamp(a);
   return MP_OKAY;
}
#endif

/* ref:         HEAD -> master, tag: v1.1.0 */
/* git commit:  08549ad6bc8b0cede0b357a9c341c5c6473a9c55 */
/* commit time: 2019-01-28 20:32:32 +0100 */