view libtommath/bn_mp_sqr.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 1051e4eea25a
line wrap: on
line source

#include "tommath_private.h"
#ifdef BN_MP_SQR_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
 */

/* computes b = a*a */
int mp_sqr(const mp_int *a, mp_int *b)
{
   int     res;

#ifdef BN_MP_TOOM_SQR_C
   /* use Toom-Cook? */
   if (a->used >= TOOM_SQR_CUTOFF) {
      res = mp_toom_sqr(a, b);
      /* Karatsuba? */
   } else
#endif
#ifdef BN_MP_KARATSUBA_SQR_C
      if (a->used >= KARATSUBA_SQR_CUTOFF) {
         res = mp_karatsuba_sqr(a, b);
      } else
#endif
      {
#ifdef BN_FAST_S_MP_SQR_C
         /* can we use the fast comba multiplier? */
         if ((((a->used * 2) + 1) < (int)MP_WARRAY) &&
             (a->used <
              (int)(1u << (((sizeof(mp_word) * (size_t)CHAR_BIT) - (2u * (size_t)DIGIT_BIT)) - 1u)))) {
            res = fast_s_mp_sqr(a, b);
         } else
#endif
         {
#ifdef BN_S_MP_SQR_C
            res = s_mp_sqr(a, b);
#else
            res = MP_VAL;
#endif
         }
      }
   b->sign = MP_ZPOS;
   return res;
}
#endif

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