release/src/router/dropbear/libtommath/bn_mp_sqr.c

   1 #include <tommath.h>
   2 #ifdef BN_MP_SQR_C
   3 /* LibTomMath, multiple-precision integer library -- Tom St Denis
   4  *
   5  * LibTomMath is a library that provides multiple-precision
   6  * integer arithmetic as well as number theoretic functionality.
   7  *
   8  * The library was designed directly after the MPI library by
   9  * Michael Fromberger but has been written from scratch with
  10  * additional optimizations in place.
  11  *
  12  * The library is free for all purposes without any express
  13  * guarantee it works.
  14  *
  15  * Tom St Denis, tomstdenis@gmail.com, http://math.libtomcrypt.com
  16  */
  17
  18 /* computes b = a*a */
  19 int
  20 mp_sqr (mp_int * a, mp_int * b)
  21 {
  22   int     res;
  23
  24 #ifdef BN_MP_TOOM_SQR_C
  25   /* use Toom-Cook? */
  26   if (a->used >= TOOM_SQR_CUTOFF) {
  27     res = mp_toom_sqr(a, b);
  28   /* Karatsuba? */
  29   } else
  30 #endif
  31 #ifdef BN_MP_KARATSUBA_SQR_C
  32 if (a->used >= KARATSUBA_SQR_CUTOFF) {
  33     res = mp_karatsuba_sqr (a, b);
  34   } else
  35 #endif
  36   {
  37 #ifdef BN_FAST_S_MP_SQR_C
  38     /* can we use the fast comba multiplier? */
  39     if ((a->used * 2 + 1) < MP_WARRAY &&
  40          a->used <
  41          (1 << (sizeof(mp_word) * CHAR_BIT - 2*DIGIT_BIT - 1))) {
  42       res = fast_s_mp_sqr (a, b);
  43     } else
  44 #endif
  45 #ifdef BN_S_MP_SQR_C
  46       res = s_mp_sqr (a, b);
  47 #else
  48       res = MP_VAL;
  49 #endif
  50   }
  51   b->sign = MP_ZPOS;
  52   return res;
  53 }
  54 #endif
  55
  56 /* $Source: /cvs/libtom/libtommath/bn_mp_sqr.c,v $ */
  57 /* $Revision: 1.3 $ */
  58 /* $Date: 2006/03/31 14:18:44 $ */