mirror of
http://galexander.org/git/simplesshd.git
synced 2024-11-30 19:28:10 +00:00
67 lines
1.8 KiB
C
67 lines
1.8 KiB
C
#include <tommath.h>
|
|
#ifdef BN_MP_MUL_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.
|
|
*
|
|
* The library is free for all purposes without any express
|
|
* guarantee it works.
|
|
*
|
|
* Tom St Denis, tomstdenis@gmail.com, http://math.libtomcrypt.com
|
|
*/
|
|
|
|
/* high level multiplication (handles sign) */
|
|
int mp_mul (mp_int * a, mp_int * b, mp_int * c)
|
|
{
|
|
int res, neg;
|
|
neg = (a->sign == b->sign) ? MP_ZPOS : MP_NEG;
|
|
|
|
/* use Toom-Cook? */
|
|
#ifdef BN_MP_TOOM_MUL_C
|
|
if (MIN (a->used, b->used) >= TOOM_MUL_CUTOFF) {
|
|
res = mp_toom_mul(a, b, c);
|
|
} else
|
|
#endif
|
|
#ifdef BN_MP_KARATSUBA_MUL_C
|
|
/* use Karatsuba? */
|
|
if (MIN (a->used, b->used) >= KARATSUBA_MUL_CUTOFF) {
|
|
res = mp_karatsuba_mul (a, b, c);
|
|
} else
|
|
#endif
|
|
{
|
|
/* can we use the fast multiplier?
|
|
*
|
|
* The fast multiplier can be used if the output will
|
|
* have less than MP_WARRAY digits and the number of
|
|
* digits won't affect carry propagation
|
|
*/
|
|
int digs = a->used + b->used + 1;
|
|
|
|
#ifdef BN_FAST_S_MP_MUL_DIGS_C
|
|
if ((digs < MP_WARRAY) &&
|
|
MIN(a->used, b->used) <=
|
|
(1 << ((CHAR_BIT * sizeof (mp_word)) - (2 * DIGIT_BIT)))) {
|
|
res = fast_s_mp_mul_digs (a, b, c, digs);
|
|
} else
|
|
#endif
|
|
#ifdef BN_S_MP_MUL_DIGS_C
|
|
res = s_mp_mul (a, b, c); /* uses s_mp_mul_digs */
|
|
#else
|
|
res = MP_VAL;
|
|
#endif
|
|
|
|
}
|
|
c->sign = (c->used > 0) ? neg : MP_ZPOS;
|
|
return res;
|
|
}
|
|
#endif
|
|
|
|
/* $Source: /cvs/libtom/libtommath/bn_mp_mul.c,v $ */
|
|
/* $Revision: 1.3 $ */
|
|
/* $Date: 2006/03/31 14:18:44 $ */
|