libtommath/bn_mp_sqr.c
Daniel Mendler 818d8fb7f5
Rework handling of tunable cutoffs
* In the default settings, a cutoff X can be modified at runtime
   by adjusting the corresponding X_CUTOFF variable.

 * Tunability of the library can be disabled at compile time
   by defining the MP_FIXED_CUTOFFS macro.

 * There is an additional file tommath_cutoffs.h, which defines
   the default cutoffs. These can be adjusted manually or by the
   autotuner.
2019-05-04 13:08:37 +02:00

44 lines
1.0 KiB
C

#include "tommath_private.h"
#ifdef BN_MP_SQR_C
/* LibTomMath, multiple-precision integer library -- Tom St Denis */
/* SPDX-License-Identifier: Unlicense */
/* computes b = a*a */
int mp_sqr(const mp_int *a, mp_int *b)
{
int res;
#ifdef BN_S_MP_TOOM_SQR_C
/* use Toom-Cook? */
if (a->used >= MP_TOOM_SQR_CUTOFF) {
res = s_mp_toom_sqr(a, b);
/* Karatsuba? */
} else
#endif
#ifdef BN_S_MP_KARATSUBA_SQR_C
if (a->used >= MP_KARATSUBA_SQR_CUTOFF) {
res = s_mp_karatsuba_sqr(a, b);
} else
#endif
{
#ifdef BN_S_MP_SQR_FAST_C
/* can we use the fast comba multiplier? */
if ((((a->used * 2) + 1) < (int)MP_WARRAY) &&
(a->used <
(int)(1u << (((CHAR_BIT * sizeof(mp_word)) - (2u * (size_t)MP_DIGIT_BIT)) - 1u)))) {
res = s_mp_sqr_fast(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