mirror of
https://github.com/Laupetin/OpenAssetTools.git
synced 2025-06-25 06:07:53 -05:00
Import code from previous AssetBuilder version
This commit is contained in:
77
thirdparty/libtommath/bn_s_mp_mul_high_digs.c
vendored
Normal file
77
thirdparty/libtommath/bn_s_mp_mul_high_digs.c
vendored
Normal file
@ -0,0 +1,77 @@
|
||||
#include "tommath_private.h"
|
||||
#ifdef BN_S_MP_MUL_HIGH_DIGS_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
|
||||
*/
|
||||
|
||||
/* multiplies |a| * |b| and does not compute the lower digs digits
|
||||
* [meant to get the higher part of the product]
|
||||
*/
|
||||
int s_mp_mul_high_digs(const mp_int *a, const mp_int *b, mp_int *c, int digs)
|
||||
{
|
||||
mp_int t;
|
||||
int res, pa, pb, ix, iy;
|
||||
mp_digit u;
|
||||
mp_word r;
|
||||
mp_digit tmpx, *tmpt, *tmpy;
|
||||
|
||||
/* can we use the fast multiplier? */
|
||||
#ifdef BN_FAST_S_MP_MUL_HIGH_DIGS_C
|
||||
if (((a->used + b->used + 1) < (int)MP_WARRAY)
|
||||
&& (MIN(a->used, b->used) < (int)(1u << (((size_t)CHAR_BIT * sizeof(mp_word)) - (2u * (size_t)DIGIT_BIT))))) {
|
||||
return fast_s_mp_mul_high_digs(a, b, c, digs);
|
||||
}
|
||||
#endif
|
||||
|
||||
if ((res = mp_init_size(&t, a->used + b->used + 1)) != MP_OKAY) {
|
||||
return res;
|
||||
}
|
||||
t.used = a->used + b->used + 1;
|
||||
|
||||
pa = a->used;
|
||||
pb = b->used;
|
||||
for (ix = 0; ix < pa; ix++) {
|
||||
/* clear the carry */
|
||||
u = 0;
|
||||
|
||||
/* left hand side of A[ix] * B[iy] */
|
||||
tmpx = a->dp[ix];
|
||||
|
||||
/* alias to the address of where the digits will be stored */
|
||||
tmpt = &(t.dp[digs]);
|
||||
|
||||
/* alias for where to read the right hand side from */
|
||||
tmpy = b->dp + (digs - ix);
|
||||
|
||||
for (iy = digs - ix; iy < pb; iy++) {
|
||||
/* calculate the double precision result */
|
||||
r = (mp_word)*tmpt +
|
||||
((mp_word)tmpx * (mp_word)*tmpy++) +
|
||||
(mp_word)u;
|
||||
|
||||
/* get the lower part */
|
||||
*tmpt++ = (mp_digit)(r & (mp_word)MP_MASK);
|
||||
|
||||
/* carry the carry */
|
||||
u = (mp_digit)(r >> (mp_word)DIGIT_BIT);
|
||||
}
|
||||
*tmpt = u;
|
||||
}
|
||||
mp_clamp(&t);
|
||||
mp_exch(&t, c);
|
||||
mp_clear(&t);
|
||||
return MP_OKAY;
|
||||
}
|
||||
#endif
|
||||
|
||||
/* ref: HEAD -> master, tag: v1.1.0 */
|
||||
/* git commit: 08549ad6bc8b0cede0b357a9c341c5c6473a9c55 */
|
||||
/* commit time: 2019-01-28 20:32:32 +0100 */
|
Reference in New Issue
Block a user