pqc/external/flint-2.4.3/nmod_vec/scalar_mul_nmod.c

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2014-05-18 22:03:37 +00:00
/*=============================================================================
This file is part of FLINT.
FLINT is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 2 of the License, or
(at your option) any later version.
FLINT is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with FLINT; if not, write to the Free Software
Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
=============================================================================*/
/******************************************************************************
Copyright (C) 2010 William Hart
******************************************************************************/
#include <gmp.h>
#include <stdlib.h>
#include "flint.h"
#include "ulong_extras.h"
#include "nmod_vec.h"
void _nmod_vec_scalar_mul_nmod(mp_ptr res, mp_srcptr vec,
slong len, mp_limb_t c, nmod_t mod)
{
if (mod.norm >= FLINT_BITS/2) /* products will fit in a limb */
{
mpn_mul_1(res, vec, len, c);
_nmod_vec_reduce(res, res, len, mod);
} else /* products may take two limbs */
{
slong i;
for (i = 0; i < len; i++)
{
mp_limb_t hi, lo;
umul_ppmm(hi, lo, vec[i], c);
NMOD_RED2(res[i], hi, lo, mod); /* hi already reduced mod n */
}
}
}