45 lines
1.5 KiB
C
45 lines
1.5 KiB
C
/*=============================================================================
|
|
|
|
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) 2009 William Hart
|
|
|
|
******************************************************************************/
|
|
|
|
#include <gmp.h>
|
|
#include "flint.h"
|
|
#include "ulong_extras.h"
|
|
|
|
mp_limb_t n_mulmod_precomp(mp_limb_t a, mp_limb_t b, mp_limb_t n, double npre)
|
|
{
|
|
mp_limb_t quot;
|
|
mp_limb_signed_t rem;
|
|
|
|
quot = (mp_limb_t) ((double) a * (double) b * npre);
|
|
rem = a * b - quot * n;
|
|
if (rem < 0)
|
|
{
|
|
rem += n;
|
|
if (rem < 0) return rem + n;
|
|
}
|
|
else if (rem >= n) return rem - n;
|
|
return rem;
|
|
}
|