pqc/external/flint-2.4.3/ulong_extras/is_strong_probabprime_precomp.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) 2008, Peter Shrimpton
Copyright (C) 2009 William Hart
******************************************************************************/
#include <gmp.h>
#include "flint.h"
#include "ulong_extras.h"
int
n_is_strong_probabprime_precomp(mp_limb_t n, double npre, mp_limb_t a,
mp_limb_t d)
{
mp_limb_t t = d;
mp_limb_t y;
y = n_powmod_ui_precomp(a, t, n, npre);
if (y == UWORD(1))
return 1;
t <<= 1;
while ((t != n - 1) && (y != n - 1))
{
y = n_mulmod_precomp(y, y, n, npre);
t <<= 1;
}
return (y == n - 1);
}