pqc/external/flint-2.4.3/ulong_extras/sqrt.c

45 lines
1.4 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>
#define ulong ulongxx /* interferes with system includes */
#include <math.h>
#undef ulong
#include "flint.h"
#include "ulong_extras.h"
mp_limb_t n_sqrt(mp_limb_t a)
{
mp_limb_t is;
is = (mp_limb_t) sqrt((double) a);
is -= (is*is > a);
#if FLINT64
if (is == UWORD(4294967296)) is--;
#endif
return is;
}