pqc/external/flint-2.4.3/mpn_extras/divrem_preinv1.c

60 lines
1.9 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) 2012 William Hart
******************************************************************************/
#include <stdlib.h>
#include <gmp.h>
#include "flint.h"
#include "longlong.h"
#include "mpn_extras.h"
#pragma GCC diagnostic ignored "-Wunused-variable"
mp_limb_t flint_mpn_divrem_preinv1(mp_ptr q, mp_ptr a, mp_size_t m,
mp_srcptr b, mp_size_t n, mp_limb_t dinv)
{
mp_limb_t ret;
mp_size_t i;
/* ensure { a + i, n } < { b, n } */
if ((ret = (mpn_cmp(a + m - n, b, n) >= 0)))
mpn_sub_n(a + m - n, a + m - n, b, n);
for (i = m - 1; i >= n; i--)
{
flint_mpn_divrem21_preinv(q[i - n], a[i], a[i - 1], dinv);
a[i] -= mpn_submul_1(a + i - n, b, n, q[i - n]);
if (mpn_cmp(a + i - n, b, n) >= 0 || a[i] != 0)
{
q[i - n]++;
a[i] -= mpn_sub_n(a + i - n, a + i - n, b, n);
}
}
return ret;
}
#pragma GCC diagnostic warning "-Wunused-variable"