pqc/external/flint-2.4.3/fmpz/mul.c
2014-05-24 23:16:06 +02:00

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) 2009 William Hart
******************************************************************************/
#include <gmp.h>
#include "flint.h"
#include "ulong_extras.h"
#include "fmpz.h"
void
fmpz_mul(fmpz_t f, const fmpz_t g, const fmpz_t h)
{
fmpz c1, c2;
__mpz_struct *mpz_ptr;
c1 = *g;
if (!COEFF_IS_MPZ(c1)) /* g is small */
{
fmpz_mul_si(f, h, c1);
return;
}
c2 = *h; /* save h in case it is aliased with f */
if (c2 == WORD(0)) /* special case, h = 0 */
{
fmpz_zero(f);
return;
}
mpz_ptr = _fmpz_promote(f); /* h is saved, g is already large */
if (!COEFF_IS_MPZ(c2)) /* g is large, h is small */
flint_mpz_mul_si(mpz_ptr, COEFF_TO_PTR(c1), c2);
else /* c1 and c2 are large */
mpz_mul(mpz_ptr, COEFF_TO_PTR(c1), COEFF_TO_PTR(c2));
}