abs.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_abs(fmpz_t f1, const fmpz_t f2)
{
    if (!COEFF_IS_MPZ(*f2))  /* coeff is small */
    {
        fmpz t = FLINT_ABS(*f2);  /* Need to save value in case of aliasing */

        _fmpz_demote(f1);

        *f1 = t;
    }
    else  /* coeff is large */
    {
        /* No need to retain value in promotion, as if aliased, both already large */
        __mpz_struct *mpz_ptr = _fmpz_promote(f1);
        mpz_abs(mpz_ptr, COEFF_TO_PTR(*f2));
    }
}