/* mpfr_add_si -- add a floating-point number with a machine integer
   mpfr_sub_si -- sub  a floating-point number with a machine integer
   mpfr_si_sub -- sub  a machine number with a floating-point number

Copyright 2004-2016 Free Software Foundation, Inc.
Contributed by the AriC and Caramba projects, INRIA.

This file is part of the GNU MPFR Library.

The GNU MPFR Library is free software; you can redistribute it and/or modify
it under the terms of the GNU Lesser General Public License as published by
the Free Software Foundation; either version 3 of the License, or (at your
option) any later version.

The GNU MPFR Library 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 Lesser General Public
License for more details.

You should have received a copy of the GNU Lesser General Public License
along with the GNU MPFR Library; see the file COPYING.LESSER.  If not, see
http://www.gnu.org/licenses/ or write to the Free Software Foundation, Inc.,
51 Franklin St, Fifth Floor, Boston, MA 02110-1301, USA. */

#include "mpfr-impl.h"

int
mpfr_add_si (mpfr_ptr y, mpfr_srcptr x, long int u, mpfr_rnd_t rnd_mode)
{
  if (u >= 0)
    return mpfr_add_ui (y, x, u, rnd_mode);
  else
    return mpfr_sub_ui (y, x, - (unsigned long) u, rnd_mode);
}

int
mpfr_sub_si (mpfr_ptr y, mpfr_srcptr x, long int u, mpfr_rnd_t rnd_mode)
{
  if (u >= 0)
    return mpfr_sub_ui (y, x, u, rnd_mode);
  else
    return mpfr_add_ui (y, x, - (unsigned long) u, rnd_mode);
}

int
mpfr_si_sub (mpfr_ptr y, long int u, mpfr_srcptr x, mpfr_rnd_t rnd_mode)
{
  if (u >= 0)
    return mpfr_ui_sub (y, u, x, rnd_mode);
  else
    {
      int res = - mpfr_add_ui (y, x, - (unsigned long) u,
                               MPFR_INVERT_RND (rnd_mode));
      MPFR_CHANGE_SIGN (y);
      return res;
    }
}
