/* mpfr_add_ui -- add a floating-point number with a machine integer

Copyright (C) 2000-2001 Free Software Foundation.

This file is part of the MPFR Library.

The 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 2.1 of the License, or (at your
option) any later version.

The 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 MPFR Library; see the file COPYING.LIB.  If not, write to
the Free Software Foundation, Inc., 59 Temple Place - Suite 330, Boston,
MA 02111-1307, USA. */

#include <stdio.h>
#include "gmp.h"
#include "gmp-impl.h"
#include "longlong.h"
#include "mpfr.h"
#include "mpfr-impl.h"

int
mpfr_add_ui (mpfr_ptr y, mpfr_srcptr x, unsigned long int u, mp_rnd_t rnd_mode)
{

  if (u)  /* if u=0, do nothing */
    {
      mpfr_t uu;
      mp_limb_t up[1];
      unsigned long cnt;
      int inex_add, inex_cr;

      MPFR_INIT1(up, uu, BITS_PER_MP_LIMB, 1);
      count_leading_zeros(cnt, (mp_limb_t) u);
      *up = (mp_limb_t) u << cnt;
      MPFR_EXP(uu) = BITS_PER_MP_LIMB-cnt;

      /* Optimization note: Exponent operations may be removed
	 if mpfr_add works even when uu is out-of-range. */
      mpfr_save_emin_emax();
      inex_add = mpfr_add(y, x, uu, rnd_mode);
      mpfr_restore_emin_emax(); /* flags are restored too */
      inex_cr = mpfr_check_range(y, rnd_mode);
      if (inex_cr)
        return inex_cr; /* underflow or overflow */
      MPFR_RET(inex_add);
    }
  else
    return mpfr_set (y, x, rnd_mode);
}