/* mpfr_ui_div -- divide a machine integer by a floating-point number

Copyright 2000, 2001, 2002 Free Software Foundation, Inc.

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_ui_div (mpfr_ptr y, unsigned long int u, mpfr_srcptr x, mp_rnd_t rnd_mode)
{
  mpfr_t uu;
  mp_limb_t up[1];
  unsigned long cnt;

  if (MPFR_IS_NAN(x))
    {
      MPFR_SET_NAN(y);
      MPFR_RET_NAN;
    }
  
  MPFR_CLEAR_NAN(y);

  if (MPFR_IS_INF(x)) /* u/Inf = 0 */
    {
      MPFR_CLEAR_INF(y);
      MPFR_SET_ZERO(y);
      if (MPFR_SIGN(x) != MPFR_SIGN(y))
	MPFR_CHANGE_SIGN(y);
      MPFR_RET(0);
    }

  MPFR_CLEAR_INF(y);

  if (u)
    {
      MPFR_INIT1(up, uu, BITS_PER_MP_LIMB, 1);
      MPFR_ASSERTN(u == (mp_limb_t) u);
      count_leading_zeros(cnt, (mp_limb_t) u);
      *up = (mp_limb_t) u << cnt;
      MPFR_EXP(uu) = BITS_PER_MP_LIMB-cnt;
  
      return mpfr_div (y, uu, x, rnd_mode);
    }
  else /* u = 0 */
    {
      if (MPFR_IS_ZERO(x)) /* 0/0 */
	{
	  MPFR_SET_NAN(y);
	  MPFR_RET_NAN; 
	}
      else
	{
	  MPFR_SET_ZERO(y); /* if u=0, then set y to 0 */
	  MPFR_RET(0);
	}
    }
}