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Import gmp 4.1.2

/* mpfr_set -- copy of a floating-point number

Copyright 1999, 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 "gmp.h"
#include "gmp-impl.h"
#include "mpfr.h"
#include "mpfr-impl.h"

/* set a to abs(b) * signb: a=b when signb = SIGN(b), a=abs(b) when signb=1 */
int
mpfr_set4 (mpfr_ptr a, mpfr_srcptr b, mp_rnd_t rnd_mode, int signb)
{
  int inex;

  if (MPFR_IS_NAN(b))
    {
      MPFR_CLEAR_FLAGS(a);
      MPFR_SET_NAN(a);
      MPFR_RET_NAN;
    }

  if (MPFR_IS_INF(b))
    {
      MPFR_CLEAR_FLAGS(a);
      MPFR_SET_INF(a);
      inex = 0;
    }
  else
    {
      mp_limb_t *ap;
      mp_prec_t aq;
      int carry;

      MPFR_CLEAR_FLAGS(a);

      ap = MPFR_MANT(a);
      aq = MPFR_PREC(a);

      carry = mpfr_round_raw(ap, MPFR_MANT(b), MPFR_PREC(b), (signb < 0),
                             aq, rnd_mode, &inex);
      MPFR_EXP(a) = MPFR_EXP(b);

      if (carry)
        {
          mp_exp_t exp = MPFR_EXP(a);

          if (exp == __mpfr_emax)
            return mpfr_set_overflow(a, rnd_mode, signb);

          MPFR_EXP(a)++;
          ap[(MPFR_PREC(a)-1)/BITS_PER_MP_LIMB] = GMP_LIMB_HIGHBIT;
        }
    }

  if (MPFR_SIGN(a) * signb < 0)
    MPFR_CHANGE_SIGN(a);
  MPFR_RET(inex);
}