1/* Copyright (C) 1995,1996,1997,1998,2002,2003 Free Software Foundation, Inc.
2   This file is part of the GNU C Library.
3
4   The GNU C Library is free software; you can redistribute it and/or
5   modify it under the terms of the GNU Lesser General Public
6   License as published by the Free Software Foundation; either
7   version 2.1 of the License, or (at your option) any later version.
8
9   The GNU C Library is distributed in the hope that it will be useful,
10   but WITHOUT ANY WARRANTY; without even the implied warranty of
11   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
12   Lesser General Public License for more details.
13
14   You should have received a copy of the GNU Lesser General Public
15   License along with the GNU C Library; if not, write to the Free
16   Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
17   02111-1307 USA.  */
18
19#include "gmp.h"
20#include "gmp-impl.h"
21#include <ieee754.h>
22#include <float.h>
23#include <math.h>
24
25/* Convert a multi-precision integer of the needed number of bits (64 for
26   long double) and an integral power of two to a `long double' in IEEE854
27   extended-precision format.  */
28
29long double
30__mpn_construct_long_double (mp_srcptr frac_ptr, int expt, int sign)
31{
32  union ieee854_long_double u;
33
34  u.ieee.negative = sign;
35  u.ieee.exponent = expt + IEEE854_LONG_DOUBLE_BIAS;
36#if BITS_PER_MP_LIMB == 32
37  u.ieee.mantissa1 = frac_ptr[0];
38  u.ieee.mantissa0 = frac_ptr[1];
39#elif BITS_PER_MP_LIMB == 64
40  u.ieee.mantissa1 = frac_ptr[0] & (((mp_limb_t) 1 << 32) - 1);
41  u.ieee.mantissa0 = frac_ptr[0] >> 32;
42#else
43  #error "mp_limb size " BITS_PER_MP_LIMB "not accounted for"
44#endif
45
46  return u.d;
47}
48