1/* mpfr_d_sub -- subtract a multiple precision floating-point number
2                 from a machine double precision float
3
4Copyright 2007, 2008, 2009, 2010, 2011 Free Software Foundation, Inc.
5Contributed by the Arenaire and Cacao projects, INRIA.
6
7This file is part of the GNU MPFR Library.
8
9The GNU MPFR Library is free software; you can redistribute it and/or modify
10it under the terms of the GNU Lesser General Public License as published by
11the Free Software Foundation; either version 3 of the License, or (at your
12option) any later version.
13
14The GNU MPFR Library is distributed in the hope that it will be useful, but
15WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
16or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU Lesser General Public
17License for more details.
18
19You should have received a copy of the GNU Lesser General Public License
20along with the GNU MPFR Library; see the file COPYING.LESSER.  If not, see
21http://www.gnu.org/licenses/ or write to the Free Software Foundation, Inc.,
2251 Franklin St, Fifth Floor, Boston, MA 02110-1301, USA. */
23
24#include "mpfr-impl.h"
25
26int
27mpfr_d_sub (mpfr_ptr a, double b, mpfr_srcptr c, mpfr_rnd_t rnd_mode)
28{
29  int inexact;
30  mpfr_t d;
31  MPFR_SAVE_EXPO_DECL (expo);
32
33  MPFR_LOG_FUNC (("b=%.20g c[%#R]=%R rnd=%d", b, c, c, rnd_mode),
34                 ("a[%#R]=%R", a, a));
35
36  MPFR_SAVE_EXPO_MARK (expo);
37
38  mpfr_init2 (d, IEEE_DBL_MANT_DIG);
39  inexact = mpfr_set_d (d, b, rnd_mode);
40  MPFR_ASSERTN (inexact == 0);
41
42  mpfr_clear_flags ();
43  inexact = mpfr_sub (a, d, c, rnd_mode);
44  MPFR_SAVE_EXPO_UPDATE_FLAGS (expo, __gmpfr_flags);
45
46  mpfr_clear(d);
47  MPFR_SAVE_EXPO_FREE (expo);
48  return mpfr_check_range (a, inexact, rnd_mode);
49}
50