1/* mpfr_modf -- Integral and fractional part.
2
3Copyright 2007, 2008, 2009, 2010, 2011, 2012, 2013 Free Software Foundation, Inc.
4Contributed by the AriC and Caramel projects, INRIA.
5
6This file is part of the GNU MPFR Library.
7
8The GNU MPFR Library is free software; you can redistribute it and/or modify
9it under the terms of the GNU Lesser General Public License as published by
10the Free Software Foundation; either version 3 of the License, or (at your
11option) any later version.
12
13The GNU MPFR Library is distributed in the hope that it will be useful, but
14WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
15or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU Lesser General Public
16License for more details.
17
18You should have received a copy of the GNU Lesser General Public License
19along with the GNU MPFR Library; see the file COPYING.LESSER.  If not, see
20http://www.gnu.org/licenses/ or write to the Free Software Foundation, Inc.,
2151 Franklin St, Fifth Floor, Boston, MA 02110-1301, USA. */
22
23#include "mpfr-impl.h"
24
25#define INEXPOS(y) ((y) == 0 ? 0 : (((y) > 0) ? 1 : 2))
26#define INEX(y,z) (INEXPOS(y) | (INEXPOS(z) << 2))
27
28/* Set iop to the integral part of op and fop to its fractional part */
29int
30mpfr_modf (mpfr_ptr iop, mpfr_ptr fop, mpfr_srcptr op, mpfr_rnd_t rnd_mode)
31{
32  mpfr_exp_t ope;
33  mpfr_prec_t opq;
34  int inexi, inexf;
35
36  MPFR_LOG_FUNC
37    (("op[%Pu]=%.*Rg rnd=%d",
38      mpfr_get_prec (op), mpfr_log_prec, op, rnd_mode),
39     ("iop[%Pu]=%.*Rg fop[%Pu]=%.*Rg",
40      mpfr_get_prec (iop), mpfr_log_prec, iop,
41      mpfr_get_prec (fop), mpfr_log_prec, fop));
42
43  MPFR_ASSERTN (iop != fop);
44
45  if ( MPFR_UNLIKELY (MPFR_IS_SINGULAR (op)) )
46    {
47      if (MPFR_IS_NAN (op))
48        {
49          MPFR_SET_NAN (iop);
50          MPFR_SET_NAN (fop);
51          MPFR_RET_NAN;
52        }
53      MPFR_SET_SAME_SIGN (iop, op);
54      MPFR_SET_SAME_SIGN (fop, op);
55      if (MPFR_IS_INF (op))
56        {
57          MPFR_SET_INF (iop);
58          MPFR_SET_ZERO (fop);
59          MPFR_RET (0);
60        }
61      else /* op is zero */
62        {
63          MPFR_ASSERTD (MPFR_IS_ZERO (op));
64          MPFR_SET_ZERO (iop);
65          MPFR_SET_ZERO (fop);
66          MPFR_RET (0);
67        }
68    }
69
70  ope = MPFR_GET_EXP (op);
71  opq = MPFR_PREC (op);
72
73  if (ope <= 0)   /* 0 < |op| < 1 */
74    {
75      inexf = (fop != op) ? mpfr_set (fop, op, rnd_mode) : 0;
76      MPFR_SET_SAME_SIGN (iop, op);
77      MPFR_SET_ZERO (iop);
78      MPFR_RET (INEX(0, inexf));
79    }
80  else if (ope >= opq) /* op has no fractional part */
81    {
82      inexi = (iop != op) ? mpfr_set (iop, op, rnd_mode) : 0;
83      MPFR_SET_SAME_SIGN (fop, op);
84      MPFR_SET_ZERO (fop);
85      MPFR_RET (INEX(inexi, 0));
86    }
87  else /* op has both integral and fractional parts */
88    {
89      if (iop != op)
90        {
91          inexi = mpfr_rint_trunc (iop, op, rnd_mode);
92          inexf = mpfr_frac (fop, op, rnd_mode);
93        }
94      else
95        {
96          MPFR_ASSERTN (fop != op);
97          inexf = mpfr_frac (fop, op, rnd_mode);
98          inexi = mpfr_rint_trunc (iop, op, rnd_mode);
99        }
100      MPFR_RET (INEX(inexi, inexf));
101    }
102}
103