xref: /netbsd-src/external/lgpl3/mpfr/dist/src/fmod_ui.c (revision c9055873d0546e63388f027d3d7f85381cde0545)
1 /* mpfr_fmod_ui -- modulo a machine integer
2 
3 Copyright 2000-2004, 2006-2023 Free Software Foundation, Inc.
4 Contributed by the AriC and Caramba projects, INRIA.
5 
6 This file is part of the GNU MPFR Library.
7 
8 The GNU MPFR Library is free software; you can redistribute it and/or modify
9 it under the terms of the GNU Lesser General Public License as published by
10 the Free Software Foundation; either version 3 of the License, or (at your
11 option) any later version.
12 
13 The GNU MPFR Library is distributed in the hope that it will be useful, but
14 WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
15 or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU Lesser General Public
16 License for more details.
17 
18 You should have received a copy of the GNU Lesser General Public License
19 along with the GNU MPFR Library; see the file COPYING.LESSER.  If not, see
20 https://www.gnu.org/licenses/ or write to the Free Software Foundation, Inc.,
21 51 Franklin St, Fifth Floor, Boston, MA 02110-1301, USA. */
22 
23 #define MPFR_NEED_LONGLONG_H
24 #include "mpfr-impl.h"
25 
26 int
27 mpfr_fmod_ui (mpfr_ptr r, mpfr_srcptr x, unsigned long u, mpfr_rnd_t rnd_mode)
28 {
29   int inex;
30 
31   MPFR_LOG_FUNC
32     (("x[%Pd]=%.*Rg u=%lu rnd=%d",
33       mpfr_get_prec(x), mpfr_log_prec, x, u, rnd_mode),
34      ("y[%Pd]=%.*Rg inexact=%d",
35       mpfr_get_prec(r), mpfr_log_prec, r, inex));
36 
37   if (MPFR_UNLIKELY (u != 0))
38     {
39       mpfr_t uu;
40 #ifdef MPFR_LONG_WITHIN_LIMB
41       mp_limb_t up[1];
42       int cnt;
43       MPFR_SAVE_EXPO_DECL (expo);
44 
45       MPFR_TMP_INIT1 (up, uu, GMP_NUMB_BITS);
46       MPFR_ASSERTN (u == (mp_limb_t) u);
47       count_leading_zeros (cnt, (mp_limb_t) u);
48       *up = (mp_limb_t) u << cnt;
49 
50       MPFR_SAVE_EXPO_MARK (expo);
51       MPFR_SET_EXP (uu, GMP_NUMB_BITS - cnt);
52       inex = mpfr_fmod (r, x, uu, rnd_mode);
53 #else
54       MPFR_SAVE_EXPO_DECL (expo);
55 
56       mpfr_init2 (uu, sizeof (unsigned long) * CHAR_BIT);
57       /* Warning: u might be outside the current exponent range! */
58       MPFR_SAVE_EXPO_MARK (expo);
59       mpfr_set_ui (uu, u, MPFR_RNDZ);
60       inex = mpfr_fmod (r, x, uu, rnd_mode);
61       mpfr_clear (uu);
62 #endif /* MPFR_LONG_WITHIN_LIMB */
63       MPFR_SAVE_EXPO_FREE (expo);
64       inex = mpfr_check_range (r, inex, rnd_mode);
65       return inex;
66     }
67   else
68     {
69       MPFR_SET_NAN (r);
70       MPFR_RET_NAN;
71     }
72 }
73