summaryrefslogtreecommitdiff
path: root/gnulib-m4/frexpl.m4
blob: c5da7446c55d2eae0ae43191556e3ad7f2702146 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
# frexpl.m4 serial 9
dnl Copyright (C) 2007-2009 Free Software Foundation, Inc.
dnl This file is free software; the Free Software Foundation
dnl gives unlimited permission to copy and/or distribute it,
dnl with or without modifications, as long as this notice is preserved.

AC_DEFUN([gl_FUNC_FREXPL],
[
  AC_REQUIRE([gl_MATH_H_DEFAULTS])
  FREXPL_LIBM=
  AC_CACHE_CHECK([whether frexpl() can be used without linking with libm],
    [gl_cv_func_frexpl_no_libm],
    [
      AC_TRY_LINK([#include <math.h>
                   long double x;],
                  [int e; return frexpl (x, &e) > 0;],
        [gl_cv_func_frexpl_no_libm=yes],
        [gl_cv_func_frexpl_no_libm=no])
    ])
  if test $gl_cv_func_frexpl_no_libm = no; then
    AC_CACHE_CHECK([whether frexpl() can be used with libm],
      [gl_cv_func_frexpl_in_libm],
      [
        save_LIBS="$LIBS"
        LIBS="$LIBS -lm"
        AC_TRY_LINK([#include <math.h>
                     long double x;],
                    [int e; return frexpl (x, &e) > 0;],
          [gl_cv_func_frexpl_in_libm=yes],
          [gl_cv_func_frexpl_in_libm=no])
        LIBS="$save_LIBS"
      ])
    if test $gl_cv_func_frexpl_in_libm = yes; then
      FREXPL_LIBM=-lm
    fi
  fi
  if test $gl_cv_func_frexpl_no_libm = yes \
     || test $gl_cv_func_frexpl_in_libm = yes; then
    save_LIBS="$LIBS"
    LIBS="$LIBS $FREXPL_LIBM"
    gl_FUNC_FREXPL_WORKS
    LIBS="$save_LIBS"
    case "$gl_cv_func_frexpl_works" in
      *yes) gl_func_frexpl=yes ;;
      *)    gl_func_frexpl=no; REPLACE_FREXPL=1; FREXPL_LIBM= ;;
    esac
  else
    gl_func_frexpl=no
  fi
  if test $gl_func_frexpl = yes; then
    AC_DEFINE([HAVE_FREXPL], [1],
      [Define if the frexpl() function is available.])
    dnl Also check whether it's declared.
    dnl MacOS X 10.3 has frexpl() in libc but doesn't declare it in <math.h>.
    AC_CHECK_DECL([frexpl], , [HAVE_DECL_FREXPL=0], [#include <math.h>])
  else
    HAVE_DECL_FREXPL=0
    AC_LIBOBJ([frexpl])
  fi
  AC_SUBST([FREXPL_LIBM])
])

AC_DEFUN([gl_FUNC_FREXPL_NO_LIBM],
[
  AC_REQUIRE([gl_MATH_H_DEFAULTS])
  AC_CACHE_CHECK([whether frexpl() can be used without linking with libm],
    [gl_cv_func_frexpl_no_libm],
    [
      AC_TRY_LINK([#include <math.h>
                   long double x;],
                  [int e; return frexpl (x, &e) > 0;],
        [gl_cv_func_frexpl_no_libm=yes],
        [gl_cv_func_frexpl_no_libm=no])
    ])
  if test $gl_cv_func_frexpl_no_libm = yes; then
    gl_FUNC_FREXPL_WORKS
    case "$gl_cv_func_frexpl_works" in
      *yes) gl_func_frexpl_no_libm=yes ;;
      *)    gl_func_frexpl_no_libm=no; REPLACE_FREXPL=1 ;;
    esac
  else
    gl_func_frexpl_no_libm=no
    dnl Set REPLACE_FREXPL here because the system may have frexpl in libm.
    REPLACE_FREXPL=1
  fi
  if test $gl_func_frexpl_no_libm = yes; then
    AC_DEFINE([HAVE_FREXPL_IN_LIBC], [1],
      [Define if the frexpl() function is available in libc.])
    dnl Also check whether it's declared.
    dnl MacOS X 10.3 has frexpl() in libc but doesn't declare it in <math.h>.
    AC_CHECK_DECL([frexpl], , [HAVE_DECL_FREXPL=0], [#include <math.h>])
  else
    HAVE_DECL_FREXPL=0
    AC_LIBOBJ([frexpl])
  fi
])

dnl Test whether frexpl() works on finite numbers (this fails on
dnl MacOS X 10.4/PowerPC, on AIX 5.1, and on BeOS), on denormalized numbers
dnl (this fails on MacOS X 10.5/i386), and also on infinite numbers (this
dnl fails e.g. on IRIX 6.5 and mingw).
AC_DEFUN([gl_FUNC_FREXPL_WORKS],
[
  AC_REQUIRE([AC_PROG_CC])
  AC_REQUIRE([AC_CANONICAL_HOST]) dnl for cross-compiles
  AC_CACHE_CHECK([whether frexpl works], [gl_cv_func_frexpl_works],
    [
      AC_TRY_RUN([
#include <float.h>
#include <math.h>
/* Override the values of <float.h>, like done in float.in.h.  */
#if defined __i386__ && (defined __BEOS__ || defined __OpenBSD__)
# undef LDBL_MIN_EXP
# define LDBL_MIN_EXP    (-16381)
#endif
extern long double frexpl (long double, int *);
int main()
{
  volatile long double x;
  /* Test on finite numbers that fails on AIX 5.1.  */
  x = 16.0L;
  {
    int exp = -9999;
    frexpl (x, &exp);
    if (exp != 5)
      return 1;
  }
  /* Test on finite numbers that fails on MacOS X 10.4, because its frexpl
     function returns an invalid (incorrectly normalized) value: it returns
               y = { 0x3fe028f5, 0xc28f5c28, 0x3c9eb851, 0xeb851eb8 }
     but the correct result is
          0.505L = { 0x3fe028f5, 0xc28f5c29, 0xbc547ae1, 0x47ae1480 }  */
  x = 1.01L;
  {
    int exp = -9999;
    long double y = frexpl (x, &exp);
    if (!(exp == 1 && y == 0.505L))
      return 1;
  }
  /* Test on large finite numbers.  This fails on BeOS at i = 16322, while
     LDBL_MAX_EXP = 16384.
     In the loop end test, we test x against Infinity, rather than comparing
     i with LDBL_MAX_EXP, because BeOS <float.h> has a wrong LDBL_MAX_EXP.  */
  {
    int i;
    for (i = 1, x = 1.0L; x != x + x; i++, x *= 2.0L)
      {
        int exp = -9999;
        frexpl (x, &exp);
        if (exp != i)
          return 1;
      }
  }
  /* Test on denormalized numbers.  */
  {
    int i;
    for (i = 1, x = 1.0L; i >= LDBL_MIN_EXP; i--, x *= 0.5L)
      ;
    if (x > 0.0L)
      {
        int exp;
        long double y = frexpl (x, &exp);
        /* On machines with IEEE854 arithmetic: x = 1.68105e-4932,
           exp = -16382, y = 0.5.  On MacOS X 10.5: exp = -16384, y = 0.5.  */
        if (exp != LDBL_MIN_EXP - 1)
          return 1;
      }
  }
  /* Test on infinite numbers.  */
  x = 1.0L / 0.0L;
  {
    int exp;
    long double y = frexpl (x, &exp);
    if (y != x)
      return 1;
  }
  return 0;
}], [gl_cv_func_frexpl_works=yes], [gl_cv_func_frexpl_works=no],
      [case "$host_os" in
         aix* | beos* | darwin* | irix* | mingw* | pw*)
            gl_cv_func_frexpl_works="guessing no";;
         *) gl_cv_func_frexpl_works="guessing yes";;
       esac
      ])
    ])
])