1# isnanl.m4 serial 12
2dnl Copyright (C) 2007-2010 Free Software Foundation, Inc.
3dnl This file is free software; the Free Software Foundation
4dnl gives unlimited permission to copy and/or distribute it,
5dnl with or without modifications, as long as this notice is preserved.
6
7AC_DEFUN([gl_FUNC_ISNANL],
8[
9  AC_REQUIRE([gl_MATH_H_DEFAULTS])
10  ISNANL_LIBM=
11  gl_HAVE_ISNANL_NO_LIBM
12  if test $gl_cv_func_isnanl_no_libm = no; then
13    gl_HAVE_ISNANL_IN_LIBM
14    if test $gl_cv_func_isnanl_in_libm = yes; then
15      ISNANL_LIBM=-lm
16    fi
17  fi
18  if test $gl_cv_func_isnanl_no_libm = yes \
19     || test $gl_cv_func_isnanl_in_libm = yes; then
20    save_LIBS="$LIBS"
21    LIBS="$LIBS $ISNANL_LIBM"
22    gl_FUNC_ISNANL_WORKS
23    LIBS="$save_LIBS"
24    case "$gl_cv_func_isnanl_works" in
25      *yes) gl_func_isnanl=yes ;;
26      *)    gl_func_isnanl=no; ISNANL_LIBM= ;;
27    esac
28  else
29    gl_func_isnanl=no
30  fi
31  if test $gl_func_isnanl != yes; then
32    HAVE_ISNANL=0
33    gl_BUILD_ISNANL
34  fi
35  AC_SUBST([ISNANL_LIBM])
36])
37
38AC_DEFUN([gl_FUNC_ISNANL_NO_LIBM],
39[
40  gl_HAVE_ISNANL_NO_LIBM
41  gl_func_isnanl_no_libm=$gl_cv_func_isnanl_no_libm
42  if test $gl_func_isnanl_no_libm = yes; then
43    gl_FUNC_ISNANL_WORKS
44    case "$gl_cv_func_isnanl_works" in
45      *yes) ;;
46      *)    gl_func_isnanl_no_libm=no ;;
47    esac
48  fi
49  if test $gl_func_isnanl_no_libm = yes; then
50    AC_DEFINE([HAVE_ISNANL_IN_LIBC], [1],
51      [Define if the isnan(long double) function is available in libc.])
52  else
53    gl_BUILD_ISNANL
54  fi
55])
56
57dnl Pull in replacement isnanl definition. It does not need -lm.
58AC_DEFUN([gl_BUILD_ISNANL],
59[
60  AC_LIBOBJ([isnanl])
61  gl_LONG_DOUBLE_EXPONENT_LOCATION
62])
63
64dnl Test whether isnanl() can be used without libm.
65AC_DEFUN([gl_HAVE_ISNANL_NO_LIBM],
66[
67  AC_CACHE_CHECK([whether isnan(long double) can be used without linking with libm],
68    [gl_cv_func_isnanl_no_libm],
69    [
70      AC_TRY_LINK([#include <math.h>
71                   #if __GNUC__ >= 4
72                   # undef isnanl
73                   # define isnanl(x) __builtin_isnanl ((long double)(x))
74                   #elif defined isnan
75                   # undef isnanl
76                   # define isnanl(x) isnan ((long double)(x))
77                   #endif
78                   long double x;],
79                  [return isnanl (x);],
80        [gl_cv_func_isnanl_no_libm=yes],
81        [gl_cv_func_isnanl_no_libm=no])
82    ])
83])
84
85dnl Test whether isnanl() can be used with libm.
86AC_DEFUN([gl_HAVE_ISNANL_IN_LIBM],
87[
88  AC_CACHE_CHECK([whether isnan(long double) can be used with libm],
89    [gl_cv_func_isnanl_in_libm],
90    [
91      save_LIBS="$LIBS"
92      LIBS="$LIBS -lm"
93      AC_TRY_LINK([#include <math.h>
94                   #if __GNUC__ >= 4
95                   # undef isnanl
96                   # define isnanl(x) __builtin_isnanl ((long double)(x))
97                   #elif defined isnan
98                   # undef isnanl
99                   # define isnanl(x) isnan ((long double)(x))
100                   #endif
101                   long double x;],
102                  [return isnanl (x);],
103        [gl_cv_func_isnanl_in_libm=yes],
104        [gl_cv_func_isnanl_in_libm=no])
105      LIBS="$save_LIBS"
106    ])
107])
108
109dnl Test whether isnanl() recognizes all numbers which are neither finite nor
110dnl infinite. This test fails e.g. on NetBSD/i386 and on glibc/ia64.
111dnl Also, the GCC >= 4.0 built-in __builtin_isnanl does not pass the tests
112dnl - for pseudo-denormals on i686 and x86_64,
113dnl - for pseudo-zeroes, unnormalized numbers, and pseudo-denormals on ia64.
114AC_DEFUN([gl_FUNC_ISNANL_WORKS],
115[
116  AC_REQUIRE([AC_PROG_CC])
117  AC_REQUIRE([gl_BIGENDIAN])
118  AC_REQUIRE([AC_CANONICAL_HOST]) dnl for cross-compiles
119  AC_CACHE_CHECK([whether isnanl works], [gl_cv_func_isnanl_works],
120    [
121      AC_TRY_RUN([
122#include <float.h>
123#include <limits.h>
124#include <math.h>
125#if __GNUC__ >= 4
126# undef isnanl
127# define isnanl(x) __builtin_isnanl ((long double)(x))
128#elif defined isnan
129# undef isnanl
130# define isnanl(x) isnan ((long double)(x))
131#endif
132#define NWORDS \
133  ((sizeof (long double) + sizeof (unsigned int) - 1) / sizeof (unsigned int))
134typedef union { unsigned int word[NWORDS]; long double value; }
135        memory_long_double;
136/* On Irix 6.5, gcc 3.4.3 can't compute compile-time NaN, and needs the
137   runtime type conversion.  */
138#ifdef __sgi
139static long double NaNl ()
140{
141  double zero = 0.0;
142  return zero / zero;
143}
144#else
145# define NaNl() (0.0L / 0.0L)
146#endif
147int main ()
148{
149  memory_long_double m;
150  unsigned int i;
151
152  if (!isnanl (NaNl ()))
153    return 1;
154
155  /* The isnanl function should be immune against changes in the sign bit and
156     in the mantissa bits.  The xor operation twiddles a bit that can only be
157     a sign bit or a mantissa bit (since the exponent never extends to
158     bit 31).  */
159  m.value = NaNl ();
160  m.word[NWORDS / 2] ^= (unsigned int) 1 << (sizeof (unsigned int) * CHAR_BIT - 1);
161  for (i = 0; i < NWORDS; i++)
162    m.word[i] |= 1;
163  if (!isnanl (m.value))
164    return 1;
165
166#if ((defined __ia64 && LDBL_MANT_DIG == 64) || (defined __x86_64__ || defined __amd64__) || (defined __i386 || defined __i386__ || defined _I386 || defined _M_IX86 || defined _X86_))
167/* Representation of an 80-bit 'long double' as an initializer for a sequence
168   of 'unsigned int' words.  */
169# ifdef WORDS_BIGENDIAN
170#  define LDBL80_WORDS(exponent,manthi,mantlo) \
171     { ((unsigned int) (exponent) << 16) | ((unsigned int) (manthi) >> 16), \
172       ((unsigned int) (manthi) << 16) | (unsigned int) (mantlo) >> 16),    \
173       (unsigned int) (mantlo) << 16                                        \
174     }
175# else
176#  define LDBL80_WORDS(exponent,manthi,mantlo) \
177     { mantlo, manthi, exponent }
178# endif
179  { /* Quiet NaN.  */
180    static memory_long_double x =
181      { LDBL80_WORDS (0xFFFF, 0xC3333333, 0x00000000) };
182    if (!isnanl (x.value))
183      return 1;
184  }
185  {
186    /* Signalling NaN.  */
187    static memory_long_double x =
188      { LDBL80_WORDS (0xFFFF, 0x83333333, 0x00000000) };
189    if (!isnanl (x.value))
190      return 1;
191  }
192  /* The isnanl function should recognize Pseudo-NaNs, Pseudo-Infinities,
193     Pseudo-Zeroes, Unnormalized Numbers, and Pseudo-Denormals, as defined in
194       Intel IA-64 Architecture Software Developer's Manual, Volume 1:
195       Application Architecture.
196       Table 5-2 "Floating-Point Register Encodings"
197       Figure 5-6 "Memory to Floating-Point Register Data Translation"
198   */
199  { /* Pseudo-NaN.  */
200    static memory_long_double x =
201      { LDBL80_WORDS (0xFFFF, 0x40000001, 0x00000000) };
202    if (!isnanl (x.value))
203      return 1;
204  }
205  { /* Pseudo-Infinity.  */
206    static memory_long_double x =
207      { LDBL80_WORDS (0xFFFF, 0x00000000, 0x00000000) };
208    if (!isnanl (x.value))
209      return 1;
210  }
211  { /* Pseudo-Zero.  */
212    static memory_long_double x =
213      { LDBL80_WORDS (0x4004, 0x00000000, 0x00000000) };
214    if (!isnanl (x.value))
215      return 1;
216  }
217  { /* Unnormalized number.  */
218    static memory_long_double x =
219      { LDBL80_WORDS (0x4000, 0x63333333, 0x00000000) };
220    if (!isnanl (x.value))
221      return 1;
222  }
223  { /* Pseudo-Denormal.  */
224    static memory_long_double x =
225      { LDBL80_WORDS (0x0000, 0x83333333, 0x00000000) };
226    if (!isnanl (x.value))
227      return 1;
228  }
229#endif
230
231  return 0;
232}], [gl_cv_func_isnanl_works=yes], [gl_cv_func_isnanl_works=no],
233      [case "$host_cpu" in
234                               # Guess no on ia64, x86_64, i386.
235         ia64 | x86_64 | i*86) gl_cv_func_isnanl_works="guessing no";;
236         *)
237           case "$host_os" in
238             netbsd*) gl_cv_func_isnanl_works="guessing no";;
239             *)       gl_cv_func_isnanl_works="guessing yes";;
240           esac
241           ;;
242       esac
243      ])
244    ])
245])
246