2 dnl Copyright (C) 2007-2010 Free Software Foundation, Inc.
3 dnl This file is free software; the Free Software Foundation
4 dnl gives unlimited permission to copy and/or distribute it,
5 dnl with or without modifications, as long as this notice is preserved.
7 AC_DEFUN([gl_FUNC_ISNANL],
9 AC_REQUIRE([gl_MATH_H_DEFAULTS])
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
18 if test $gl_cv_func_isnanl_no_libm = yes \
19 || test $gl_cv_func_isnanl_in_libm = yes; then
21 LIBS="$LIBS $ISNANL_LIBM"
24 case "$gl_cv_func_isnanl_works" in
25 *yes) gl_func_isnanl=yes ;;
26 *) gl_func_isnanl=no; ISNANL_LIBM= ;;
31 if test $gl_func_isnanl != yes; then
35 AC_SUBST([ISNANL_LIBM])
38 AC_DEFUN([gl_FUNC_ISNANL_NO_LIBM],
40 gl_HAVE_ISNANL_NO_LIBM
41 gl_func_isnanl_no_libm=$gl_cv_func_isnanl_no_libm
42 if test $gl_func_isnanl_no_libm = yes; then
44 case "$gl_cv_func_isnanl_works" in
46 *) gl_func_isnanl_no_libm=no ;;
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.])
57 dnl Pull in replacement isnanl definition. It does not need -lm.
58 AC_DEFUN([gl_BUILD_ISNANL],
61 gl_LONG_DOUBLE_EXPONENT_LOCATION
64 dnl Test whether isnanl() can be used without libm.
65 AC_DEFUN([gl_HAVE_ISNANL_NO_LIBM],
67 AC_CACHE_CHECK([whether isnan(long double) can be used without linking with libm],
68 [gl_cv_func_isnanl_no_libm],
70 AC_TRY_LINK([#include <math.h>
73 # define isnanl(x) __builtin_isnanl ((long double)(x))
76 # define isnanl(x) isnan ((long double)(x))
80 [gl_cv_func_isnanl_no_libm=yes],
81 [gl_cv_func_isnanl_no_libm=no])
85 dnl Test whether isnanl() can be used with libm.
86 AC_DEFUN([gl_HAVE_ISNANL_IN_LIBM],
88 AC_CACHE_CHECK([whether isnan(long double) can be used with libm],
89 [gl_cv_func_isnanl_in_libm],
93 AC_TRY_LINK([#include <math.h>
96 # define isnanl(x) __builtin_isnanl ((long double)(x))
99 # define isnanl(x) isnan ((long double)(x))
102 [return isnanl (x);],
103 [gl_cv_func_isnanl_in_libm=yes],
104 [gl_cv_func_isnanl_in_libm=no])
109 dnl Test whether isnanl() recognizes all numbers which are neither finite nor
110 dnl infinite. This test fails e.g. on NetBSD/i386 and on glibc/ia64.
111 dnl Also, the GCC >= 4.0 built-in __builtin_isnanl does not pass the tests
112 dnl - for pseudo-denormals on i686 and x86_64,
113 dnl - for pseudo-zeroes, unnormalized numbers, and pseudo-denormals on ia64.
114 AC_DEFUN([gl_FUNC_ISNANL_WORKS],
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],
127 # define isnanl(x) __builtin_isnanl ((long double)(x))
130 # define isnanl(x) isnan ((long double)(x))
133 ((sizeof (long double) + sizeof (unsigned int) - 1) / sizeof (unsigned int))
134 typedef union { unsigned int word[NWORDS]; long double value; }
136 /* On Irix 6.5, gcc 3.4.3 can't compute compile-time NaN, and needs the
137 runtime type conversion. */
139 static long double NaNl ()
145 # define NaNl() (0.0L / 0.0L)
149 memory_long_double m;
152 if (!isnanl (NaNl ()))
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
160 m.word[NWORDS / 2] ^= (unsigned int) 1 << (sizeof (unsigned int) * CHAR_BIT - 1);
161 for (i = 0; i < NWORDS; i++)
163 if (!isnanl (m.value))
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 \
176 # define LDBL80_WORDS(exponent,manthi,mantlo) \
177 { mantlo, manthi, exponent }
180 static memory_long_double x =
181 { LDBL80_WORDS (0xFFFF, 0xC3333333, 0x00000000) };
182 if (!isnanl (x.value))
186 /* Signalling NaN. */
187 static memory_long_double x =
188 { LDBL80_WORDS (0xFFFF, 0x83333333, 0x00000000) };
189 if (!isnanl (x.value))
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"
200 static memory_long_double x =
201 { LDBL80_WORDS (0xFFFF, 0x40000001, 0x00000000) };
202 if (!isnanl (x.value))
205 { /* Pseudo-Infinity. */
206 static memory_long_double x =
207 { LDBL80_WORDS (0xFFFF, 0x00000000, 0x00000000) };
208 if (!isnanl (x.value))
212 static memory_long_double x =
213 { LDBL80_WORDS (0x4004, 0x00000000, 0x00000000) };
214 if (!isnanl (x.value))
217 { /* Unnormalized number. */
218 static memory_long_double x =
219 { LDBL80_WORDS (0x4000, 0x63333333, 0x00000000) };
220 if (!isnanl (x.value))
223 { /* Pseudo-Denormal. */
224 static memory_long_double x =
225 { LDBL80_WORDS (0x0000, 0x83333333, 0x00000000) };
226 if (!isnanl (x.value))
232 }], [gl_cv_func_isnanl_works=yes], [gl_cv_func_isnanl_works=no],
234 # Guess no on ia64, x86_64, i386.
235 ia64 | x86_64 | i*86) gl_cv_func_isnanl_works="guessing no";;
238 netbsd*) gl_cv_func_isnanl_works="guessing no";;
239 *) gl_cv_func_isnanl_works="guessing yes";;