2 dnl Copyright (C) 2007 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],
10 gl_HAVE_ISNANL_NO_LIBM
11 if test $gl_cv_func_isnanl_no_libm = no; then
12 gl_HAVE_ISNANL_IN_LIBM
13 if test $gl_cv_func_isnanl_in_libm = yes; then
17 if test $gl_cv_func_isnanl_no_libm = yes \
18 || test $gl_cv_func_isnanl_in_libm = yes; then
20 LIBS="$LIBS $ISNANL_LIBM"
23 case "$gl_cv_func_isnanl_works" in
24 *yes) gl_func_isnanl=yes ;;
25 *) gl_func_isnanl=no; ISNANL_LIBM= ;;
30 if test $gl_func_isnanl = yes; then
31 AC_DEFINE([HAVE_ISNANL], 1,
32 [Define if the isnan(long double) function is available.])
35 gl_LONG_DOUBLE_EXPONENT_LOCATION
37 AC_SUBST([ISNANL_LIBM])
40 AC_DEFUN([gl_FUNC_ISNANL_NO_LIBM],
42 gl_HAVE_ISNANL_NO_LIBM
43 gl_func_isnanl_no_libm=$gl_cv_func_isnanl_no_libm
44 if test $gl_func_isnanl_no_libm = yes; then
46 case "$gl_cv_func_isnanl_works" in
48 *) gl_func_isnanl_no_libm=no ;;
51 if test $gl_func_isnanl_no_libm = yes; then
52 AC_DEFINE([HAVE_ISNANL_IN_LIBC], 1,
53 [Define if the isnan(long double) function is available in libc.])
56 gl_LONG_DOUBLE_EXPONENT_LOCATION
60 dnl Test whether isnanl() can be used without libm.
61 AC_DEFUN([gl_HAVE_ISNANL_NO_LIBM],
63 AC_CACHE_CHECK([whether isnan(long double) can be used without linking with libm],
64 [gl_cv_func_isnanl_no_libm],
66 AC_TRY_LINK([#include <math.h>
69 # define isnanl(x) isnan ((long double)(x))
73 [gl_cv_func_isnanl_no_libm=yes],
74 [gl_cv_func_isnanl_no_libm=no])
78 dnl Test whether isnanl() can be used with libm.
79 AC_DEFUN([gl_HAVE_ISNANL_IN_LIBM],
81 AC_CACHE_CHECK([whether isnan(long double) can be used with libm],
82 [gl_cv_func_isnanl_in_libm],
86 AC_TRY_LINK([#include <math.h>
89 # define isnanl(x) isnan ((long double)(x))
93 [gl_cv_func_isnanl_in_libm=yes],
94 [gl_cv_func_isnanl_in_libm=no])
99 dnl Test whether isnanl() recognizes all numbers which are neither finite nor
100 dnl infinite. This test fails e.g. on NetBSD/i386 and on glibc/ia64.
101 AC_DEFUN([gl_FUNC_ISNANL_WORKS],
103 AC_REQUIRE([AC_PROG_CC])
104 AC_REQUIRE([AC_C_BIGENDIAN])
105 AC_REQUIRE([AC_CANONICAL_HOST]) dnl for cross-compiles
106 AC_CACHE_CHECK([whether isnanl works], [gl_cv_func_isnanl_works],
114 # define isnanl(x) isnan ((long double)(x))
117 ((sizeof (long double) + sizeof (unsigned int) - 1) / sizeof (unsigned int))
118 typedef union { unsigned int word[NWORDS]; long double value; }
122 memory_long_double m;
125 /* The isnanl function should be immune against changes in the sign bit and
126 in the mantissa bits. The xor operation twiddles a bit that can only be
127 a sign bit or a mantissa bit (since the exponent never extends to
129 m.value = 0.0L / 0.0L;
130 m.word[NWORDS / 2] ^= (unsigned int) 1 << (sizeof (unsigned int) * CHAR_BIT - 1);
131 for (i = 0; i < NWORDS; i++)
133 if (!isnanl (m.value))
136 #if ((defined __ia64 && LDBL_MANT_DIG == 64) || (defined __x86_64__ || defined __amd64__) || (defined __i386 || defined __i386__ || defined _I386 || defined _M_IX86 || defined _X86_))
137 /* Representation of an 80-bit 'long double' as an initializer for a sequence
138 of 'unsigned int' words. */
139 # ifdef WORDS_BIGENDIAN
140 # define LDBL80_WORDS(exponent,manthi,mantlo) \
141 { ((unsigned int) (exponent) << 16) | ((unsigned int) (manthi) >> 16), \
142 ((unsigned int) (manthi) << 16) | (unsigned int) (mantlo) >> 16), \
143 (unsigned int) (mantlo) << 16 \
146 # define LDBL80_WORDS(exponent,manthi,mantlo) \
147 { mantlo, manthi, exponent }
150 static memory_long_double x =
151 { LDBL80_WORDS (0xFFFF, 0xC3333333, 0x00000000) };
152 if (!isnanl (x.value))
156 /* Signalling NaN. */
157 static memory_long_double x =
158 { LDBL80_WORDS (0xFFFF, 0x83333333, 0x00000000) };
159 if (!isnanl (x.value))
162 /* The isnanl function should recognize Pseudo-NaNs, Pseudo-Infinities,
163 Pseudo-Zeroes, Unnormalized Numbers, and Pseudo-Denormals, as defined in
164 Intel IA-64 Architecture Software Developer's Manual, Volume 1:
165 Application Architecture.
166 Table 5-2 "Floating-Point Register Encodings"
167 Figure 5-6 "Memory to Floating-Point Register Data Translation"
170 static memory_long_double x =
171 { LDBL80_WORDS (0xFFFF, 0x40000001, 0x00000000) };
172 if (!isnanl (x.value))
175 { /* Pseudo-Infinity. */
176 static memory_long_double x =
177 { LDBL80_WORDS (0xFFFF, 0x00000000, 0x00000000) };
178 if (!isnanl (x.value))
182 static memory_long_double x =
183 { LDBL80_WORDS (0x4004, 0x00000000, 0x00000000) };
184 if (!isnanl (x.value))
187 { /* Unnormalized number. */
188 static memory_long_double x =
189 { LDBL80_WORDS (0x4000, 0x63333333, 0x00000000) };
190 if (!isnanl (x.value))
193 { /* Pseudo-Denormal. */
194 static memory_long_double x =
195 { LDBL80_WORDS (0x0000, 0x83333333, 0x00000000) };
196 if (!isnanl (x.value))
202 }], [gl_cv_func_isnanl_works=yes], [gl_cv_func_isnanl_works=no],
204 netbsd*) gl_cv_func_isnanl_works="guessing no";;
205 *) gl_cv_func_isnanl_works="guessing yes";;
211 AC_DEFUN([gl_LONG_DOUBLE_EXPONENT_LOCATION],
213 AC_REQUIRE([AC_C_BIGENDIAN])
214 AC_CACHE_CHECK([where to find the exponent in a 'long double'],
215 [gl_cv_cc_long_double_expbit0],
223 ((sizeof (long double) + sizeof (unsigned int) - 1) / sizeof (unsigned int))
224 typedef union { long double value; unsigned int word[NWORDS]; }
226 static unsigned int ored_words[NWORDS];
227 static unsigned int anded_words[NWORDS];
228 static void add_to_ored_words (long double x)
230 memory_long_double m;
232 /* Clear it first, in case
233 sizeof (long double) < sizeof (memory_long_double). */
234 memset (&m, 0, sizeof (memory_long_double));
236 for (i = 0; i < NWORDS; i++)
238 ored_words[i] |= m.word[i];
239 anded_words[i] &= m.word[i];
245 FILE *fp = fopen ("conftest.out", "w");
248 for (j = 0; j < NWORDS; j++)
249 anded_words[j] = ~ (unsigned int) 0;
250 add_to_ored_words (0.25L);
251 add_to_ored_words (0.5L);
252 add_to_ored_words (1.0L);
253 add_to_ored_words (2.0L);
254 add_to_ored_words (4.0L);
255 /* Remove bits that are common (e.g. if representation of the first mantissa
257 for (j = 0; j < NWORDS; j++)
258 ored_words[j] &= ~anded_words[j];
259 /* Now find the nonzero word. */
260 for (j = 0; j < NWORDS; j++)
261 if (ored_words[j] != 0)
266 for (i = j + 1; i < NWORDS; i++)
267 if (ored_words[i] != 0)
269 fprintf (fp, "unknown");
270 return (fclose (fp) != 0);
273 if ((ored_words[j] >> i) & 1)
275 fprintf (fp, "word %d bit %d", (int) j, (int) i);
276 return (fclose (fp) != 0);
279 fprintf (fp, "unknown");
280 return (fclose (fp) != 0);
283 [gl_cv_cc_long_double_expbit0=`cat conftest.out`],
284 [gl_cv_cc_long_double_expbit0="unknown"],
286 dnl When cross-compiling, we don't know. It depends on the
287 dnl ABI and compiler version. There are too many cases.
288 gl_cv_cc_long_double_expbit0="unknown"
292 case "$gl_cv_cc_long_double_expbit0" in
294 word=`echo "$gl_cv_cc_long_double_expbit0" | sed -e 's/word //' -e 's/ bit.*//'`
295 bit=`echo "$gl_cv_cc_long_double_expbit0" | sed -e 's/word.*bit //'`
296 AC_DEFINE_UNQUOTED([LDBL_EXPBIT0_WORD], [$word],
297 [Define as the word index where to find the exponent of 'long double'.])
298 AC_DEFINE_UNQUOTED([LDBL_EXPBIT0_BIT], [$bit],
299 [Define as the bit index in the word where to find bit 0 of the exponent of 'long double'.])