--- /dev/null
+/* Test for NaN that does not need libm.
+ Copyright (C) 2007 Free Software Foundation, Inc.
+
+ This program is free software; you can redistribute it and/or modify
+ it under the terms of the GNU General Public License as published by
+ the Free Software Foundation; either version 2, or (at your option)
+ any later version.
+
+ This program is distributed in the hope that it will be useful,
+ but WITHOUT ANY WARRANTY; without even the implied warranty of
+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ GNU General Public License for more details.
+
+ You should have received a copy of the GNU General Public License along
+ with this program; if not, write to the Free Software Foundation,
+ Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA. */
+
+/* Written by Bruno Haible <bruno@clisp.org>, 2007. */
+
+#include <config.h>
+
+#include <float.h>
+#include <string.h>
+
+#define DBL_EXP_MASK ((DBL_MAX_EXP - DBL_MIN_EXP) | 7)
+
+#define NWORDS \
+ ((sizeof (double) + sizeof (unsigned int) - 1) / sizeof (unsigned int))
+typedef union { double value; unsigned int word[NWORDS]; } memory_double;
+
+int
+rpl_isnan (double x)
+{
+#if defined DBL_EXPBIT0_WORD && defined DBL_EXPBIT0_BIT
+ /* Be careful to not do any floating-point operation on x, such as x == x,
+ because x may be a signaling NaN. */
+ static memory_double nan = { 0.0 / 0.0 };
+ static double plus_inf = 1.0 / 0.0;
+ static double minus_inf = -1.0 / 0.0;
+ memory_double m;
+
+ /* A NaN can be recognized through its exponent. But exclude +Infinity and
+ -Infinity, which have the same exponent. */
+ m.value = x;
+ if ((((m.word[DBL_EXPBIT0_WORD] >> DBL_EXPBIT0_BIT)
+ ^ (nan.word[DBL_EXPBIT0_WORD] >> DBL_EXPBIT0_BIT))
+ & DBL_EXP_MASK)
+ == 0)
+ return (memcmp (&m.value, &plus_inf, sizeof (double)) != 0
+ && memcmp (&m.value, &minus_inf, sizeof (double)) != 0);
+ else
+ return 0;
+#else
+ /* The configuration did not find sufficient information. Give up about
+ the signaling NaNs, handle only the quiet NaNs. */
+ if (x == x)
+ return 0;
+ else
+ return 1;
+#endif
+}
--- /dev/null
+/* Test for NaN that does not need libm.
+ Copyright (C) 2007 Free Software Foundation, Inc.
+
+ This program is free software; you can redistribute it and/or modify
+ it under the terms of the GNU General Public License as published by
+ the Free Software Foundation; either version 2, or (at your option)
+ any later version.
+
+ This program is distributed in the hope that it will be useful,
+ but WITHOUT ANY WARRANTY; without even the implied warranty of
+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ GNU General Public License for more details.
+
+ You should have received a copy of the GNU General Public License along
+ with this program; if not, write to the Free Software Foundation,
+ Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA. */
+
+#if HAVE_ISNAN_IN_LIBC
+/* Get declaration of isnan. */
+# include <math.h>
+#else
+/* Test whether X is a NaN. */
+# undef isnan
+# define isnan rpl_isnan
+extern int isnan (double x);
+#endif
--- /dev/null
+# isnan.m4 serial 1
+dnl Copyright (C) 2007 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.
+
+dnl Check how to get or define isnan() without linking with libm.
+
+AC_DEFUN([gl_FUNC_ISNAN_NO_LIBM],
+[
+ AC_CHECK_FUNC([isnan],
+ [gl_cv_func_isnan_no_libm=yes],
+ [gl_cv_func_isnan_no_libm=no])
+ if test $gl_cv_func_isnan_no_libm = yes; then
+ AC_DEFINE([HAVE_ISNAN_IN_LIBC], 1,
+ [Define if the isnan() function is available in libc.])
+ else
+ AC_LIBOBJ([isnan])
+ gl_DOUBLE_EXPONENT_LOCATION
+ fi
+])
+
+AC_DEFUN([gl_DOUBLE_EXPONENT_LOCATION],
+[
+ AC_CACHE_CHECK([where to find the exponent in a 'double'],
+ [gl_cv_cc_double_expbit0],
+ [
+ AC_TRY_RUN([
+#include <float.h>
+#include <stddef.h>
+#include <stdio.h>
+#include <string.h>
+#define NWORDS \
+ ((sizeof (double) + sizeof (unsigned int) - 1) / sizeof (unsigned int))
+typedef union { double value; unsigned int word[NWORDS]; } memory_double;
+static unsigned int ored_words[NWORDS];
+static unsigned int anded_words[NWORDS];
+static void add_to_ored_words (double x)
+{
+ memory_double m;
+ size_t i;
+ /* Clear it first, in case sizeof (double) < sizeof (memory_double). */
+ memset (&m, 0, sizeof (memory_double));
+ m.value = x;
+ for (i = 0; i < NWORDS; i++)
+ {
+ ored_words[i] |= m.word[i];
+ anded_words[i] &= m.word[i];
+ }
+}
+int main ()
+{
+ size_t j;
+ FILE *fp = fopen ("conftest.out", "w");
+ if (fp == NULL)
+ return 1;
+ for (j = 0; j < NWORDS; j++)
+ anded_words[j] = ~ (unsigned int) 0;
+ add_to_ored_words (0.25);
+ add_to_ored_words (0.5);
+ add_to_ored_words (1.0);
+ add_to_ored_words (2.0);
+ add_to_ored_words (4.0);
+ /* Remove bits that are common (e.g. if representation of the first mantissa
+ bit is explicit). */
+ for (j = 0; j < NWORDS; j++)
+ ored_words[j] &= ~anded_words[j];
+ /* Now find the nonzero word. */
+ for (j = 0; j < NWORDS; j++)
+ if (ored_words[j] != 0)
+ break;
+ if (j < NWORDS)
+ {
+ size_t i;
+ for (i = j + 1; i < NWORDS; i++)
+ if (ored_words[i] != 0)
+ {
+ fprintf (fp, "unknown");
+ return (fclose (fp) != 0);
+ }
+ for (i = 0; ; i++)
+ if ((ored_words[j] >> i) & 1)
+ {
+ fprintf (fp, "word %d bit %d", (int) j, (int) i);
+ return (fclose (fp) != 0);
+ }
+ }
+ fprintf (fp, "unknown");
+ return (fclose (fp) != 0);
+}
+ ],
+ [gl_cv_cc_double_expbit0=`cat conftest.out`],
+ [gl_cv_cc_double_expbit0="unknown"],
+ [
+ dnl On ARM, integer types are stored in little-endian byte order,
+ dnl but floats are stored in big-endian word order.
+ AC_EGREP_CPP([mixed_endianness], [
+#if defined arm || defined __arm || defined __arm__
+ mixed_endianness
+#endif
+ ],
+ [gl_cv_cc_double_expbit0="word 0 bit 20"],
+ [
+ AC_C_BIGENDIAN(
+ [gl_cv_cc_double_expbit0="word 0 bit 20"],
+ [gl_cv_cc_double_expbit0="word 1 bit 20"],
+ [gl_cv_cc_double_expbit0="unknown"])
+ ])
+ ])
+ rm -f conftest.out
+ ])
+ case "$gl_cv_cc_double_expbit0" in
+ word*bit*)
+ word=`echo "$gl_cv_cc_double_expbit0" | sed -e 's/word //' -e 's/ bit.*//'`
+ bit=`echo "$gl_cv_cc_double_expbit0" | sed -e 's/word.*bit //'`
+ AC_DEFINE_UNQUOTED([DBL_EXPBIT0_WORD], [$word],
+ [Define as the word index where to find the exponent of 'double'.])
+ AC_DEFINE_UNQUOTED([DBL_EXPBIT0_BIT], [$bit],
+ [Define as the bit index in the word where to find bit 0 of the exponent of 'double'.])
+ ;;
+ esac
+])
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