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# isnanl.m4 serial 2
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.
AC_DEFUN([gl_FUNC_ISNANL],
[
AC_REQUIRE([gt_TYPE_LONGDOUBLE])
ISNANL_LIBM=
if test $gt_cv_c_long_double = yes; then
gl_HAVE_ISNANL_NO_LIBM
if test $gl_cv_func_isnanl_no_libm = no; then
gl_HAVE_ISNANL_IN_LIBM
if test $gl_cv_func_isnanl_in_libm = yes; then
ISNANL_LIBM=-lm
fi
fi
if test $gl_cv_func_isnanl_no_libm = yes \
|| test $gl_cv_func_isnanl_in_libm = yes; then
save_LIBS="$LIBS"
LIBS="$LIBS $ISNANL_LIBM"
gl_FUNC_ISNANL_WORKS
LIBS="$save_LIBS"
case "$gl_cv_func_isnanl_works" in
*yes) gl_func_isnanl=yes ;;
*) gl_func_isnanl=no; ISNANL_LIBM= ;;
esac
else
gl_func_isnanl=no
fi
if test $gl_func_isnanl = yes; then
AC_DEFINE([HAVE_ISNANL], 1,
[Define if the isnan(long double) function is available.])
else
AC_LIBOBJ([isnanl])
gl_LONG_DOUBLE_EXPONENT_LOCATION
fi
fi
AC_SUBST([ISNANL_LIBM])
])
AC_DEFUN([gl_FUNC_ISNANL_NO_LIBM],
[
AC_REQUIRE([gt_TYPE_LONGDOUBLE])
if test $gt_cv_c_long_double = yes; then
gl_HAVE_ISNANL_NO_LIBM
gl_func_isnanl_no_libm=$gl_cv_func_isnanl_no_libm
if test $gl_func_isnanl_no_libm = yes; then
gl_FUNC_ISNANL_WORKS
case "$gl_cv_func_isnanl_works" in
*yes) ;;
*) gl_func_isnanl_no_libm=no ;;
esac
fi
if test $gl_func_isnanl_no_libm = yes; then
AC_DEFINE([HAVE_ISNANL_IN_LIBC], 1,
[Define if the isnan(long double) function is available in libc.])
else
AC_LIBOBJ([isnanl])
gl_LONG_DOUBLE_EXPONENT_LOCATION
fi
fi
])
dnl Test whether isnanl() can be used without libm.
AC_DEFUN([gl_HAVE_ISNANL_NO_LIBM],
[
AC_CACHE_CHECK([whether isnan(long double) can be used without linking with libm],
[gl_cv_func_isnanl_no_libm],
[
AC_TRY_LINK([#include <math.h>
#ifdef isnan
# undef isnanl
# define isnanl(x) isnan ((long double)(x))
#endif
long double x;],
[return isnanl (x);],
[gl_cv_func_isnanl_no_libm=yes],
[gl_cv_func_isnanl_no_libm=no])
])
])
dnl Test whether isnanl() can be used with libm.
AC_DEFUN([gl_HAVE_ISNANL_IN_LIBM],
[
AC_CACHE_CHECK([whether isnan(long double) can be used with libm],
[gl_cv_func_isnanl_in_libm],
[
save_LIBS="$LIBS"
LIBS="$LIBS -lm"
AC_TRY_LINK([#include <math.h>
#ifdef isnan
# undef isnanl
# define isnanl(x) isnan ((long double)(x))
#endif
long double x;],
[return isnanl (x);],
[gl_cv_func_isnanl_in_libm=yes],
[gl_cv_func_isnanl_in_libm=no])
LIBS="$save_LIBS"
])
])
dnl Test whether isnanl() recognizes all numbers which are neither finite nor
dnl infinite. This test fails e.g. on NetBSD/i386.
AC_DEFUN([gl_FUNC_ISNANL_WORKS],
[
AC_REQUIRE([AC_PROG_CC])
AC_REQUIRE([gt_TYPE_LONGDOUBLE])
AC_REQUIRE([AC_CANONICAL_HOST]) dnl for cross-compiles
AC_CACHE_CHECK([whether isnanl works], [gl_cv_func_isnanl_works],
[
AC_TRY_RUN([
#include <limits.h>
#include <math.h>
#ifdef isnan
# undef isnanl
# define isnanl(x) isnan ((long double)(x))
#endif
#define NWORDS \
((sizeof (long double) + sizeof (unsigned int) - 1) / sizeof (unsigned int))
typedef union { long double value; unsigned int word[NWORDS]; }
memory_long_double;
int main ()
{
memory_long_double m;
unsigned int i;
/* The isnanl function should be immune against changes in the sign bit and
in the mantissa bits. The xor operation twiddles a bit that can only be
a sign bit or a mantissa bit (since the exponent never extends to
bit 31). */
m.value = 0.0L / 0.0L;
m.word[NWORDS / 2] ^= (unsigned int) 1 << (sizeof (unsigned int) * CHAR_BIT - 1);
for (i = 0; i < NWORDS; i++)
m.word[i] |= 1;
if (!isnanl (m.value))
return 1;
return 0;
}], [gl_cv_func_isnanl_works=yes], [gl_cv_func_isnanl_works=no],
[case "$host_os" in
netbsd*) gl_cv_func_isnanl_works="guessing no";;
*) gl_cv_func_isnanl_works="guessing yes";;
esac
])
])
])
AC_DEFUN([gl_LONG_DOUBLE_EXPONENT_LOCATION],
[
AC_CACHE_CHECK([where to find the exponent in a 'long double'],
[gl_cv_cc_long_double_expbit0],
[
AC_TRY_RUN([
#include <float.h>
#include <stddef.h>
#include <stdio.h>
#include <string.h>
#define NWORDS \
((sizeof (long double) + sizeof (unsigned int) - 1) / sizeof (unsigned int))
typedef union { long double value; unsigned int word[NWORDS]; }
memory_long_double;
static unsigned int ored_words[NWORDS];
static unsigned int anded_words[NWORDS];
static void add_to_ored_words (long double x)
{
memory_long_double m;
size_t i;
/* Clear it first, in case
sizeof (long double) < sizeof (memory_long_double). */
memset (&m, 0, sizeof (memory_long_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 (0.25L);
add_to_ored_words (0.5L);
add_to_ored_words (1.0L);
add_to_ored_words (2.0L);
add_to_ored_words (4.0L);
/* 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_long_double_expbit0=`cat conftest.out`],
[gl_cv_cc_long_double_expbit0="unknown"],
[
dnl When cross-compiling, we don't know. It depends on the
dnl ABI and compiler version. There are too many cases.
gl_cv_cc_long_double_expbit0="unknown"
])
rm -f conftest.out
])
case "$gl_cv_cc_long_double_expbit0" in
word*bit*)
word=`echo "$gl_cv_cc_long_double_expbit0" | sed -e 's/word //' -e 's/ bit.*//'`
bit=`echo "$gl_cv_cc_long_double_expbit0" | sed -e 's/word.*bit //'`
AC_DEFINE_UNQUOTED([LDBL_EXPBIT0_WORD], [$word],
[Define as the word index where to find the exponent of 'long double'.])
AC_DEFINE_UNQUOTED([LDBL_EXPBIT0_BIT], [$bit],
[Define as the bit index in the word where to find bit 0 of the exponent of 'long double'.])
;;
esac
])
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