-# isnan.m4 serial 2
-dnl Copyright (C) 2007 Free Software Foundation, Inc.
+# isnan.m4 serial 5
+dnl Copyright (C) 2007-2014 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_DEFUN([gl_ISNAN],
[
- AC_CACHE_CHECK([whether isnan(double) can be used without linking with libm],
- [gl_cv_func_isnan_no_libm],
- [
- AC_TRY_LINK([#include <math.h>
- double x;],
- [return isnan (x);],
- [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(double) function is available in libc.])
+ AC_REQUIRE([gl_MATH_H_DEFAULTS])
+ AC_REQUIRE([gl_FUNC_ISNANF])
+ AC_REQUIRE([gl_FUNC_ISNAND])
+ AC_REQUIRE([gl_FUNC_ISNANL])
+
+ # If we replaced any of the underlying isnan* functions, replace
+ # the isnan macro; it undoubtedly suffers from the same flaws.
+ AC_MSG_CHECKING([whether isnan macro works])
+ if test $gl_func_isnanf = yes \
+ && test $gl_func_isnand = yes \
+ && test $gl_func_isnanl = yes; then
+ AC_MSG_RESULT([yes])
+ ISNAN_LIBM=
+ dnl Append $ISNANF_LIBM to ISNAN_LIBM, avoiding gratuitous duplicates.
+ case " $ISNAN_LIBM " in
+ *" $ISNANF_LIBM "*) ;;
+ *) ISNAN_LIBM="$ISNAN_LIBM $ISNANF_LIBM" ;;
+ esac
+ dnl Append $ISNAND_LIBM to ISNAN_LIBM, avoiding gratuitous duplicates.
+ case " $ISNAN_LIBM " in
+ *" $ISNAND_LIBM "*) ;;
+ *) ISNAN_LIBM="$ISNAN_LIBM $ISNAND_LIBM" ;;
+ esac
+ dnl Append $ISNANL_LIBM to ISNAN_LIBM, avoiding gratuitous duplicates.
+ case " $ISNAN_LIBM " in
+ *" $ISNANL_LIBM "*) ;;
+ *) ISNAN_LIBM="$ISNAN_LIBM $ISNANL_LIBM" ;;
+ esac
else
- AC_LIBOBJ([isnan])
- gl_DOUBLE_EXPONENT_LOCATION
+ AC_MSG_RESULT([no])
+ dnl REPLACE_ISNAN=1 also makes sure the rpl_isnan[fdl] functions get built.
+ REPLACE_ISNAN=1
+ ISNAN_LIBM=
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, there are two 'double' floating-point formats, used by
- dnl different sets of instructions: The older FPA instructions assume
- dnl that they are stored in big-endian word order, while the words
- dnl (like integer types) are stored in little-endian byte order.
- dnl The newer VFP instructions assume little-endian order consistenly.
- AC_EGREP_CPP([mixed_endianness], [
-#if defined arm || defined __arm || defined __arm__
- mixed_endianness
-#endif
- ],
- [gl_cv_cc_double_expbit0="unknown"],
- [
- pushdef([AC_MSG_CHECKING],[:])dnl
- pushdef([AC_MSG_RESULT],[:])dnl
- pushdef([AC_MSG_RESULT_UNQUOTED],[:])dnl
- 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"])
- popdef([AC_MSG_RESULT_UNQUOTED])dnl
- popdef([AC_MSG_RESULT])dnl
- popdef([AC_MSG_CHECKING])dnl
- ])
- ])
- 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
+ AC_SUBST([ISNAN_LIBM])
])
projects / gnulib.git / blobdiff