X-Git-Url: http://erislabs.net/gitweb/?a=blobdiff_plain;f=m4%2Fisnan.m4;h=a99cbb3b9a7708fed87089e3fbc08d495e52f917;hb=9a4ef223da492c45a9913fb232e3256044f8115e;hp=d4729cdc376faba736a3f649876de30484d1fc7b;hpb=89aab6dde9b5afaf958c645afa8a135466f8d4f7;p=gnulib.git

diff --git a/m4/isnan.m4 b/m4/isnan.m4
index d4729cdc3..a99cbb3b9 100644
--- a/m4/isnan.m4
+++ b/m4/isnan.m4
@@ -1,131 +1,44 @@
-# isnan.m4 serial 1
-dnl Copyright (C) 2007 Free Software Foundation, Inc.
+# isnan.m4 serial 5
+dnl Copyright (C) 2007-2011 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"],
-            [
-              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
+  AC_SUBST([ISNAN_LIBM])
 ])