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_NO_LIBM],
9 AC_REQUIRE([gt_TYPE_LONGDOUBLE])
10 if test $gt_cv_c_long_double = yes; then
11 AC_CHECK_FUNC([isnanl],
12 [gl_cv_func_isnanl_no_libm=yes],
13 [gl_cv_func_isnanl_no_libm=no])
14 if test $gl_cv_func_isnanl_no_libm = yes; then
15 AC_DEFINE([HAVE_ISNANL_IN_LIBC], 1,
16 [Define if the isnanl() function is available in libc.])
19 gl_LONG_DOUBLE_EXPONENT_LOCATION
24 AC_DEFUN([gl_LONG_DOUBLE_EXPONENT_LOCATION],
26 AC_CACHE_CHECK([where to find the exponent in a 'long double'],
27 [gl_cv_cc_long_double_expbit0],
35 ((sizeof (long double) + sizeof (unsigned int) - 1) / sizeof (unsigned int))
36 typedef union { long double value; unsigned int word[NWORDS]; }
38 static unsigned int ored_words[NWORDS];
39 static unsigned int anded_words[NWORDS];
40 static void add_to_ored_words (long double x)
44 /* Clear it first, in case
45 sizeof (long double) < sizeof (memory_long_double). */
46 memset (&m, 0, sizeof (memory_long_double));
48 for (i = 0; i < NWORDS; i++)
50 ored_words[i] |= m.word[i];
51 anded_words[i] &= m.word[i];
57 FILE *fp = fopen ("conftest.out", "w");
60 for (j = 0; j < NWORDS; j++)
61 anded_words[j] = ~ (unsigned int) 0;
62 add_to_ored_words (0.25L);
63 add_to_ored_words (0.5L);
64 add_to_ored_words (1.0L);
65 add_to_ored_words (2.0L);
66 add_to_ored_words (4.0L);
67 /* Remove bits that are common (e.g. if representation of the first mantissa
69 for (j = 0; j < NWORDS; j++)
70 ored_words[j] &= ~anded_words[j];
71 /* Now find the nonzero word. */
72 for (j = 0; j < NWORDS; j++)
73 if (ored_words[j] != 0)
78 for (i = j + 1; i < NWORDS; i++)
79 if (ored_words[i] != 0)
81 fprintf (fp, "unknown");
82 return (fclose (fp) != 0);
85 if ((ored_words[j] >> i) & 1)
87 fprintf (fp, "word %d bit %d", (int) j, (int) i);
88 return (fclose (fp) != 0);
91 fprintf (fp, "unknown");
92 return (fclose (fp) != 0);
95 [gl_cv_cc_long_double_expbit0=`cat conftest.out`],
96 [gl_cv_cc_long_double_expbit0="unknown"],
98 dnl When cross-compiling, we don't know. It depends on the
99 dnl ABI and compiler version. There are too many cases.
100 gl_cv_cc_long_double_expbit0="unknown"
104 case "$gl_cv_cc_long_double_expbit0" in
106 word=`echo "$gl_cv_cc_long_double_expbit0" | sed -e 's/word //' -e 's/ bit.*//'`
107 bit=`echo "$gl_cv_cc_long_double_expbit0" | sed -e 's/word.*bit //'`
108 AC_DEFINE_UNQUOTED([LDBL_EXPBIT0_WORD], [$word],
109 [Define as the word index where to find the exponent of 'long double'.])
110 AC_DEFINE_UNQUOTED([LDBL_EXPBIT0_BIT], [$bit],
111 [Define as the bit index in the word where to find bit 0 of the exponent of 'long double'.])