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authorHolger Weiss <holger@zedat.fu-berlin.de>2013-08-19 21:27:12 (GMT)
committerHolger Weiss <holger@zedat.fu-berlin.de>2013-08-19 21:27:12 (GMT)
commit26fbe7f1e68bb0c96da32491efcf3696fe6c299b (patch)
treec4d95289187a64e9c7517bf73d8208026c3d2fb3 /gl/m4/exponentd.m4
parent5f79e3e9f62ca5487d9881973149136ba1d19d3e (diff)
downloadmonitoring-plugins-26fbe7f1e68bb0c96da32491efcf3696fe6c299b.tar.gz
Sync with the latest Gnulib code (6f2d632)
Diffstat (limited to 'gl/m4/exponentd.m4')
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1 files changed, 116 insertions, 0 deletions
diff --git a/gl/m4/exponentd.m4 b/gl/m4/exponentd.m4
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1# exponentd.m4 serial 3
2dnl Copyright (C) 2007-2008, 2010-2013 Free Software Foundation, Inc.
3dnl This file is free software; the Free Software Foundation
4dnl gives unlimited permission to copy and/or distribute it,
5dnl with or without modifications, as long as this notice is preserved.
6AC_DEFUN([gl_DOUBLE_EXPONENT_LOCATION],
7[
8 AC_CACHE_CHECK([where to find the exponent in a 'double'],
9 [gl_cv_cc_double_expbit0],
10 [
11 AC_RUN_IFELSE(
12 [AC_LANG_SOURCE([[
13#include <float.h>
14#include <stddef.h>
15#include <stdio.h>
16#include <string.h>
17#define NWORDS \
18 ((sizeof (double) + sizeof (unsigned int) - 1) / sizeof (unsigned int))
19typedef union { double value; unsigned int word[NWORDS]; } memory_double;
20static unsigned int ored_words[NWORDS];
21static unsigned int anded_words[NWORDS];
22static void add_to_ored_words (double x)
23{
24 memory_double m;
25 size_t i;
26 /* Clear it first, in case sizeof (double) < sizeof (memory_double). */
27 memset (&m, 0, sizeof (memory_double));
28 m.value = x;
29 for (i = 0; i < NWORDS; i++)
30 {
31 ored_words[i] |= m.word[i];
32 anded_words[i] &= m.word[i];
33 }
34}
35int main ()
36{
37 size_t j;
38 FILE *fp = fopen ("conftest.out", "w");
39 if (fp == NULL)
40 return 1;
41 for (j = 0; j < NWORDS; j++)
42 anded_words[j] = ~ (unsigned int) 0;
43 add_to_ored_words (0.25);
44 add_to_ored_words (0.5);
45 add_to_ored_words (1.0);
46 add_to_ored_words (2.0);
47 add_to_ored_words (4.0);
48 /* Remove bits that are common (e.g. if representation of the first mantissa
49 bit is explicit). */
50 for (j = 0; j < NWORDS; j++)
51 ored_words[j] &= ~anded_words[j];
52 /* Now find the nonzero word. */
53 for (j = 0; j < NWORDS; j++)
54 if (ored_words[j] != 0)
55 break;
56 if (j < NWORDS)
57 {
58 size_t i;
59 for (i = j + 1; i < NWORDS; i++)
60 if (ored_words[i] != 0)
61 {
62 fprintf (fp, "unknown");
63 return (fclose (fp) != 0);
64 }
65 for (i = 0; ; i++)
66 if ((ored_words[j] >> i) & 1)
67 {
68 fprintf (fp, "word %d bit %d", (int) j, (int) i);
69 return (fclose (fp) != 0);
70 }
71 }
72 fprintf (fp, "unknown");
73 return (fclose (fp) != 0);
74}
75 ]])],
76 [gl_cv_cc_double_expbit0=`cat conftest.out`],
77 [gl_cv_cc_double_expbit0="unknown"],
78 [
79 dnl On ARM, there are two 'double' floating-point formats, used by
80 dnl different sets of instructions: The older FPA instructions assume
81 dnl that they are stored in big-endian word order, while the words
82 dnl (like integer types) are stored in little-endian byte order.
83 dnl The newer VFP instructions assume little-endian order
84 dnl consistently.
85 AC_EGREP_CPP([mixed_endianness], [
86#if defined arm || defined __arm || defined __arm__
87 mixed_endianness
88#endif
89 ],
90 [gl_cv_cc_double_expbit0="unknown"],
91 [
92 pushdef([AC_MSG_CHECKING],[:])dnl
93 pushdef([AC_MSG_RESULT],[:])dnl
94 pushdef([AC_MSG_RESULT_UNQUOTED],[:])dnl
95 AC_C_BIGENDIAN(
96 [gl_cv_cc_double_expbit0="word 0 bit 20"],
97 [gl_cv_cc_double_expbit0="word 1 bit 20"],
98 [gl_cv_cc_double_expbit0="unknown"])
99 popdef([AC_MSG_RESULT_UNQUOTED])dnl
100 popdef([AC_MSG_RESULT])dnl
101 popdef([AC_MSG_CHECKING])dnl
102 ])
103 ])
104 rm -f conftest.out
105 ])
106 case "$gl_cv_cc_double_expbit0" in
107 word*bit*)
108 word=`echo "$gl_cv_cc_double_expbit0" | sed -e 's/word //' -e 's/ bit.*//'`
109 bit=`echo "$gl_cv_cc_double_expbit0" | sed -e 's/word.*bit //'`
110 AC_DEFINE_UNQUOTED([DBL_EXPBIT0_WORD], [$word],
111 [Define as the word index where to find the exponent of 'double'.])
112 AC_DEFINE_UNQUOTED([DBL_EXPBIT0_BIT], [$bit],
113 [Define as the bit index in the word where to find bit 0 of the exponent of 'double'.])
114 ;;
115 esac
116])