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author | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-27 17:39:29 +0000 |
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committer | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-27 17:39:29 +0000 |
commit | 8ffec2a3aba6f114784e11f89ef1d57a096ae540 (patch) | |
tree | ccebcbad06203e8241a8e7249f8e6c478a3682ea /m4/exponentl.m4 | |
parent | Initial commit. (diff) | |
download | coreutils-8ffec2a3aba6f114784e11f89ef1d57a096ae540.tar.xz coreutils-8ffec2a3aba6f114784e11f89ef1d57a096ae540.zip |
Adding upstream version 8.32.upstream/8.32upstream
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'm4/exponentl.m4')
-rw-r--r-- | m4/exponentl.m4 | 114 |
1 files changed, 114 insertions, 0 deletions
diff --git a/m4/exponentl.m4 b/m4/exponentl.m4 new file mode 100644 index 0000000..b33b3bf --- /dev/null +++ b/m4/exponentl.m4 @@ -0,0 +1,114 @@ +# exponentl.m4 serial 4 +dnl Copyright (C) 2007-2020 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_LONG_DOUBLE_EXPONENT_LOCATION], +[ + AC_REQUIRE([gl_BIGENDIAN]) + AC_REQUIRE([AC_CANONICAL_HOST]) dnl for cross-compiles + AC_CACHE_CHECK([where to find the exponent in a 'long double'], + [gl_cv_cc_long_double_expbit0], + [ + AC_RUN_IFELSE( + [AC_LANG_SOURCE([[ +#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, in general 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" + case "$host_os" in + mingw*) # On native Windows (little-endian), we know the result + # in two cases: mingw, MSVC. + AC_EGREP_CPP([Known], [ +#ifdef __MINGW32__ + Known +#endif + ], [gl_cv_cc_long_double_expbit0="word 2 bit 0"]) + AC_EGREP_CPP([Known], [ +#ifdef _MSC_VER + Known +#endif + ], [gl_cv_cc_long_double_expbit0="word 1 bit 20"]) + ;; + esac + ]) + rm -f conftest.out + ]) + case "$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 +]) |