130 lines
4.2 KiB
Plaintext
130 lines
4.2 KiB
Plaintext
# logbl.m4
|
|
# serial 8
|
|
dnl Copyright (C) 2012-2024 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 This file is offered as-is, without any warranty.
|
|
|
|
AC_DEFUN([gl_FUNC_LOGBL],
|
|
[
|
|
AC_REQUIRE([gl_MATH_H_DEFAULTS])
|
|
AC_REQUIRE([gl_LONG_DOUBLE_VS_DOUBLE])
|
|
AC_REQUIRE([gl_FUNC_LOGB])
|
|
|
|
dnl Persuade glibc <math.h> to declare logbl().
|
|
AC_REQUIRE([gl_USE_SYSTEM_EXTENSIONS])
|
|
|
|
dnl Test whether logbl() exists and determine LOGBL_LIBM. We cannot assume
|
|
dnl that logbl(), if it exists, is defined in the same library as logb().
|
|
dnl This is not the case on AIX >= 5.2, Solaris >= 10.
|
|
gl_MATHFUNC([logbl], [long double], [(long double)])
|
|
if test $gl_cv_func_logbl_no_libm = yes \
|
|
|| test $gl_cv_func_logbl_in_libm = yes; then
|
|
saved_LIBS="$LIBS"
|
|
LIBS="$LIBS $LOGBL_LIBM"
|
|
gl_FUNC_LOGBL_WORKS
|
|
LIBS="$saved_LIBS"
|
|
case "$gl_cv_func_logbl_works" in
|
|
*yes) ;;
|
|
*) REPLACE_LOGBL=1 ;;
|
|
esac
|
|
else
|
|
HAVE_LOGBL=0
|
|
fi
|
|
if test $HAVE_LOGBL = 0 || test $REPLACE_LOGBL = 1; then
|
|
dnl Find libraries needed to link lib/logbl.c.
|
|
if test $HAVE_SAME_LONG_DOUBLE_AS_DOUBLE = 1; then
|
|
LOGBL_LIBM="$LOGB_LIBM"
|
|
else
|
|
AC_REQUIRE([gl_FUNC_FREXPL])
|
|
AC_REQUIRE([gl_FUNC_ISNANL])
|
|
LOGBL_LIBM=
|
|
dnl Append $FREXPL_LIBM to LOGBL_LIBM, avoiding gratuitous duplicates.
|
|
case " $LOGBL_LIBM " in
|
|
*" $FREXPL_LIBM "*) ;;
|
|
*) LOGBL_LIBM="$LOGBL_LIBM $FREXPL_LIBM" ;;
|
|
esac
|
|
dnl Append $ISNANL_LIBM to LOGBL_LIBM, avoiding gratuitous duplicates.
|
|
case " $LOGBL_LIBM " in
|
|
*" $ISNANL_LIBM "*) ;;
|
|
*) LOGBL_LIBM="$LOGBL_LIBM $ISNANL_LIBM" ;;
|
|
esac
|
|
fi
|
|
fi
|
|
AC_SUBST([LOGBL_LIBM])
|
|
])
|
|
|
|
dnl Test whether logbl() works.
|
|
dnl On glibc 2.11/powerpc, glibc 2.7/sparc, glibc 2.7/hppa, Solaris 10/SPARC,
|
|
dnl Solaris 11.4/x86_64, the return value for subnormal (denormalized) arguments
|
|
dnl is too large.
|
|
dnl On glibc 2.23/powerpc64le, the return value for negative subnormal arguments
|
|
dnl is too large.
|
|
AC_DEFUN([gl_FUNC_LOGBL_WORKS],
|
|
[
|
|
AC_REQUIRE([AC_PROG_CC])
|
|
AC_REQUIRE([AC_CANONICAL_HOST]) dnl for cross-compiles
|
|
AC_CACHE_CHECK([whether logbl works], [gl_cv_func_logbl_works],
|
|
[
|
|
AC_RUN_IFELSE(
|
|
[AC_LANG_SOURCE([[
|
|
#include <float.h>
|
|
#include <math.h>
|
|
#include <signal.h> /* for signal */
|
|
#ifdef SIGALRM
|
|
# include <unistd.h> /* for alarm, _exit */
|
|
static void quit (int sig) { _exit (sig + 128); }
|
|
#endif
|
|
/* Override the values of <float.h>, like done in float.in.h. */
|
|
#if defined __i386__ && (defined __BEOS__ || defined __OpenBSD__)
|
|
# undef LDBL_MIN_EXP
|
|
# define LDBL_MIN_EXP (-16381)
|
|
#endif
|
|
#if defined __i386__ && (defined __FreeBSD__ || defined __DragonFly__)
|
|
# undef LDBL_MIN_EXP
|
|
# define LDBL_MIN_EXP (-16381)
|
|
#endif
|
|
#if (defined _ARCH_PPC || defined _POWER) && defined _AIX && (LDBL_MANT_DIG == 106) && defined __GNUC__
|
|
# undef LDBL_MIN_EXP
|
|
# define LDBL_MIN_EXP DBL_MIN_EXP
|
|
#endif
|
|
#if defined __sgi && (LDBL_MANT_DIG >= 106)
|
|
# if defined __GNUC__
|
|
# undef LDBL_MIN_EXP
|
|
# define LDBL_MIN_EXP DBL_MIN_EXP
|
|
# endif
|
|
#endif
|
|
volatile long double x;
|
|
int main ()
|
|
{
|
|
int i;
|
|
#ifdef SIGALRM
|
|
signal (SIGALRM, quit);
|
|
alarm (5);
|
|
#endif
|
|
for (i = 1, x = 1.0L; i >= LDBL_MIN_EXP - 54; i--, x *= 0.5L)
|
|
/* Either x = 2^(i-1) or x = 0.0. */
|
|
if ((i == LDBL_MIN_EXP - 1 || i == LDBL_MIN_EXP - 54)
|
|
&& (x > 0.0L && !(logbl (x) == (long double)(i - 1))))
|
|
return 1;
|
|
for (i = 1, x = -1.0L; i >= LDBL_MIN_EXP - 54; i--, x *= 0.5L)
|
|
/* Either x = -2^(i-1) or x = 0.0. */
|
|
if ((i == LDBL_MIN_EXP - 1 || i == LDBL_MIN_EXP - 54)
|
|
&& (x < 0.0L && !(logbl (x) == (long double)(i - 1))))
|
|
return 1;
|
|
return 0;
|
|
}
|
|
]])],
|
|
[gl_cv_func_logbl_works=yes],
|
|
[gl_cv_func_logbl_works=no],
|
|
[case "$host_os" in
|
|
*gnu* | solaris*) gl_cv_func_logbl_works="guessing no" ;;
|
|
# Guess yes on native Windows.
|
|
mingw* | windows*) gl_cv_func_logbl_works="guessing yes" ;;
|
|
*) gl_cv_func_logbl_works="guessing yes" ;;
|
|
esac
|
|
])
|
|
])
|
|
])
|