-# signbit.m4 serial 6
-dnl Copyright (C) 2007-2010 Free Software Foundation, Inc.
+# signbit.m4 serial 12
+dnl Copyright (C) 2007-2012 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_SIGNBIT],
[
AC_REQUIRE([gl_MATH_H_DEFAULTS])
+ AC_REQUIRE([AC_CANONICAL_HOST]) dnl for cross-compiles
AC_CACHE_CHECK([for signbit macro], [gl_cv_func_signbit],
[
- AC_TRY_RUN([
+ AC_RUN_IFELSE(
+ [AC_LANG_SOURCE([[
#include <math.h>
/* If signbit is defined as a function, don't use it, since calling it for
'float' or 'long double' arguments would involve conversions.
#endif
#include <string.h>
]gl_SIGNBIT_TEST_PROGRAM
-, [gl_cv_func_signbit=yes], [gl_cv_func_signbit=no],
- [gl_cv_func_signbit="guessing no"])
+])],
+ [gl_cv_func_signbit=yes],
+ [gl_cv_func_signbit=no],
+ [case "$host_os" in
+ # Guess yes on glibc systems.
+ *-gnu*) gl_cv_func_signbit="guessing yes" ;;
+ # If we don't know, assume the worst.
+ *) gl_cv_func_signbit="guessing no" ;;
+ esac
+ ])
])
dnl GCC 4.0 and newer provides three built-ins for signbit.
dnl They can be used without warnings, also in C++, regardless of <math.h>.
dnl libc.
AC_CACHE_CHECK([for signbit compiler built-ins], [gl_cv_func_signbit_gcc],
[
- AC_TRY_RUN([
+ AC_RUN_IFELSE(
+ [AC_LANG_SOURCE([[
#if __GNUC__ >= 4
# define signbit(x) \
(sizeof (x) == sizeof (long double) ? __builtin_signbitl (x) : \
#endif
#include <string.h>
]gl_SIGNBIT_TEST_PROGRAM
-, [gl_cv_func_signbit_gcc=yes], [gl_cv_func_signbit_gcc=no],
- [gl_cv_func_signbit_gcc="guessing no"])
+])],
+ [gl_cv_func_signbit_gcc=yes],
+ [gl_cv_func_signbit_gcc=no],
+ [case "$host_os" in
+ # Guess yes on glibc systems.
+ *-gnu*) gl_cv_func_signbit_gcc="guessing yes" ;;
+ # If we don't know, assume the worst.
+ *) gl_cv_func_signbit_gcc="guessing no" ;;
+ esac
+ ])
])
dnl Use the compiler built-ins whenever possible, because they are more
dnl efficient than the system library functions (if they exist).
- if test "$gl_cv_func_signbit_gcc" = yes; then
- REPLACE_SIGNBIT_USING_GCC=1
- else
- if test "$gl_cv_func_signbit" != yes; then
- REPLACE_SIGNBIT=1
- AC_LIBOBJ([signbitf])
- AC_LIBOBJ([signbitd])
- AC_LIBOBJ([signbitl])
- gl_FLOAT_SIGN_LOCATION
- gl_DOUBLE_SIGN_LOCATION
- gl_LONG_DOUBLE_SIGN_LOCATION
- if test "$gl_cv_cc_float_signbit" = unknown; then
- dnl Test whether copysignf() is declared.
- AC_CHECK_DECLS([copysignf], , , [#include <math.h>])
- if test "$ac_cv_have_decl_copysignf" = yes; then
- dnl Test whether copysignf() can be used without libm.
- AC_CACHE_CHECK([whether copysignf can be used without linking with libm],
- [gl_cv_func_copysignf_no_libm],
- [
- AC_TRY_LINK([#include <math.h>
- float x, y;],
- [return copysignf (x, y) < 0;],
- [gl_cv_func_copysignf_no_libm=yes],
- [gl_cv_func_copysignf_no_libm=no])
- ])
- if test $gl_cv_func_copysignf_no_libm = yes; then
- AC_DEFINE([HAVE_COPYSIGNF_IN_LIBC], [1],
- [Define if the copysignf function is declared in <math.h> and available in libc.])
+ case "$gl_cv_func_signbit_gcc" in
+ *yes)
+ REPLACE_SIGNBIT_USING_GCC=1
+ ;;
+ *)
+ case "$gl_cv_func_signbit" in
+ *yes) ;;
+ *)
+ dnl REPLACE_SIGNBIT=1 makes sure the signbit[fdl] functions get built.
+ REPLACE_SIGNBIT=1
+ gl_FLOAT_SIGN_LOCATION
+ gl_DOUBLE_SIGN_LOCATION
+ gl_LONG_DOUBLE_SIGN_LOCATION
+ if test "$gl_cv_cc_float_signbit" = unknown; then
+ dnl Test whether copysignf() is declared.
+ AC_CHECK_DECLS([copysignf], , , [[#include <math.h>]])
+ if test "$ac_cv_have_decl_copysignf" = yes; then
+ dnl Test whether copysignf() can be used without libm.
+ AC_CACHE_CHECK([whether copysignf can be used without linking with libm],
+ [gl_cv_func_copysignf_no_libm],
+ [
+ AC_LINK_IFELSE(
+ [AC_LANG_PROGRAM(
+ [[#include <math.h>
+ float x, y;]],
+ [[return copysignf (x, y) < 0;]])],
+ [gl_cv_func_copysignf_no_libm=yes],
+ [gl_cv_func_copysignf_no_libm=no])
+ ])
+ if test $gl_cv_func_copysignf_no_libm = yes; then
+ AC_DEFINE([HAVE_COPYSIGNF_IN_LIBC], [1],
+ [Define if the copysignf function is declared in <math.h> and available in libc.])
+ fi
+ fi
fi
- fi
- fi
- if test "$gl_cv_cc_double_signbit" = unknown; then
- dnl Test whether copysign() is declared.
- AC_CHECK_DECLS([copysign], , , [#include <math.h>])
- if test "$ac_cv_have_decl_copysign" = yes; then
- dnl Test whether copysign() can be used without libm.
- AC_CACHE_CHECK([whether copysign can be used without linking with libm],
- [gl_cv_func_copysign_no_libm],
- [
- AC_TRY_LINK([#include <math.h>
- double x, y;],
- [return copysign (x, y) < 0;],
- [gl_cv_func_copysign_no_libm=yes],
- [gl_cv_func_copysign_no_libm=no])
- ])
- if test $gl_cv_func_copysign_no_libm = yes; then
- AC_DEFINE([HAVE_COPYSIGN_IN_LIBC], [1],
- [Define if the copysign function is declared in <math.h> and available in libc.])
+ if test "$gl_cv_cc_double_signbit" = unknown; then
+ dnl Test whether copysign() is declared.
+ AC_CHECK_DECLS([copysign], , , [[#include <math.h>]])
+ if test "$ac_cv_have_decl_copysign" = yes; then
+ dnl Test whether copysign() can be used without libm.
+ AC_CACHE_CHECK([whether copysign can be used without linking with libm],
+ [gl_cv_func_copysign_no_libm],
+ [
+ AC_LINK_IFELSE(
+ [AC_LANG_PROGRAM(
+ [[#include <math.h>
+ double x, y;]],
+ [[return copysign (x, y) < 0;]])],
+ [gl_cv_func_copysign_no_libm=yes],
+ [gl_cv_func_copysign_no_libm=no])
+ ])
+ if test $gl_cv_func_copysign_no_libm = yes; then
+ AC_DEFINE([HAVE_COPYSIGN_IN_LIBC], [1],
+ [Define if the copysign function is declared in <math.h> and available in libc.])
+ fi
+ fi
fi
- fi
- fi
- if test "$gl_cv_cc_long_double_signbit" = unknown; then
- dnl Test whether copysignl() is declared.
- AC_CHECK_DECLS([copysignl], , , [#include <math.h>])
- if test "$ac_cv_have_decl_copysignl" = yes; then
- dnl Test whether copysignl() can be used without libm.
- AC_CACHE_CHECK([whether copysignl can be used without linking with libm],
- [gl_cv_func_copysignl_no_libm],
- [
- AC_TRY_LINK([#include <math.h>
- long double x, y;],
- [return copysignl (x, y) < 0;],
- [gl_cv_func_copysignl_no_libm=yes],
- [gl_cv_func_copysignl_no_libm=no])
- ])
- if test $gl_cv_func_copysignl_no_libm = yes; then
- AC_DEFINE([HAVE_COPYSIGNL_IN_LIBC], [1],
- [Define if the copysignl function is declared in <math.h> and available in libc.])
+ if test "$gl_cv_cc_long_double_signbit" = unknown; then
+ dnl Test whether copysignl() is declared.
+ AC_CHECK_DECLS([copysignl], , , [[#include <math.h>]])
+ if test "$ac_cv_have_decl_copysignl" = yes; then
+ dnl Test whether copysignl() can be used without libm.
+ AC_CACHE_CHECK([whether copysignl can be used without linking with libm],
+ [gl_cv_func_copysignl_no_libm],
+ [
+ AC_LINK_IFELSE(
+ [AC_LANG_PROGRAM(
+ [[#include <math.h>
+ long double x, y;]],
+ [[return copysignl (x, y) < 0;]])],
+ [gl_cv_func_copysignl_no_libm=yes],
+ [gl_cv_func_copysignl_no_libm=no])
+ ])
+ if test $gl_cv_func_copysignl_no_libm = yes; then
+ AC_DEFINE([HAVE_COPYSIGNL_IN_LIBC], [1],
+ [Define if the copysignl function is declared in <math.h> and available in libc.])
+ fi
+ fi
fi
- fi
- fi
- fi
- fi
+ ;;
+ esac
+ ;;
+ esac
])
AC_DEFUN([gl_SIGNBIT_TEST_PROGRAM], [[
#else
long double m0l = -p0l;
#endif
- if (signbit (vf))
+ int result = 0;
+ if (signbit (vf)) /* link check */
vf++;
{
float plus_inf = 1.0f / p0f;
&& (memcmp (&m0f, &p0f, sizeof (float)) == 0 || signbit (m0f))
&& !signbit (plus_inf)
&& signbit (minus_inf)))
- return 1;
+ result |= 1;
}
- if (signbit (vd))
+ if (signbit (vd)) /* link check */
vd++;
{
double plus_inf = 1.0 / p0d;
&& (memcmp (&m0d, &p0d, sizeof (double)) == 0 || signbit (m0d))
&& !signbit (plus_inf)
&& signbit (minus_inf)))
- return 1;
+ result |= 2;
}
- if (signbit (vl))
+ if (signbit (vl)) /* link check */
vl++;
{
long double plus_inf = 1.0L / p0l;
long double minus_inf = -1.0L / p0l;
- if (!(!signbit (255.0L)
- && signbit (-255.0L)
- && !signbit (p0l)
- && (memcmp (&m0l, &p0l, sizeof (long double)) == 0 || signbit (m0l))
- && !signbit (plus_inf)
- && signbit (minus_inf)))
- return 1;
+ if (signbit (255.0L))
+ result |= 4;
+ if (!signbit (-255.0L))
+ result |= 4;
+ if (signbit (p0l))
+ result |= 8;
+ if (!(memcmp (&m0l, &p0l, sizeof (long double)) == 0 || signbit (m0l)))
+ result |= 16;
+ if (signbit (plus_inf))
+ result |= 32;
+ if (!signbit (minus_inf))
+ result |= 64;
}
- return 0;
+ return result;
}
]])
AC_CACHE_CHECK([where to find the sign bit in a '$1'],
[$2],
[
- AC_TRY_RUN([
+ AC_RUN_IFELSE(
+ [AC_LANG_SOURCE([[
#include <stddef.h>
#include <stdio.h>
#define NWORDS \
{
/* More than one bit difference. */
fprintf (fp, "unknown");
- return 1;
+ return 2;
}
if (x)
{
{
/* No difference. */
fprintf (fp, "unknown");
- return 1;
+ return 3;
}
/* Now m = plus.word[k] ^ ~minus.word[k]. */
if (plus.word[k] & ~minus.word[k])
/* Oh? The sign bit is set in the positive and cleared in the negative
numbers? */
fprintf (fp, "unknown");
- return 1;
+ return 4;
}
for (i = 0; ; i++)
if ((m >> i) & 1)
break;
fprintf (fp, "word %d bit %d", (int) k, (int) i);
- return (fclose (fp) != 0);
+ if (fclose (fp) != 0)
+ return 5;
+ return 0;
}
- ],
+ ]])],
[$2=`cat conftest.out`],
[$2="unknown"],
[
;;
esac
])
+
+# Expands to code that defines a function signbitf(float).
+# It extracts the sign bit of a non-NaN value.
+AC_DEFUN([gl_FLOAT_SIGNBIT_CODE],
+[
+ gl_FLOATTYPE_SIGNBIT_CODE([float], [f], [f])
+])
+
+# Expands to code that defines a function signbitd(double).
+# It extracts the sign bit of a non-NaN value.
+AC_DEFUN([gl_DOUBLE_SIGNBIT_CODE],
+[
+ gl_FLOATTYPE_SIGNBIT_CODE([double], [d], [])
+])
+
+# Expands to code that defines a function signbitl(long double).
+# It extracts the sign bit of a non-NaN value.
+AC_DEFUN([gl_LONG_DOUBLE_SIGNBIT_CODE],
+[
+ gl_FLOATTYPE_SIGNBIT_CODE([long double], [l], [L])
+])
+
+AC_DEFUN([gl_FLOATTYPE_SIGNBIT_CODE],
+[[
+static int
+signbit$2 ($1 value)
+{
+ typedef union { $1 f; unsigned char b[sizeof ($1)]; } float_union;
+ static float_union plus_one = { 1.0$3 }; /* unused bits are zero here */
+ static float_union minus_one = { -1.0$3 }; /* unused bits are zero here */
+ /* Compute the sign bit mask as the XOR of plus_one and minus_one. */
+ float_union u;
+ unsigned int i;
+ u.f = value;
+ for (i = 0; i < sizeof ($1); i++)
+ if (u.b[i] & (plus_one.b[i] ^ minus_one.b[i]))
+ return 1;
+ return 0;
+}
+]])
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