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dnl Copyright (C) 2007-2010 Free Software Foundation, Inc.
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dnl This file is free software; the Free Software Foundation
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dnl gives unlimited permission to copy and/or distribute it,
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dnl with or without modifications, as long as this notice is preserved.
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AC_DEFUN([gl_FUNC_FREXPL],
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AC_REQUIRE([gl_MATH_H_DEFAULTS])
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AC_CACHE_CHECK([whether frexpl() can be used without linking with libm],
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[gl_cv_func_frexpl_no_libm],
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AC_TRY_LINK([#include <math.h>
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[int e; return frexpl (x, &e) > 0;],
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[gl_cv_func_frexpl_no_libm=yes],
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[gl_cv_func_frexpl_no_libm=no])
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if test $gl_cv_func_frexpl_no_libm = no; then
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AC_CACHE_CHECK([whether frexpl() can be used with libm],
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[gl_cv_func_frexpl_in_libm],
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AC_TRY_LINK([#include <math.h>
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[int e; return frexpl (x, &e) > 0;],
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[gl_cv_func_frexpl_in_libm=yes],
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[gl_cv_func_frexpl_in_libm=no])
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if test $gl_cv_func_frexpl_in_libm = yes; then
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if test $gl_cv_func_frexpl_no_libm = yes \
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|| test $gl_cv_func_frexpl_in_libm = yes; then
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LIBS="$LIBS $FREXPL_LIBM"
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case "$gl_cv_func_frexpl_works" in
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*yes) gl_func_frexpl=yes ;;
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*) gl_func_frexpl=no; REPLACE_FREXPL=1; FREXPL_LIBM= ;;
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if test $gl_func_frexpl = yes; then
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AC_DEFINE([HAVE_FREXPL], [1],
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[Define if the frexpl() function is available.])
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dnl Also check whether it's declared.
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dnl MacOS X 10.3 has frexpl() in libc but doesn't declare it in <math.h>.
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AC_CHECK_DECL([frexpl], , [HAVE_DECL_FREXPL=0], [#include <math.h>])
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AC_SUBST([FREXPL_LIBM])
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AC_DEFUN([gl_FUNC_FREXPL_NO_LIBM],
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AC_REQUIRE([gl_MATH_H_DEFAULTS])
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AC_CACHE_CHECK([whether frexpl() can be used without linking with libm],
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[gl_cv_func_frexpl_no_libm],
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AC_TRY_LINK([#include <math.h>
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[int e; return frexpl (x, &e) > 0;],
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[gl_cv_func_frexpl_no_libm=yes],
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[gl_cv_func_frexpl_no_libm=no])
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if test $gl_cv_func_frexpl_no_libm = yes; then
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case "$gl_cv_func_frexpl_works" in
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*yes) gl_func_frexpl_no_libm=yes ;;
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*) gl_func_frexpl_no_libm=no; REPLACE_FREXPL=1 ;;
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gl_func_frexpl_no_libm=no
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dnl Set REPLACE_FREXPL here because the system may have frexpl in libm.
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if test $gl_func_frexpl_no_libm = yes; then
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AC_DEFINE([HAVE_FREXPL_IN_LIBC], [1],
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[Define if the frexpl() function is available in libc.])
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dnl Also check whether it's declared.
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dnl MacOS X 10.3 has frexpl() in libc but doesn't declare it in <math.h>.
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AC_CHECK_DECL([frexpl], , [HAVE_DECL_FREXPL=0], [#include <math.h>])
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dnl Test whether frexpl() works on finite numbers (this fails on
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dnl MacOS X 10.4/PowerPC, on AIX 5.1, and on BeOS), on denormalized numbers
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dnl (this fails on MacOS X 10.5/i386), and also on infinite numbers (this
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dnl fails e.g. on IRIX 6.5 and mingw).
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AC_DEFUN([gl_FUNC_FREXPL_WORKS],
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AC_REQUIRE([AC_PROG_CC])
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AC_REQUIRE([AC_CANONICAL_HOST]) dnl for cross-compiles
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AC_CACHE_CHECK([whether frexpl works], [gl_cv_func_frexpl_works],
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/* Override the values of <float.h>, like done in float.in.h. */
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#if defined __i386__ && (defined __BEOS__ || defined __OpenBSD__)
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# define LDBL_MIN_EXP (-16381)
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extern long double frexpl (long double, int *);
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volatile long double x;
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/* Test on finite numbers that fails on AIX 5.1. */
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/* Test on finite numbers that fails on MacOS X 10.4, because its frexpl
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function returns an invalid (incorrectly normalized) value: it returns
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y = { 0x3fe028f5, 0xc28f5c28, 0x3c9eb851, 0xeb851eb8 }
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but the correct result is
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0.505L = { 0x3fe028f5, 0xc28f5c29, 0xbc547ae1, 0x47ae1480 } */
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long double y = frexpl (x, &exp);
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if (!(exp == 1 && y == 0.505L))
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/* Test on large finite numbers. This fails on BeOS at i = 16322, while
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LDBL_MAX_EXP = 16384.
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In the loop end test, we test x against Infinity, rather than comparing
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i with LDBL_MAX_EXP, because BeOS <float.h> has a wrong LDBL_MAX_EXP. */
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for (i = 1, x = 1.0L; x != x + x; i++, x *= 2.0L)
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/* Test on denormalized numbers. */
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for (i = 1, x = 1.0L; i >= LDBL_MIN_EXP; i--, x *= 0.5L)
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long double y = frexpl (x, &exp);
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/* On machines with IEEE854 arithmetic: x = 1.68105e-4932,
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exp = -16382, y = 0.5. On MacOS X 10.5: exp = -16384, y = 0.5. */
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if (exp != LDBL_MIN_EXP - 1)
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/* Test on infinite numbers. */
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long double y = frexpl (x, &exp);
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}], [gl_cv_func_frexpl_works=yes], [gl_cv_func_frexpl_works=no],
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aix* | beos* | darwin* | irix* | mingw* | pw*)
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gl_cv_func_frexpl_works="guessing no";;
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*) gl_cv_func_frexpl_works="guessing yes";;