104 lines
3.6 KiB
Plaintext
104 lines
3.6 KiB
Plaintext
# truncf.m4
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# serial 18
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dnl Copyright (C) 2007, 2010-2024 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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dnl This file is offered as-is, without any warranty.
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AC_DEFUN([gl_FUNC_TRUNCF],
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[
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m4_divert_text([DEFAULTS], [gl_truncf_required=plain])
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AC_REQUIRE([gl_MATH_H_DEFAULTS])
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dnl Persuade glibc <math.h> to declare truncf().
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AC_REQUIRE([gl_USE_SYSTEM_EXTENSIONS])
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dnl Test whether truncf() is declared.
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AC_CHECK_DECLS([truncf], , , [[#include <math.h>]])
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if test "$ac_cv_have_decl_truncf" = yes; then
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dnl Test whether truncf() can be used without libm.
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TRUNCF_LIBM=?
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AC_LINK_IFELSE(
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[AC_LANG_PROGRAM(
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[[#ifndef __NO_MATH_INLINES
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# define __NO_MATH_INLINES 1 /* for glibc */
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#endif
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#include <math.h>
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float (*funcptr) (float) = truncf;
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float x;]],
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[[x = funcptr(x) + truncf(x);]])],
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[TRUNCF_LIBM=])
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if test "$TRUNCF_LIBM" = "?"; then
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saved_LIBS="$LIBS"
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LIBS="$LIBS -lm"
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AC_LINK_IFELSE(
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[AC_LANG_PROGRAM(
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[[#ifndef __NO_MATH_INLINES
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# define __NO_MATH_INLINES 1 /* for glibc */
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#endif
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#include <math.h>
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float (*funcptr) (float) = truncf;
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float x;]],
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[[x = funcptr(x) + truncf(x);]])],
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[TRUNCF_LIBM="-lm"])
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LIBS="$saved_LIBS"
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fi
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if test "$TRUNCF_LIBM" = "?"; then
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TRUNCF_LIBM=
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fi
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m4_ifdef([gl_FUNC_TRUNCF_IEEE], [
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if test $gl_truncf_required = ieee && test $REPLACE_TRUNCF = 0; then
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AC_REQUIRE([AC_CANONICAL_HOST]) dnl for cross-compiles
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AC_CACHE_CHECK([whether truncf works according to ISO C 99 with IEC 60559],
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[gl_cv_func_truncf_ieee],
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[
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saved_LIBS="$LIBS"
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LIBS="$LIBS $TRUNCF_LIBM"
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AC_RUN_IFELSE(
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[AC_LANG_SOURCE([[
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#ifndef __NO_MATH_INLINES
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# define __NO_MATH_INLINES 1 /* for glibc */
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#endif
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#include <math.h>
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]gl_FLOAT_MINUS_ZERO_CODE[
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]gl_FLOAT_SIGNBIT_CODE[
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static float dummy (float f) { return 0; }
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int main (int argc, char *argv[])
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{
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float (* volatile my_truncf) (float) = argc ? truncf : dummy;
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/* Test whether truncf (-0.0f) is -0.0f. */
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if (signbitf (minus_zerof) && !signbitf (my_truncf (minus_zerof)))
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return 1;
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return 0;
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}
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]])],
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[gl_cv_func_truncf_ieee=yes],
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[gl_cv_func_truncf_ieee=no],
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[case "$host_os" in
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# Guess yes on glibc systems.
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*-gnu* | gnu*) gl_cv_func_truncf_ieee="guessing yes" ;;
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# Guess yes on musl systems.
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*-musl* | midipix*) gl_cv_func_truncf_ieee="guessing yes" ;;
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# Guess yes on native Windows.
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mingw* | windows*) gl_cv_func_truncf_ieee="guessing yes" ;;
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# If we don't know, obey --enable-cross-guesses.
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*) gl_cv_func_truncf_ieee="$gl_cross_guess_normal" ;;
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esac
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])
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LIBS="$saved_LIBS"
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])
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case "$gl_cv_func_truncf_ieee" in
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*yes) ;;
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*) REPLACE_TRUNCF=1 ;;
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esac
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fi
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])
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else
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HAVE_DECL_TRUNCF=0
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fi
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if test $HAVE_DECL_TRUNCF = 0 || test $REPLACE_TRUNCF = 1; then
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dnl No libraries are needed to link lib/truncf.c.
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TRUNCF_LIBM=
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fi
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AC_SUBST([TRUNCF_LIBM])
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])
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