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# floatparam.m4 serial 3 -*- Autoconf -*-
dnl Copyright (C) 2005-2008, 2017 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 From Bruno Haible, Sam Steingold.
AC_DEFUN([CL_FLOATPARAM_CROSS],
[
cl_machine_file_h=$1
{
echo "/* Rounding modes, for use below */"
echo "#define rounds_to_nearest 0 /* 0.5 ulp */"
echo "#define rounds_to_zero 1 /* 1 ulp */"
echo "#define rounds_to_infinity 2 /* 1 ulp */"
echo "#define rounds_to_minus_infinity 3 /* 1 ulp */"
echo
for type in float double "long double"; do
if test -n "$type"; then
epsilon_bits=-1; y="($type)1.0"
while true; do
AC_COMPILE_IFELSE(
[AC_LANG_PROGRAM([],
[[typedef int verify[2*(
(($type)(($type)1.0 + ($type)($y)) == ($type)1.0)
|| ($type)(($type)(($type)1.0 + ($type)($y)) - ($type)1.0) != ($type)($y)
) - 1];]])
],
[break;])
epsilon_bits=`expr $epsilon_bits + 1`; y="$y * ($type)0.5"
done
negepsilon_bits=-1; y="($type)-1.0"
while true; do
AC_COMPILE_IFELSE(
[AC_LANG_PROGRAM([],
[[typedef int verify[2*(
(($type)(($type)1.0 + ($type)($y)) == ($type)1.0)
|| ($type)(($type)(($type)1.0 + ($type)($y)) - ($type)1.0) != ($type)($y)
) - 1];]])
],
[break;])
negepsilon_bits=`expr $negepsilon_bits + 1`; y="$y * ($type)0.5"
done
echo "/* Properties of type \`$type': */"
echo "/* Largest n for which 1+2^(-n) is exactly represented is $epsilon_bits. */"
echo "/* Largest n for which 1-2^(-n) is exactly represented is $negepsilon_bits. */"
if test `expr $negepsilon_bits '<=' $epsilon_bits` = 1; then
echo "#error \"No exponent jump at 1.0 for type $type!\""
else
if test `expr $negepsilon_bits '>' $epsilon_bits + 1` = 1; then
echo "/* Base for type '$type' is 2^"`expr $negepsilon_bits - $epsilon_bits`
fi
echo "#define "`echo $type | sed -e 's, ,_,g'`"_mant_bits "`expr $epsilon_bits + 1`
fi
x="($type)1.0"
i=$epsilon_bits
while test $i != 0; do
x="$x * ($type)0.5"
i=`expr $i - 1`
done
x="($type)($x)"
y1="($type)(($type)1.0 + ($type)5.0*$x)"
y2="($type)(($type)1.0 + ($type)6.0*$x)"
ys1="($type)(($type)1.0 + ($type)5.4*$x)"
ys2="($type)(($type)1.0 + ($type)5.6*$x)"
z1="($type)(($type)-1.0 + ($type)(-5.0)*$x)"
z2="($type)(($type)-1.0 + ($type)(-6.0)*$x)"
zs1="($type)(($type)-1.0 + ($type)(-5.4)*$x)"
zs2="($type)(($type)-1.0 + ($type)(-5.6)*$x)"
rounds=
if test -z "$rounds"; then
AC_COMPILE_IFELSE(
[AC_LANG_PROGRAM([],
[[typedef int verify[2*(
$ys1 == $y1 && $ys2 == $y2 && $zs1 == $z1 && $zs2 == $z2
) - 1];]])
],
[rounds=rounds_to_nearest])
fi
if test -z "$rounds"; then
AC_COMPILE_IFELSE(
[AC_LANG_PROGRAM([],
[[typedef int verify[2*(
$ys1 == $y1 && $ys2 == $y1 && $zs1 == $z1 && $zs2 == $z1
) - 1];]])
],
[rounds=rounds_to_zero])
fi
if test -z "$rounds"; then
AC_COMPILE_IFELSE(
[AC_LANG_PROGRAM([],
[[typedef int verify[2*(
$ys1 == $y2 && $ys2 == $y2 && $zs1 == $z1 && $zs2 == $z1
) - 1];]])
],
[rounds=rounds_to_infinity])
fi
if test -z "$rounds"; then
AC_COMPILE_IFELSE(
[AC_LANG_PROGRAM([],
[[typedef int verify[2*(
$ys1 == $y1 && $ys2 == $y1 && $zs1 == $z2 && $zs2 == $z2
) - 1];]])
],
[rounds=rounds_to_minus_infinity])
fi
if test -n "$rounds"; then
echo "#define "`echo $type | sed -e 's, ,_,g'`"_rounds $rounds"
else
echo "#error \"Unknown rounding mode for type $type!\""
fi
echo
fi
done
dnl Words-in-a-double endianness test. Note that, assuming IEEE 754 format,
dnl 2.5479915693083957 = { 0x40 0x04 0x62 0x49 0x67 0x65 0x4E 0x64 } ..bIgeNd
dnl 1.4396527506122064e164 = { 0x62 0x04 0x00 0x00 0x4E 0x65 0x67 0x49 } b...NegI
dnl 2.5495230282078065 = { 0x40 0x04 0x65 0x6C 0x54 0x54 0x69 0x4C } ..elTTiL
dnl 1.4139248369879473e214 = { 0x6C 0x65 0x00 0x00 0x4C 0x69 0x54 0x54 } le..LiTT
double_wordorder_bigendian_p=
AC_COMPILE_IFELSE(
[AC_LANG_PROGRAM([[
double a[9] = {
0, 2.5479915693083957, 0, 1.4396527506122064e164,
0, 2.5495230282078065, 0, 1.4139248369879473e214,
0 };
]],
[])
],
[if grep LiTTle conftest.$ac_objext >/dev/null; then
double_wordorder_bigendian_p=0
else
if grep bIgeN conftest.$ac_objext >/dev/null; then
double_wordorder_bigendian_p=1
fi
fi
])
if test -n "$double_wordorder_bigendian_p"; then
echo "#define double_wordorder_bigendian_p $double_wordorder_bigendian_p"
else
echo "/* Dazed and confused! Better not define anything. */"
fi
echo
} > "$cl_machine_file_h"
])
|
