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Refactor float_t, double_t information into bits/flt-eval-method.h.

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At present, definitions of float_t and double_t are split among many
bits/mathdef.h headers.

For all but three architectures, these types are float and double.
Furthermore, if you assume __FLT_EVAL_METHOD__ to be defined, that
provides a more generic way of determining the correct values of these
typedefs.  Defining these typedefs more generally based on
__FLT_EVAL_METHOD__ was previously proposed by Paul Eggert in
<https://sourceware.org/ml/libc-alpha/2012-02/msg00002.html>.

This patch refactors things in the way I proposed in
<https://sourceware.org/ml/libc-alpha/2016-11/msg00745.html>.  A new
header bits/flt-eval-method.h defines a single macro,
__GLIBC_FLT_EVAL_METHOD, which is then used by math.h to define
float_t and double_t.  The default is based on __FLT_EVAL_METHOD__
(although actually a default to 0 would have the same effect for
current ports, because ports where values other than 0 or 16 are
possible all have their own headers).

To avoid changing the existing semantics in any case, including for
compilers not defining __FLT_EVAL_METHOD__, architecture-specific
files are then added for m68k, s390, x86 which replicate the existing
semantics.  At least with __FLT_EVAL_METHOD__ values possible with
GCC, there should be no change to the choices of float_t and double_t
for any supported configuration.

Architecture maintainer notes:

* m68k: sysdeps/m68k/m680x0/bits/flt-eval-method.h always defines
  __GLIBC_FLT_EVAL_METHOD to 2 to replicate the existing logic.  But
  actually GCC defines __FLT_EVAL_METHOD__ to 0 if TARGET_68040.  It
  might make sense to make the header prefer to base things on
  __FLT_EVAL_METHOD__ if defined, like the x86 version, and so make
  the choices of these types more accurate (with a NEWS entry as for
  the other changes to these types on particular architectures).

* s390: sysdeps/s390/bits/flt-eval-method.h always defines
  __GLIBC_FLT_EVAL_METHOD to 1 to replicate the existing logic.  As
  previously discussed, it might make sense in coordination with GCC
  to eliminate the historic mistake, avoid excess precision in the
  -fexcess-precision=standard case and make the typedefs match (with a
  NEWS entry, again).

Tested for x86-64 and x86.  Also did compilation-only testing with
build-many-glibcs.py.

	* bits/flt-eval-method.h: New file.
	* sysdeps/m68k/m680x0/bits/flt-eval-method.h: Likewise.
	* sysdeps/s390/bits/flt-eval-method.h: Likewise.
	* sysdeps/x86/bits/flt-eval-method.h: Likewise.
	* math/Makefile (headers): Add bits/flt-eval-method.h.
	* math/math.h: Include <bits/flt-eval-method.h>.
	[__USE_ISOC99] (float_t): Define based on __GLIBC_FLT_EVAL_METHOD.
	[__USE_ISOC99] (double_t): Likewise.
	* bits/mathdef.h (float_t): Remove.
	(double_t): Likewise.
	* sysdeps/aarch64/bits/mathdef.h (float_t): Likewise.
	(double_t): Likewise.
	* sysdeps/alpha/bits/mathdef.h (float_t): Likewise.
	(double_t): Likewise.
	* sysdeps/arm/bits/mathdef.h (float_t): Likewise.
	(double_t): Likewise.
	* sysdeps/hppa/fpu/bits/mathdef.h (float_t): Likewise.
	(double_t): Likewise.
	* sysdeps/ia64/bits/mathdef.h (float_t): Likewise.
	(double_t): Likewise.
	* sysdeps/m68k/m680x0/bits/mathdef.h (float_t): Likewise.
	(double_t): Likewise.
	* sysdeps/mips/bits/mathdef.h (float_t): Likewise.
	(double_t): Likewise.
	* sysdeps/powerpc/bits/mathdef.h (float_t): Likewise.
	(double_t): Likewise.
	* sysdeps/s390/bits/mathdef.h (float_t): Likewise.
	(double_t): Likewise.
	* sysdeps/sh/sh4/bits/mathdef.h (float_t): Likewise.
	(double_t): Likewise.
	* sysdeps/sparc/bits/mathdef.h (float_t): Likewise.
	(double_t): Likewise.
	* sysdeps/tile/bits/mathdef.h (float_t): Likewise.
	(double_t): Likewise.
	* sysdeps/x86/bits/mathdef.h (float_t): Likewise.
	(double_t): Likewise.
This commit is contained in:
Joseph Myers 2016-11-24 18:44:50 +00:00
parent 380ec16d62
commit 93eb85ceb2
21 changed files with 205 additions and 93 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

39
ChangeLog
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@ -1,3 +1,42 @@
2016-11-24 Joseph Myers <joseph@codesourcery.com>
* bits/flt-eval-method.h: New file.
* sysdeps/m68k/m680x0/bits/flt-eval-method.h: Likewise.
* sysdeps/s390/bits/flt-eval-method.h: Likewise.
* sysdeps/x86/bits/flt-eval-method.h: Likewise.
* math/Makefile (headers): Add bits/flt-eval-method.h.
* math/math.h: Include <bits/flt-eval-method.h>.
[__USE_ISOC99] (float_t): Define based on __GLIBC_FLT_EVAL_METHOD.
[__USE_ISOC99] (double_t): Likewise.
* bits/mathdef.h (float_t): Remove.
(double_t): Likewise.
* sysdeps/aarch64/bits/mathdef.h (float_t): Likewise.
(double_t): Likewise.
* sysdeps/alpha/bits/mathdef.h (float_t): Likewise.
(double_t): Likewise.
* sysdeps/arm/bits/mathdef.h (float_t): Likewise.
(double_t): Likewise.
* sysdeps/hppa/fpu/bits/mathdef.h (float_t): Likewise.
(double_t): Likewise.
* sysdeps/ia64/bits/mathdef.h (float_t): Likewise.
(double_t): Likewise.
* sysdeps/m68k/m680x0/bits/mathdef.h (float_t): Likewise.
(double_t): Likewise.
* sysdeps/mips/bits/mathdef.h (float_t): Likewise.
(double_t): Likewise.
* sysdeps/powerpc/bits/mathdef.h (float_t): Likewise.
(double_t): Likewise.
* sysdeps/s390/bits/mathdef.h (float_t): Likewise.
(double_t): Likewise.
* sysdeps/sh/sh4/bits/mathdef.h (float_t): Likewise.
(double_t): Likewise.
* sysdeps/sparc/bits/mathdef.h (float_t): Likewise.
(double_t): Likewise.
* sysdeps/tile/bits/mathdef.h (float_t): Likewise.
(double_t): Likewise.
* sysdeps/x86/bits/mathdef.h (float_t): Likewise.
(double_t): Likewise.
2016-11-24 Aurelien Jarno <aurelien@aurel32.net>
* sysdeps/x86_64/memcpy_chk.S (__memcpy_chk): Check for SHARED

42
bits/flt-eval-method.h Normal file
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@ -0,0 +1,42 @@
/* Define __GLIBC_FLT_EVAL_METHOD.
Copyright (C) 2016 Free Software Foundation, Inc.
This file is part of the GNU C Library.
The GNU C Library is free software; you can redistribute it and/or
modify it under the terms of the GNU Lesser General Public
License as published by the Free Software Foundation; either
version 2.1 of the License, or (at your option) any later version.
The GNU C Library is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public
License along with the GNU C Library; if not, see
<http://www.gnu.org/licenses/>. */
#ifndef _MATH_H
# error "Never use <bits/flt-eval-method.h> directly; include <math.h> instead."
#endif
/* __GLIBC_FLT_EVAL_METHOD is the value of FLT_EVAL_METHOD used to
determine the evaluation method typedefs such as float_t and
double_t. It must be a value from C11 or TS 18661-3:2015, and not
-1. */
/* In the default version of this header, follow __FLT_EVAL_METHOD__.
-1 is mapped to 2 (considering evaluation as long double to be a
conservatively safe assumption), and if __FLT_EVAL_METHOD__ is not
defined then assume there is no excess precision and use the value
0. */
#ifdef __FLT_EVAL_METHOD__
# if __FLT_EVAL_METHOD__ == -1
# define __GLIBC_FLT_EVAL_METHOD 2
# else
# define __GLIBC_FLT_EVAL_METHOD __FLT_EVAL_METHOD__
# endif
#else
# define __GLIBC_FLT_EVAL_METHOD 0
#endif

7
bits/mathdef.h
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@ -22,13 +22,6 @@
#if defined __USE_ISOC99 && defined _MATH_H && !defined _MATH_H_MATHDEF
# define _MATH_H_MATHDEF 1
/* Expressions are evaluated with the range and precision of their
type. */
typedef float float_t; /* `float' expressions are evaluated as
`float'. */
typedef double double_t; /* `double' expressions are evaluated as
`double'. */
/* The values returned by `ilogb' for 0 and NaN respectively. */
# define FP_ILOGB0 (-2147483647)
# define FP_ILOGBNAN 2147483647

3
math/Makefile
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@ -27,7 +27,8 @@ headers := math.h bits/mathcalls.h bits/mathinline.h bits/huge_val.h \
fpu_control.h complex.h bits/cmathcalls.h fenv.h \
bits/fenv.h bits/fenvinline.h bits/mathdef.h tgmath.h \
bits/math-finite.h bits/math-vector.h \
bits/libm-simd-decl-stubs.h bits/iscanonical.h
bits/libm-simd-decl-stubs.h bits/iscanonical.h \
bits/flt-eval-method.h
# FPU support code.
aux := setfpucw fpu_control

42
math/math.h
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@ -54,13 +54,51 @@ __BEGIN_DECLS
# endif
#endif
/* Get the architecture specific values describing the floating-point
evaluation. The following symbols will get defined:
/* Get __GLIBC_FLT_EVAL_METHOD. */
#include <bits/flt-eval-method.h>
#ifdef __USE_ISOC99
/* Define the following typedefs.
float_t floating-point type at least as wide as `float' used
to evaluate `float' expressions
double_t floating-point type at least as wide as `double' used
to evaluate `double' expressions
*/
# if __GLIBC_FLT_EVAL_METHOD == 0 || __GLIBC_FLT_EVAL_METHOD == 16
typedef float float_t;
typedef double double_t;
# elif __GLIBC_FLT_EVAL_METHOD == 1
typedef double float_t;
typedef double double_t;
# elif __GLIBC_FLT_EVAL_METHOD == 2
typedef long double float_t;
typedef long double double_t;
# elif __GLIBC_FLT_EVAL_METHOD == 32
typedef _Float32 float_t;
typedef double double_t;
# elif __GLIBC_FLT_EVAL_METHOD == 33
typedef _Float32x float_t;
typedef _Float32x double_t;
# elif __GLIBC_FLT_EVAL_METHOD == 64
typedef _Float64 float_t;
typedef _Float64 double_t;
# elif __GLIBC_FLT_EVAL_METHOD == 65
typedef _Float64x float_t;
typedef _Float64x double_t;
# elif __GLIBC_FLT_EVAL_METHOD == 128
typedef _Float128 float_t;
typedef _Float128 double_t;
# elif __GLIBC_FLT_EVAL_METHOD == 129
typedef _Float128x float_t;
typedef _Float128x double_t;
# else
# error "Unknown __GLIBC_FLT_EVAL_METHOD"
# endif
#endif
/* Get the architecture specific values describing the floating-point
evaluation. The following symbols will get defined:
FP_FAST_FMA
FP_FAST_FMAF

6
sysdeps/aarch64/bits/mathdef.h
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@ -23,12 +23,6 @@
#if defined __USE_ISOC99 && defined _MATH_H && !defined _MATH_H_MATHDEF
# define _MATH_H_MATHDEF 1
/* GCC does not promote `float' values to `double'. */
typedef float float_t; /* `float' expressions are evaluated as
`float'. */
typedef double double_t; /* `double' expressions are evaluated as
`double'. */
/* The values returned by `ilogb' for 0 and NaN respectively. */
# define FP_ILOGB0 (-2147483647)
# define FP_ILOGBNAN (2147483647)

4
sysdeps/alpha/bits/mathdef.h
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@ -25,10 +25,6 @@
#if defined __USE_ISOC99 && defined _MATH_H && !defined _MATH_H_MATHDEF
# define _MATH_H_MATHDEF 1
/* Alpha has "float" and "double" operations. */
typedef float float_t; /* float expressions are evaluated as float. */
typedef double double_t; /* double expressions are evaluated as double. */
/* The values returned by `ilogb' for 0 and NaN respectively. */
# define FP_ILOGB0 (-2147483647)
# define FP_ILOGBNAN (2147483647)

6
sysdeps/arm/bits/mathdef.h
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@ -22,12 +22,6 @@
#if defined __USE_ISOC99 && defined _MATH_H && !defined _MATH_H_MATHDEF
# define _MATH_H_MATHDEF 1
/* GCC does not promote `float' values to `double'. */
typedef float float_t; /* `float' expressions are evaluated as
`float'. */
typedef double double_t; /* `double' expressions are evaluated as
`double'. */
/* The values returned by `ilogb' for 0 and NaN respectively. */
# define FP_ILOGB0 (-2147483647)
# define FP_ILOGBNAN (2147483647)

6
sysdeps/hppa/fpu/bits/mathdef.h
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@ -22,12 +22,6 @@
#if defined __USE_ISOC99 && defined _MATH_H && !defined _MATH_H_MATHDEF
# define _MATH_H_MATHDEF 1
/* GCC does not promote `float' values to `double'. */
typedef float float_t; /* `float' expressions are evaluated as
`float'. */
typedef double double_t; /* `double' expressions are evaluated as
`double'. */
/* The values returned by `ilogb' for 0 and NaN respectively. */
# define FP_ILOGB0 (-2147483647)
# define FP_ILOGBNAN (2147483647)

7
sysdeps/ia64/bits/mathdef.h
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@ -22,13 +22,6 @@
#if defined __USE_ISOC99 && defined _MATH_H && !defined _MATH_H_MATHDEF
# define _MATH_H_MATHDEF 1
/* The IA-64 architecture computes values with the precision of the
used type. */
typedef float float_t; /* `float' expressions are evaluated as
`float'. */
typedef double double_t; /* `double' expressions are evaluated as
`double'. */
/* The values returned by `ilogb' for 0 and NaN respectively. */
# define FP_ILOGB0 (-2147483647 - 1)
# define FP_ILOGBNAN 2147483647

25
sysdeps/m68k/m680x0/bits/flt-eval-method.h Normal file
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@ -0,0 +1,25 @@
/* Define __GLIBC_FLT_EVAL_METHOD. M68K version.
Copyright (C) 2016 Free Software Foundation, Inc.
This file is part of the GNU C Library.
The GNU C Library is free software; you can redistribute it and/or
modify it under the terms of the GNU Lesser General Public
License as published by the Free Software Foundation; either
version 2.1 of the License, or (at your option) any later version.
The GNU C Library is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public
License along with the GNU C Library; if not, see
<http://www.gnu.org/licenses/>. */
#ifndef _MATH_H
# error "Never use <bits/flt-eval-method.h> directly; include <math.h> instead."
#endif
/* The m68k FPUs evaluate all values in the 96-bit floating-point
format which is also available for the user as 'long double'. */
#define __GLIBC_FLT_EVAL_METHOD 2

8
sysdeps/m68k/m680x0/bits/mathdef.h
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@ -22,14 +22,6 @@
#if defined __USE_ISOC99 && defined _MATH_H && !defined _MATH_H_MATHDEF
# define _MATH_H_MATHDEF 1
/* The m68k FPUs evaluate all values in the 96 bit floating-point format
which is also available for the user as `long double'. Therefore we
define: */
typedef long double float_t; /* `float' expressions are evaluated as
`long double'. */
typedef long double double_t; /* `double' expressions are evaluated as
`long double'. */
/* The values returned by `ilogb' for 0 and NaN respectively. */
# define FP_ILOGB0 (-2147483647 - 1)
# define FP_ILOGBNAN (2147483647)

6
sysdeps/mips/bits/mathdef.h
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@ -24,12 +24,6 @@
#if defined __USE_ISOC99 && defined _MATH_H && !defined _MATH_H_MATHDEF
# define _MATH_H_MATHDEF 1
/* MIPS has `float' and `double' operations. */
typedef float float_t; /* `float' expressions are evaluated as
`float'. */
typedef double double_t; /* `double' expressions are evaluated as
`double'. */
/* The values returned by `ilogb' for 0 and NaN respectively. */
# define FP_ILOGB0 (-2147483647)
# define FP_ILOGBNAN 2147483647

4
sysdeps/powerpc/bits/mathdef.h
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@ -29,10 +29,6 @@
#if defined __USE_ISOC99 && defined _MATH_H && !defined _MATH_H_MATHDEF
# define _MATH_H_MATHDEF 1
/* PowerPC has both `float' and `double' arithmetic. */
typedef float float_t;
typedef double double_t;
/* The values returned by `ilogb' for 0 and NaN respectively. */
# define FP_ILOGB0 (-2147483647)
# define FP_ILOGBNAN (2147483647)

24
sysdeps/s390/bits/flt-eval-method.h Normal file
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@ -0,0 +1,24 @@
/* Define __GLIBC_FLT_EVAL_METHOD. S/390 version.
Copyright (C) 2016 Free Software Foundation, Inc.
This file is part of the GNU C Library.
The GNU C Library is free software; you can redistribute it and/or
modify it under the terms of the GNU Lesser General Public
License as published by the Free Software Foundation; either
version 2.1 of the License, or (at your option) any later version.
The GNU C Library is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public
License along with the GNU C Library; if not, see
<http://www.gnu.org/licenses/>. */
#ifndef _MATH_H
# error "Never use <bits/flt-eval-method.h> directly; include <math.h> instead."
#endif
/* This value is used because of a historical mistake. */
#define __GLIBC_FLT_EVAL_METHOD 1

7
sysdeps/s390/bits/mathdef.h
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@ -22,13 +22,6 @@
#if defined __USE_ISOC99 && defined _MATH_H && !defined _MATH_H_MATHDEF
# define _MATH_H_MATHDEF 1
/* Normally, there is no long double type and the `float' and `double'
expressions are evaluated as `double'. */
typedef double float_t; /* `float' expressions are evaluated as
`double'. */
typedef double double_t; /* `double' expressions are evaluated as
`double'. */
/* The values returned by `ilogb' for 0 and NaN respectively. */
# define FP_ILOGB0 (-2147483647)
# define FP_ILOGBNAN 2147483647

4
sysdeps/sh/sh4/bits/mathdef.h
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@ -29,10 +29,6 @@
#if defined __USE_ISOC99 && defined _MATH_H && !defined _MATH_H_MATHDEF
# define _MATH_H_MATHDEF 1
/* SH has both `float' and `double' arithmetic. */
typedef float float_t;
typedef double double_t;
/* The values returned by `ilogb' for 0 and NaN respectively. */
# define FP_ILOGB0 (-0x7fffffff)
# define FP_ILOGBNAN 0x7fffffff

4
sysdeps/sparc/bits/mathdef.h
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@ -27,10 +27,6 @@
#if defined __USE_ISOC99 && defined _MATH_H && !defined _MATH_H_MATHDEF
# define _MATH_H_MATHDEF 1
/* SPARC has both `float' and `double' arithmetic. */
typedef float float_t;
typedef double double_t;
/* The values returned by `ilogb' for 0 and NaN respectively. */
# define FP_ILOGB0 (-2147483647)
# define FP_ILOGBNAN (2147483647)

4
sysdeps/tile/bits/mathdef.h
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@ -23,10 +23,6 @@
#if defined __USE_ISOC99 && defined _MATH_H && !defined _MATH_H_MATHDEF
# define _MATH_H_MATHDEF 1
/* "float" and "double" expressions evaluated as "float" and "double". */
typedef float float_t;
typedef double double_t;
/* The values returned by `ilogb' for 0 and NaN respectively. */
# define FP_ILOGB0 (-2147483647)
# define FP_ILOGBNAN (2147483647)

33
sysdeps/x86/bits/flt-eval-method.h Normal file
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@ -0,0 +1,33 @@
/* Define __GLIBC_FLT_EVAL_METHOD. x86 version.
Copyright (C) 2016 Free Software Foundation, Inc.
This file is part of the GNU C Library.
The GNU C Library is free software; you can redistribute it and/or
modify it under the terms of the GNU Lesser General Public
License as published by the Free Software Foundation; either
version 2.1 of the License, or (at your option) any later version.
The GNU C Library is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public
License along with the GNU C Library; if not, see
<http://www.gnu.org/licenses/>. */
#ifndef _MATH_H
# error "Never use <bits/flt-eval-method.h> directly; include <math.h> instead."
#endif
#ifdef __FLT_EVAL_METHOD__
# if __FLT_EVAL_METHOD__ == -1
# define __GLIBC_FLT_EVAL_METHOD 2
# else
# define __GLIBC_FLT_EVAL_METHOD __FLT_EVAL_METHOD__
# endif
#elif defined __x86_64__
# define __GLIBC_FLT_EVAL_METHOD 0
#else
# define __GLIBC_FLT_EVAL_METHOD 2
#endif

17
sysdeps/x86/bits/mathdef.h
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@ -22,23 +22,6 @@
#if defined __USE_ISOC99 && defined _MATH_H && !defined _MATH_H_MATHDEF
# define _MATH_H_MATHDEF 1
# if ((defined __x86_64__ && !defined __FLT_EVAL_METHOD__) \
|| (defined __FLT_EVAL_METHOD__ && __FLT_EVAL_METHOD__ == 0))
/* The x86-64 architecture computes values with the precission of the
used type. Similarly for -m32 -mfpmath=sse. */
typedef float float_t; /* `float' expressions are evaluated as `float'. */
typedef double double_t; /* `double' expressions are evaluated
as `double'. */
# else
/* The ix87 FPUs evaluate all values in the 80 bit floating-point format
which is also available for the user as `long double'. Therefore we
define: */
typedef long double float_t; /* `float' expressions are evaluated as
`long double'. */
typedef long double double_t; /* `double' expressions are evaluated as
`long double'. */
# endif
/* The values returned by `ilogb' for 0 and NaN respectively. */
# define FP_ILOGB0 (-2147483647 - 1)
# define FP_ILOGBNAN (-2147483647 - 1)