Current File : //usr/include/x86_64-linux-gnu/ieee754.h
/* Copyright (C) 1992-2024 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
<https://www.gnu.org/licenses/>. */
#ifndef _IEEE754_H
#define _IEEE754_H 1
#include <features.h>
#include <bits/endian.h>
__BEGIN_DECLS
union ieee754_float
{
float f;
/* This is the IEEE 754 single-precision format. */
struct
{
#if __BYTE_ORDER == __BIG_ENDIAN
unsigned int negative:1;
unsigned int exponent:8;
unsigned int mantissa:23;
#endif /* Big endian. */
#if __BYTE_ORDER == __LITTLE_ENDIAN
unsigned int mantissa:23;
unsigned int exponent:8;
unsigned int negative:1;
#endif /* Little endian. */
} ieee;
/* This format makes it easier to see if a NaN is a signalling NaN. */
struct
{
#if __BYTE_ORDER == __BIG_ENDIAN
unsigned int negative:1;
unsigned int exponent:8;
unsigned int quiet_nan:1;
unsigned int mantissa:22;
#endif /* Big endian. */
#if __BYTE_ORDER == __LITTLE_ENDIAN
unsigned int mantissa:22;
unsigned int quiet_nan:1;
unsigned int exponent:8;
unsigned int negative:1;
#endif /* Little endian. */
} ieee_nan;
};
#define IEEE754_FLOAT_BIAS 0x7f /* Added to exponent. */
union ieee754_double
{
double d;
/* This is the IEEE 754 double-precision format. */
struct
{
#if __BYTE_ORDER == __BIG_ENDIAN
unsigned int negative:1;
unsigned int exponent:11;
/* Together these comprise the mantissa. */
unsigned int mantissa0:20;
unsigned int mantissa1:32;
#endif /* Big endian. */
#if __BYTE_ORDER == __LITTLE_ENDIAN
# if __FLOAT_WORD_ORDER == __BIG_ENDIAN
unsigned int mantissa0:20;
unsigned int exponent:11;
unsigned int negative:1;
unsigned int mantissa1:32;
# else
/* Together these comprise the mantissa. */
unsigned int mantissa1:32;
unsigned int mantissa0:20;
unsigned int exponent:11;
unsigned int negative:1;
# endif
#endif /* Little endian. */
} ieee;
/* This format makes it easier to see if a NaN is a signalling NaN. */
struct
{
#if __BYTE_ORDER == __BIG_ENDIAN
unsigned int negative:1;
unsigned int exponent:11;
unsigned int quiet_nan:1;
/* Together these comprise the mantissa. */
unsigned int mantissa0:19;
unsigned int mantissa1:32;
#else
# if __FLOAT_WORD_ORDER == __BIG_ENDIAN
unsigned int mantissa0:19;
unsigned int quiet_nan:1;
unsigned int exponent:11;
unsigned int negative:1;
unsigned int mantissa1:32;
# else
/* Together these comprise the mantissa. */
unsigned int mantissa1:32;
unsigned int mantissa0:19;
unsigned int quiet_nan:1;
unsigned int exponent:11;
unsigned int negative:1;
# endif
#endif
} ieee_nan;
};
#define IEEE754_DOUBLE_BIAS 0x3ff /* Added to exponent. */
union ieee854_long_double
{
long double d;
/* This is the IEEE 854 double-extended-precision format. */
struct
{
#if __BYTE_ORDER == __BIG_ENDIAN
unsigned int negative:1;
unsigned int exponent:15;
unsigned int empty:16;
unsigned int mantissa0:32;
unsigned int mantissa1:32;
#endif
#if __BYTE_ORDER == __LITTLE_ENDIAN
# if __FLOAT_WORD_ORDER == __BIG_ENDIAN
unsigned int exponent:15;
unsigned int negative:1;
unsigned int empty:16;
unsigned int mantissa0:32;
unsigned int mantissa1:32;
# else
unsigned int mantissa1:32;
unsigned int mantissa0:32;
unsigned int exponent:15;
unsigned int negative:1;
unsigned int empty:16;
# endif
#endif
} ieee;
/* This is for NaNs in the IEEE 854 double-extended-precision format. */
struct
{
#if __BYTE_ORDER == __BIG_ENDIAN
unsigned int negative:1;
unsigned int exponent:15;
unsigned int empty:16;
unsigned int one:1;
unsigned int quiet_nan:1;
unsigned int mantissa0:30;
unsigned int mantissa1:32;
#endif
#if __BYTE_ORDER == __LITTLE_ENDIAN
# if __FLOAT_WORD_ORDER == __BIG_ENDIAN
unsigned int exponent:15;
unsigned int negative:1;
unsigned int empty:16;
unsigned int mantissa0:30;
unsigned int quiet_nan:1;
unsigned int one:1;
unsigned int mantissa1:32;
# else
unsigned int mantissa1:32;
unsigned int mantissa0:30;
unsigned int quiet_nan:1;
unsigned int one:1;
unsigned int exponent:15;
unsigned int negative:1;
unsigned int empty:16;
# endif
#endif
} ieee_nan;
};
#define IEEE854_LONG_DOUBLE_BIAS 0x3fff
__END_DECLS
#endif /* ieee754.h */
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