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799f78a92c
* lib/endian.c, lib/endian.in.h, m4/endian_h.m4, m4/sys_cdefs_h.m4: New files, copied from Gnulib.
216 lines
5.5 KiB
C
216 lines
5.5 KiB
C
/* Copyright (C) 1992-2024 Free Software Foundation, Inc.
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This file is part of the GNU C Library.
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The GNU C Library is free software; you can redistribute it and/or
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modify it under the terms of the GNU Lesser General Public
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License as published by the Free Software Foundation; either
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version 2.1 of the License, or (at your option) any later version.
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The GNU C Library is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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Lesser General Public License for more details.
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You should have received a copy of the GNU Lesser General Public
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License along with the GNU C Library; if not, see
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<https://www.gnu.org/licenses/>. */
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#ifndef _IEEE754_H
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#define _IEEE754_H 1
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#ifndef _GL_GNULIB_HEADER
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/* Ordinary glibc usage. */
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# include <features.h>
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# include <bits/endian.h>
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# define _IEEE754_BYTE_ORDER __BYTE_ORDER
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# define _IEEE754_BIG_ENDIAN __BIG_ENDIAN
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# define _IEEE754_LITTLE_ENDIAN __LITTLE_ENDIAN
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# define _IEEE754_FLOAT_WORD_ORDER __FLOAT_WORD_ORDER
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#else
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/* Gnulib usage. */
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# include <endian.h>
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# define _IEEE754_BYTE_ORDER BYTE_ORDER
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# define _IEEE754_BIG_ENDIAN BIG_ENDIAN
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# define _IEEE754_LITTLE_ENDIAN LITTLE_ENDIAN
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# define _IEEE754_FLOAT_WORD_ORDER BYTE_ORDER
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#endif
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#ifdef __cplusplus
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extern "C" {
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#endif
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union ieee754_float
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{
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float f;
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/* This is the IEEE 754 single-precision format. */
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struct
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{
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#if _IEEE754_BYTE_ORDER == _IEEE754_BIG_ENDIAN
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unsigned int negative:1;
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unsigned int exponent:8;
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unsigned int mantissa:23;
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#endif /* Big endian. */
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#if _IEEE754_BYTE_ORDER == _IEEE754_LITTLE_ENDIAN
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unsigned int mantissa:23;
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unsigned int exponent:8;
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unsigned int negative:1;
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#endif /* Little endian. */
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} ieee;
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/* This format makes it easier to see if a NaN is a signalling NaN. */
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struct
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{
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#if _IEEE754_BYTE_ORDER == _IEEE754_BIG_ENDIAN
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unsigned int negative:1;
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unsigned int exponent:8;
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unsigned int quiet_nan:1;
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unsigned int mantissa:22;
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#endif /* Big endian. */
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#if _IEEE754_BYTE_ORDER == _IEEE754_LITTLE_ENDIAN
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unsigned int mantissa:22;
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unsigned int quiet_nan:1;
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unsigned int exponent:8;
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unsigned int negative:1;
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#endif /* Little endian. */
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} ieee_nan;
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};
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#define IEEE754_FLOAT_BIAS 0x7f /* Added to exponent. */
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union ieee754_double
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{
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double d;
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/* This is the IEEE 754 double-precision format. */
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struct
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{
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#if _IEEE754_BYTE_ORDER == _IEEE754_BIG_ENDIAN
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unsigned int negative:1;
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unsigned int exponent:11;
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/* Together these comprise the mantissa. */
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unsigned int mantissa0:20;
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unsigned int mantissa1:32;
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#endif /* Big endian. */
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#if _IEEE754_BYTE_ORDER == _IEEE754_LITTLE_ENDIAN
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# if _IEEE754_FLOAT_WORD_ORDER == _IEEE754_BIG_ENDIAN
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unsigned int mantissa0:20;
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unsigned int exponent:11;
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unsigned int negative:1;
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unsigned int mantissa1:32;
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# else
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/* Together these comprise the mantissa. */
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unsigned int mantissa1:32;
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unsigned int mantissa0:20;
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unsigned int exponent:11;
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unsigned int negative:1;
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# endif
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#endif /* Little endian. */
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} ieee;
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/* This format makes it easier to see if a NaN is a signalling NaN. */
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struct
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{
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#if _IEEE754_BYTE_ORDER == _IEEE754_BIG_ENDIAN
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unsigned int negative:1;
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unsigned int exponent:11;
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unsigned int quiet_nan:1;
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/* Together these comprise the mantissa. */
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unsigned int mantissa0:19;
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unsigned int mantissa1:32;
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#else
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# if _IEEE754_FLOAT_WORD_ORDER == _IEEE754_BIG_ENDIAN
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unsigned int mantissa0:19;
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unsigned int quiet_nan:1;
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unsigned int exponent:11;
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unsigned int negative:1;
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unsigned int mantissa1:32;
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# else
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/* Together these comprise the mantissa. */
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unsigned int mantissa1:32;
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unsigned int mantissa0:19;
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unsigned int quiet_nan:1;
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unsigned int exponent:11;
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unsigned int negative:1;
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# endif
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#endif
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} ieee_nan;
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};
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#define IEEE754_DOUBLE_BIAS 0x3ff /* Added to exponent. */
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union ieee854_long_double
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{
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long double d;
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/* This is the IEEE 854 double-extended-precision format. */
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struct
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{
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#if _IEEE754_BYTE_ORDER == _IEEE754_BIG_ENDIAN
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unsigned int negative:1;
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unsigned int exponent:15;
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unsigned int empty:16;
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unsigned int mantissa0:32;
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unsigned int mantissa1:32;
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#endif
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#if _IEEE754_BYTE_ORDER == _IEEE754_LITTLE_ENDIAN
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# if _IEEE754_FLOAT_WORD_ORDER == _IEEE754_BIG_ENDIAN
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unsigned int exponent:15;
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unsigned int negative:1;
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unsigned int empty:16;
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unsigned int mantissa0:32;
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unsigned int mantissa1:32;
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# else
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unsigned int mantissa1:32;
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unsigned int mantissa0:32;
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unsigned int exponent:15;
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unsigned int negative:1;
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unsigned int empty:16;
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# endif
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#endif
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} ieee;
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/* This is for NaNs in the IEEE 854 double-extended-precision format. */
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struct
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{
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#if _IEEE754_BYTE_ORDER == _IEEE754_BIG_ENDIAN
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unsigned int negative:1;
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unsigned int exponent:15;
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unsigned int empty:16;
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unsigned int one:1;
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unsigned int quiet_nan:1;
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unsigned int mantissa0:30;
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unsigned int mantissa1:32;
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#endif
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#if _IEEE754_BYTE_ORDER == _IEEE754_LITTLE_ENDIAN
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# if _IEEE754_FLOAT_WORD_ORDER == _IEEE754_BIG_ENDIAN
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unsigned int exponent:15;
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unsigned int negative:1;
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unsigned int empty:16;
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unsigned int mantissa0:30;
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unsigned int quiet_nan:1;
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unsigned int one:1;
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unsigned int mantissa1:32;
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# else
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unsigned int mantissa1:32;
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unsigned int mantissa0:30;
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unsigned int quiet_nan:1;
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unsigned int one:1;
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unsigned int exponent:15;
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unsigned int negative:1;
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unsigned int empty:16;
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# endif
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#endif
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} ieee_nan;
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};
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#define IEEE854_LONG_DOUBLE_BIAS 0x3fff
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#ifdef __cplusplus
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}
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#endif
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#endif /* ieee754.h */
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