--- /dev/null
+/* Copyright (C) 1992-2018 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 _IEEE754_H
+
+#define _IEEE754_H 1
+
+#ifndef _GL_GNULIB_HEADER
+/* Ordinary glibc usage. */
+# include <features.h>
+# include <endian.h>
+#else
+/* Gnulib usage. */
+# ifndef __BEGIN_DECLS
+# ifdef __cplusplus
+# define __BEGIN_DECLS extern "C" {
+# define __END_DECLS }
+# else
+# define __BEGIN_DECLS
+# define __END_DECLS
+# endif
+# endif
+# ifndef __FLOAT_WORD_ORDER
+# define __LITTLE_ENDIAN 1234
+# define __BIG_ENDIAN 4321
+# ifdef WORDS_BIGENDIAN
+# define __BYTE_ORDER __BIG_ENDIAN
+# else
+# define __BYTE_ORDER __LITTLE_ENDIAN
+# endif
+# define __FLOAT_WORD_ORDER __BYTE_ORDER
+# endif
+#endif
+
+__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 */
--- /dev/null
+/* Test <ieee754.h>.
+ Copyright 2018 Free Software Foundation, Inc.
+
+ This program is free software: you can redistribute it and/or modify
+ it under the terms of the GNU General Public License as published by
+ the Free Software Foundation; either version 3 of the License, or
+ (at your option) any later version.
+
+ This program 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 General Public License for more details.
+
+ You should have received a copy of the GNU General Public License
+ along with this program. If not, see <https://www.gnu.org/licenses/>. */
+
+/* Written by Paul Eggert. */
+
+#include <config.h>
+
+#include <ieee754.h>
+#include <stdio.h>
+
+static struct {
+ float x;
+ unsigned sign; unsigned exponent; unsigned frac;
+} const float_tests[] =
+ {
+ {0, 0, 0, 0},
+ {-0.0, 1, 0, 0},
+ {0.1, 0, 0x7b, 0x4ccccd}
+ };
+
+static struct {
+ double x;
+ unsigned sign; unsigned exponent; unsigned frac_hi; unsigned frac_lo;
+} const double_tests[] =
+ {
+ {0, 0, 0, 0},
+ {-0.0, 1, 0, 0 },
+ {0.1, 0, 0x3fb, 0x99999, 0x9999999a}
+ };
+
+int
+main (void)
+{
+ int i;
+
+ for (i = 0; i < sizeof float_tests / sizeof *float_tests; i++)
+ {
+ union ieee754_float u;
+ u.f = float_tests[i].x;
+ if (float_tests[i].sign != u.ieee.negative)
+ return 1;
+ if (float_tests[i].exponent != u.ieee.exponent)
+ return 2;
+ if (float_tests[i].frac != u.ieee.mantissa)
+ return 3;
+ }
+
+ for (i = 0; i < sizeof double_tests / sizeof *double_tests; i++)
+ {
+ union ieee754_double u;
+ u.d = double_tests[i].x;
+ if (double_tests[i].sign != u.ieee.negative)
+ return 4;
+ if (double_tests[i].exponent != u.ieee.exponent)
+ return 5;
+ if (double_tests[i].frac_hi != u.ieee.mantissa0)
+ return 6;
+ if (double_tests[i].frac_lo != u.ieee.mantissa1)
+ return 7;
+ }
+
+ return 0;
+}