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ieee754.h
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ieee754.h
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#ifndef _IEEE754_H
#define _IEEE754_H 1
#define __LITTLE_ENDIAN 1234
#define __BIG_ENDIAN 4321
#define __BYTE_ORDER __LITTLE_ENDIAN
#define __FLOAT_WORD_ORDER __LITTLE_ENDIAN
#include <float.h>
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
#define isnan(x) _isnan(x)
#define isinf(x) (!isnan(x) && !_finite(x))
#endif /* ieee754.h */