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trionan.c
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trionan.c
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/*************************************************************************
*
* $Id$
*
* Copyright (C) 2001 Bjorn Reese <[email protected]>
*
* Permission to use, copy, modify, and distribute this software for any
* purpose with or without fee is hereby granted, provided that the above
* copyright notice and this permission notice appear in all copies.
*
* THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR IMPLIED
* WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED WARRANTIES OF
* MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. THE AUTHORS AND
* CONTRIBUTORS ACCEPT NO RESPONSIBILITY IN ANY CONCEIVABLE MANNER.
*
************************************************************************
*
* Functions to handle special quantities in floating-point numbers
* (that is, NaNs and infinity). They provide the capability to detect
* and fabricate special quantities.
*
* Although written to be as portable as possible, it can never be
* guaranteed to work on all platforms, as not all hardware supports
* special quantities.
*
* The approach used here (approximately) is to:
*
* 1. Use C99 functionality when available.
* 2. Use IEEE 754 bit-patterns if possible.
* 3. Use platform-specific techniques.
*
************************************************************************/
/*************************************************************************
* Include files
*/
#include "triodef.h"
#include "trionan.h"
#include <math.h>
#include <string.h>
#include <limits.h>
#if !defined(TRIO_PLATFORM_SYMBIAN)
# include <float.h>
#endif
#if defined(TRIO_PLATFORM_UNIX)
# include <signal.h>
#endif
#if defined(TRIO_COMPILER_DECC)
# include <fp_class.h>
#endif
#include <assert.h>
#if defined(TRIO_DOCUMENTATION)
# include "doc/doc_nan.h"
#endif
/** @addtogroup SpecialQuantities
@{
*/
/*************************************************************************
* Definitions
*/
#if !defined(TRIO_PUBLIC_NAN)
# define TRIO_PUBLIC_NAN TRIO_PUBLIC
#endif
#if !defined(TRIO_INLINE_NAN)
# define TRIO_INLINE_NAN TRIO_INLINE
#endif
#define TRIO_TRUE (1 == 1)
#define TRIO_FALSE (0 == 1)
/*
* We must enable IEEE floating-point on Alpha
*/
#if defined(__alpha) && !defined(_IEEE_FP)
# if defined(TRIO_COMPILER_DECC)
# if defined(TRIO_PLATFORM_VMS)
# error "Must be compiled with option /IEEE_MODE=UNDERFLOW_TO_ZERO/FLOAT=IEEE"
# else
# if !defined(_CFE)
# error "Must be compiled with option -ieee"
# endif
# endif
# else
# if defined(TRIO_COMPILER_GCC)
# error "Must be compiled with option -mieee"
# endif
# endif
#endif /* __alpha && ! _IEEE_FP */
/*
* In ANSI/IEEE 754-1985 64-bits double format numbers have the
* following properties (amongst others)
*
* o FLT_RADIX == 2: binary encoding
* o DBL_MAX_EXP == 1024: 11 bits exponent, where one bit is used
* to indicate special numbers (e.g. NaN and Infinity), so the
* maximum exponent is 10 bits wide (2^10 == 1024).
* o DBL_MANT_DIG == 53: The mantissa is 52 bits wide, but because
* numbers are normalized the initial binary 1 is represented
* implicitly (the so-called "hidden bit"), which leaves us with
* the ability to represent 53 bits wide mantissa.
*/
#if defined(__STDC_IEC_559__)
# define TRIO_IEEE_754
#else
# if (FLT_RADIX - 0 == 2) && (DBL_MAX_EXP - 0 == 1024) && (DBL_MANT_DIG - 0 == 53)
# define TRIO_IEEE_754
# endif
#endif
/*
* Determine which fpclassify_and_sign() function to use.
*/
#if defined(TRIO_FUNC_FPCLASSIFY_AND_SIGNBIT)
# if defined(PREDEF_STANDARD_C99) && defined(fpclassify)
# define TRIO_FUNC_C99_FPCLASSIFY_AND_SIGNBIT
# else
# if defined(TRIO_COMPILER_DECC)
# define TRIO_FUNC_DECC_FPCLASSIFY_AND_SIGNBIT
# else
# if defined(TRIO_COMPILER_VISUALC) || defined(TRIO_COMPILER_BORLAND)
# define TRIO_FUNC_MS_FPCLASSIFY_AND_SIGNBIT
# else
# if defined(TRIO_COMPILER_HP) && defined(FP_PLUS_NORM)
# define TRIO_FUNC_HP_FPCLASSIFY_AND_SIGNBIT
# else
# if defined(TRIO_COMPILER_XLC) && defined(FP_PLUS_NORM)
# define TRIO_FUNC_XLC_FPCLASSIFY_AND_SIGNBIT
# else
# define TRIO_FUNC_INTERNAL_FPCLASSIFY_AND_SIGNBIT
# endif
# endif
# endif
# endif
# endif
#endif
/*
* Determine how to generate negative zero.
*/
#if defined(TRIO_FUNC_NZERO)
# if defined(TRIO_IEEE_754)
# define TRIO_NZERO_IEEE_754
# else
# define TRIO_NZERO_FALLBACK
# endif
#endif
/*
* Determine how to generate positive infinity.
*/
#if defined(TRIO_FUNC_PINF)
# if defined(INFINITY) && defined(__STDC_IEC_559__)
# define TRIO_PINF_C99_MACRO
# else
# if defined(TRIO_IEEE_754)
# define TRIO_PINF_IEEE_754
# else
# define TRIO_PINF_FALLBACK
# endif
# endif
#endif
/*
* Determine how to generate NaN.
*/
#if defined(TRIO_FUNC_NAN)
# if defined(PREDEF_STANDARD_C99) && !defined(TRIO_COMPILER_DECC)
# define TRIO_NAN_C99_FUNCTION
# else
# if defined(NAN) && defined(__STDC_IEC_559__)
# define TRIO_NAN_C99_MACRO
# else
# if defined(TRIO_IEEE_754)
# define TRIO_NAN_IEEE_754
# else
# define TRIO_NAN_FALLBACK
# endif
# endif
# endif
#endif
/*
* Resolve internal dependencies.
*/
#if defined(TRIO_FUNC_INTERNAL_FPCLASSIFY_AND_SIGNBIT)
# define TRIO_FUNC_INTERNAL_ISNAN
# define TRIO_FUNC_INTERNAL_ISINF
# if defined(TRIO_IEEE_754)
# define TRIO_FUNC_INTERNAL_IS_SPECIAL_QUANTITY
# define TRIO_FUNC_INTERNAL_IS_NEGATIVE
# endif
#endif
#if defined(TRIO_NZERO_IEEE_754) \
|| defined(TRIO_PINF_IEEE_754) \
|| defined(TRIO_NAN_IEEE_754)
# define TRIO_FUNC_INTERNAL_MAKE_DOUBLE
#endif
#if defined(TRIO_FUNC_INTERNAL_ISNAN)
# if defined(PREDEF_STANDARD_XPG3)
# define TRIO_INTERNAL_ISNAN_XPG3
# else
# if defined(TRIO_IEEE_754)
# define TRIO_INTERNAL_ISNAN_IEEE_754
# else
# define TRIO_INTERNAL_ISNAN_FALLBACK
# endif
# endif
#endif
#if defined(TRIO_FUNC_INTERNAL_ISINF)
# if defined(TRIO_IEEE_754)
# define TRIO_INTERNAL_ISINF_IEEE_754
# else
# define TRIO_INTERNAL_ISINF_FALLBACK
# endif
#endif
/*************************************************************************
* Constants
*/
#if defined(TRIO_FUNC_INTERNAL_MAKE_DOUBLE) \
|| defined(TRIO_FUNC_INTERNAL_IS_SPECIAL_QUANTITY) \
|| defined(TRIO_FUNC_INTERNAL_IS_NEGATIVE)
/*
* Endian-agnostic indexing macro.
*
* The value of internalEndianMagic, when converted into a 64-bit
* integer, becomes 0x0706050403020100 (we could have used a 64-bit
* integer value instead of a double, but not all platforms supports
* that type). The value is automatically encoded with the correct
* endianness by the compiler, which means that we can support any
* kind of endianness. The individual bytes are then used as an index
* for the IEEE 754 bit-patterns and masks.
*/
#define TRIO_DOUBLE_INDEX(x) (((unsigned char *)&internalEndianMagic)[7-(x)])
static TRIO_CONST double internalEndianMagic = 7.949928895127363e-275;
#endif
#if defined(TRIO_FUNC_INTERNAL_IS_SPECIAL_QUANTITY)
/* Mask for the exponent */
static TRIO_CONST unsigned char ieee_754_exponent_mask[] = {
0x7F, 0xF0, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00
};
/* Mask for the mantissa */
static TRIO_CONST unsigned char ieee_754_mantissa_mask[] = {
0x00, 0x0F, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF
};
#endif
#if defined(TRIO_FUNC_INTERNAL_IS_NEGATIVE)
/* Mask for the sign bit */
static TRIO_CONST unsigned char ieee_754_sign_mask[] = {
0x80, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00
};
#endif
#if defined(TRIO_NZERO_IEEE_754)
/* Bit-pattern for negative zero */
static TRIO_CONST unsigned char ieee_754_negzero_array[] = {
0x80, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00
};
#endif
#if defined(TRIO_PINF_IEEE_754)
/* Bit-pattern for infinity */
static TRIO_CONST unsigned char ieee_754_infinity_array[] = {
0x7F, 0xF0, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00
};
#endif
#if defined(TRIO_NAN_IEEE_754)
/* Bit-pattern for quiet NaN */
static TRIO_CONST unsigned char ieee_754_qnan_array[] = {
0x7F, 0xF8, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00
};
#endif
/*************************************************************************
* Internal functions
*/
/*
*
*/
#if defined(TRIO_PLATFORM_UNIX) && defined(TRIO_INTERNAL_ISNAN_FALLBACK)
/* Assume that if SA_SIGINFO is defined, then sigaction() and
* 'struct sigaction' are also properly defined on this platform.
*/
#ifndef TRIO_USE_SIGACTION
# ifdef SA_SIGINFO
# define TRIO_USE_SIGACTION 1
# else
# define TRIO_USE_SIGACTION 0
# endif
#endif
# if TRIO_USE_SIGACTION
typedef struct sigaction signal_handler_t;
# else
typedef void (*signal_handler_t) TRIO_PROTO((int));
# endif
/*
* internal_ignore_signal_handler
*/
static signal_handler_t
internal_ignore_signal_handler
TRIO_ARGS1((signum),
int signum)
{
# if TRIO_USE_SIGACTION
signal_handler_t old_handler, new_handler;
memset(&new_handler, '\0', sizeof(new_handler));
new_handler.sa_handler = SIG_IGN;
new_handler.sa_flags = SA_RESTART;
sigaction(signum, &new_handler, &old_handler);
return old_handler;
# else
return signal(signum, SIG_IGN);
# endif
}
/*
* internal_restore_signal_handler
*/
static void
internal_restore_signal_handler
TRIO_ARGS2((signum, handler),
int signum,
signal_handler_t handler)
{
# if TRIO_USE_SIGACTION
sigaction(signum, &handler, NULL);
# else
signal(signum, handler);
# endif
}
#endif
/*
* internal_make_double
*/
#if defined(TRIO_FUNC_INTERNAL_MAKE_DOUBLE)
static double
internal_make_double
TRIO_ARGS1((values),
TRIO_CONST unsigned char *values)
{
TRIO_VOLATILE double result;
int i;
for (i = 0; i < (int)sizeof(double); i++) {
((TRIO_VOLATILE unsigned char *)&result)[TRIO_DOUBLE_INDEX(i)] = values[i];
}
return result;
}
#endif
/*
* internal_is_special_quantity
*/
#if defined(TRIO_FUNC_INTERNAL_IS_SPECIAL_QUANTITY)
static int
internal_is_special_quantity
TRIO_ARGS2((number, has_mantissa),
double number,
int *has_mantissa)
{
unsigned int i;
unsigned char current;
int is_special_quantity = TRIO_TRUE;
*has_mantissa = 0;
for (i = 0; i < (unsigned int)sizeof(double); i++) {
current = ((unsigned char *)&number)[TRIO_DOUBLE_INDEX(i)];
is_special_quantity
&= ((current & ieee_754_exponent_mask[i]) == ieee_754_exponent_mask[i]);
*has_mantissa |= (current & ieee_754_mantissa_mask[i]);
}
return is_special_quantity;
}
#endif
/*
* internal_is_negative
*/
#if defined(TRIO_FUNC_INTERNAL_IS_NEGATIVE)
static int
internal_is_negative
TRIO_ARGS1((number),
double number)
{
unsigned int i;
int is_negative = TRIO_FALSE;
for (i = 0; i < (unsigned int)sizeof(double); i++) {
is_negative |= (((unsigned char *)&number)[TRIO_DOUBLE_INDEX(i)]
& ieee_754_sign_mask[i]);
}
return is_negative;
}
#endif
#if defined(TRIO_FUNC_C99_FPCLASSIFY_AND_SIGNBIT)
static int
c99_fpclassify_and_signbit
TRIO_ARGS2((number, is_negative),
double number,
int *is_negative)
{
*is_negative = signbit(number);
switch (fpclassify(number)) {
case FP_NAN:
return TRIO_FP_NAN;
case FP_INFINITE:
return TRIO_FP_INFINITE;
case FP_SUBNORMAL:
return TRIO_FP_SUBNORMAL;
case FP_ZERO:
return TRIO_FP_ZERO;
default:
return TRIO_FP_NORMAL;
}
}
#endif /* TRIO_FUNC_C99_FPCLASSIFY_AND_SIGNBIT */
#if defined(TRIO_FUNC_DECC_FPCLASSIFY_AND_SIGNBIT)
static TRIO_INLINE_NAN int
decc_fpclassify_and_signbit
TRIO_ARGS2((number, is_negative),
double number,
int *is_negative)
{
switch (fp_class(number)) {
case FP_QNAN:
case FP_SNAN:
*is_negative = TRIO_FALSE; /* NaN has no sign */
return TRIO_FP_NAN;
case FP_POS_INF:
*is_negative = TRIO_FALSE;
return TRIO_FP_INFINITE;
case FP_NEG_INF:
*is_negative = TRIO_TRUE;
return TRIO_FP_INFINITE;
case FP_POS_DENORM:
*is_negative = TRIO_FALSE;
return TRIO_FP_SUBNORMAL;
case FP_NEG_DENORM:
*is_negative = TRIO_TRUE;
return TRIO_FP_SUBNORMAL;
case FP_POS_ZERO:
*is_negative = TRIO_FALSE;
return TRIO_FP_ZERO;
case FP_NEG_ZERO:
*is_negative = TRIO_TRUE;
return TRIO_FP_ZERO;
case FP_POS_NORM:
*is_negative = TRIO_FALSE;
return TRIO_FP_NORMAL;
case FP_NEG_NORM:
*is_negative = TRIO_TRUE;
return TRIO_FP_NORMAL;
default:
*is_negative = (number < 0.0);
return TRIO_FP_NORMAL;
}
}
#endif /* TRIO_FUNC_DECC_FPCLASSIFY_AND_SIGNBIT */
#if defined(TRIO_FUNC_MS_FPCLASSIFY_AND_SIGNBIT)
static int
ms_fpclassify_and_signbit
TRIO_ARGS2((number, is_negative),
double number,
int *is_negative)
{
int result;
# if defined(TRIO_COMPILER_BORLAND)
/*
* The floating-point precision may be changed by the Borland _fpclass()
* function, so we have to save and restore the floating-point control mask.
*/
unsigned int mask;
/* Remember the old mask */
mask = _control87(0, 0);
# endif
switch (_fpclass(number)) {
case _FPCLASS_QNAN:
case _FPCLASS_SNAN:
*is_negative = TRIO_FALSE; /* NaN has no sign */
result = TRIO_FP_NAN;
break;
case _FPCLASS_PINF:
*is_negative = TRIO_FALSE;
result = TRIO_FP_INFINITE;
break;
case _FPCLASS_NINF:
*is_negative = TRIO_TRUE;
result = TRIO_FP_INFINITE;
break;
case _FPCLASS_PD:
*is_negative = TRIO_FALSE;
result = TRIO_FP_SUBNORMAL;
break;
case _FPCLASS_ND:
*is_negative = TRIO_TRUE;
result = TRIO_FP_SUBNORMAL;
break;
case _FPCLASS_PZ:
*is_negative = TRIO_FALSE;
result = TRIO_FP_ZERO;
break;
case _FPCLASS_NZ:
*is_negative = TRIO_TRUE;
result = TRIO_FP_ZERO;
break;
case _FPCLASS_PN:
*is_negative = TRIO_FALSE;
result = TRIO_FP_NORMAL;
break;
case _FPCLASS_NN:
*is_negative = TRIO_TRUE;
result = TRIO_FP_NORMAL;
break;
default:
*is_negative = (number < 0.0);
result = TRIO_FP_NORMAL;
break;
}
# if defined(TRIO_COMPILER_BORLAND)
/* Restore the old precision */
(void)_control87(mask, MCW_PC);
# endif
return result;
}
#endif /* TRIO_FUNC_MS_FPCLASSIFY_AND_SIGNBIT */
#if defined(TRIO_FUNC_HP_FPCLASSIFY_AND_SIGNBIT)
static TRIO_INLINE_NAN int
hp_fpclassify_and_signbit
TRIO_ARGS2((number, is_negative),
double number,
int *is_negative)
{
/*
* HP-UX 9.x and 10.x have an fpclassify() function, that is different
* from the C99 fpclassify() macro supported on HP-UX 11.x.
*/
switch (fpclassify(number)) {
case FP_QNAN:
case FP_SNAN:
*is_negative = TRIO_FALSE; /* NaN has no sign */
return TRIO_FP_NAN;
case FP_PLUS_INF:
*is_negative = TRIO_FALSE;
return TRIO_FP_INFINITE;
case FP_MINUS_INF:
*is_negative = TRIO_TRUE;
return TRIO_FP_INFINITE;
case FP_PLUS_DENORM:
*is_negative = TRIO_FALSE;
return TRIO_FP_SUBNORMAL;
case FP_MINUS_DENORM:
*is_negative = TRIO_TRUE;
return TRIO_FP_SUBNORMAL;
case FP_PLUS_ZERO:
*is_negative = TRIO_FALSE;
return TRIO_FP_ZERO;
case FP_MINUS_ZERO:
*is_negative = TRIO_TRUE;
return TRIO_FP_ZERO;
case FP_PLUS_NORM:
*is_negative = TRIO_FALSE;
return TRIO_FP_NORMAL;
case FP_MINUS_NORM:
*is_negative = TRIO_TRUE;
return TRIO_FP_NORMAL;
default:
*is_negative = (number < 0.0);
return TRIO_FP_NORMAL;
}
}
#endif /* TRIO_FUNC_HP_FPCLASSIFY_AND_SIGNBIT */
#if defined(TRIO_FUNC_XLC_FPCLASSIFY_AND_SIGNBIT)
static TRIO_INLINE_NAN int
xlc_fpclassify_and_signbit
TRIO_ARGS2((number, is_negative),
double number,
int *is_negative)
{
/*
* AIX has class() for C, and _class() for C++
*/
# if defined(__cplusplus)
# define AIX_CLASS(n) _class(n)
# else
# define AIX_CLASS(n) class(n)
# endif
switch (AIX_CLASS(number)) {
case FP_QNAN:
case FP_SNAN:
*is_negative = TRIO_FALSE; /* NaN has no sign */
return TRIO_FP_NAN;
case FP_PLUS_INF:
*is_negative = TRIO_FALSE;
return TRIO_FP_INFINITE;
case FP_MINUS_INF:
*is_negative = TRIO_TRUE;
return TRIO_FP_INFINITE;
case FP_PLUS_DENORM:
*is_negative = TRIO_FALSE;
return TRIO_FP_SUBNORMAL;
case FP_MINUS_DENORM:
*is_negative = TRIO_TRUE;
return TRIO_FP_SUBNORMAL;
case FP_PLUS_ZERO:
*is_negative = TRIO_FALSE;
return TRIO_FP_ZERO;
case FP_MINUS_ZERO:
*is_negative = TRIO_TRUE;
return TRIO_FP_ZERO;
case FP_PLUS_NORM:
*is_negative = TRIO_FALSE;
return TRIO_FP_NORMAL;
case FP_MINUS_NORM:
*is_negative = TRIO_TRUE;
return TRIO_FP_NORMAL;
default:
*is_negative = (number < 0.0);
return TRIO_FP_NORMAL;
}
}
#endif /* TRIO_FUNC_XLC_FPCLASSIFY_AND_SIGNBIT */
#if defined(TRIO_FUNC_INTERNAL_ISNAN)
static TRIO_INLINE int
internal_isnan
TRIO_ARGS1((number),
double number)
{
# if defined(TRIO_INTERNAL_ISNAN_XPG3) || defined(TRIO_PLATFORM_SYMBIAN)
/*
* XPG3 defines isnan() as a function.
*/
return isnan(number);
# endif
# if defined(TRIO_INTERNAL_ISNAN_IEEE_754)
/*
* Examine IEEE 754 bit-pattern. A NaN must have a special exponent
* pattern, and a non-empty mantissa.
*/
int has_mantissa;
int is_special_quantity;
is_special_quantity = internal_is_special_quantity(number, &has_mantissa);
return (is_special_quantity && has_mantissa);
# endif
# if defined(TRIO_INTERNAL_ISNAN_FALLBACK)
/*
* Fallback solution
*/
int status;
double integral, fraction;
# if defined(TRIO_PLATFORM_UNIX)
signal_handler_t sigfpe_handler = internal_ignore_signal_handler(SIGFPE);
# endif
status = (/*
* NaN is the only number which does not compare to itself
*/
((TRIO_VOLATILE double)number != (TRIO_VOLATILE double)number) ||
/*
* Fallback solution if NaN compares to NaN
*/
((number != 0.0) &&
(fraction = modf(number, &integral),
integral == fraction)));
# if defined(TRIO_PLATFORM_UNIX)
internal_restore_signal_handler(SIGFPR, sigfpe_handler);
# endif
return status;
# endif
}
#endif /* TRIO_FUNC_INTERNAL_ISNAN */
#if defined(TRIO_FUNC_INTERNAL_ISINF)
static TRIO_INLINE int
internal_isinf
TRIO_ARGS1((number),
double number)
{
# if defined(TRIO_PLATFORM_SYMBIAN)
return isinf(number);
# endif
# if defined(TRIO_INTERNAL_ISINF_IEEE_754)
/*
* Examine IEEE 754 bit-pattern. Infinity must have a special exponent
* pattern, and an empty mantissa.
*/
int has_mantissa;
int is_special_quantity;
is_special_quantity = internal_is_special_quantity(number, &has_mantissa);
return (is_special_quantity && !has_mantissa)
? ((number < 0.0) ? -1 : 1)
: 0;
# endif
# if defined(TRIO_INTERNAL_ISINF_FALLBACK)
/*
* Fallback solution.
*/
int status;
# if defined(TRIO_PLATFORM_UNIX)
signal_handler_t sigfpe_handler = internal_ignore_signal_handler(SIGFPE);
# endif
double infinity = trio_pinf();
status = ((number == infinity)
? 1
: ((number == -infinity) ? -1 : 0));
# if defined(TRIO_PLATFORM_UNIX)
internal_restore_signal_handler(SIGFPE, sigfpe_handler);
# endif
return status;
# endif
}
#endif /* TRIO_FUNC_INTERNAL_ISINF */
/*************************************************************************
* Public functions
*/
#if defined(TRIO_FUNC_FPCLASSIFY_AND_SIGNBIT)
TRIO_PUBLIC_NAN int
trio_fpclassify_and_signbit
TRIO_ARGS2((number, is_negative),
double number,
int *is_negative)
{
/* The TRIO_FUNC_xxx_FPCLASSIFY_AND_SIGNBIT macros are mutually exclusive */
#if defined(TRIO_FUNC_C99_FPCLASSIFY_AND_SIGNBIT)
return c99_fpclassify_and_signbit(number, is_negative);
#endif
#if defined(TRIO_FUNC_DECC_FPCLASSIFY_AND_SIGNBIT)
return decc_fpclassify_and_signbit(number, is_negative);
#endif
#if defined(TRIO_FUNC_MS_FPCLASSIFY_AND_SIGNBIT)
return ms_fpclassify_and_signbit(number, is_negative);
#endif
#if defined(TRIO_FUNC_HP_FPCLASSIFY_AND_SIGNBIT)
return hp_fpclassify_and_signbit(number, is_negative);
#endif
#if defined(TRIO_FUNC_XLC_FPCLASSIFY_AND_SIGNBIT)
return xlc_fpclassify_and_signbit(number, is_negative);
#endif
#if defined(TRIO_FUNC_INTERNAL_FPCLASSIFY_AND_SIGNBIT)
/*
* Fallback solution.
*/
int rc;
if (number == 0.0) {
/*
* In IEEE 754 the sign of zero is ignored in comparisons, so we
* have to handle this as a special case by examining the sign bit
* directly.
*/
# if defined(TRIO_IEEE_754)
*is_negative = internal_is_negative(number);
# else
*is_negative = TRIO_FALSE; /* FIXME */
# endif
return TRIO_FP_ZERO;
}
if (internal_isnan(number)) {
*is_negative = TRIO_FALSE;
return TRIO_FP_NAN;
}
rc = internal_isinf(number);
if (rc != 0) {
*is_negative = (rc == -1);
return TRIO_FP_INFINITE;
}
if ((number > 0.0) && (number < DBL_MIN)) {
*is_negative = TRIO_FALSE;
return TRIO_FP_SUBNORMAL;
}
if ((number < 0.0) && (number > -DBL_MIN)) {
*is_negative = TRIO_TRUE;
return TRIO_FP_SUBNORMAL;
}
*is_negative = (number < 0.0);
return TRIO_FP_NORMAL;
#endif
}
#endif
/**
Check for NaN.
@param number An arbitrary floating-point number.
@return Boolean value indicating whether or not the number is a NaN.
*/
#if defined(TRIO_FUNC_ISNAN)
TRIO_PUBLIC_NAN int
trio_isnan
TRIO_ARGS1((number),
double number)
{
int dummy;
return (trio_fpclassify_and_signbit(number, &dummy) == TRIO_FP_NAN);
}
#endif
/**
Check for infinity.
@param number An arbitrary floating-point number.
@return 1 if positive infinity, -1 if negative infinity, 0 otherwise.
*/
#if defined(TRIO_FUNC_ISINF)
TRIO_PUBLIC_NAN int
trio_isinf
TRIO_ARGS1((number),
double number)
{
int is_negative;
if (trio_fpclassify_and_signbit(number, &is_negative) == TRIO_FP_INFINITE)
{
return (is_negative) ? -1 : 1;
}
else
{
return 0;
}
}
#endif
/**
Check for finity.
@param number An arbitrary floating-point number.
@return Boolean value indicating whether or not the number is a finite.
*/
#if defined(TRIO_FUNC_ISFINITE)
TRIO_PUBLIC_NAN int
trio_isfinite
TRIO_ARGS1((number),
double number)
{
int dummy;
switch (trio_fpclassify_and_signbit(number, &dummy))
{
case TRIO_FP_INFINITE:
case TRIO_FP_NAN:
return 0;
default:
return 1;
}
}
#endif
/**
Examine the sign of a number.
@param number An arbitrary floating-point number.
@return Boolean value indicating whether or not the number has the
sign bit set (i.e. is negative).
*/
#if defined(TRIO_FUNC_SIGNBIT)
TRIO_PUBLIC_NAN int
trio_signbit
TRIO_ARGS1((number),
double number)
{
int is_negative;
(void)trio_fpclassify_and_signbit(number, &is_negative);
return is_negative;
}
#endif
/**
Examine the class of a number.
@param number An arbitrary floating-point number.
@return Enumerable value indicating the class of @p number
*/
#if defined(TRIO_FUNC_FPCLASSIFY)
TRIO_PUBLIC_NAN int
trio_fpclassify
TRIO_ARGS1((number),
double number)
{
int dummy;
return trio_fpclassify_and_signbit(number, &dummy);
}
#endif
/**
Generate negative zero.
@return Floating-point representation of negative zero.
*/
#if defined(TRIO_FUNC_NZERO)