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/* @(#)s_isnan.c 5.1 93/09/24 */
/*
* ====================================================
* Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved.
*
* Developed at SunPro, a Sun Microsystems, Inc. business.
* Permission to use, copy, modify, and distribute this
* software is freely granted, provided that this notice
* is preserved.
* ====================================================
*/
/*
FUNCTION
<<isnan>>,<<isnanf>>,<<isinf>>,<<isinff>>,<<finite>>,<<finitef>>---test for exceptional numbers
INDEX
isnan
INDEX
isinf
INDEX
finite
INDEX
isnanf
INDEX
isinff
INDEX
finitef
ANSI_SYNOPSIS
#include <ieeefp.h>
int isnan(double <[arg]>);
int isinf(double <[arg]>);
int finite(double <[arg]>);
int isnanf(float <[arg]>);
int isinff(float <[arg]>);
int finitef(float <[arg]>);
TRAD_SYNOPSIS
#include <ieeefp.h>
int isnan(<[arg]>)
double <[arg]>;
int isinf(<[arg]>)
double <[arg]>;
int finite(<[arg]>);
double <[arg]>;
int isnanf(<[arg]>);
float <[arg]>;
int isinff(<[arg]>);
float <[arg]>;
int finitef(<[arg]>);
float <[arg]>;
DESCRIPTION
These functions provide information on the floating point
argument supplied.
There are five major number formats -
o+
o zero
a number which contains all zero bits.
o subnormal
Is used to represent number with a zero exponent, but a non zero fraction.
o normal
A number with an exponent, and a fraction
o infinity
A number with an all 1's exponent and a zero fraction.
o NAN
A number with an all 1's exponent and a non zero fraction.
o-
<<isnan>> returns 1 if the argument is a nan. <<isinf>>
returns 1 if the argument is infinity. <<finite>> returns 1 if the
argument is zero, subnormal or normal.
The <<isnanf>>, <<isinff>> and <<finitef>> perform the same
operations as their <<isnan>>, <<isinf>> and <<finite>>
counterparts, but on single precision floating point numbers.
QUICKREF
isnan - pure
QUICKREF
isinf - pure
QUICKREF
finite - pure
QUICKREF
isnan - pure
QUICKREF
isinf - pure
QUICKREF
finite - pure
*/
/*
* isnan(x) returns 1 is x is nan, else 0;
* no branching!
*/
#include "fdlibm.h"
#ifndef _DOUBLE_IS_32BITS
#ifdef __STDC__
int isnan(double x)
#else
int isnan(x)
double x;
#endif
{
__int32_t hx,lx;
EXTRACT_WORDS(hx,lx,x);
hx &= 0x7fffffff;
hx |= (__uint32_t)(lx|(-lx))>>31;
hx = 0x7ff00000 - hx;
return (int)(((__uint32_t)(hx))>>31);
}
#endif /* _DOUBLE_IS_32BITS */
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