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/* @(#)z_isnan.c 1.0 98/08/13 */
/*
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 fract
ion.
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
*
* Input:
* x - pointer to a floating point value
*
* Output:
* An integer that indicates if the number is NaN.
*
* Description:
* This routine returns an integer that indicates if the number
* passed in is NaN (1) or is finite (0).
*
*****************************************************************/
#include "fdlibm.h"
#include "zmath.h"
#ifndef _DOUBLE_IS_32BITS
int isnan (double x)
{
__uint32_t lx, hx;
int exp;
EXTRACT_WORDS (hx, lx, x);
exp = (hx & 0x7ff00000) >> 20;
if ((exp == 0x7ff) && (hx & 0xf0000 || lx))
return (1);
else
return (0);
}
#endif /* _DOUBLE_IS_32BITS */
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