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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

          A number with a zero exponent but a nonzero 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 nonzero 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>> functions perform the same

        operations as their <<isnan>>, <<isinf>> and <<finite>>

        counterparts, but on single-precision floating-point numbers.

        It should be noted that the C99 standard dictates that <<isnan>>

        and <<isinf>> are macros that operate on multiple types of

        floating-point.  The SUSv2 standard declares <<isnan>> as

        a function taking double.  Newlib has decided to declare

        them both as macros in math.h and as functions in ieeefp.h.

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!

 *

 * The C99 standard dictates that isnan is a macro taking

 * multiple floating-point types while the SUSv2 standard

 * notes it is a function taking a double argument.  Newlib

 * has chosen to implement it as a macro in <math.h> and

 * declare it as a function in <ieeefp.h>.

 */

#include "fdlibm.h"

#include <ieeefp.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 */