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/*

 * ====================================================

 * 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

<>, <>, <>, <>, and <>--floating-point classification macros; <>, <>, <>, <>, <>, <>--test for exceptional numbers

INDEX

	fpclassify

INDEX

	isfinite

INDEX

	isinf

INDEX

	isnan

INDEX

	isnormal

@c C99 end)

@c SUSv2 (start

INDEX

	isnan

INDEX

	isinf

INDEX

	finite

	isnanf

INDEX

	isinff

INDEX

	finitef

@c SUSv2 end)

	[C99 standard macros:]

	#include 

	int fpclassify(real-floating <[x]>);

	int isfinite(real-floating <[x]>);

	int isinf(real-floating <[x]>);

	int isnan(real-floating <[x]>);

	int isnormal(real-floating <[x]>);

	#include 

	int isnan(double <[arg]>);

	int isinf(double <[arg]>);

	int finite(double <[arg]>);

	int isnanf(float <[arg]>);

	int isinff(float <[arg]>);

	int finitef(float <[arg]>);

<>, <>, <>, <>, and <> are macros

defined for use in classifying floating-point numbers.  This is a help because

of special "values" like NaN and infinities.  In the synopses shown,

"real-floating" indicates that the argument is an expression of real floating

type.  These function-like macros are C99 and POSIX-compliant, and should be

used instead of the now-archaic SUSv2 functions.

subnormal, zero, or into another implementation-defined category.  First, an

argument represented in a format wider than its semantic type is converted to

its semantic type.  Then classification is based on the type of the argument.

The <> macro returns the value of the number classification macro

appropriate to the value of its argument:

o FP_INFINITE

	<[x]> is either plus or minus infinity;

o FP_NAN

	<[x]> is "Not A Number" (plus or minus);

o FP_NORMAL

	<[x]> is a "normal" number (i.e. is none of the other special forms);

o FP_SUBNORMAL

	<[x]> is too small be stored as a regular normalized number (i.e. loss of precision is likely); or

o FP_ZERO

	<[x]> is 0 (either plus or minus).

o-

classifying floating-point numbers, providing the following equivalent

relations:

o <>(<[x]>)

returns non-zero if <[x]> is finite.  (It is equivalent to

(<>(<[x]>) != FP_INFINITE  &&  <>(<[x]>) != FP_NAN).)

returns non-zero if <[x]> is infinite.  (It is equivalent to

(<>(<[x]>) == FP_INFINITE).)

returns non-zero if <[x]> is NaN.  (It is equivalent to

(<>(<[x]>) == FP_NAN).)

returns non-zero if <[x]> is normal.  (It is equivalent to

(<>(<[x]>) == FP_NORMAL).)

o-

	argument supplied.

	biased exponent in the binary-encoded number):

	o+

	o zero

	  A number which contains all zero bits, excluding the sign bit.

	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.

	returns 1 if the argument is infinity.  <> returns 1 if the

	argument is zero, subnormal or normal.

	operations as their <>, <> and <>

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

	and <> are macros that operate on multiple types of

	floating-point.  The SUSv2 standard declares <> as

	a function taking double.  Newlib has decided to declare

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

	maintain backward compatibility.

@comment Formatting note:  "$@" forces a new line

The fpclassify macro returns the value corresponding to the appropriate FP_ macro.@*

The isfinite macro returns nonzero if <[x]> is finite, else 0.@*

The isinf macro returns nonzero if <[x]> is infinite, else 0.@*

The isnan macro returns nonzero if <[x]> is an NaN, else 0.@*

The isnormal macro returns nonzero if <[x]> has a normal value, else 0.

math.h macros are C99, POSIX.

	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  and

 * declare it as a function in .

 */

#include 

	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);

}