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/***********************************************************************

**  File:  fpmacros.c

**

**  Contains:  C source code for implementations of floating-point

**             functions which involve float format numbers, as

**             defined in header <fp.h>.  In particular, this file

**             contains implementations of functions

**              __fpclassify(d,f), __isnormal(d,f), __isfinite(d,f),

**             __isnan(d,f), and __signbit(d,f).  This file targets

**             PowerPC platforms.

**

**  Written by:   Robert A. Murley, Ali Sazegari

**

**  Copyright:   c 2001 by Apple Computer, Inc., all rights reserved

**

**  Change History (most recent first):

**

**     07 Jul 01   ram      First created from fpfloatfunc.c, fp.c,

**                              classify.c and sign.c in MathLib v3 Mac OS9.

**

***********************************************************************/

#include     <features.h>

#include     <sys/types.h>

#include     <math.h>

#include     "fp_private.h"

#define SIGN_MASK 0x80000000

#define NSIGN_MASK 0x7fffffff

#define FEXP_MASK 0x7f800000

#define FFRAC_MASK 0x007fffff

/***********************************************************************

   int __fpclassifyf(float x) returns the classification code of the

   argument x, as defined in <fp.h>.

   Exceptions:  INVALID signaled if x is a signaling NaN; in this case,

                the FP_QNAN code is returned.

   Calls:  none

***********************************************************************/

int __fpclassifyf ( float x )

{

   unsigned int iexp;

   union {

      u_int32_t lval;

      float fval;

   } z;

   z.fval = x;

   iexp = z.lval & FEXP_MASK;                 /* isolate float exponent */

   if (iexp == FEXP_MASK) {                   /* NaN or INF case */

      if ((z.lval & 0x007fffff) == 0)

         return FP_INFINITE;

        return FP_NAN;

   }

   if (iexp != 0)                             /* normal float */

      return FP_NORMAL;

   if (x == 0.0)

      return FP_ZERO;             /* zero */

   else

      return FP_SUBNORMAL;        /* must be subnormal */

}

/***********************************************************************

      Function __fpclassify,

      Implementation of classify of a double number for the PowerPC.

   Exceptions:  INVALID signaled if x is a signaling NaN; in this case,

                the FP_QNAN code is returned.

   Calls:  none

***********************************************************************/

int __fpclassify ( double arg )

{

        register unsigned int exponent;

      union

            {

            dHexParts hex;

            double dbl;

            } x;

        x.dbl = arg;

        exponent = x.hex.high & dExpMask;

        if ( exponent == dExpMask )

                {

                if ( ( ( x.hex.high & dHighMan ) | x.hex.low ) == 0 )

                        return FP_INFINITE;

                else

                return FP_NAN;

                }

        else if ( exponent != 0)

                return FP_NORMAL;

        else {

                if ( arg == 0.0 )

                        return FP_ZERO;

                else

                        return FP_SUBNORMAL;

                }

}

/***********************************************************************

   int __isnormalf(float x) returns nonzero if and only if x is a

   normalized float number and zero otherwise.

   Exceptions:  INVALID is raised if x is a signaling NaN; in this case,

                zero is returned.

   Calls:  none

***********************************************************************/

int __isnormalf ( float x )

{

   unsigned int iexp;

   union {

      u_int32_t lval;

      float fval;

   } z;

   z.fval = x;

   iexp = z.lval & FEXP_MASK;                 /* isolate float exponent */

   return ((iexp != FEXP_MASK) && (iexp != 0));

}

int __isnormal ( double x )

{

        return ( __fpclassify ( x ) == FP_NORMAL );

}

/***********************************************************************

   int __isfinitef(float x) returns nonzero if and only if x is a

   finite (normal, subnormal, or zero) float number and zero otherwise.

   Exceptions:  INVALID is raised if x is a signaling NaN; in this case,

                zero is returned.

   Calls:  none

***********************************************************************/

int __finitef ( float x )

{

   union {

      u_int32_t lval;

      float fval;

   } z;

   z.fval = x;

   return ((z.lval & FEXP_MASK) != FEXP_MASK);

}

weak_alias (__finitef, finitef)

int __finite ( double x )

{

        return ( __fpclassify ( x ) >= FP_ZERO );

}

weak_alias (__finite, finite)

/***********************************************************************

   int __signbitf(float x) returns nonzero if and only if the sign

   bit of x is set and zero otherwise.

   Exceptions:  INVALID is raised if x is a signaling NaN.

   Calls:  none

***********************************************************************/

int __signbitf ( float x )

{

   union {

      u_int32_t lval;

      float fval;

   } z;

   z.fval = x;

   return ((z.lval & SIGN_MASK) != 0);

}

/***********************************************************************

      Function sign of a double.

      Implementation of sign bit for the PowerPC.

   Calls:  none

***********************************************************************/

int __signbit ( double arg )

{

      union

            {

            dHexParts hex;

            double dbl;

            } x;

      int sign;

      x.dbl = arg;

      sign = ( ( x.hex.high & dSgnMask ) == dSgnMask ) ? 1 : 0;

      return sign;

}

/***********************************************************************

* int __isinff(float x) returns -1 if value represents  negative

*       infinity,  1  if value represents positive infinity,

*       and 0 otherwise.

*

* Calls:  __signbit

* +***********************************************************************/

int __isinff ( float x )

{

    int class = __fpclassifyf(x);

    if ( class == FP_INFINITE ) {

        return ( (__signbitf(x)) ? -1 : 1);

    }

    return 0;

}

weak_alias (__isinff, isinff)

int __isinf ( double x )

{

    int class = __fpclassify(x);

    if ( class == FP_INFINITE ) {

        return ( (__signbit(x)) ? -1 : 1);

    }

    return 0;

}

weak_alias (__isinf, isinf)

#if 0

int __isinfl ( long double x )

{

    int class = __fpclassify(x);

    if ( class == FP_INFINITE ) {

        return ( (__signbit(x)) ? -1 : 1);

    }

    return 0;

}

weak_alias (__isinfl, isinfl);

#endif

/***********************************************************************

   int __isnanf(float x) returns nonzero if and only if x is a

   NaN and zero otherwise.

   Exceptions:  INVALID is raised if x is a signaling NaN; in this case,

                nonzero is returned.

   Calls:  none

***********************************************************************/

int __isnanf ( float x )

{

   union {

      u_int32_t lval;

      float fval;

   } z;

   z.fval = x;

   return (((z.lval&FEXP_MASK) == FEXP_MASK) && ((z.lval&FFRAC_MASK) != 0));

}

weak_alias (__isnanf, isnanf);

int __isnan ( double x )

{

        int class = __fpclassify(x);

        return ( class == FP_NAN );

}

weak_alias (__isnan, isnan);

#if 0

int __isnanl ( long double x )

{

        int class = __fpclassify(x);

        return ( class == FP_NAN );

}

weak_alias (__isnanl, isnanl);

#endif