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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 "fpP.h"
#define SIGN_MASK 0x80000000
#define NSIGN_MASK 0x7fffffff
#define FEXP_MASK 0x7f800000
#define FFRAC_MASK 0x007fffff
/***********************************************************************
long 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
***********************************************************************/
long int __fpclassifyf ( float x )
{
unsigned long int iexp;
union {
unsigned long int 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 (long int) FP_INFINITE;
else if ((z.lval & 0x00400000) != 0)
return (long int) FP_QNAN;
else
return (long int) FP_SNAN;
}
if (iexp != 0) /* normal float */
return (long int) FP_NORMAL;
if (x == 0.0)
return (long int) FP_ZERO; /* zero */
else
return (long int) 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
***********************************************************************/
long int __fpclassify ( double arg )
{
register unsigned long 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 (long int) FP_INFINITE;
else
return ( x.hex.high & 0x00080000 ) ? FP_QNAN : FP_SNAN;
}
else if ( exponent != 0)
return (long int) FP_NORMAL;
else {
if ( arg == 0.0 )
return (long int) FP_ZERO;
else
return (long int) FP_SUBNORMAL;
}
}
/***********************************************************************
long 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
***********************************************************************/
long int __isnormalf ( float x )
{
unsigned long int iexp;
union {
unsigned long int lval;
float fval;
} z;
z.fval = x;
iexp = z.lval & FEXP_MASK; /* isolate float exponent */
return ((iexp != FEXP_MASK) && (iexp != 0));
}
long int __isnorma ( double x )
{
return ( __fpclassify ( x ) == FP_NORMAL );
}
/***********************************************************************
long 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
***********************************************************************/
long int __isfinitef ( float x )
{
union {
unsigned long int lval;
float fval;
} z;
z.fval = x;
return ((z.lval & FEXP_MASK) != FEXP_MASK);
}
long int __isfinite ( double x )
{
return ( __fpclassify ( x ) >= FP_ZERO );
}
/***********************************************************************
long 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
***********************************************************************/
long int __isnanf ( float x )
{
union {
unsigned long int lval;
float fval;
} z;
z.fval = x;
return (((z.lval&FEXP_MASK) == FEXP_MASK) && ((z.lval&FFRAC_MASK) != 0));
}
long int __isnan ( double x )
{
long int class = __fpclassify(x);
return ( ( class == FP_SNAN ) || ( class == FP_QNAN ) );
}
/***********************************************************************
long 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
***********************************************************************/
long int __signbitf ( float x )
{
union {
unsigned long int 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
***********************************************************************/
long int __signbit ( double arg )
{
union
{
dHexParts hex;
double dbl;
} x;
long int sign;
x.dbl = arg;
sign = ( ( x.hex.high & dSgnMask ) == dSgnMask ) ? 1 : 0;
return sign;
}
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