/*********************************************************************** ** 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 "fp_private.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 __isinff(float x) returns -1 if value represents negative * infinity, 1 if value represents positive infinity, * and 0 otherwise. * * Calls: __signbit * +***********************************************************************/ long int __isinff ( float x ) { long int class = __fpclassifyf(x); if ( class == FP_INFINITE ) { return ( (__signbitf(x)) ? -1 : 1); } return 0; } long int __isinf ( double x ) { long int class = __fpclassify(x); if ( class == FP_INFINITE ) { return ( (__signbit(x)) ? -1 : 1); } return 0; } /*********************************************************************** 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; }