math/w_powf.c

   1 /* w_powf.c -- float version of w_pow.c.
   2  * Conversion to float by Ian Lance Taylor, Cygnus Support, ian@cygnus.com.
   3  */
   4
   5 /*
   6  * ====================================================
   7  * Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved.
   8  *
   9  * Developed at SunPro, a Sun Microsystems, Inc. business.
  10  * Permission to use, copy, modify, and distribute this
  11  * software is freely granted, provided that this notice
  12  * is preserved.
  13  * ====================================================
  14  */
  15
  16 #if defined(LIBM_SCCS) && !defined(lint)
  17 static char rcsid[] = "$NetBSD: w_powf.c,v 1.3 1995/05/10 20:49:41 jtc Exp $";
  18 #endif
  19
  20 /*
  21  * wrapper powf(x,y) return x**y
  22  */
  23
  24 #include <math.h>
  25 #include "math_private.h"
  26
  27
  28 #ifdef __STDC__
  29         float __powf(float x, float y)  /* wrapper powf */
  30 #else
  31         float __powf(x,y)                       /* wrapper powf */
  32         float x,y;
  33 #endif
  34 {
  35 #ifdef _IEEE_LIBM
  36         return  __ieee754_powf(x,y);
  37 #else
  38         float z;
  39         z=__ieee754_powf(x,y);
  40         if(_LIB_VERSION == _IEEE_|| __isnanf(y)) return z;
  41         if(__isnanf(x)) {
  42             if(y==(float)0.0)
  43                 /* powf(NaN,0.0) */
  44                 return (float)__kernel_standard((double)x,(double)y,142);
  45             else
  46                 return z;
  47         }
  48         if(x==(float)0.0) {
  49             if(y==(float)0.0)
  50                 /* powf(0.0,0.0) */
  51                 return (float)__kernel_standard((double)x,(double)y,120);
  52             if(__finitef(y)&&y<(float)0.0) {
  53               if (signbit (x) && signbit (z))
  54                 /* powf(0.0,negative) */
  55                 return (float)__kernel_standard((double)x,(double)y,123);
  56               else
  57                 return (float)__kernel_standard((double)x,(double)y,143);
  58             }
  59             return z;
  60         }
  61         if(!__finitef(z)) {
  62             if(__finitef(x)&&__finitef(y)) {
  63                 if(__isnanf(z))
  64                     /* powf neg**non-int */
  65                     return (float)__kernel_standard((double)x,(double)y,124);
  66                 else
  67                     /* powf overflow */
  68                     return (float)__kernel_standard((double)x,(double)y,121);
  69             }
  70         }
  71         if(z==(float)0.0&&__finitef(x)&&__finitef(y))
  72             /* powf underflow */
  73             return (float)__kernel_standard((double)x,(double)y,122);
  74         return z;
  75 #endif
  76 }
  77 weak_alias (__powf, powf)