lib/msun/src/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 #ifndef lint
  17 static char rcsid[] = "$FreeBSD: src/lib/msun/src/w_powf.c,v 1.5 1999/08/28 00:07:07 peter 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                 /* powf(0.0,negative) */
  54                 return (float)__kernel_standard((double)x,(double)y,123);
  55             return z;
  56         }
  57         if(!finitef(z)) {
  58             if(finitef(x)&&finitef(y)) {
  59                 if(isnanf(z))
  60                     /* powf neg**non-int */
  61                     return (float)__kernel_standard((double)x,(double)y,124);
  62                 else
  63                     /* powf overflow */
  64                     return (float)__kernel_standard((double)x,(double)y,121);
  65             }
  66         }
  67         if(z==(float)0.0&&finitef(x)&&finitef(y))
  68             /* powf underflow */
  69             return (float)__kernel_standard((double)x,(double)y,122);
  70         return z;
  71 #endif
  72 }