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  * $FreeBSD: src/lib/msun/src/w_powf.c,v 1.5 1999/08/28 00:07:07 peter Exp $
   5  * $DragonFly: src/lib/msun/src/Attic/w_powf.c,v 1.3 2004/12/29 15:22:57 asmodai Exp $
   6  */
   7
   8 /*
   9  * ====================================================
  10  * Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved.
  11  *
  12  * Developed at SunPro, a Sun Microsystems, Inc. business.
  13  * Permission to use, copy, modify, and distribute this
  14  * software is freely granted, provided that this notice
  15  * is preserved.
  16  * ====================================================
  17  */
  18
  19 /*
  20  * wrapper powf(x,y) return x**y
  21  */
  22
  23 #include "math.h"
  24 #include "math_private.h"
  25
  26
  27 float
  28 powf(float x, float y)  /* wrapper powf */
  29 {
  30 #ifdef _IEEE_LIBM
  31         return  __ieee754_powf(x,y);
  32 #else
  33         float z;
  34         z=__ieee754_powf(x,y);
  35         if(_LIB_VERSION == _IEEE_|| isnanf(y)) return z;
  36         if(isnanf(x)) {
  37             if(y==(float)0.0)
  38                 /* powf(NaN,0.0) */
  39                 return (float)__kernel_standard((double)x,(double)y,142);
  40             else
  41                 return z;
  42         }
  43         if(x==(float)0.0){
  44             if(y==(float)0.0)
  45                 /* powf(0.0,0.0) */
  46                 return (float)__kernel_standard((double)x,(double)y,120);
  47             if(finitef(y)&&y<(float)0.0)
  48                 /* powf(0.0,negative) */
  49                 return (float)__kernel_standard((double)x,(double)y,123);
  50             return z;
  51         }
  52         if(!finitef(z)) {
  53             if(finitef(x)&&finitef(y)) {
  54                 if(isnanf(z))
  55                     /* powf neg**non-int */
  56                     return (float)__kernel_standard((double)x,(double)y,124);
  57                 else
  58                     /* powf overflow */
  59                     return (float)__kernel_standard((double)x,(double)y,121);
  60             }
  61         }
  62         if(z==(float)0.0&&finitef(x)&&finitef(y))
  63             /* powf underflow */
  64             return (float)__kernel_standard((double)x,(double)y,122);
  65         return z;
  66 #endif
  67 }