libm/w_pow.c

   1
   2
   3 /* @(#)w_pow.c 5.2 93/10/01 */
   4 /*
   5  * ====================================================
   6  * Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved.
   7  *
   8  * Developed at SunPro, a Sun Microsystems, Inc. business.
   9  * Permission to use, copy, modify, and distribute this
  10  * software is freely granted, provided that this notice
  11  * is preserved.
  12  * ====================================================
  13  */
  14
  15 /*
  16  * wrapper pow(x,y) return x**y
  17  */
  18
  19 #include "math.h"
  20 #include "math_private.h"
  21
  22 #ifdef __STDC__
  23         double pow(double x, double y)  /* wrapper pow */
  24 #else
  25         double pow(x,y)                 /* wrapper pow */
  26         double x,y;
  27 #endif
  28 {
  29 #ifdef _IEEE_LIBM
  30         return  __ieee754_pow(x,y);
  31 #else
  32         double z;
  33         z=__ieee754_pow(x,y);
  34         if(_LIB_VERSION == _IEEE_|| isnan(y)) return z;
  35         if(isnan(x)) {
  36             if(y==0.0)
  37                 return __kernel_standard(x,y,42); /* pow(NaN,0.0) */
  38             else
  39                 return z;
  40         }
  41         if(x==0.0){
  42             if(y==0.0)
  43                 return __kernel_standard(x,y,20); /* pow(0.0,0.0) */
  44             if(finite(y)&&y<0.0)
  45                 return __kernel_standard(x,y,23); /* pow(0.0,negative) */
  46             return z;
  47         }
  48         if(!finite(z)) {
  49             if(finite(x)&&finite(y)) {
  50                 if(isnan(z))
  51                     return __kernel_standard(x,y,24); /* pow neg**non-int */
  52                 else
  53                     return __kernel_standard(x,y,21); /* pow overflow */
  54             }
  55         }
  56         if(z==0.0&&finite(x)&&finite(y))
  57             return __kernel_standard(x,y,22); /* pow underflow */
  58         return z;
  59 #endif
  60 }
  61 libm_hidden_def(pow)