RTAI API: base/math/w_pow.c Source File

00001 
00002 
00003 /* @(#)w_pow.c 5.2 93/10/01 */
00004 /*
00005  * ====================================================
00006  * Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved.
00007  *
00008  * Developed at SunPro, a Sun Microsystems, Inc. business.
00009  * Permission to use, copy, modify, and distribute this
00010  * software is freely granted, provided that this notice 
00011  * is preserved.
00012  * ====================================================
00013  */
00014 
00015 /* 
00016  * wrapper pow(x,y) return x**y
00017  */
00018 
00019 #include "math.h"
00020 #include "mathP.h"
00021 
00022 
00023 #ifdef __STDC__
00024     double pow(double x, double y)  /* wrapper pow */
00025 #else
00026     double pow(x,y)         /* wrapper pow */
00027     double x,y;
00028 #endif
00029 {
00030 #ifdef _IEEE_LIBM
00031     return  __ieee754_pow(x,y);
00032 #else
00033     double z;
00034     z=__ieee754_pow(x,y);
00035     if(_LIB_VERSION == _IEEE_|| isnan(y)) return z;
00036     if(isnan(x)) {
00037         if(y==0.0) 
00038             return __kernel_standard(x,y,42); /* pow(NaN,0.0) */
00039         else 
00040         return z;
00041     }
00042     if(x==0.0){ 
00043         if(y==0.0)
00044             return __kernel_standard(x,y,20); /* pow(0.0,0.0) */
00045         if(finite(y)&&y<0.0)
00046             return __kernel_standard(x,y,23); /* pow(0.0,negative) */
00047         return z;
00048     }
00049     if(!finite(z)) {
00050         if(finite(x)&&finite(y)) {
00051             if(isnan(z))
00052                 return __kernel_standard(x,y,24); /* pow neg**non-int */
00053             else 
00054                 return __kernel_standard(x,y,21); /* pow overflow */
00055         }
00056     } 
00057     if(z==0.0&&finite(x)&&finite(y))
00058         return __kernel_standard(x,y,22); /* pow underflow */
00059     return z;
00060 #endif
00061 }