w_pow.c (1472B)
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 #ifndef lint 23 static char rcsid[] = "$FreeBSD: src/lib/msun/src/w_pow.c,v 1.3 2002/05/28 17:51:46 alfred Exp $"; 24 #endif 25 26 double 27 pow(double x, double y) /* wrapper pow */ 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 }