1 /* @(#)w_log.c 5.1 93/09/24 */ 2 /* 3 * ==================================================== 4 * Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved. 5 * 6 * Developed at SunPro, a Sun Microsystems, Inc. business. 7 * Permission to use, copy, modify, and distribute this 8 * software is freely granted, provided that this notice 9 * is preserved. 10 * ==================================================== 11 */ 12 13 #ifndef lint 14 static char rcsid[] = "$Id: w_log.c,v 1.4 1994/08/10 20:35:09 jtc Exp $"; 15 #endif 16 17 /* 18 * wrapper log(x) 19 */ 20 21 #include "math.h" 22 #include "math_private.h" 23 24 25 #ifdef __STDC__ 26 double log(double x) /* wrapper log */ 27 #else 28 double log(x) /* wrapper log */ 29 double x; 30 #endif 31 { 32 #ifdef _IEEE_LIBM 33 return __ieee754_log(x); 34 #else 35 double z; 36 z = __ieee754_log(x); 37 if(_LIB_VERSION == _IEEE_ || isnan(x) || x > 0.0) return z; 38 if(x==0.0) 39 return __kernel_standard(x,x,16); /* log(0) */ 40 else 41 return __kernel_standard(x,x,17); /* log(x<0) */ 42 #endif 43 } 44