1/* @(#)w_log10.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#include <sys/cdefs.h> 14#if defined(LIBM_SCCS) && !defined(lint) 15__RCSID("$NetBSD: w_log10.c,v 1.9 2002/05/26 22:02:02 wiz Exp $"); 16#endif 17 18/* 19 * wrapper log2(X) 20 */ 21 22#include "math.h" 23#include "math_private.h" 24 25 26double 27log2(double x) /* wrapper log10 */ 28{ 29#ifdef _IEEE_LIBM 30 return __ieee754_log2(x); 31#else 32 double z; 33 z = __ieee754_log2(x); 34 if(_LIB_VERSION == _IEEE_ || isnan(x)) return z; 35 if(x<=0.0) { 36 if(x==0.0) 37 return __kernel_standard(x,x,48); /* log2(0) */ 38 else 39 return __kernel_standard(x,x,49); /* log2(x<0) */ 40 } else 41 return z; 42#endif 43} 44