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

00001 /* @(#)e_scalb.c 5.1 93/09/24 */
00002 /*
00003  * ====================================================
00004  * Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved.
00005  *
00006  * Developed at SunPro, a Sun Microsystems, Inc. business.
00007  * Permission to use, copy, modify, and distribute this
00008  * software is freely granted, provided that this notice 
00009  * is preserved.
00010  * ====================================================
00011  */
00012 
00013 #if defined(LIBM_SCCS) && !defined(lint)
00014 static char rcsid[] = "$NetBSD: e_scalb.c,v 1.6 1995/05/10 20:46:09 jtc Exp $";
00015 #endif
00016 
00017 /*
00018  * __ieee754_scalb(x, fn) is provide for
00019  * passing various standard test suite. One 
00020  * should use scalbn() instead.
00021  */
00022 
00023 #include "math.h"
00024 #include "mathP.h"
00025 
00026 #ifdef _SCALB_INT
00027 #ifdef __STDC__
00028     double __ieee754_scalb(double x, int fn)
00029 #else
00030     double __ieee754_scalb(x,fn)
00031     double x; int fn;
00032 #endif
00033 #else
00034 #ifdef __STDC__
00035     double __ieee754_scalb(double x, double fn)
00036 #else
00037     double __ieee754_scalb(x,fn)
00038     double x, fn;
00039 #endif
00040 #endif
00041 {
00042 #ifdef _SCALB_INT
00043     return scalbn(x,fn);
00044 #else
00045     if (isnan(x)||isnan(fn)) return x*fn;
00046     if (!finite(fn)) {
00047         if(fn>0.0) return x*fn;
00048         else       return x/(-fn);
00049     }
00050     if (rint(fn)!=fn) return (fn-fn)/(fn-fn);
00051     if ( fn > 65000.0) return scalbn(x, 65000);
00052     if (-fn > 65000.0) return scalbn(x,-65000);
00053     return scalbn(x,(int)fn);
00054 #endif
00055 }