lib/libm/src/e_scalb.c

   1 /* @(#)e_scalb.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  * $NetBSD: e_scalb.c,v 1.9 2002/05/26 22:01:52 wiz Exp $
  13  * $DragonFly: src/lib/libm/src/e_scalb.c,v 1.1 2005/07/26 21:15:20 joerg Exp $
  14  */
  15
  16 /*
  17  * scalb(x, fn) is provide for
  18  * passing various standard test suite. One
  19  * should use scalbn() instead.
  20  */
  21
  22 #include <math.h>
  23 #include "math_private.h"
  24
  25 #ifdef _SCALB_INT
  26 double
  27 scalb(double x, int fn)
  28 #else
  29 double
  30 scalb(double x, double fn)
  31 #endif
  32 {
  33 #ifdef _SCALB_INT
  34         return scalbn(x,fn);
  35 #else
  36         if (isnan(x)||isnan(fn)) return x*fn;
  37         if (!finite(fn)) {
  38             if(fn>0.0) return x*fn;
  39             else       return x/(-fn);
  40         }
  41         if (rint(fn)!=fn) return (fn-fn)/(fn-fn);
  42         if ( fn > 65000.0) return scalbn(x, 65000);
  43         if (-fn > 65000.0) return scalbn(x,-65000);
  44         return scalbn(x,(int)fn);
  45 #endif
  46 }