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
  13 #include <sys/cdefs.h>
  14 #if defined(LIBM_SCCS) && !defined(lint)
  15 __RCSID("$NetBSD: e_scalb.c,v 1.10 2010/04/23 19:17:07 drochner Exp $");
  16 #endif
  17
  18 /*
  19  * __ieee754_scalb(x, fn) is provide for
  20  * passing various standard test suite. One
  21  * should use scalbn() instead.
  22  */
  23
  24 #include "namespace.h"
  25 #include "math.h"
  26 #include "math_private.h"
  27
  28 #ifdef _SCALB_INT
  29 double
  30 __ieee754_scalb(double x, int fn)
  31 #else
  32 double
  33 __ieee754_scalb(double x, double fn)
  34 #endif
  35 {
  36 #ifdef _SCALB_INT
  37         return scalbn(x,fn);
  38 #else
  39         if (isnan(x)||isnan(fn)) return x*fn;
  40         if (!finite(fn)) {
  41             if(fn>0.0) return x*fn;
  42             else       return x/(-fn);
  43         }
  44         if (rint(fn)!=fn) return (fn-fn)/(fn-fn);
  45         if ( fn > 65000.0) return scalbn(x, 65000);
  46         if (-fn > 65000.0) return scalbn(x,-65000);
  47         return scalbn(x,(int)fn);
  48 #endif
  49 }