contrib/openbsd_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 /*
  14  * scalb(x, fn) is provide for
  15  * passing various standard test suite. One
  16  * should use scalbn() instead.
  17  */
  18
  19 #include "math.h"
  20 #include "math_private.h"
  21
  22 #ifdef _SCALB_INT
  23 double
  24 scalb(double x, int fn)
  25 {
  26         return scalbn(x, fn);
  27 }
  28
  29 #else
  30
  31 double
  32 scalb(double x, double fn)
  33 {
  34         if (isnan(x)||isnan(fn)) return x*fn;
  35         if (!finite(fn)) {
  36             if(fn>0.0) return x*fn;
  37             else       return x/(-fn);
  38         }
  39         if (rint(fn)!=fn) return (fn-fn)/(fn-fn);
  40         if ( fn > 65000.0) return scalbn(x, 65000);
  41         if (-fn > 65000.0) return scalbn(x,-65000);
  42         return scalbn(x,(int)fn);
  43 }
  44 #endif