src/math/scalbf.c

   1 /* origin: FreeBSD /usr/src/lib/msun/src/e_scalbf.c */
   2 /*
   3  * Conversion to float by Ian Lance Taylor, Cygnus Support, ian@cygnus.com.
   4  */
   5 /*
   6  * ====================================================
   7  * Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved.
   8  *
   9  * Developed at SunPro, a Sun Microsystems, Inc. business.
  10  * Permission to use, copy, modify, and distribute this
  11  * software is freely granted, provided that this notice
  12  * is preserved.
  13  * ====================================================
  14  */
  15
  16 #include <math.h>
  17
  18 float scalbf(float x, float fn)
  19 {
  20         if (isnan(x) || isnan(fn)) return x*fn;
  21         if (!isfinite(fn)) {
  22                 if (fn > 0.0f)
  23                         return x*fn;
  24                 else
  25                         return x/(-fn);
  26         }
  27         if (rintf(fn) != fn) return (fn-fn)/(fn-fn);
  28         if ( fn > 65000.0f) return scalbnf(x, 65000);
  29         if (-fn > 65000.0f) return scalbnf(x,-65000);
  30         return scalbnf(x,(int)fn);
  31 }