newlib/libm/math/ef_scalb.c

   1 /* ef_scalb.c -- float version of e_scalb.c.
   2  * Conversion to float by Ian Lance Taylor, Cygnus Support, ian@cygnus.com.
   3  */
   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 "fdlibm.h"
  17 #include <limits.h>
  18
  19 #ifdef _SCALB_INT
  20 #ifdef __STDC__
  21         float __ieee754_scalbf(float x, int fn)
  22 #else
  23         float __ieee754_scalbf(x,fn)
  24         float x; int fn;
  25 #endif
  26 #else
  27 #ifdef __STDC__
  28         float __ieee754_scalbf(float x, float fn)
  29 #else
  30         float __ieee754_scalbf(x,fn)
  31         float x, fn;
  32 #endif
  33 #endif
  34 {
  35 #ifdef _SCALB_INT
  36         return scalbnf(x,fn);
  37 #else
  38         if (isnan(x)||isnan(fn)) return x*fn;
  39         if (!finitef(fn)) {
  40             if(fn>(float)0.0) return x*fn;
  41             else       return x/(-fn);
  42         }
  43         if (rintf(fn)!=fn) return (fn-fn)/(fn-fn);
  44 #if INT_MAX > 65000
  45         if ( fn > (float)65000.0) return scalbnf(x, 65000);
  46         if (-fn > (float)65000.0) return scalbnf(x,-65000);
  47 #else
  48         if ( fn > (float)32000.0) return scalbnf(x, 32000);
  49         if (-fn > (float)32000.0) return scalbnf(x,-32000);
  50 #endif
  51         return scalbnf(x,(int)fn);
  52 #endif
  53 }