libm/e_scalb.c

   1 /*
   2  * ====================================================
   3  * Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved.
   4  *
   5  * Developed at SunPro, a Sun Microsystems, Inc. business.
   6  * Permission to use, copy, modify, and distribute this
   7  * software is freely granted, provided that this notice
   8  * is preserved.
   9  * ====================================================
  10  */
  11
  12 /*
  13  * __ieee754_scalb(x, fn) is provide for
  14  * passing various standard test suite. One
  15  * should use scalbn() instead.
  16  */
  17
  18 #include "math.h"
  19 #include "math_private.h"
  20 #include <errno.h>
  21
  22 double attribute_hidden __ieee754_scalb(double x, double fn)
  23 {
  24         return scalbn(x,fn);
  25         if (isnan(x)||isnan(fn)) return x*fn;
  26         if (!isfinite(fn)) {
  27             if(fn>0.0) return x*fn;
  28             else       return x/(-fn);
  29         }
  30         if (rint(fn)!=fn) return (fn-fn)/(fn-fn);
  31         if ( fn > 65000.0) return scalbn(x, 65000);
  32         if (-fn > 65000.0) return scalbn(x,-65000);
  33         return scalbn(x,(int)fn);
  34 }
  35
  36 #if defined __UCLIBC_SUSV3_LEGACY__
  37 /*
  38  * wrapper scalb(double x, double fn) is provide for
  39  * passing various standard test suite. One
  40  * should use scalbn() instead.
  41  */
  42 #ifndef _IEEE_LIBM
  43 double scalb(double x, double fn)
  44 {
  45         double z = __ieee754_scalb(x, fn);
  46         if (_LIB_VERSION == _IEEE_)
  47                 return z;
  48         if (!(isfinite(z) || isnan(z)) && isfinite(x))
  49                 return __kernel_standard(x, (double)fn, 32); /* scalb overflow */
  50         if (z == 0.0 && z != x)
  51                 return __kernel_standard(x, (double)fn, 33); /* scalb underflow */
  52         if (!isfinite(fn))
  53                 errno = ERANGE;
  54         return z;
  55 }
  56 #else
  57 strong_alias(__ieee754_scalb, scalb)
  58 #endif
  59
  60 #endif /* UCLIBC_SUSV3_LEGACY */