toolchain/gcc/newlib/libm/math/w_exp2.c

   1
   2 /* @(#)w_exp2.c 5.1 93/09/24 */
   3 /*
   4  * ====================================================
   5  * Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved.
   6  *
   7  * Developed at SunPro, a Sun Microsystems, Inc. business.
   8  * Permission to use, copy, modify, and distribute this
   9  * software is freely granted, provided that this notice
  10  * is preserved.
  11  * ====================================================
  12  */
  13
  14 /*
  15 FUNCTION
  16         <<exp2>>, <<exp2f>>---exponential
  17 INDEX
  18         exp2
  19 INDEX
  20         exp2f
  21
  22 ANSI_SYNOPSIS
  23         #include <math.h>
  24         double exp2(double <[x]>);
  25         float exp2f(float <[x]>);
  26
  27 TRAD_SYNOPSIS
  28         #include <math.h>
  29         double exp2(<[x]>);
  30         double <[x]>;
  31
  32         float exp2f(<[x]>);
  33         float <[x]>;
  34
  35 DESCRIPTION
  36         <<exp2>> and <<exp2f>> calculate 2 ^ <[x]>, that is,
  37         @ifnottex
  38         2 raised to the power <[x]>.
  39         @end ifnottex
  40         @tex
  41         $2^x$
  42         @end tex
  43
  44         You can use the (non-ANSI) function <<matherr>> to specify
  45         error handling for these functions.
  46
  47 RETURNS
  48         On success, <<exp2>> and <<exp2f>> return the calculated value.
  49         If the result underflows, the returned value is <<0>>.  If the
  50         result overflows, the returned value is <<HUGE_VAL>>.  In
  51         either case, <<errno>> is set to <<ERANGE>>.
  52
  53 */
  54
  55 /*
  56  * wrapper exp2(x)
  57  */
  58
  59 #include "fdlibm.h"
  60 #include <errno.h>
  61 #include <math.h>
  62
  63 #ifndef _DOUBLE_IS_32BITS
  64
  65 #ifdef __STDC__
  66         double exp2(double x)           /* wrapper exp2 */
  67 #else
  68         double exp2(x)                  /* wrapper exp2 */
  69         double x;
  70 #endif
  71 {
  72   return pow(2.0, x);
  73 }
  74
  75 #endif /* defined(_DOUBLE_IS_32BITS) */