sysdeps/libm-ieee754/w_expf.c

   1 /* w_expf.c -- float version of w_exp.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 #if defined(LIBM_SCCS) && !defined(lint)
  17 static char rcsid[] = "$NetBSD: w_expf.c,v 1.3 1995/05/10 20:48:53 jtc Exp $";
  18 #endif
  19
  20 /*
  21  * wrapper expf(x)
  22  */
  23
  24 #include "math.h"
  25 #include "math_private.h"
  26
  27 #ifdef __STDC__
  28 static const float
  29 #else
  30 static float
  31 #endif
  32 o_threshold=  8.8721679688e+01,  /* 0x42b17180 */
  33 u_threshold= -1.0397208405e+02;  /* 0xc2cff1b5 */
  34
  35 #ifdef __STDC__
  36         float __expf(float x)           /* wrapper expf */
  37 #else
  38         float __expf(x)                 /* wrapper expf */
  39         float x;
  40 #endif
  41 {
  42 #ifdef _IEEE_LIBM
  43         return __ieee754_expf(x);
  44 #else
  45         float z;
  46         z = __ieee754_expf(x);
  47         if(_LIB_VERSION == _IEEE_) return z;
  48         if(__finitef(x)) {
  49             if(x>o_threshold)
  50                 /* exp overflow */
  51                 return (float)__kernel_standard((double)x,(double)x,106);
  52             else if(x<u_threshold)
  53                 /* exp underflow */
  54                 return (float)__kernel_standard((double)x,(double)x,107);
  55         }
  56         return z;
  57 #endif
  58 }
  59 weak_alias (__expf, expf)