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/*

 * ====================================================

 * Copyright (C) 1998,2002 by Red Hat Inc. All rights reserved.

 *

 * Permission to use, copy, modify, and distribute this

 * software is freely granted, provided that this notice

 * is preserved.

 * ====================================================

 */

#if !defined(_SOFT_FLOAT)

/*

Fast version of exp using Intel float instructions.

   double _f_exp (double x);

Function computes e ** x.  The following special cases exist:

   1. if x is 0.0 ==> return 1.0

   2. if x is infinity ==> return infinity

   3. if x is -infinity ==> return 0.0

   4. if x is NaN ==> return x

There is no error checking or setting of errno.

*/

#include <math.h>

#include <ieeefp.h>

#include "f_math.h"

double _f_exp (double x)

{

   if (check_finite(x))

     {

       double result;

       asm ("fldl2e; fmulp; fld %%st; frndint; fsub %%st,%%st(1); fxch;" \

          "fchs; f2xm1; fld1; faddp; fxch; fld1; fscale; fstp %%st(1); fmulp" :

          "=t"(result) : "0"(x));

       return result;

     }

   else if (x == -infinity())

     return 0.0;

   return x;

}

#endif