exp.c

/*
 *                               POK header
 * 
 * The following file is a part of the POK project. Any modification should
 * made according to the POK licence. You CANNOT use this file or a part of
 * this file is this part of a file for your own project
 *
 * For more information on the POK licence, please see our LICENCE FILE
 *
 * Please follow the coding guidelines described in doc/CODING_GUIDELINES
 *
 *                                      Copyright (c) 2007-2009 POK team 
 *
 * Created by julien on Fri Jan 30 14:41:34 2009 
 */

/* @(#)w_exp.c 5.1 93/09/24 */
/*
 * ====================================================
 * Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved.
 *
 * Developed at SunPro, a Sun Microsystems, Inc. business.
 * Permission to use, copy, modify, and distribute this
 * software is freely granted, provided that this notice
 * is preserved.
 * ====================================================
 */

#ifdef POK_NEEDS_LIBMATH

/*
 * wrapper exp(x)
 */

#include <libm.h>
#include "namespace.h"
#include "math_private.h"

#ifdef __weak_alias
__weak_alias(exp, _exp)
#endif

static const double
o_threshold=  7.09782712893383973096e+02,  /* 0x40862E42, 0xFEFA39EF */
u_threshold= -7.45133219101941108420e+02;  /* 0xc0874910, 0xD52D3051 */

double
exp(double x)           /* wrapper exp */
{
#ifdef _IEEE_LIBM
        return __ieee754_exp(x);
#else
        double z;
        z = __ieee754_exp(x);
        if(_LIB_VERSION == _IEEE_) return z;
        if(finite(x)) {
            if(x>o_threshold)
                return __kernel_standard(x,x,6); /* exp overflow */
            else if(x<u_threshold)
                return __kernel_standard(x,x,7); /* exp underflow */
        }
        return z;
#endif
}

#endif