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//===========================================================================

//

//      w_jn.c

//

//      Part of the standard mathematical function library

//

//===========================================================================

//####ECOSGPLCOPYRIGHTBEGIN####

// -------------------------------------------

// This file is part of eCos, the Embedded Configurable Operating System.

// Copyright (C) 1998, 1999, 2000, 2001, 2002 Red Hat, Inc.

//

// eCos is free software; you can redistribute it and/or modify it under

// the terms of the GNU General Public License as published by the Free

// Software Foundation; either version 2 or (at your option) any later version.

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// FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License

// for more details.

//

// You should have received a copy of the GNU General Public License along

// with eCos; if not, write to the Free Software Foundation, Inc.,

// 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA.

//

// As a special exception, if other files instantiate templates or use macros

// or inline functions from this file, or you compile this file and link it

// with other works to produce a work based on this file, this file does not

// by itself cause the resulting work to be covered by the GNU General Public

// License. However the source code for this file must still be made available

// in accordance with section (3) of the GNU General Public License.

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// this file might be covered by the GNU General Public License.

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//####ECOSGPLCOPYRIGHTEND####

//===========================================================================

//#####DESCRIPTIONBEGIN####

//

// Author(s):   jlarmour

// Contributors:  jlarmour

// Date:        1998-02-13

// Purpose:     

// Description: 

// Usage:       

//

//####DESCRIPTIONEND####

//

//===========================================================================

// CONFIGURATION

#include <pkgconf/libm.h>   // Configuration header

// Include the Math library?

#ifdef CYGPKG_LIBM     

// Derived from code with the following copyright

/* @(#)w_jn.c 1.3 95/01/18 */

/*

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

 * Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved.

 *

 * Developed at SunSoft, a Sun Microsystems, Inc. business.

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

 * software is freely granted, provided that this notice

 * is preserved.

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

 */

/*

 * wrapper jn(int n, double x), yn(int n, double x)

 * floating point Bessel's function of the 1st and 2nd kind

 * of order n

 *

 * Special cases:

 *      y0(0)=y1(0)=yn(n,0) = -inf with division by zero signal;

 *      y0(-ve)=y1(-ve)=yn(n,-ve) are NaN with invalid signal.

 * Note 2. About jn(n,x), yn(n,x)

 *      For n=0, j0(x) is called,

 *      for n=1, j1(x) is called,

 *      for n<x, forward recursion us used starting

 *      from values of j0(x) and j1(x).

 *      for n>x, a continued fraction approximation to

 *      j(n,x)/j(n-1,x) is evaluated and then backward

 *      recursion is used starting from a supposed value

 *      for j(n,x). The resulting value of j(0,x) is

 *      compared with the actual value to correct the

 *      supposed value of j(n,x).

 *

 *      yn(n,x) is similar in all respects, except

 *      that forward recursion is used for all

 *      values of n>1.

 *

 */

#include "mathincl/fdlibm.h"

        double jn(int n, double x)      /* wrapper jn */

{

#ifdef CYGSEM_LIBM_COMPAT_IEEE_ONLY

        return __ieee754_jn(n,x);

#else

        double z;

        z = __ieee754_jn(n,x);

        if(cyg_libm_get_compat_mode() == CYGNUM_LIBM_COMPAT_IEEE || isnan(x) ) return z;

        if(fabs(x)>X_TLOSS) {

            return __kernel_standard((double)n,x,38); /* jn(|x|>X_TLOSS,n) */

        } else

            return z;

#endif

}

        double yn(int n, double x)      /* wrapper yn */

{

#ifdef CYGSEM_LIBM_COMPAT_IEEE_ONLY

        return __ieee754_yn(n,x);

#else

        double z;

        z = __ieee754_yn(n,x);

        if(cyg_libm_get_compat_mode() == CYGNUM_LIBM_COMPAT_IEEE || isnan(x) ) return z;

        if(x <= 0.0){

                if(x==0.0)

                    /* d= -one/(x-x); */

                    return __kernel_standard((double)n,x,12);

                else

                    /* d = zero/(x-x); */

                    return __kernel_standard((double)n,x,13);

        }

        if(x>X_TLOSS) {

            return __kernel_standard((double)n,x,39); /* yn(x>X_TLOSS,n) */

        } else

            return z;

#endif

}

#endif // ifdef CYGPKG_LIBM     

// EOF w_jn.c