//===========================================================================
//
//      ef_cosh.c
//
//      Part of the standard mathematical function library
//
//===========================================================================
// ####ECOSGPLCOPYRIGHTBEGIN####
// -------------------------------------------
// This file is part of eCos, the Embedded Configurable Operating System.
// Copyright (C) 2012 Free Software Foundation, 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.
//
// eCos is distributed in the hope that it will be useful, but WITHOUT
// ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
// 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.,
// 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, 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 v2.
//
// This exception does not invalidate any other reasons why a work based
// on this file might be covered by the GNU General Public License.
// -------------------------------------------
// ####ECOSGPLCOPYRIGHTEND####
//===========================================================================
//#####DESCRIPTIONBEGIN####
//
// Author(s):
// Contributors: visar, ilijak
// Date:        2012-03-08
// 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


/* ef_cosh.c -- float version of e_cosh.c.
 * Conversion to float by Ian Lance Taylor, Cygnus Support, ian@cygnus.com.
 */

/*
 * ====================================================
 * 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.
 * ====================================================
 */


#include "mathincl/fdlibm.h"

#ifdef __STDC__
static const float one = 1.0, half=0.5, huge = 1.0e30;
#else
static float one = 1.0, half=0.5, huge = 1.0e30;
#endif

#ifdef __STDC__
	float __ieee754_coshf(float x)
#else
	float __ieee754_coshf(x)
	float x;
#endif
{
	float t,w;
	__int32_t ix;

	ix = CYG_LIBM_WORD(x);
	ix &= 0x7fffffff;

    /* x is INF or NaN */
	if(!FLT_UWORD_IS_FINITE(ix)) return x*x;

    /* |x| in [0,0.5*ln2], return 1+expm1(|x|)^2/(2*exp(|x|)) */
	if(ix<0x3eb17218) {
	    t = expm1f(fabsf(x));
	    w = one+t;
	    if (ix<0x24000000) return w;	/* cosh(tiny) = 1 */
	    return one+(t*t)/(w+w);
	}

    /* |x| in [0.5*ln2,22], return (exp(|x|)+1/exp(|x|)/2; */
	if (ix < 0x41b00000) {
		t = __ieee754_expf(fabsf(x));
		return half*t+half/t;
	}

    /* |x| in [22, log(maxdouble)] return half*exp(|x|) */
	if (ix <= FLT_UWORD_LOG_MAX)
	  return half*__ieee754_expf(fabsf(x));

    /* |x| in [log(maxdouble), overflowthresold] */
	if (ix <= FLT_UWORD_LOG_2MAX) {
	    w = __ieee754_expf(half*fabsf(x));
	    t = half*w;
	    return t*w;
	}

    /* |x| > overflowthresold, cosh(x) overflow */
	return huge*huge;
}

#endif // ifdef CYGPKG_LIBM

// EOF ef_cosh.c
