//===========================================================================
//
//      ef_acosh.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_acosh.c -- float version of e_acosh.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
#else
static float
#endif
one	= 1.0,
ln2	= 6.9314718246e-01;  /* 0x3f317218 */

#ifdef __STDC__
	float __ieee754_acoshf(float x)
#else
	float __ieee754_acoshf(x)
	float x;
#endif
{
	float t;
	__int32_t hx;
	hx = CYG_LIBM_WORD(x);
	if(hx<0x3f800000) {		/* x < 1 */
	    return (x-x)/(x-x);
	} else if(hx >=0x4d800000) {	/* x > 2**28 */
	    if(!FLT_UWORD_IS_FINITE(hx)) {	/* x is inf of NaN */
	        return x+x;
	    } else
		return __ieee754_logf(x)+ln2;	/* acosh(huge)=log(2x) */
	} else if (hx==0x3f800000) {
	    return 0.0;			/* acosh(1) = 0 */
	} else if (hx > 0x40000000) {	/* 2**28 > x > 2 */
	    t=x*x;
	    return __ieee754_logf((float)2.0*x-one/(x+__ieee754_sqrtf(t-one)));
	} else {			/* 1<x<2 */
	    t = x-one;
	    return log1pf(t+__ieee754_sqrtf((float)2.0*t+t*t));
	}
}

#endif // ifdef CYGPKG_LIBM

// EOF e_acosh.c
