/* e_acoshf.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.

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

 */

#if defined(LIBM_SCCS) && !defined(lint)

static char rcsid[] = "$NetBSD: e_acoshf.c,v 1.5 1995/05/12 04:57:20 jtc Exp $";

#endif

#include <math.h>

#include <math_private.h>

static const float

one	= 1.0,

ln2	= 6.9314718246e-01;  /* 0x3f317218 */

float __ieee754_acoshf(float x)

{

	float t;

	int32_t hx;

	GET_FLOAT_WORD(hx,x);

	if(hx<0x3f800000) {		/* x < 1 */

	    return (x-x)/(x-x);

	} else if(hx >=0x4d800000) {	/* x > 2**28 */

	    if(hx >=0x7f800000) {	/* 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+sqrtf(t-one)));

	} else {			/* 1

	    t = x-one;

	    return __log1pf(t+sqrtf((float)2.0*t+t*t));

	}

}

strong_alias (__ieee754_acoshf, __acoshf_finite)