1 /* e_acoshf.c -- float version of e_acosh.c.
2 * Conversion to float by Ian Lance Taylor, Cygnus Support, ian@cygnus.com.
4 * $FreeBSD: src/lib/msun/src/e_acoshf.c,v 1.6 1999/08/28 00:06:28 peter Exp $
5 * $DragonFly: src/lib/msun/src/Attic/e_acoshf.c,v 1.2 2003/06/17 04:26:52 dillon Exp $
9 * ====================================================
10 * Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved.
12 * Developed at SunPro, a Sun Microsystems, Inc. business.
13 * Permission to use, copy, modify, and distribute this
14 * software is freely granted, provided that this notice
16 * ====================================================
20 #include "math_private.h"
28 ln2 = 6.9314718246e-01; /* 0x3f317218 */
31 float __ieee754_acoshf(float x)
33 float __ieee754_acoshf(x)
40 if(hx<0x3f800000) { /* x < 1 */
42 } else if(hx >=0x4d800000) { /* x > 2**28 */
43 if(hx >=0x7f800000) { /* x is inf of NaN */
46 return __ieee754_logf(x)+ln2; /* acosh(huge)=log(2x) */
47 } else if (hx==0x3f800000) {
48 return 0.0; /* acosh(1) = 0 */
49 } else if (hx > 0x40000000) { /* 2**28 > x > 2 */
51 return __ieee754_logf((float)2.0*x-one/(x+__ieee754_sqrtf(t-one)));
54 return log1pf(t+__ieee754_sqrtf((float)2.0*t+t*t));