1 /* e_acoshf.c -- float version of e_acosh.c.
2 * Conversion to float by Ian Lance Taylor, Cygnus Support, ian@cygnus.com.
6 * ====================================================
7 * Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved.
9 * Developed at SunPro, a Sun Microsystems, Inc. business.
10 * Permission to use, copy, modify, and distribute this
11 * software is freely granted, provided that this notice
13 * ====================================================
15 * $FreeBSD: head/lib/msun/src/e_acoshf.c 176451 2008-02-22 02:30:36Z das $
19 #include "math_private.h"
23 ln2 = 6.9314718246e-01; /* 0x3f317218 */
26 __ieee754_acoshf(float x)
31 if(hx<0x3f800000) { /* x < 1 */
33 } else if(hx >=0x4d800000) { /* x > 2**28 */
34 if(hx >=0x7f800000) { /* x is inf of NaN */
37 return __ieee754_logf(x)+ln2; /* acosh(huge)=log(2x) */
38 } else if (hx==0x3f800000) {
39 return 0.0; /* acosh(1) = 0 */
40 } else if (hx > 0x40000000) { /* 2**28 > x > 2 */
42 return __ieee754_logf((float)2.0*x-one/(x+__ieee754_sqrtf(t-one)));
45 return log1pf(t+__ieee754_sqrtf((float)2.0*t+t*t));