1 /* s_asinhf.c -- float version of s_asinh.c.
2  * Conversion to float by Ian Lance Taylor, Cygnus Support, ian@cygnus.com.
3  */
4 
5 /*
6  * ====================================================
7  * Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved.
8  *
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
12  * is preserved.
13  * ====================================================
14  */
15 
16 #include "math.h"
17 #include "math_private.h"
18 
19 static const float
20 one =  1.0000000000e+00, /* 0x3F800000 */
21 ln2 =  6.9314718246e-01, /* 0x3f317218 */
22 huge=  1.0000000000e+30;
23 
24 float
25 asinhf(float x)
26 {
27 	float t,w;
28 	int32_t hx,ix;
29 	GET_FLOAT_WORD(hx,x);
30 	ix = hx&0x7fffffff;
31 	if(ix>=0x7f800000) return x+x;	/* x is inf or NaN */
32 	if(ix< 0x31800000) {	/* |x|<2**-28 */
33 	    if(huge+x>one) return x;	/* return x inexact except 0 */
34 	}
35 	if(ix>0x4d800000) {	/* |x| > 2**28 */
36 	    w = logf(fabsf(x))+ln2;
37 	} else if (ix>0x40000000) {	/* 2**28 > |x| > 2.0 */
38 	    t = fabsf(x);
39 	    w = logf((float)2.0*t+one/(sqrtf(x*x+one)+t));
40 	} else {		/* 2.0 > |x| > 2**-28 */
41 	    t = x*x;
42 	    w =log1pf(fabsf(x)+t/(one+sqrtf(one+t)));
43 	}
44 	if(hx>0) return w; else return -w;
45 }
46