1 /* e_sinhf.c -- float version of e_sinh.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 one = 1.0, shuge = 1.0e37;
20 
21 float
22 sinhf(float x)
23 {
24 	float t,w,h;
25 	int32_t ix,jx;
26 
27 	GET_FLOAT_WORD(jx,x);
28 	ix = jx&0x7fffffff;
29 
30     /* x is INF or NaN */
31 	if(ix>=0x7f800000) return x+x;
32 
33 	h = 0.5;
34 	if (jx<0) h = -h;
35     /* |x| in [0,22], return sign(x)*0.5*(E+E/(E+1))) */
36 	if (ix < 0x41b00000) {		/* |x|<22 */
37 	    if (ix<0x31800000) 		/* |x|<2**-28 */
38 		if(shuge+x>one) return x;/* sinh(tiny) = tiny with inexact */
39 	    t = expm1f(fabsf(x));
40 	    if(ix<0x3f800000) return h*((float)2.0*t-t*t/(t+one));
41 	    return h*(t+t/(t+one));
42 	}
43 
44     /* |x| in [22, log(maxdouble)] return 0.5*exp(|x|) */
45 	if (ix < 0x42b17180)  return h*expf(fabsf(x));
46 
47     /* |x| in [log(maxdouble), overflowthresold] */
48 	if (ix<=0x42b2d4fc) {
49 	    w = expf((float)0.5*fabsf(x));
50 	    t = h*w;
51 	    return t*w;
52 	}
53 
54     /* |x| > overflowthresold, sinh(x) overflow */
55 	return x*shuge;
56 }
57