e_sinhf.c revision 152353 
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#ifndef lint
17static char rcsid[] = "$FreeBSD: head/lib/msun/src/e_sinhf.c 152353 2005-11-13 00:41:46Z bde $";
18#endif
19
20#include "math.h"
21#include "math_private.h"
22
23static const float one = 1.0, shuge = 1.0e37;
24
25float
26__ieee754_sinhf(float x)
27{
28	float t,w,h;
29	int32_t ix,jx;
30
31	GET_FLOAT_WORD(jx,x);
32	ix = jx&0x7fffffff;
33
34    /* x is INF or NaN */
35	if(ix>=0x7f800000) return x+x;
36
37	h = 0.5;
38	if (jx<0) h = -h;
39    /* |x| in [0,9], return sign(x)*0.5*(E+E/(E+1))) */
40	if (ix < 0x41100000) {		/* |x|<9 */
41	    if (ix<0x39800000) 		/* |x|<2**-12 */
42		if(shuge+x>one) return x;/* sinh(tiny) = tiny with inexact */
43	    t = expm1f(fabsf(x));
44	    if(ix<0x3f800000) return h*((float)2.0*t-t*t/(t+one));
45	    return h*(t+t/(t+one));
46	}
47
48    /* |x| in [9, logf(maxfloat)] return 0.5*exp(|x|) */
49	if (ix < 0x42b17217)  return h*__ieee754_expf(fabsf(x));
50
51    /* |x| in [logf(maxfloat), overflowthresold] */
52	if (ix<=0x42b2d4fc) {
53	    w = __ieee754_expf((float)0.5*fabsf(x));
54	    t = h*w;
55	    return t*w;
56	}
57
58    /* |x| > overflowthresold, sinh(x) overflow */
59	return x*shuge;
60}
61