e_sinhf.c revision 22993 
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[] = "$Id$";
18#endif
19
20#include "math.h"
21#include "math_private.h"
22
23#ifdef __STDC__
24static const float one = 1.0, shuge = 1.0e37;
25#else
26static float one = 1.0, shuge = 1.0e37;
27#endif
28
29#ifdef __STDC__
30	float __ieee754_sinhf(float x)
31#else
32	float __ieee754_sinhf(x)
33	float x;
34#endif
35{
36	float t,w,h;
37	int32_t ix,jx;
38
39	GET_FLOAT_WORD(jx,x);
40	ix = jx&0x7fffffff;
41
42    /* x is INF or NaN */
43	if(ix>=0x7f800000) return x+x;
44
45	h = 0.5;
46	if (jx<0) h = -h;
47    /* |x| in [0,22], return sign(x)*0.5*(E+E/(E+1))) */
48	if (ix < 0x41b00000) {		/* |x|<22 */
49	    if (ix<0x31800000) 		/* |x|<2**-28 */
50		if(shuge+x>one) return x;/* sinh(tiny) = tiny with inexact */
51	    t = expm1f(fabsf(x));
52	    if(ix<0x3f800000) return h*((float)2.0*t-t*t/(t+one));
53	    return h*(t+t/(t+one));
54	}
55
56    /* |x| in [22, log(maxdouble)] return 0.5*exp(|x|) */
57	if (ix < 0x42b17180)  return h*__ieee754_expf(fabsf(x));
58
59    /* |x| in [log(maxdouble), overflowthresold] */
60	if (ix<=0x42b2d4fc) {
61	    w = __ieee754_expf((float)0.5*fabsf(x));
62	    t = h*w;
63	    return t*w;
64	}
65
66    /* |x| > overflowthresold, sinh(x) overflow */
67	return x*shuge;
68}
69