1/* e_coshf.c -- float version of e_cosh.c.
2 * Conversion to float by Ian Lance Taylor, Cygnus Support, ian@cygnus.com.
3 * Optimizations by Ulrich Drepper <drepper@gmail.com>, 2011
4 */
5
6/*
7 * ====================================================
8 * Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved.
9 *
10 * Developed at SunPro, a Sun Microsystems, Inc. business.
11 * Permission to use, copy, modify, and distribute this
12 * software is freely granted, provided that this notice
13 * is preserved.
14 * ====================================================
15 */
16
17#include <math.h>
18#include <math-narrow-eval.h>
19#include <math_private.h>
20
21static const float huge = 1.0e30;
22static const float one = 1.0, half=0.5;
23
24float
25__ieee754_coshf (float x)
26{
27 float t,w;
28 int32_t ix;
29
30 GET_FLOAT_WORD(ix,x);
31 ix &= 0x7fffffff;
32
33 /* |x| in [0,22] */
34 if (ix < 0x41b00000) {
35 /* |x| in [0,0.5*ln2], return 1+expm1(|x|)^2/(2*exp(|x|)) */
36 if(ix<0x3eb17218) {
37 if (ix<0x24000000) return one; /* cosh(tiny) = 1 */
38 t = __expm1f(fabsf(x));
39 w = one+t;
40 return one+(t*t)/(w+w);
41 }
42
43 /* |x| in [0.5*ln2,22], return (exp(|x|)+1/exp(|x|)/2; */
44 t = __ieee754_expf(fabsf(x));
45 return half*t+half/t;
46 }
47
48 /* |x| in [22, log(maxdouble)] return half*exp(|x|) */
49 if (ix < 0x42b17180) return half*__ieee754_expf(fabsf(x));
50
51 /* |x| in [log(maxdouble), overflowthresold] */
52 if (ix<=0x42b2d4fc) {
53 w = __ieee754_expf(half*fabsf(x));
54 t = half*w;
55 return t*w;
56 }
57
58 /* x is INF or NaN */
59 if(ix>=0x7f800000) return x*x;
60
61 /* |x| > overflowthresold, cosh(x) overflow */
62 return math_narrow_eval (huge*huge);
63}
64strong_alias (__ieee754_coshf, __coshf_finite)
65