1 /* e_coshf.c -- float version of e_cosh.c.
2 * Conversion to float by Ian Lance Taylor, Cygnus Support, ian@cygnus.com.
6 * ====================================================
7 * Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved.
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
13 * ====================================================
17 #include "math_private.h"
19 static const float one = 1.0, half=0.5, huge = 1.0e30;
31 if(ix>=0x7f800000) return x*x;
33 /* |x| in [0,0.5*ln2], return 1+expm1(|x|)^2/(2*exp(|x|)) */
37 if (ix<0x39800000) return one; /* cosh(tiny) = 1 */
38 return one+(t*t)/(w+w);
41 /* |x| in [0.5*ln2,9], return (exp(|x|)+1/exp(|x|))/2; */
42 if (ix < 0x41100000) {
47 /* |x| in [9, log(maxfloat)] return half*exp(|x|) */
48 if (ix < 0x42b17217) return half*expf(fabsf(x));
50 /* |x| in [log(maxfloat), overflowthresold] */
52 return __ldexp_expf(fabsf(x), -1);
54 /* |x| > overflowthresold, cosh(x) overflow */