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 * ====================================================
16 #include <sys/cdefs.h>
17 __FBSDID("$FreeBSD$");
20 #include "math_private.h"
22 static const float one = 1.0, half=0.5, huge = 1.0e30;
25 __ieee754_coshf(float x)
34 if(ix>=0x7f800000) return x*x;
36 /* |x| in [0,0.5*ln2], return 1+expm1(|x|)^2/(2*exp(|x|)) */
40 if (ix<0x39800000) return one; /* cosh(tiny) = 1 */
41 return one+(t*t)/(w+w);
44 /* |x| in [0.5*ln2,9], return (exp(|x|)+1/exp(|x|))/2; */
45 if (ix < 0x41100000) {
46 t = __ieee754_expf(fabsf(x));
50 /* |x| in [9, log(maxfloat)] return half*exp(|x|) */
51 if (ix < 0x42b17217) return half*__ieee754_expf(fabsf(x));
53 /* |x| in [log(maxfloat), overflowthresold] */
55 w = __ieee754_expf(half*fabsf(x));
60 /* |x| > overflowthresold, cosh(x) overflow */