1 /* e_coshf.c -- float version of e_cosh.c.
5 * ====================================================
6 * Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved.
8 * Developed at SunPro, a Sun Microsystems, Inc. business.
9 * Permission to use, copy, modify, and distribute this
10 * software is freely granted, provided that this notice
12 * ====================================================
16 #include <math-narrow-eval.h>
17 #include <math_private.h>
18 #include <libm-alias-finite.h>
20 static const float huge
= 1.0e30
;
21 static const float one
= 1.0, half
=0.5;
24 __ieee754_coshf (float x
)
33 if (ix
< 0x41b00000) {
34 /* |x| in [0,0.5*ln2], return 1+expm1(|x|)^2/(2*exp(|x|)) */
36 if (ix
<0x24000000) return one
; /* cosh(tiny) = 1 */
37 t
= __expm1f(fabsf(x
));
39 return one
+(t
*t
)/(w
+w
);
42 /* |x| in [0.5*ln2,22], return (exp(|x|)+1/exp(|x|)/2; */
43 t
= __ieee754_expf(fabsf(x
));
47 /* |x| in [22, log(maxdouble)] return half*exp(|x|) */
48 if (ix
< 0x42b17180) return half
*__ieee754_expf(fabsf(x
));
50 /* |x| in [log(maxdouble), overflowthresold] */
52 w
= __ieee754_expf(half
*fabsf(x
));
58 if(ix
>=0x7f800000) return x
*x
;
60 /* |x| > overflowthresold, cosh(x) overflow */
61 return math_narrow_eval (huge
*huge
);
63 libm_alias_finite (__ieee754_coshf
, __coshf
)