1 /* s_tanhf.c -- float version of s_tanh.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 static char rcsid
[] = "$FreeBSD: src/lib/msun/src/s_tanhf.c,v 1.9 2008/02/22 02:30:36 das Exp $";
21 #include "math_private.h"
23 static const volatile float tiny
__attribute__ ((__section__(".rodata"))) = 1.0e-30;
24 static const float one
=1.0, two
=2.0, huge
= 1.0e30
;
37 if (jx
>=0) return one
/x
+one
; /* tanh(+-inf)=+-1 */
38 else return one
/x
-one
; /* tanh(NaN) = NaN */
42 if (ix
< 0x41100000) { /* |x|<9 */
43 if (ix
<0x39800000) { /* |x|<2**-12 */
44 if(huge
+x
>one
) return x
; /* tanh(tiny) = tiny with inexact */
46 if (ix
>=0x3f800000) { /* |x|>=1 */
47 t
= expm1f(two
*fabsf(x
));
48 z
= one
- two
/(t
+two
);
50 t
= expm1f(-two
*fabsf(x
));
53 /* |x| >= 9, return +-1 */
55 z
= one
- tiny
; /* raise inexact flag */
57 return (jx
>=0)? z
: -z
;