diff options
Diffstat (limited to 'sysdeps/ieee754/flt-32/s_tanhf.c')
| -rw-r--r-- | sysdeps/ieee754/flt-32/s_tanhf.c | 67 |
1 files changed, 67 insertions, 0 deletions
diff --git a/sysdeps/ieee754/flt-32/s_tanhf.c b/sysdeps/ieee754/flt-32/s_tanhf.c new file mode 100644 index 0000000000..2a0ca9f3df --- /dev/null +++ b/sysdeps/ieee754/flt-32/s_tanhf.c @@ -0,0 +1,67 @@ +/* s_tanhf.c -- float version of s_tanh.c. + * Conversion to float by Ian Lance Taylor, Cygnus Support, ian@cygnus.com. + */ + +/* + * ==================================================== + * Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved. + * + * Developed at SunPro, a Sun Microsystems, Inc. business. + * Permission to use, copy, modify, and distribute this + * software is freely granted, provided that this notice + * is preserved. + * ==================================================== + */ + +#if defined(LIBM_SCCS) && !defined(lint) +static char rcsid[] = "$NetBSD: s_tanhf.c,v 1.4 1995/05/10 20:48:24 jtc Exp $"; +#endif + +#include "math.h" +#include "math_private.h" + +#ifdef __STDC__ +static const float one=1.0, two=2.0, tiny = 1.0e-30; +#else +static float one=1.0, two=2.0, tiny = 1.0e-30; +#endif + +#ifdef __STDC__ + float __tanhf(float x) +#else + float __tanhf(x) + float x; +#endif +{ + float t,z; + int32_t jx,ix; + + GET_FLOAT_WORD(jx,x); + ix = jx&0x7fffffff; + + /* x is INF or NaN */ + if(ix>=0x7f800000) { + if (jx>=0) return one/x+one; /* tanh(+-inf)=+-1 */ + else return one/x-one; /* tanh(NaN) = NaN */ + } + + /* |x| < 22 */ + if (ix < 0x41b00000) { /* |x|<22 */ + if (ix == 0) + return x; /* x == +-0 */ + if (ix<0x24000000) /* |x|<2**-55 */ + return x*(one+x); /* tanh(small) = small */ + if (ix>=0x3f800000) { /* |x|>=1 */ + t = __expm1f(two*fabsf(x)); + z = one - two/(t+two); + } else { + t = __expm1f(-two*fabsf(x)); + z= -t/(t+two); + } + /* |x| > 22, return +-1 */ + } else { + z = one - tiny; /* raised inexact flag */ + } + return (jx>=0)? z: -z; +} +weak_alias (__tanhf, tanhf) |