/* e_atanhf.c -- float version of e_atanh.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. * ==================================================== */ #include <sys/cdefs.h> #if defined(LIBM_SCCS) && !defined(lint) __RCSID("$NetBSD: e_atanhf.c,v 1.7 2002/05/26 22:01:49 wiz Exp $"); #endif #include "math.h" #include "math_private.h" static const float one = 1.0, huge = 1e30; static const float zero = 0.0; float __ieee754_atanhf(float x) { float t; int32_t hx,ix; GET_FLOAT_WORD(hx,x); ix = hx&0x7fffffff; if (ix>0x3f800000) /* |x|>1 */ return (x-x)/(x-x); if(ix==0x3f800000) return x/zero; if(ix<0x31800000&&(huge+x)>zero) return x; /* x<2**-28 */ SET_FLOAT_WORD(x,ix); if(ix<0x3f000000) { /* x < 0.5 */ t = x+x; t = (float)0.5*log1pf(t+t*x/(one-x)); } else t = (float)0.5*log1pf((x+x)/(one-x)); if(hx>=0) return t; else return -t; } |