1 /* e_atanhf.c -- float version of e_atanh.c. 2 * Conversion to float by Ian Lance Taylor, Cygnus Support, ian@cygnus.com. 3 */ 4 5 /* 6 * ==================================================== 7 * Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved. 8 * 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 12 * is preserved. 13 * ==================================================== 14 */ 15 16 #include <sys/cdefs.h> 17 #if defined(LIBM_SCCS) && !defined(lint) 18 __RCSID("$NetBSD: e_atanhf.c,v 1.6 1999/07/02 15:37:38 simonb Exp $"); 19 #endif 20 21 #include "math.h" 22 #include "math_private.h" 23 24 #ifdef __STDC__ 25 static const float one = 1.0, huge = 1e30; 26 #else 27 static float one = 1.0, huge = 1e30; 28 #endif 29 30 #ifdef __STDC__ 31 static const float zero = 0.0; 32 #else 33 static float zero = 0.0; 34 #endif 35 36 #ifdef __STDC__ 37 float __ieee754_atanhf(float x) 38 #else 39 float __ieee754_atanhf(x) 40 float x; 41 #endif 42 { 43 float t; 44 int32_t hx,ix; 45 GET_FLOAT_WORD(hx,x); 46 ix = hx&0x7fffffff; 47 if (ix>0x3f800000) /* |x|>1 */ 48 return (x-x)/(x-x); 49 if(ix==0x3f800000) 50 return x/zero; 51 if(ix<0x31800000&&(huge+x)>zero) return x; /* x<2**-28 */ 52 SET_FLOAT_WORD(x,ix); 53 if(ix<0x3f000000) { /* x < 0.5 */ 54 t = x+x; 55 t = (float)0.5*log1pf(t+t*x/(one-x)); 56 } else 57 t = (float)0.5*log1pf((x+x)/(one-x)); 58 if(hx>=0) return t; else return -t; 59 } 60