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 #ifndef lint 17 static char rcsid[] = "$FreeBSD$"; 18 #endif 19 20 #include "math.h" 21 #include "math_private.h" 22 23 static const float one = 1.0, huge = 1e30; 24 25 static const float zero = 0.0; 26 27 float 28 __ieee754_atanhf(float x) 29 { 30 float t; 31 int32_t hx,ix; 32 GET_FLOAT_WORD(hx,x); 33 ix = hx&0x7fffffff; 34 if (ix>0x3f800000) /* |x|>1 */ 35 return (x-x)/(x-x); 36 if(ix==0x3f800000) 37 return x/zero; 38 if(ix<0x31800000&&(huge+x)>zero) return x; /* x<2**-28 */ 39 SET_FLOAT_WORD(x,ix); 40 if(ix<0x3f000000) { /* x < 0.5 */ 41 t = x+x; 42 t = (float)0.5*log1pf(t+t*x/(one-x)); 43 } else 44 t = (float)0.5*log1pf((x+x)/(one-x)); 45 if(hx>=0) return t; else return -t; 46 } 47