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[] = "$Id$"; 18 #endif 19 20 #include "math.h" 21 #include "math_private.h" 22 23 #ifdef __STDC__ 24 static const float one = 1.0, huge = 1e30; 25 #else 26 static float one = 1.0, huge = 1e30; 27 #endif 28 29 #ifdef __STDC__ 30 static const float zero = 0.0; 31 #else 32 static float zero = 0.0; 33 #endif 34 35 #ifdef __STDC__ 36 float __ieee754_atanhf(float x) 37 #else 38 float __ieee754_atanhf(x) 39 float x; 40 #endif 41 { 42 float t; 43 int32_t hx,ix; 44 GET_FLOAT_WORD(hx,x); 45 ix = hx&0x7fffffff; 46 if (ix>0x3f800000) /* |x|>1 */ 47 return (x-x)/(x-x); 48 if(ix==0x3f800000) 49 return x/zero; 50 if(ix<0x31800000&&(huge+x)>zero) return x; /* x<2**-28 */ 51 SET_FLOAT_WORD(x,ix); 52 if(ix<0x3f000000) { /* x < 0.5 */ 53 t = x+x; 54 t = (float)0.5*log1pf(t+t*x/(one-x)); 55 } else 56 t = (float)0.5*log1pf((x+x)/(one-x)); 57 if(hx>=0) return t; else return -t; 58 } 59