mirror of
https://github.com/autc04/Retro68.git
synced 2024-12-04 01:50:38 +00:00
55 lines
1.2 KiB
C
55 lines
1.2 KiB
C
/* ef_atanh.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 "fdlibm.h"
|
|
|
|
#ifdef __STDC__
|
|
static const float one = 1.0, huge = 1e30;
|
|
#else
|
|
static float one = 1.0, huge = 1e30;
|
|
#endif
|
|
|
|
#ifdef __STDC__
|
|
static const float zero = 0.0;
|
|
#else
|
|
static float zero = 0.0;
|
|
#endif
|
|
|
|
#ifdef __STDC__
|
|
float atanhf(float x)
|
|
#else
|
|
float atanhf(x)
|
|
float x;
|
|
#endif
|
|
{
|
|
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;
|
|
}
|