lib/libm/src/s_asinhf.c

   1 /* s_asinhf.c -- float version of s_asinh.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  * $NetBSD: s_asinhf.c,v 1.8 2002/05/26 22:01:54 wiz Exp $
  16  * $DragonFly: src/lib/libm/src/s_asinhf.c,v 1.1 2005/07/26 21:15:20 joerg Exp $
  17  */
  18
  19 #include <math.h>
  20 #include "math_private.h"
  21
  22 static const float
  23 one =  1.0000000000e+00, /* 0x3F800000 */
  24 ln2 =  6.9314718246e-01, /* 0x3f317218 */
  25 huge=  1.0000000000e+30;
  26
  27 float
  28 asinhf(float x)
  29 {
  30         float t,w;
  31         int32_t hx,ix;
  32         GET_FLOAT_WORD(hx,x);
  33         ix = hx&0x7fffffff;
  34         if(ix>=0x7f800000) return x+x;  /* x is inf or NaN */
  35         if(ix< 0x31800000) {    /* |x|<2**-28 */
  36             if(huge+x>one) return x;    /* return x inexact except 0 */
  37         }
  38         if(ix>0x4d800000) {     /* |x| > 2**28 */
  39             w = logf(fabsf(x))+ln2;
  40         } else if (ix>0x40000000) {     /* 2**28 > |x| > 2.0 */
  41             t = fabsf(x);
  42             w = logf((float)2.0*t+one/(sqrtf(x*x+one)+t));
  43         } else {                /* 2.0 > |x| > 2**-28 */
  44             t = x*x;
  45             w =log1pf(fabsf(x)+t/(one+sqrtf(one+t)));
  46         }
  47         if(hx>0) return w; else return -w;
  48 }