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
  16 #include <sys/cdefs.h>
  17 #if defined(LIBM_SCCS) && !defined(lint)
  18 __RCSID("$NetBSD: s_asinhf.c,v 1.8 2002/05/26 22:01:54 wiz Exp $");
  19 #endif
  20
  21 #include "math.h"
  22 #include "math_private.h"
  23
  24 static const float
  25 one =  1.0000000000e+00, /* 0x3F800000 */
  26 ln2 =  6.9314718246e-01, /* 0x3f317218 */
  27 huge=  1.0000000000e+30;
  28
  29 float
  30 asinhf(float x)
  31 {
  32         float t,w;
  33         int32_t hx,ix;
  34         GET_FLOAT_WORD(hx,x);
  35         ix = hx&0x7fffffff;
  36         if(ix>=0x7f800000) return x+x;  /* x is inf or NaN */
  37         if(ix< 0x31800000) {    /* |x|<2**-28 */
  38             if(huge+x>one) return x;    /* return x inexact except 0 */
  39         }
  40         if(ix>0x4d800000) {     /* |x| > 2**28 */
  41             w = __ieee754_logf(fabsf(x))+ln2;
  42         } else if (ix>0x40000000) {     /* 2**28 > |x| > 2.0 */
  43             t = fabsf(x);
  44             w = __ieee754_logf((float)2.0*t+one/(__ieee754_sqrtf(x*x+one)+t));
  45         } else {                /* 2.0 > |x| > 2**-28 */
  46             t = x*x;
  47             w =log1pf(fabsf(x)+t/(one+__ieee754_sqrtf(one+t)));
  48         }
  49         if(hx>0) return w; else return -w;
  50 }