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Viewing changes to android/bionic/libm/src/e_acoshf.c

  • Committer: Package Import Robot
  • Author(s): Dmitrijs Ledkovs
  • Date: 2013-07-05 10:12:24 UTC
  • Revision ID: package-import@ubuntu.com-20130705101224-6qo3e8jbz8p31aa1
Tags: upstream-0.20130705.1
Import upstream version 0.20130705.1

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android/bionic/libm/src/e_acoshf.c
 
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/* e_acoshf.c -- float version of e_acosh.c.
 
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 * Conversion to float by Ian Lance Taylor, Cygnus Support, ian@cygnus.com.
 
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 */
 
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/*
 
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 * ====================================================
 
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 * Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved.
 
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 *
 
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 * Developed at SunPro, a Sun Microsystems, Inc. business.
 
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 * Permission to use, copy, modify, and distribute this
 
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 * software is freely granted, provided that this notice
 
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 * is preserved.
 
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 * ====================================================
 
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 */
 
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#ifndef lint
 
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static char rcsid[] = "$FreeBSD: src/lib/msun/src/e_acoshf.c,v 1.7 2002/05/28 17:03:12 alfred Exp $";
 
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#endif
 
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#include "math.h"
 
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#include "math_private.h"
 
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static const float
 
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one     = 1.0,
 
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ln2     = 6.9314718246e-01;  /* 0x3f317218 */
 
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float
 
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__ieee754_acoshf(float x)
 
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{
 
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        float t;
 
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        int32_t hx;
 
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        GET_FLOAT_WORD(hx,x);
 
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        if(hx<0x3f800000) {             /* x < 1 */
 
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            return (x-x)/(x-x);
 
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        } else if(hx >=0x4d800000) {    /* x > 2**28 */
 
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            if(hx >=0x7f800000) {       /* x is inf of NaN */
 
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                return x+x;
 
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            } else
 
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                return __ieee754_logf(x)+ln2;   /* acosh(huge)=log(2x) */
 
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        } else if (hx==0x3f800000) {
 
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            return 0.0;                 /* acosh(1) = 0 */
 
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        } else if (hx > 0x40000000) {   /* 2**28 > x > 2 */
 
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            t=x*x;
 
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            return __ieee754_logf((float)2.0*x-one/(x+__ieee754_sqrtf(t-one)));
 
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        } else {                        /* 1<x<2 */
 
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            t = x-one;
 
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            return log1pf(t+__ieee754_sqrtf((float)2.0*t+t*t));
 
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        }
 
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}