GCC Code Coverage Report
Directory: ./ Exec Total Coverage
File: lib/libm/src/ld80/e_coshl.c Lines: 0 19 0.0 %
Date: 2017-11-13 Branches: 0 22 0.0 %

Line Branch Exec Source
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/* @(#)e_cosh.c 5.1 93/09/24 */
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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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/* coshl(x)
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 * Method :
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 * mathematically coshl(x) if defined to be (exp(x)+exp(-x))/2
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 *	1. Replace x by |x| (coshl(x) = coshl(-x)).
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 *	2.
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 *		                                        [ exp(x) - 1 ]^2
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 *	    0        <= x <= ln2/2  :  coshl(x) := 1 + -------------------
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 *						           2*exp(x)
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 *
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 *		                                   exp(x) +  1/exp(x)
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 *	    ln2/2    <= x <= 22     :  coshl(x) := -------------------
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 *						           2
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 *	    22       <= x <= lnovft :  coshl(x) := expl(x)/2
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 *	    lnovft   <= x <= ln2ovft:  coshl(x) := expl(x/2)/2 * expl(x/2)
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 *	    ln2ovft  <  x	    :  coshl(x) := huge*huge (overflow)
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 *
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 * Special cases:
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 *	coshl(x) is |x| if x is +INF, -INF, or NaN.
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 *	only coshl(0)=1 is exact for finite x.
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 */
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#include "math.h"
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#include "math_private.h"
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static const long double one = 1.0, half=0.5, huge = 1.0e4900L;
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long double
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coshl(long double x)
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{
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	long double t,w;
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	int32_t ex;
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	u_int32_t mx,lx;
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    /* High word of |x|. */
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	GET_LDOUBLE_WORDS(ex,mx,lx,x);
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	ex &= 0x7fff;
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    /* x is INF or NaN */
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	if(ex==0x7fff) return x*x;
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    /* |x| in [0,0.5*ln2], return 1+expm1l(|x|)^2/(2*expl(|x|)) */
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	if(ex < 0x3ffd || (ex == 0x3ffd && mx < 0xb17217f7u)) {
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	    t = expm1l(fabsl(x));
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	    w = one+t;
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	    if (ex<0x3fbc) return w;	/* cosh(tiny) = 1 */
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	    return one+(t*t)/(w+w);
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	}
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    /* |x| in [0.5*ln2,22], return (exp(|x|)+1/exp(|x|)/2; */
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	if (ex < 0x4003 || (ex == 0x4003 && mx < 0xb0000000u)) {
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		t = expl(fabsl(x));
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		return half*t+half/t;
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	}
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    /* |x| in [22, ln(maxdouble)] return half*exp(|x|) */
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	if (ex < 0x400c || (ex == 0x400c && mx < 0xb1700000u))
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		return half*expl(fabsl(x));
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    /* |x| in [log(maxdouble), log(2*maxdouble)) */
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	if (ex == 0x400c && (mx < 0xb174ddc0u
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			     || (mx == 0xb174ddc0u && lx < 0x31aec0ebu)))
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	{
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	    w = expl(half*fabsl(x));
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	    t = half*w;
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	    return t*w;
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	}
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    /* |x| >= log(2*maxdouble), cosh(x) overflow */
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	return huge*huge;
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}
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DEF_STD(coshl);