symport/e32/euser/maths/um_log.cpp
author Pat Downey <patrick.downey@nokia.com>
Thu, 25 Jun 2009 15:59:54 +0100
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// Copyright (c) 1995-2009 Nokia Corporation and/or its subsidiary(-ies).
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// All rights reserved.
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// This component and the accompanying materials are made available
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// under the terms of the License "Symbian Foundation License v1.0"
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// which accompanies this distribution, and is available
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// at the URL "http://www.symbianfoundation.org/legal/sfl-v10.html".
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//
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// Initial Contributors:
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// Nokia Corporation - initial contribution.
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//
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// Contributors:
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//
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// Description:
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// e32\euser\maths\um_log.cpp
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// Floating point base 10 logarithm
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// 
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//
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#include "um_std.h"
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#if defined(__USE_VFP_MATH) && !defined(__CPU_HAS_VFP)
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#error	__USE_VFP_MATH was defined but not __CPU_HAS_VFP - impossible combination, check variant.mmh 
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#endif
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#ifndef __USE_VFP_MATH
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EXPORT_C TInt Math::Log(TReal &aTrg,const TReal &aSrc)
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/**
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Calculates the logarithm to base 10 of a number.
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@param aTrg  A reference containing the result. 
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@param aSrc  The number whose logarithm is required. 
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@return KErrNone if successful, otherwise another of
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        the system-wide error codes. 
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*/
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//
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// Base 10 log routine. See Software manual by W.J.Cody & W.Waite
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//
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	{
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	TInt ret=Math::Ln(aTrg,aSrc);
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	if (ret!=KErrNone)
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		return(ret);    	
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	aTrg*=KRln10;
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	return(ret);
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	}
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#else // __USE_VFP_MATH
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// definitions come from RVCT math library
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extern "C" TReal log10(TReal);
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EXPORT_C TInt Math::Log(TReal& aTrg, const TReal& aSrc)
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	{
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	aTrg = log10(aSrc);
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	if (Math::IsFinite(aTrg))
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		return KErrNone;
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	if (Math::IsInfinite(aTrg))
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		return KErrOverflow;
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	SetNaN(aTrg);
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	return KErrArgument;
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	}
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#endif