kernel/eka/euser/maths/um_mod.cpp
author Mark Wilcox <markw@symbian.org>
Tue, 25 May 2010 13:20:47 +0100
changeset 116 57eea1054f46
parent 0 a41df078684a
permissions -rw-r--r--
Use RVCT assembler for __crash() when running armcc with the --gnu option. Fix for bug 2742.
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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 "Eclipse Public License v1.0"
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// which accompanies this distribution, and is available
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// at the URL "http://www.eclipse.org/legal/epl-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_mod.cpp
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// Writes the remainder of aSrc/aModulus to aTrg
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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::Mod(TReal &aTrg,const TReal &aSrc,const TReal &aModulus)
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/**
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Calculates the modulo remainder.
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This is the value of p mod q, the modulo remainder when dividing p by q.
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The result is given by p - q int (p/q):
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it has the same sign as p:
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thus, 5 mod 3 = 2, -5 mod 3 = -2.
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No error is raised if non-integer arguments are passed.
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@param aTrg      A reference containing the result.
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@param aSrc      The p argument to the mod function.
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@param aModulus  The q argument to the mod function.
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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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// Floating point modulo arithmetic.
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//
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	{
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	TRealX f1,f2;
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	TInt r=f1.Set(aSrc);
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	if (r!=KErrNone)
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		{
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		SetNaN(aTrg);
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		return KErrArgument;
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		}
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	r=f2.Set(aModulus);
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	if (r==KErrArgument || f2.IsZero())
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		{
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		SetNaN(aTrg);
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		return KErrArgument;
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		}
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	if (r==KErrOverflow)
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		{
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		aTrg=aSrc;
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		return KErrNone;
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		}
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	if ((TInt(f1.iExp)-TInt(f2.iExp))>KMantissaBits)
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		{
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		SetZero(aTrg);
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		return KErrTotalLossOfPrecision;
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		}
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	f1.ModEq(f2);
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	return f1.GetTReal(aTrg);
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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 fmod(TReal,TReal);
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EXPORT_C TInt Math::Mod(TReal& aTrg, const TReal& aSrc, const TReal &aModulus)
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	{
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	SReal64 *pSrc=(SReal64 *)&aSrc;
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	SReal64 *pModulus=(SReal64 *)&aModulus;
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	if (pSrc->exp==0 || pModulus->exp==0 || pSrc->exp==KSpecialExponent || pModulus->exp==KSpecialExponent)
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		{
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		TRealX f1,f2;
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		TInt r=f1.Set(aSrc);
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		if (r!=KErrNone)
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			{
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			SetNaN(aTrg);
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			return KErrArgument;
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			}
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		r=f2.Set(aModulus);
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		if (r==KErrArgument || f2.IsZero())
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			{
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			SetNaN(aTrg);
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			return KErrArgument;
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			}
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		if (r==KErrOverflow)
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			{
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			aTrg=aSrc;
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			return KErrNone;
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			}
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		if ((TInt(f1.iExp)-TInt(f2.iExp))>KMantissaBits)
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			{
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			SetZero(aTrg);
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			return KErrTotalLossOfPrecision;
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			}
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		}
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	else if ((pSrc->exp - pModulus->exp) > KMantissaBits)
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		{
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		SetZero(aTrg);
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		return KErrTotalLossOfPrecision;
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		}
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	aTrg = fmod(aSrc,aModulus);
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	return KErrNone;
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	}
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#endif