// Copyright (c) 1995-2009 Nokia Corporation and/or its subsidiary(-ies).

// All rights reserved.

// This component and the accompanying materials are made available

// under the terms of the License "Eclipse Public License v1.0"

// which accompanies this distribution, and is available

// at the URL "http://www.eclipse.org/legal/epl-v10.html".

//

// Initial Contributors:

// Nokia Corporation - initial contribution.

//

// Contributors:

//

// Description:

// e32\euser\maths\um_sin.cpp

// Floating point sine and cosine functions

// 

//

#include "um_std.h"

#if defined(__USE_VFP_MATH) && !defined(__CPU_HAS_VFP)

#error	__USE_VFP_MATH was defined but not __CPU_HAS_VFP - impossible combination, check variant.mmh 

#endif

#ifndef __USE_VFP_MATH

LOCAL_D const TUint32 SinCoeffs[] =

	{

	0x2168C235,0xC90FDAA2,0x80000000,	// polynomial approximation to sin(pi*x)

	0x2DF200BF,0xA55DE731,0x80010001,	// for |x| <= 0.25

	0xAC273AA1,0xA335E33B,0x80000000,

	0x5AB23F44,0x99696671,0x7FFE0001,

	0xD585EAFE,0xA83C17D9,0x7FFB0000,

	0xA30DE7AD,0xF1802BAC,0x7FF70001,

	0xF57FD821,0xF1F6A1C9,0x7FF30000

	};

LOCAL_D const TUint32 CosCoeffs[] =

	{

	0x00000000,0x80000000,0x7FFF0000,	// polynomial approximation to cos(pi*x)

	0xF22EF286,0x9DE9E64D,0x80010001,	// for |x| <= 0.25

	0xDAD59F90,0x81E0F840,0x80010000,

	0xE4E45144,0xAAE9E3F1,0x7FFF0001,

	0x3232D733,0xF0FA8342,0x7FFC0000,

	0x03E16BB8,0xD368F6A3,0x7FF90001,

	0x712FD084,0xFCE66DE2,0x7FF50000,

	0x9E5353EE,0xD94951B0,0x7FF10001

	};

LOCAL_D const TUint32 PiInvdata[] = {0x4E44152A,0xA2F9836E,0x7FFD0000};			// 1/pi

LOCAL_D const TUint32 Halfdata[] = {0x00000000,0x80000000,0x7FFE0000};			// 0.5

LOCAL_D const TUint32 Onedata[] = {0x00000000,0x80000000,0x7FFF0000};			// 1.0

LOCAL_C TInt CalcSinCos(TReal& aTrg, TRealX& aSrc, TBool aCos)

	{

	// Calculate sin(aSrc) if aCos=false or cos(aSrc) if aCos=true

	// and write result to aTrg.

	// Algorithm:

	//		Divide aSrc by pi and throw away integer part, but change sign

	//			of result if integer part odd. Replace aSrc with remainder.

	//			( use identities	sin(x+n*pi)=(-1)^n*sin(x)

	//								cos(x+n*pi)=(-1)^n*cos(x) )

	//		If aSrc>=0.5 replace aSrc with 1-aSrc, and change sign of result

	//			if cos required.

	//			( use identities sin(pi-x)=sin(x), cos(pi-x)=-cos(x) )

	//		If aSrc>=0.25 replace aSrc with 0.5-aSrc and swap sin and cos

	//			( use identities sin(pi/2-x)=cos(x), cos(pi/2-x)=sin(x) )

	//		Use polynomial approximation to evaluate sin(pi*x) or cos(pi*x)

	//		for |x|<=0.25

	const TRealX& One = *(const TRealX*)Onedata;

	const TRealX& Half = *(const TRealX*)Halfdata;

	const TRealX& PiInv = *(const TRealX*)PiInvdata;

	TRealX y;

	aSrc*=PiInv;

	TInt n=(TInt)aSrc;

	if (n<KMaxTInt && n>KMinTInt)

		{

		aSrc-=TRealX(n);

		TInt sign=0;

		if (!aCos)

			sign=aSrc.iSign & 1;

		sign^=n;

		aSrc.iSign=0;

		if (aSrc.iExp>=0x7FFE)			// if remainder>=pi/2

			{

			aSrc=One-aSrc;

			if (aCos)

				sign^=1;

			}

		if (aSrc.iExp>=0x7FFD)			// if remainder>=pi/4

			{

			aSrc=Half-aSrc;				// take complementary angle

			aCos=!aCos;					// and swap sin and cos

			}

		if (aCos)

			Math::PolyX(y,aSrc*aSrc,7,(const TRealX*)CosCoeffs);

		else

			{

			Math::PolyX(y,aSrc*aSrc,6,(const TRealX*)SinCoeffs);

			y*=aSrc;

			}

		if (sign & 1)

			y=-y;

		return y.GetTReal(aTrg);

		}

	return KErrArgument;

	}

EXPORT_C TInt Math::Sin(TReal& aTrg, const TReal& aSrc)

/**

Calculates the sine of a number.

@param aTrg A reference containing the result. 

@param aSrc The argument of the sin function in radians.

@return KErrNone if successful, otherwise another of

        the system-wide error codes.

*/

	{

	TRealX x;

	TInt r=x.Set(aSrc);

	if (r==KErrNone)

		r=CalcSinCos(aTrg,x,EFalse);

	if (r==KErrNone)

		return r;

	SetNaN(aTrg);

	return KErrArgument;

	}

EXPORT_C TInt Math::Cos(TReal& aTrg, const TReal& aSrc)

/**

Calculates the cosine of a number.

@param aTrg A reference containing the result. 

@param aSrc The argument of the cos function in radians

@return KErrNone if successful, otherwise another of

        the system-wide error codes.

*/

	{

	TRealX x;

	TInt r=x.Set(aSrc);

	if (r==KErrNone)

		r=CalcSinCos(aTrg,x,ETrue);

	if (r==KErrNone)

		return r;

	SetNaN(aTrg);

	return KErrArgument;

	}

#else // __USE_VFP_MATH

// definitions come from RVCT math library

extern "C" TReal sin(TReal);

extern "C" TReal cos(TReal);

EXPORT_C TInt Math::Sin(TReal& aTrg, const TReal& aSrc)

	{

	if (aSrc<KMaxTInt && aSrc>KMinTInt)

		{

		aTrg = sin(aSrc);

		if (Math::IsFinite(aTrg))

			return KErrNone;

		}

	SetNaN(aTrg);

	return KErrArgument;

	}

EXPORT_C TInt Math::Cos(TReal& aTrg, const TReal& aSrc)

	{

	if (aSrc<KMaxTInt && aSrc>KMinTInt)

		{

		aTrg = cos(aSrc);

		if (Math::IsFinite(aTrg))

			return KErrNone;

		}

	SetNaN(aTrg);

	return KErrArgument;

	}

#endif