--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/kernel/eka/euser/maths/um_asin.cpp	Thu Dec 17 09:24:54 2009 +0200
@@ -0,0 +1,183 @@
+// 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_asin.cpp
+// Arc sin.
+// 
+//
+
+#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 ArcsinCoeffs[] =
+	{
+	0x00000000,0x80000000,0x7FFF0000,	// polynomial approximation to arcsin(x)
+	0xAA893CD8,0xAAAAAAAA,0x7FFC0000,	// for -0.5<=x<=0.5
+	0xD07ED410,0x99999999,0x7FFB0000,
+	0xB6C64A72,0xB6DB6D94,0x7FFA0000,
+	0xF5527DD4,0xF8E3995C,0x7FF90000,
+	0xA87499FB,0xB744B969,0x7FF90000,
+	0x2E8953AD,0x8E392B24,0x7FF90000,
+	0xFEDBB4E4,0xE3481C4A,0x7FF80000,
+	0x4A32ED70,0xC89998E1,0x7FF80000,
+	0x848A2B53,0xCCAE4AE5,0x7FF70000,
+	0x09C1F387,0xA587A043,0x7FF90000,
+	0x722B9041,0x8C9BD20B,0x7FF90001,
+	0xC88B75CC,0x850CE779,0x7FFA0000
+	};
+
+LOCAL_D const TUint32 Onedata[] = {0x00000000,0x80000000,0x7FFF0000};		// 1.0
+LOCAL_D const TUint32 Halfdata[] = {0x00000000,0x80000000,0x7FFE0000};		// 0.5
+LOCAL_D const TUint32 Pidata[] = {0x2168C235,0xC90FDAA2,0x80000000};		// pi
+LOCAL_D const TUint32 PiBy2data[] = {0x2168C235,0xC90FDAA2,0x7FFF0000};		// pi/2
+
+LOCAL_C TInt CalcArcsinArccos(TReal& aTrg, TRealX& x, TBool aCos)
+	{
+	//	Calculate arcsin (if aCos false) or arccos (if aCos true) of x
+	//	and write result to aTrg.
+	//	Algorithm (arcsin):
+	//		If x>0.5, replace x with Sqrt((1-x)/2)
+	//			( use identity cos(x)=2(cos(x/2))^2-1 )
+	//		Use polynomial approximation for arcsin(x), 0<=x<=0.5
+	//		If original x>0.5, replace result y with pi/2-2y
+
+	const TRealX One = *(const TRealX*)Onedata;
+	const TRealX Half = *(const TRealX*)Halfdata;
+	const TRealX Pi = *(const TRealX*)Pidata;
+	const TRealX PiBy2 = *(const TRealX*)PiBy2data;
+
+	TInt sign=x.iSign&1;
+	x.iSign=0;
+	if (x<=One)
+		{
+		TBool big=(x>Half);
+		if (big)
+			{
+			x=One-x;
+			if (x.iExp>1)
+				x.iExp--;
+			TReal temp;
+			Math::Sqrt(temp, (TReal)x);
+			x=temp;
+			}
+		TRealX y;
+		Math::PolyX(y,x*x,12,(const TRealX*)ArcsinCoeffs);
+		y*=x;
+		if (big)
+			{
+			if (y.iExp)
+				y.iExp++;
+			if (aCos)
+				{
+				if (sign)
+					y=Pi-y;
+				}
+			else
+				{
+				y=PiBy2-y;
+				y.iSign=TInt8(sign);
+				}
+			}
+		else
+			{
+			y.iSign=TInt8(sign);
+			if (aCos)
+				y=PiBy2-y;
+			}
+		return y.GetTReal(aTrg);
+		}
+	return KErrArgument;
+	}
+
+
+
+
+EXPORT_C TInt Math::ASin(TReal& aTrg, const TReal& aSrc)
+/**
+Calculates the principal value of the inverse sine of a number.
+
+@param aTrg A reference containing the result in radians,
+            a value between -pi/2 and +pi/2. 
+@param aSrc The argument of the arcsin function, a value
+            between -1 and +1 inclusive.
+
+@return KErrNone if successful, otherwise another of the system-wide
+        error codes.
+*/
+	{
+	TRealX x;
+	TInt r=x.Set(aSrc);
+	if (r==KErrNone)
+		r=CalcArcsinArccos(aTrg,x,EFalse);
+	if (r==KErrNone)
+		return r;
+	SetNaN(aTrg);
+	return KErrArgument;
+	}
+
+
+
+
+EXPORT_C TInt Math::ACos(TReal& aTrg, const TReal& aSrc)
+/**
+Calculates the principal value of the inverse cosine of a number.
+
+@param aTrg A reference containing the result in radians,
+            a value between 0 and pi. 
+@param aSrc The argument of the arccos function, a value
+            between -1 and +1 inclusive. 
+
+@return KErrNone if successful, otherwise another of the system-wide
+        error codes.
+*/
+	{
+	TRealX x;
+	TInt r=x.Set(aSrc);
+	if (r==KErrNone)
+		r=CalcArcsinArccos(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 asin(TReal);
+extern "C" TReal acos(TReal);
+
+EXPORT_C TInt Math::ASin(TReal& aTrg, const TReal& aSrc)
+	{
+	aTrg = asin(aSrc);
+	if (Math::IsFinite(aTrg))
+		return KErrNone;
+	SetNaN(aTrg);
+	return KErrArgument;
+	}
+
+EXPORT_C TInt Math::ACos(TReal& aTrg, const TReal& aSrc)
+	{
+	aTrg = acos(aSrc);
+	if (Math::IsFinite(aTrg))
+		return KErrNone;
+	SetNaN(aTrg);
+	return KErrArgument;
+	}
+
+#endif