--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/symport/e32/euser/maths/um_exp.cpp	Thu Jun 25 15:59:54 2009 +0100
@@ -0,0 +1,149 @@
+// 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 "Symbian Foundation License v1.0"
+// which accompanies this distribution, and is available
+// at the URL "http://www.symbianfoundation.org/legal/sfl-v10.html".
+//
+// Initial Contributors:
+// Nokia Corporation - initial contribution.
+//
+// Contributors:
+//
+// Description:
+// e32\euser\maths\um_exp.cpp
+// Floating point exponentiation
+// 
+//
+
+#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 ExpCoeffs[] =
+	{
+	0x00000000,0x80000000,0x7FFF0000,	// polynomial approximation to 2^(x/8)
+	0xD1CF79AC,0xB17217F7,0x7FFB0000,	// for 0<=x<=1
+	0x1591EF2B,0xF5FDEFFC,0x7FF60000,
+	0x23B940A9,0xE35846B9,0x7FF10000,
+	0xDD73C23F,0x9D955ADE,0x7FEC0000,
+	0x8728EBE7,0xAEC4616C,0x7FE60000,
+	0xAF177130,0xA1646F7D,0x7FE00000,
+	0xC44EAC22,0x8542C46E,0x7FDA0000
+	};
+
+LOCAL_D const TUint32 TwoToNover8[] =
+	{
+	0xEA8BD6E7,0x8B95C1E3,0x7FFF0000,	// 2^0.125
+	0x8DB8A96F,0x9837F051,0x7FFF0000,	// 2^0.250
+	0xB15138EA,0xA5FED6A9,0x7FFF0000,	// 2^0.375
+	0xF9DE6484,0xB504F333,0x7FFF0000,	// 2^0.500
+	0x5506DADD,0xC5672A11,0x7FFF0000,	// 2^0.625
+	0xD69D6AF4,0xD744FCCA,0x7FFF0000,	// 2^0.750
+	0xDD24392F,0xEAC0C6E7,0x7FFF0000	// 2^0.875
+	};
+
+LOCAL_D const TUint32 EightLog2edata[] = {0x5C17F0BC,0xB8AA3B29,0x80020000};	// 8/ln2
+
+
+
+
+EXPORT_C TInt Math::Exp(TReal& aTrg, const TReal& aSrc)
+/**
+Calculates the value of e to the power of x.
+
+@param aTrg A reference containing the result. 
+@param aSrc The power to which e is to be raised. 
+
+@return KErrNone if successful, otherwise another of
+        the system-wide error codes. 
+*/	
+	{
+	// Calculate exp(aSrc) and write result to aTrg
+	// Algorithm:
+	//		Let x=aSrc/ln2 and calculate 2^x
+	//		2^x = 2^int(x).2^frac(x)
+	//		2^int(x) just adds int(x) to the final result exponent
+	//		Reduce frac(x) to the range [0,0.125] (modulo 0.125)
+	//		Use polynomial to calculate 2^x for 0<=x<=0.125
+	//		Multiply by 2^(n/8) for n=0,1,2,3,4,5,6,7 to give 2^frac(x)
+
+	const TRealX& EightLog2e=*(const TRealX*)EightLog2edata;
+
+	TRealX x;
+	TRealX y;
+	TInt r=x.Set(aSrc);
+	if (r==KErrNone)
+		{
+		x*=EightLog2e;
+		TInt n=(TInt)x;
+		if (n<16384 && n>-16384)
+			{
+			if (x.iSign&1)
+				n--;
+			x-=TRealX(n);
+			PolyX(y,x,7,(const TRealX*)ExpCoeffs);
+			y.iExp=TUint16(TInt(y.iExp)+(n>>3));
+			n&=7;
+			if (n)
+				y*= (*(const TRealX*)(TwoToNover8+3*n-3));
+			return y.GetTReal(aTrg);
+			}
+		else
+			{
+			if (n<0)
+				{
+				SetZero(aTrg);
+				r=KErrUnderflow;
+				}
+			else
+				{
+				SetInfinite(aTrg,0);
+				r=KErrOverflow;
+				}
+			return r;
+			}
+		}
+	else
+		{
+		if (r==KErrArgument)
+			SetNaN(aTrg);
+		if (r==KErrOverflow)
+			{
+			if (x.iSign&1)
+				{
+				SetZero(aTrg);
+				r=KErrUnderflow;
+				}
+			else
+				{
+				SetInfinite(aTrg,0);
+				}
+			}
+		return r;
+		}
+	}
+
+#else // __USE_VFP_MATH
+
+// definitions come from RVCT math library
+extern "C" TReal exp(TReal);
+
+EXPORT_C TInt Math::Exp(TReal& aTrg, const TReal& aSrc)
+	{
+	aTrg = exp(aSrc);
+	if (Math::IsZero(aTrg))
+		return KErrUnderflow;
+	if (Math::IsFinite(aTrg))
+		return KErrNone;
+	if (Math::IsInfinite(aTrg))
+		return KErrOverflow;
+	SetNaN(aTrg);
+	return KErrArgument;
+	}
+
+#endif