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

     2 // All rights reserved.

     3 // This component and the accompanying materials are made available

     4 // under the terms of the License "Symbian Foundation License v1.0"

     5 // which accompanies this distribution, and is available

     6 // at the URL "http://www.symbianfoundation.org/legal/sfl-v10.html".

     7 //

     8 // Initial Contributors:

     9 // Nokia Corporation - initial contribution.

    10 //

    11 // Contributors:

    12 //

    13 // Description:

    14 // e32\euser\maths\um_log.cpp

    15 // Floating point base 10 logarithm

    16 // 

    17 //

    18 

    19 #include "um_std.h"

    20 

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

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

    23 #endif

    24 

    25 

    26 #ifndef __USE_VFP_MATH

    27 

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

    29 /**

    30 Calculates the logarithm to base 10 of a number.

    31 

    32 @param aTrg  A reference containing the result. 

    33 @param aSrc  The number whose logarithm is required. 

    34  

    35 @return KErrNone if successful, otherwise another of

    36         the system-wide error codes. 

    37 */

    38 //

    39 // Base 10 log routine. See Software manual by W.J.Cody & W.Waite

    40 //

    41 	{

    42 

    43 	TInt ret=Math::Ln(aTrg,aSrc);

    44 	if (ret!=KErrNone)

    45 		return(ret);    	

    46 	aTrg*=KRln10;

    47 	return(ret);

    48 	}

    49 

    50 #else // __USE_VFP_MATH

    51 

    52 // definitions come from RVCT math library

    53 extern "C" TReal log10(TReal);

    54 

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

    56 	{

    57 	aTrg = log10(aSrc);

    58 	if (Math::IsFinite(aTrg))

    59 		return KErrNone;

    60 	if (Math::IsInfinite(aTrg))

    61 		return KErrOverflow;

    62 	SetNaN(aTrg);

    63 	return KErrArgument;

    64 	}

    65 

    66 #endif