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 "Eclipse Public License v1.0"

     5 // which accompanies this distribution, and is available

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

     7 //

     8 // Initial Contributors:

     9 // Nokia Corporation - initial contribution.

    10 //

    11 // Contributors:

    12 //

    13 // Description:

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

    15 // Writes the fractional part of aTrg to aSrc

    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 #ifndef __USE_VFP_MATH

    26 

    27 #ifndef __REALS_MACHINE_CODED__

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

    29 /**

    30 Calculates the fractional part of a number.

    31 

    32 The fractional part is that after a decimal point.

    33 Truncation is toward zero, so that

    34 Frac(2.4)=0.4, Frac(2)=0, Frac(-1)=0, Frac(-1.4)=0.4.

    35 

    36 @param aTrg A reference containing the result.

    37 @param aSrc The number whose fractional part is required. 

    38 

    39 @return KErrNone if successful, otherwise another of

    40         the system-wide error codes.

    41 */

    42 	{

    43 	TRealX f;

    44 	TInt ret=f.Set(aSrc);

    45 	if (ret!=KErrNone)

    46 		{

    47 		if (ret==KErrArgument)

    48 			SetNaN(aTrg);

    49 		if (ret==KErrOverflow)

    50 			SetZero(aTrg,f.iSign&1);

    51 		return(ret);

    52 		}

    53 	TInt intbits=f.iExp-0x7FFE;

    54 	if (intbits<=0)	 // aSrc is already a fraction

    55 		{

    56 		aTrg=aSrc;

    57 		return(KErrNone);

    58 		}

    59 	if (intbits>KMantissaBits)

    60 		{

    61 		SetZero(aTrg,f.iSign&1);

    62 		return(KErrNone);

    63 		}

    64 

    65 	// calculate integer part and subtract

    66 	// this means that the subtraction normalises the result

    67 	TRealX g=f;

    68 

    69 	TUint64 mask = ~(UI64LIT(0));

    70 	mask <<= (64 - intbits);

    71 

    72 	g.iMantHi &= static_cast<TUint32>(mask >> 32);

    73 	g.iMantLo &= static_cast<TUint32>(mask);

    74 

    75 	f-=g;

    76 	f.GetTReal(aTrg);

    77 	return(KErrNone);

    78 	}

    79 

    80 #endif //__REALS_MACHINE_CODED__

    81 

    82 #else // __USE_VFP_MATH

    83 

    84 // definitions come from RVCT math library

    85 extern "C" TReal modf(TReal,TReal*);

    86 

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

    88 	{

    89 	if (Math::IsNaN(aSrc))

    90 		{

    91 		SetNaN(aTrg);

    92 		return KErrArgument;

    93 		}

    94 	if (Math::IsInfinite(aSrc))

    95 		{

    96 		SetZero(aTrg);

    97 		return KErrOverflow;

    98 		}

    99 

   100 	TReal temp;

   101 	aTrg = modf(aSrc,&temp);

   102 	return KErrNone;

   103 	}

   104 

   105 #endif