Symaptic: os/kernelhwsrv/kernel/eka/euser/maths/um

     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_mod.cpp

    15 // Writes the remainder of aSrc/aModulus to aTrg

    16 //

    17 //

    19 #include "um_std.h"

    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

    25 #ifndef __USE_VFP_MATH

    27 EXPORT_C TInt Math::Mod(TReal &aTrg,const TReal &aSrc,const TReal &aModulus)

    28 /**

    29 Calculates the modulo remainder.

    31 This is the value of p mod q, the modulo remainder when dividing p by q.

    32 The result is given by p - q int (p/q):

    33 it has the same sign as p:

    34 thus, 5 mod 3 = 2, -5 mod 3 = -2.

    35 No error is raised if non-integer arguments are passed.

    37 @param aTrg      A reference containing the result.

    38 @param aSrc      The p argument to the mod function.

    39 @param aModulus  The q argument to the mod function.

    41 @return KErrNone if successful, otherwise another of

    42         the system-wide error codes.

    43 */

    44 //

    45 // Floating point modulo arithmetic.

    46 //

    47 	{

    49 	TRealX f1,f2;

    50 	TInt r=f1.Set(aSrc);

    51 	if (r!=KErrNone)

    52 		{

    53 		SetNaN(aTrg);

    54 		return KErrArgument;

    55 		}

    56 	r=f2.Set(aModulus);

    57 	if (r==KErrArgument || f2.IsZero())

    58 		{

    59 		SetNaN(aTrg);

    60 		return KErrArgument;

    61 		}

    62 	if (r==KErrOverflow)

    63 		{

    64 		aTrg=aSrc;

    65 		return KErrNone;

    66 		}

    67 	if ((TInt(f1.iExp)-TInt(f2.iExp))>KMantissaBits)

    68 		{

    69 		SetZero(aTrg);

    70 		return KErrTotalLossOfPrecision;

    71 		}

    72 	f1.ModEq(f2);

    73 	return f1.GetTReal(aTrg);

    74 	}

    76 #else // __USE_VFP_MATH

    78 // definitions come from RVCT math library

    79 extern "C" TReal fmod(TReal,TReal);

    81 EXPORT_C TInt Math::Mod(TReal& aTrg, const TReal& aSrc, const TReal &aModulus)

    82 	{

    83 	SReal64 *pSrc=(SReal64 *)&aSrc;

    84 	SReal64 *pModulus=(SReal64 *)&aModulus;

    86 	if (pSrc->exp==0 || pModulus->exp==0 || pSrc->exp==KSpecialExponent || pModulus->exp==KSpecialExponent)

    87 		{

    88 		TRealX f1,f2;

    89 		TInt r=f1.Set(aSrc);

    90 		if (r!=KErrNone)

    91 			{

    92 			SetNaN(aTrg);

    93 			return KErrArgument;

    94 			}

    95 		r=f2.Set(aModulus);

    96 		if (r==KErrArgument || f2.IsZero())

    97 			{

    98 			SetNaN(aTrg);

    99 			return KErrArgument;

   100 			}

   101 		if (r==KErrOverflow)

   102 			{

   103 			aTrg=aSrc;

   104 			return KErrNone;

   105 			}

   106 		if ((TInt(f1.iExp)-TInt(f2.iExp))>KMantissaBits)

   107 			{

   108 			SetZero(aTrg);

   109 			return KErrTotalLossOfPrecision;

   110 			}

   111 		}

   112 	else if ((pSrc->exp - pModulus->exp) > KMantissaBits)

   113 		{

   114 		SetZero(aTrg);

   115 		return KErrTotalLossOfPrecision;

   116 		}

   118 	aTrg = fmod(aSrc,aModulus);

   119 	return KErrNone;

   120 	}

   122 #endif

author	sl@SLION-WIN7.fritz.box
	Fri, 15 Jun 2012 03:10:57 +0200
changeset 0	bde4ae8d615e
permissions	-rw-r--r--