1 <?xml version="1.0" encoding="utf-8"?>

     2 <!-- Copyright (c) 2007-2010 Nokia Corporation and/or its subsidiary(-ies) All rights reserved. -->

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     4 "Eclipse Public License v1.0" which accompanies this distribution, 

     5 and is available at the URL "http://www.eclipse.org/legal/epl-v10.html". -->

     6 <!-- Initial Contributors:

     7     Nokia Corporation - initial contribution.

     8 Contributors: 

     9 -->

    10 <!DOCTYPE concept

    11   PUBLIC "-//OASIS//DTD DITA Concept//EN" "concept.dtd">

    12 <concept id="GUID-AF2E227B-C5BD-5F05-98D4-7D15530161C8" xml:lang="en"><title>Interrupt::Clear()</title><shortdesc>Describes the implementation of the clear function.</shortdesc><prolog><metadata><keywords/></metadata></prolog><conbody>

    13 <p>The function <xref href="GUID-E7A7083C-97B9-39B9-A147-4A6E314EE3A3.dita#GUID-E7A7083C-97B9-39B9-A147-4A6E314EE3A3/GUID-DB641A23-82B2-373E-A514-E11118CB6E69"><apiname>Interrupt::Clear()</apiname></xref> is used by device drivers

    14 to acknowledge that they have serviced the interrupt and cleared the pending

    15 flag in the interrupt controller hardware. </p>

    16 <p>This is useful in situations where an interrupt must be cleared explicitly

    17 rather than as a side effect of an I/O register access, especially where the

    18 clearing is done from generic code such as in the PC card and MMC controllers. </p>

    19 <p>The implementation of this function is completely dependent on the interrupt

    20 hardware. </p>

    21 <p>In the template port, <codeph>Interrupt::Clear()</codeph> is implemented

    22 in <filepath>...\template_assp\interrupts.cpp</filepath>. </p>

    23 <codeblock id="GUID-7612CEB2-7ADA-552D-9BB9-B0B1B2D8E4BC" xml:space="preserve">EXPORT_C TInt Interrupt::Clear(TInt anId)

    24     {

    25      __KTRACE_OPT(KEXTENSION,Kern::Printf("Interrupt::Clear id=%d",anId));

    26      TInt r=KErrNone;

    27      // if ID indicates a chained interrupt, call variant...

    28      if (anId<0 && ((((TUint)anId)>>16)&0x7fff)<(TUint)KNumTemplateInts)

    29          r=TemplateAssp::Variant->InterruptClear(anId);

    30      else if ((TUint)anId>=(TUint)KNumTemplateInts)

    31          r=KErrArgument;

    32      else

    33          {

    34          //

    35          // TO DO: (mandatory)

    36          //

    37          // Clear the corresponding Hardware Interrupt source

    38          //

    39         }

    40     return r;

    41     }</codeblock>

    42 </conbody></concept>