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

<!-- Copyright (c) 2007-2010 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 

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

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

<!-- Initial Contributors:

    Nokia Corporation - initial contribution.

Contributors: 

-->

<!DOCTYPE concept

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

<concept id="GUID-947317B7-7E12-509B-9A16-F0604D7F8BA2" xml:lang="en"><title>armfpu</title><prolog><metadata><keywords/></metadata></prolog><conbody>

<p> <codeph>armfpu [ vfpv2 | softvfp ]</codeph>  </p>

<p>Use the <codeph>armfpu</codeph> statement to specify how the compiler is

to deal with floating point instructions. </p>

<p>There are two ways in which floating point instructions can be handled

on an ARM processor: </p>

<ul>

<li id="GUID-929D9EEB-1D4A-58DD-8E62-7E14EAB6566B"><p>through the use of floating

point support functions. </p> </li>

<li id="GUID-B28E550A-0785-50B5-B260-7F8C85F1CA2A"><p>directly on a hardware

floating point co-processor, the Vector Floating Point (VFP) unit. </p> </li>

</ul>

<table id="GUID-A0C3733D-2744-5094-AF89-EF15737C68E9">

<tgroup cols="2"><colspec colname="col0"/><colspec colname="col1"/>

<tbody>

<row>

<entry><p> <codeph>softvfp</codeph>  </p> </entry>

<entry><p>This keyword specifies that floating point instructions are handled

by floating point support functions. </p> <p>On a device without a VFP unit,

floating point support functions are implemented in software and operate slowly.

On a device with a VFP unit, the floating point support functions are handled

by the VFP unit, and operate faster than when implemented in software. </p> <p>Note

that applications do not need to make any changes to take advantage of VFP-enabled

floating point support functions, if they are provided in the device's ROM.

Such functions are used automatically at run time. </p> <p>If <codeph>armfpu</codeph> is

not specified in a <filepath>.mmp</filepath> file, then <codeph>armfpu softvfp</codeph> is

assumed by default. </p> </entry>

</row>

<row>

<entry><p> <codeph>vfpv2</codeph>  </p> </entry>

<entry><p>This keyword specifies that VFP specific code is to be generated

at compile time whenever floating point instructions are used. </p> <p>On

a device with a VFP unit, this option results in code that runs faster than

the floating point support functions generated by <codeph>softvfp</codeph>.

Note, however, that binaries produced with VFP specific code do not work on

devices without a VFP unit. <i>Software Install</i> attempts to prevent their

installation, but if any such binaries are installed onto a device in some

other way, for example by inclusion into the ROM at device creation time,

then a call to VFP specific code results in a KERN-EXEC 3 panic (see also <xref href="GUID-0AF47934-0A16-51A2-9254-992D7C6B322B.dita">Application Installation

Guide</xref>). </p> </entry>

</row>

</tbody>

</tgroup>