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<concept id="GUID-CBC1E46A-E254-5A01-86AE-F5EB6135E3E3" xml:lang="en"><title>Vector

Floating Point (VFP)</title><shortdesc>ARM provide a hardware floating point coprocessor that provides

floating point computation that is fully compliant with IEEE Std 754-1985.</shortdesc><prolog><metadata><keywords/></metadata></prolog><conbody>

<p> When a phone has this hardware, the base port must be configured to use

it. </p>

<p>The ARM architecture is called the ARM Vector Floating Point Architecture

(VFPv2), and the coprocessor is also called the <i>VFP unit</i>. </p>

<p>Symbian platform supports the use of VFPv2 on platforms where the required

hardware is present in both <i>RunFast</i> mode and in <i>IEEE-without-exceptions</i> mode.

See ARM's Vector Floating-point Coprocessor Technical reference Manual for

more details on the coprocessor, its architecture, and its execution modes. </p>

<p>Applications and, in a more limited sense, kernel side code can use VFP

in one of two ways: </p>

<ul>

<li id="GUID-D74E3541-3D8F-5338-A488-E40385D1C293"><p>indirectly through the

use of floating point support (helper) functions generated by the compiler. </p> </li>

<li id="GUID-7316F251-5292-510C-9496-30C0B7A7A25C"><p>directly, either through

instructions generated by the compiler, or hand-written instructions written

in assembler. </p> </li>

</ul>

<p>An application uses the <codeph>armfpu</codeph> statement in its <filepath>.mmp</filepath> file

to specify how it wants floating point to be handled. By choosing to use the

floating point support functions, an application does not need to know how

they are implemented or even whether these functions make use of a VFP unit.

However, if a device does have a VFP unit, then the base port needs to replace

the default floating point support functions with VFP-enabled functions if

applications are to take advantage of the hardware. </p>

</conbody><related-links>

<link href="GUID-D525B9A9-6B32-535B-A282-60C85A48D3FB.dita"><linktext>Floating

point                 support</linktext></link>

<link href="GUID-3046453A-AB3A-5491-87A0-00F3514D4768.dita"><linktext>Vector Floating

Point Implementation Tutorial</linktext></link>