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    10 <!DOCTYPE concept

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

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

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

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

    15 to deal with floating point instructions. </p>

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

    17 on an ARM processor: </p>

    18 <ul>

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

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

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

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

    23 </ul>

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

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

    26 <tbody>

    27 <row>

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

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

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

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

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

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

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

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

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

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

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

    39 </row>

    40 <row>

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

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

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

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

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

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

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

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

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

    50 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

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

    52 </row>

    53 </tbody>

    54 </tgroup>

    55 </table></conbody></concept>