| 1 | <?xml version="1.0" encoding="ISO-8859-1"?>
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| 2 | <!DOCTYPE sect1 PUBLIC "-//OASIS//DTD DocBook XML V4.5//EN"
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| 3 |   "http://www.oasis-open.org/docbook/xml/4.5/docbookx.dtd" [
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| 4 |   <!ENTITY % general-entities SYSTEM "../../general.ent">
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| 5 |   %general-entities;
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| 6 | ]>
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| 7 | 
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| 8 | <sect1 id="ch-cross-tools-variables">
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| 9 |   <?dbhtml filename="variables.html"?>
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| 10 | 
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| 11 |   <title>Build Variables</title>
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| 12 | 
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| 13 |   <bridgehead renderas="sect4">Setting Host and Target</bridgehead>
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| 14 | 
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| 15 |   <para os="a">During the building of the cross-compile tools, you will need to
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| 16 |   set a few variables that will be dependent on your particular needs.
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| 17 |   You will need to select the target triplet for the target architecture, the CPU
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| 18 |   endianess, the CPU architecture, the CPU mode, the CPU floating point hardware
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| 19 |   availability, and (if available) the type of floating point hardware. If you 
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| 20 |   do not know what values can be chosen for each of these, you can use the 
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| 21 |   tables at the bottom of this page as a reference.</para>
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| 22 | 
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| 23 |   <para os="a1">Most ARM processors are little endian, it is a safe choice.
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| 24 |   If your processor is an ARM9, good choices include: triplet of
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| 25 |   armv5l-unknown-linux-uclibeabi, ARM arch of armv5t, float of softfp, and fpu
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| 26 |   of either none or softvfp. ARM9 processors do not always have hardware
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| 27 |   floating point abilities. If your processor is a Cortex-A8 or Cortex-A9, good
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| 28 |   choices include: triplet of armv7a-unknown-linux-uclibceabi, ARM arch of
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| 29 |   armv7-a, float of hard, and fpu of vfpv3-d16.</para>
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| 30 | 
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| 31 |   <para os="a2">First, set the host and target triplets:</para>
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| 32 | 
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| 33 |   <xi:include xmlns:xi="http://www.w3.org/2003/XInclude"
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| 34 |   href="../common/variables.xml"
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| 35 |   xpointer="xpointer(//*[@os='b'])"/>
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| 36 | 
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| 37 |   <xi:include xmlns:xi="http://www.w3.org/2003/XInclude"
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| 38 |   href="../common/variables.xml"
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| 39 |   xpointer="xpointer(//*[@os='c'])"/>
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| 40 | 
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| 41 | <screen os="d"><userinput>export CLFS_ARCH=arm
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| 42 | export CLFS_ENDIAN="<replaceable>[endianess]</replaceable>"</userinput></screen>
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| 43 | 
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| 44 |   <para os="e">Choose the ARM architecture (see table below) and mode of 
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| 45 |   your CPU:</para>
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| 46 | 
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| 47 | <screen os="f"><userinput>export CLFS_ARM_ARCH="<replaceable>[architecture]</replaceable>"
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| 48 | export CLFS_ARM_MODE="<replaceable>[arm or thumb]</replaceable>"</userinput></screen>
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| 49 | 
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| 50 |   <para os="f1">If your target CPU has hard floating point support (not all ARM
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| 51 |   CPUs do), set the following CLFS_FLOAT variable to either "hard" or "softfp".
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| 52 |   If your target CPU does not have hard floating point support, set the following
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| 53 |   CLFS_FLOAT vairable to "soft".</para>
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| 54 | 
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| 55 | <screen os="f2"><userinput>export CLFS_FLOAT="<replaceable>[hard, softfp, or soft]"</replaceable></userinput></screen>
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| 56 | 
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| 57 |   <para os="f3">If you chose either "hard" or "softfp" for CLFS_FLOAT, you now
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| 58 |   need to set which floating point hardware is actually included (see table below)
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| 59 |   with your ARM CPU:</para>
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| 60 | 
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| 61 | <screen os="f4"><userinput>export CLFS_FPU="<replaceable>[fpu version]</replaceable>"</userinput></screen>
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| 62 | 
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| 63 |   <xi:include xmlns:xi="http://www.w3.org/2003/XInclude"
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| 64 |   href="../common/variables.xml"
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| 65 |   xpointer="xpointer(//*[@os='g'])"/>
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| 66 | 
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| 67 | <screen os="h"><userinput>echo export CLFS_HOST=\""${CLFS_HOST}\"" >> ~/.bashrc
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| 68 | echo export CLFS_TARGET=\""${CLFS_TARGET}\"" >> ~/.bashrc
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| 69 | echo export CLFS_ARCH=\""${CLFS_ARCH}\"" >> ~/.bashrc
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| 70 | echo export CLFS_ENDIAN=\""${CLFS_ENDIAN}\"" >> ~/.bashrc
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| 71 | echo export CLFS_ARM_ARCH=\""${CLFS_ARM_ARCH}\"" >> ~/.bashrc
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| 72 | echo export CLFS_ARM_MODE=\""${CLFS_ARM_MODE}\"" >> ~/.bashrc
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| 73 | echo export CLFS_FLOAT=\""${CLFS_FLOAT}\"" >> ~/.bashrc
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| 74 | echo export CLFS_FPU=\""${CLFS_FPU}\"" >> ~/.bashrc</userinput></screen>
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| 75 | 
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| 76 |   <table os="i">
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| 77 |     <title>Example Processor Type, ABI, and  Target Triplets</title>
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| 78 |     <?dbfo table-width="7in" ?>
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| 79 | 
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| 80 |     <tgroup cols="4">
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| 81 | 
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| 82 |       <colspec colnum="1" colwidth="2.5in" colname="Processor"/>
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| 83 |       <colspec colnum="2" colwidth="1in" colname="Endianess"/>
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| 84 |       <colspec colnum="3" colwidth="1in" colname="ABI"/>
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| 85 |       <colspec colnum="4" colwidth="2.5in" colname="Triplet"/>
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| 86 | 
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| 87 |       <thead>
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| 88 |         <row>
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| 89 |           <entry>Processor</entry>
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| 90 |           <entry>Endianess</entry>
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| 91 |           <entry>ABI</entry>
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| 92 |           <entry>Target Triplet</entry>
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| 93 |         </row>
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| 94 |       </thead>
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| 95 | 
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| 96 |       <tbody>
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| 97 |         <row>
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| 98 |           <entry>Generic arm, version 5</entry>
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| 99 |           <entry>little</entry>
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| 100 |           <entry>EABI</entry>
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| 101 |           <entry>armv5l-unknown-linux-uclibceabi</entry>
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| 102 |         </row>
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| 103 |         <row>
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| 104 |           <entry>Generic arm, version 5</entry>
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| 105 |           <entry>big</entry>
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| 106 |           <entry>EABI</entry>
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| 107 |           <entry>armv5b-unknown-linux-uclibceabi</entry>
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| 108 |         </row>
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| 109 |         <row>
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| 110 |           <entry>Generic arm</entry>
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| 111 |           <entry>little</entry>
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| 112 |           <entry>EABI</entry>
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| 113 |           <entry>arm-unknown-linux-uclibceabi</entry>
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| 114 |         </row>
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| 115 |         <row>
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| 116 |           <entry>Generic arm, version 7-a </entry>
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| 117 |           <entry>little</entry>
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| 118 |           <entry>EABI</entry>
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| 119 |           <entry>armv7a-unknown-linux-uclibceabi</entry>
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| 120 |         </row>
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| 121 |       </tbody>
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| 122 | 
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| 123 |     </tgroup>
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| 124 | 
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| 125 |   </table>
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| 126 | 
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| 127 |   <table os="j">
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| 128 |     <title>ARM Archiecture Choices</title>
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| 129 |     <?dbfo table-width="4in" ?>
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| 130 | 
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| 131 |     <tgroup cols="4">
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| 132 | 
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| 133 |       <colspec colnum="1" colwidth="1in" colname="Arch Choice"/>
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| 134 |       <colspec colnum="2" colwidth="1in" colname="Arch Choice"/>
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| 135 |       <colspec colnum="3" colwidth="1in" colname="Arch Choice"/>
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| 136 |       <colspec colnum="4" colwidth="1in" colname="Arch Choice"/>
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| 137 | 
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| 138 |       <tbody>
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| 139 |         <row>
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| 140 |           <entry>armv2</entry>
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| 141 |           <entry>armv2a</entry>
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| 142 |           <entry>armv3</entry>
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| 143 |           <entry>armv3m</entry>
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| 144 |         </row>
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| 145 |         <row>
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| 146 |           <entry>armv4</entry>
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| 147 |           <entry>armv4t</entry>
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| 148 |           <entry>armv5</entry>
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| 149 |           <entry>armv5t</entry>
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| 150 |         </row>
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| 151 |         <row>
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| 152 |           <entry>armv5te</entry>
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| 153 |           <entry>armv6</entry>
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| 154 |           <entry>armv6j</entry>
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| 155 |           <entry>armv6t2</entry>
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| 156 |         </row>
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| 157 |         <row>
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| 158 |           <entry>armv6z</entry>
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| 159 |           <entry>armv6zk</entry>
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| 160 |           <entry>armv6-m</entry>
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| 161 |           <entry>armv7</entry>
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| 162 |         </row>
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| 163 |         <row>
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| 164 |           <entry>armv7-a</entry>
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| 165 |           <entry>armv7-r</entry>
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| 166 |           <entry>armv7-m</entry>
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| 167 |           <entry>iwmmxt</entry>
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| 168 |         </row>
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| 169 |         <row>
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| 170 |           <entry>iwmmxt2</entry>
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| 171 |           <entry>ep9312</entry>
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| 172 |         </row>
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| 173 |       </tbody>
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| 174 |     </tgroup>
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| 175 |   </table>
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| 176 | 
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| 177 |   <table os="j">
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| 178 |     <title>ARM Hard Floating Point Versions</title>
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| 179 |     <?dbfo table-width="4in" ?>
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| 180 | 
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| 181 |     <tgroup cols="4">
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| 182 | 
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| 183 |       <colspec colnum="1" colwidth="1in" colname="FPU Choice"/>
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| 184 |       <colspec colnum="2" colwidth="1in" colname="FPU Choice"/>
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| 185 |       <colspec colnum="3" colwidth="1in" colname="FPU Choice"/>
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| 186 |       <colspec colnum="4" colwidth="1in" colname="FPU Choice"/>
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| 187 | 
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| 188 |       <tbody>
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| 189 |         <row>
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| 190 |           <entry>fpa</entry>
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| 191 |           <entry>fpe2</entry>
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| 192 |           <entry>fpe3</entry>
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| 193 |           <entry>maverick</entry>
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| 194 |         </row>
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| 195 |         <row>
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| 196 |           <entry>vfp</entry>
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| 197 |           <entry>vfpv3</entry>
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| 198 |           <entry>vfpv3-fp16</entry>
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| 199 |           <entry>vfpv3-d16</entry>
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| 200 |         </row>
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| 201 |         <row>
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| 202 |           <entry>vfpv3-d16-fp16</entry>
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| 203 |           <entry>vfpv3xd</entry>
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| 204 |           <entry>vfpv3xd-fp16</entry>
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| 205 |           <entry>neon</entry>
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| 206 |         </row>
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| 207 |         <row>
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| 208 |           <entry>neon-fp16</entry>
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| 209 |           <entry>vfpv4</entry>
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| 210 |           <entry>vfpv4-d16</entry>
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| 211 |           <entry>fpv4-sp-d16</entry>
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| 212 |         </row>
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| 213 |         <row>
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| 214 |           <entry>neon-vfpv4</entry>
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| 215 |           <entry>softvfp</entry>
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| 216 |           <entry>none</entry>
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| 217 |         </row>
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| 218 |       </tbody>
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| 219 |     </tgroup>
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| 220 |   </table>
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| 221 | 
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| 222 | </sect1>
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