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<instructionsection id="VEXT" title="VEXT (byte elements) -- AArch32" type="instruction">
  <docvars>
    <docvar key="instr-class" value="fpsimd" />
    <docvar key="mnemonic" value="VEXT" />
  </docvars>
  <heading>VEXT (byte elements)</heading>
  <desc>
    <brief>
      <para>Vector Extract</para>
    </brief>
    <authored>
      <para>Vector Extract extracts elements from the bottom end of the second operand vector and the top end of the first, concatenates them and places the result in the destination vector.</para>
      <para>The elements of the vectors are treated as being 8-bit fields. There is no distinction between data types.</para>
      <para><image file="vext_doubleword_operation_for_imm_3.svg" label="VEXT doubleword operation for imm = 3"></image></para>
      <para>Depending on settings in the <xref linkend="AArch32.cpacr">CPACR</xref>, <xref linkend="AArch32.nsacr">NSACR</xref>, and <xref linkend="AArch32.hcptr">HCPTR</xref> registers, and the Security state and PE mode in which the instruction is executed, an attempt to execute the instruction might be <arm-defined-word>undefined</arm-defined-word>, or trapped to Hyp mode. For more information see <xref linkend="CIHIDDFF">Enabling Advanced SIMD and floating-point support</xref>.</para>
    </authored>
  </desc>
  <operationalnotes>
    <para>If CPSR.DIT is 1 and this instruction passes its condition execution check:</para>
    <list type="unordered">
      <listitem><content>The execution time of this instruction is independent of:<list type="unordered"><listitem><content>The values of the data supplied in any of its registers.</content></listitem><listitem><content>The values of the NZCV flags.</content></listitem></list></content></listitem>
      <listitem><content>The response of this instruction to asynchronous exceptions does not vary based on:<list type="unordered"><listitem><content>The values of the data supplied in any of its registers.</content></listitem><listitem><content>The values of the NZCV flags.</content></listitem></list></content></listitem>
    </list>
  </operationalnotes>
  <alias_list howmany="1">
    <alias_list_intro>This instruction is used by the alias </alias_list_intro>
    <aliasref aliaspageid="VEXT_VEXT" aliasfile="vext_vext.xml" hover="Vector Extract" punct=".">
      <text>VEXT (multibyte elements)</text>
      <aliaspref>Never</aliaspref>
    </aliasref>
    <alias_list_outro>
      <text>  See </text>
      <aliastablelink />
      <text> below for details of when the alias is preferred.</text>
    </alias_list_outro>
  </alias_list>
  <classes>
    <classesintro count="2">
      <txt>It has encodings from the following instruction sets:</txt>
      <txt> A32 (</txt>
      <a href="#iclass_a1">A1</a>
      <txt>)</txt>
      <txt> and </txt>
      <txt> T32 (</txt>
      <a href="#iclass_t1">T1</a>
      <txt>)</txt>
      <txt>.</txt>
    </classesintro>
    <iclass name="A1" oneof="2" id="iclass_a1" no_encodings="2" isa="A32">
      <docvars>
        <docvar key="armarmheading" value="A1" />
        <docvar key="instr-class" value="fpsimd" />
        <docvar key="isa" value="A32" />
        <docvar key="mnemonic" value="VEXT" />
      </docvars>
      <iclassintro count="2"></iclassintro>
      <regdiagram form="32" psname="aarch32/instrs/VEXT/T1A1_A.txt">
        <box hibit="31" width="9" settings="9">
          <c>1</c>
          <c>1</c>
          <c>1</c>
          <c>1</c>
          <c>0</c>
          <c>0</c>
          <c>1</c>
          <c>0</c>
          <c>1</c>
        </box>
        <box hibit="22" name="D" usename="1">
          <c></c>
        </box>
        <box hibit="21" width="2" settings="2">
          <c>1</c>
          <c>1</c>
        </box>
        <box hibit="19" width="4" name="Vn" usename="1">
          <c colspan="4"></c>
        </box>
        <box hibit="15" width="4" name="Vd" usename="1">
          <c colspan="4"></c>
        </box>
        <box hibit="11" width="4" name="imm4" usename="1">
          <c colspan="4"></c>
        </box>
        <box hibit="7" name="N" usename="1">
          <c></c>
        </box>
        <box hibit="6" name="Q" usename="1">
          <c></c>
        </box>
        <box hibit="5" name="M" usename="1">
          <c></c>
        </box>
        <box hibit="4" settings="1">
          <c>0</c>
        </box>
        <box hibit="3" width="4" name="Vm" usename="1">
          <c colspan="4"></c>
        </box>
      </regdiagram>
      <encoding name="VEXT_A1_D" oneofinclass="2" oneof="4" label="64-bit SIMD vector" bitdiffs="Q == 0">
        <docvars>
          <docvar key="armarmheading" value="A1" />
          <docvar key="instr-class" value="fpsimd" />
          <docvar key="isa" value="A32" />
          <docvar key="mnemonic" value="VEXT" />
          <docvar key="simdvectorsize" value="double" />
        </docvars>
        <box hibit="6" width="1" name="Q">
          <c>0</c>
        </box>
        <asmtemplate><text>VEXT</text><text>{</text><a link="sa_c_1" hover="See {xref{ARMARM_Babbefhf}{Standard assembler syntax fields}}">&lt;c&gt;</a><text>}</text><text>{</text><a link="sa_q" hover="See {xref{ARMARM_Babbefhf}{Standard assembler syntax fields}}">&lt;q&gt;</a><text>}</text><text>.8 </text><text>{</text><a link="sa_dd" hover="64-bit SIMD&amp;FP destination register (field &quot;D:Vd&quot;)">&lt;Dd&gt;</a><text>,</text><text>}</text><text> </text><a link="sa_dn" hover="First 64-bit SIMD&amp;FP source register (field &quot;N:Vn&quot;)">&lt;Dn&gt;</a><text>, </text><a link="sa_dm" hover="Second 64-bit SIMD&amp;FP source register (field &quot;M:Vm&quot;)">&lt;Dm&gt;</a><text>, #</text><a link="sa_imm_1" hover="Location of extracted result in the concatenation of the operands (field &quot;imm4&quot;)">&lt;imm&gt;</a></asmtemplate>
      </encoding>
      <encoding name="VEXT_A1_Q" oneofinclass="2" oneof="4" label="128-bit SIMD vector" bitdiffs="Q == 1">
        <docvars>
          <docvar key="armarmheading" value="A1" />
          <docvar key="instr-class" value="fpsimd" />
          <docvar key="isa" value="A32" />
          <docvar key="mnemonic" value="VEXT" />
          <docvar key="simdvectorsize" value="quad" />
        </docvars>
        <box hibit="6" width="1" name="Q">
          <c>1</c>
        </box>
        <asmtemplate><text>VEXT</text><text>{</text><a link="sa_c_1" hover="See {xref{ARMARM_Babbefhf}{Standard assembler syntax fields}}">&lt;c&gt;</a><text>}</text><text>{</text><a link="sa_q" hover="See {xref{ARMARM_Babbefhf}{Standard assembler syntax fields}}">&lt;q&gt;</a><text>}</text><text>.8 </text><text>{</text><a link="sa_qd" hover="128-bit SIMD&amp;FP destination register (field &quot;D:Vd&quot;)">&lt;Qd&gt;</a><text>,</text><text>}</text><text> </text><a link="sa_qn" hover="First 128-bit SIMD&amp;FP source register (field &quot;N:Vn&quot;)">&lt;Qn&gt;</a><text>, </text><a link="sa_qm" hover="Second 128-bit SIMD&amp;FP source register (field &quot;M:Vm&quot;)">&lt;Qm&gt;</a><text>, #</text><a link="sa_imm" hover="Location of extracted result in the concatenation of the operands (field &quot;imm4&quot;)">&lt;imm&gt;</a></asmtemplate>
      </encoding>
      <ps_section howmany="1">
        <ps name="aarch32/instrs/VEXT/T1A1_A.txt" mylink="aarch32.instrs.VEXT.T1A1_A.txt" enclabels="" sections="1" secttype="noheading">
          <pstext mayhavelinks="1" section="Decode" rep_section="decode">if Q == '1' &amp;&amp; (Vd&lt;0&gt; == '1' || Vn&lt;0&gt; == '1' || Vm&lt;0&gt; == '1') then UNDEFINED;
if Q == '0' &amp;&amp; imm4&lt;3&gt; == '1' then UNDEFINED;
quadword_operation = (Q == '1');  position = 8 * <a link="impl-shared.UInt.1" file="shared_pseudocode.xml" hover="function: integer UInt(bits(N) x)">UInt</a>(imm4);
d = <a link="impl-shared.UInt.1" file="shared_pseudocode.xml" hover="function: integer UInt(bits(N) x)">UInt</a>(D:Vd);  n = <a link="impl-shared.UInt.1" file="shared_pseudocode.xml" hover="function: integer UInt(bits(N) x)">UInt</a>(N:Vn);  m = <a link="impl-shared.UInt.1" file="shared_pseudocode.xml" hover="function: integer UInt(bits(N) x)">UInt</a>(M:Vm);</pstext>
        </ps>
      </ps_section>
    </iclass>
    <iclass name="T1" oneof="2" id="iclass_t1" no_encodings="2" isa="T32">
      <docvars>
        <docvar key="armarmheading" value="T1" />
        <docvar key="instr-class" value="fpsimd" />
        <docvar key="isa" value="T32" />
        <docvar key="mnemonic" value="VEXT" />
      </docvars>
      <iclassintro count="2"></iclassintro>
      <regdiagram form="16x2" psname="aarch32/instrs/VEXT/T1A1_A.txt">
        <box hibit="31" width="9" settings="9">
          <c>1</c>
          <c>1</c>
          <c>1</c>
          <c>0</c>
          <c>1</c>
          <c>1</c>
          <c>1</c>
          <c>1</c>
          <c>1</c>
        </box>
        <box hibit="22" name="D" usename="1">
          <c></c>
        </box>
        <box hibit="21" width="2" settings="2">
          <c>1</c>
          <c>1</c>
        </box>
        <box hibit="19" width="4" name="Vn" usename="1">
          <c colspan="4"></c>
        </box>
        <box hibit="15" width="4" name="Vd" usename="1">
          <c colspan="4"></c>
        </box>
        <box hibit="11" width="4" name="imm4" usename="1">
          <c colspan="4"></c>
        </box>
        <box hibit="7" name="N" usename="1">
          <c></c>
        </box>
        <box hibit="6" name="Q" usename="1">
          <c></c>
        </box>
        <box hibit="5" name="M" usename="1">
          <c></c>
        </box>
        <box hibit="4" settings="1">
          <c>0</c>
        </box>
        <box hibit="3" width="4" name="Vm" usename="1">
          <c colspan="4"></c>
        </box>
      </regdiagram>
      <encoding name="VEXT_T1_D" oneofinclass="2" oneof="4" label="64-bit SIMD vector" bitdiffs="Q == 0">
        <docvars>
          <docvar key="armarmheading" value="T1" />
          <docvar key="instr-class" value="fpsimd" />
          <docvar key="isa" value="T32" />
          <docvar key="mnemonic" value="VEXT" />
          <docvar key="simdvectorsize" value="double" />
        </docvars>
        <box hibit="6" width="1" name="Q">
          <c>0</c>
        </box>
        <asmtemplate><text>VEXT</text><text>{</text><a link="sa_c" hover="See {xref{ARMARM_Babbefhf}{Standard assembler syntax fields}}">&lt;c&gt;</a><text>}</text><text>{</text><a link="sa_q" hover="See {xref{ARMARM_Babbefhf}{Standard assembler syntax fields}}">&lt;q&gt;</a><text>}</text><text>.8 </text><text>{</text><a link="sa_dd" hover="64-bit SIMD&amp;FP destination register (field &quot;D:Vd&quot;)">&lt;Dd&gt;</a><text>,</text><text>}</text><text> </text><a link="sa_dn" hover="First 64-bit SIMD&amp;FP source register (field &quot;N:Vn&quot;)">&lt;Dn&gt;</a><text>, </text><a link="sa_dm" hover="Second 64-bit SIMD&amp;FP source register (field &quot;M:Vm&quot;)">&lt;Dm&gt;</a><text>, #</text><a link="sa_imm_1" hover="Location of extracted result in the concatenation of the operands (field &quot;imm4&quot;)">&lt;imm&gt;</a></asmtemplate>
      </encoding>
      <encoding name="VEXT_T1_Q" oneofinclass="2" oneof="4" label="128-bit SIMD vector" bitdiffs="Q == 1">
        <docvars>
          <docvar key="armarmheading" value="T1" />
          <docvar key="instr-class" value="fpsimd" />
          <docvar key="isa" value="T32" />
          <docvar key="mnemonic" value="VEXT" />
          <docvar key="simdvectorsize" value="quad" />
        </docvars>
        <box hibit="6" width="1" name="Q">
          <c>1</c>
        </box>
        <asmtemplate><text>VEXT</text><text>{</text><a link="sa_c" hover="See {xref{ARMARM_Babbefhf}{Standard assembler syntax fields}}">&lt;c&gt;</a><text>}</text><text>{</text><a link="sa_q" hover="See {xref{ARMARM_Babbefhf}{Standard assembler syntax fields}}">&lt;q&gt;</a><text>}</text><text>.8 </text><text>{</text><a link="sa_qd" hover="128-bit SIMD&amp;FP destination register (field &quot;D:Vd&quot;)">&lt;Qd&gt;</a><text>,</text><text>}</text><text> </text><a link="sa_qn" hover="First 128-bit SIMD&amp;FP source register (field &quot;N:Vn&quot;)">&lt;Qn&gt;</a><text>, </text><a link="sa_qm" hover="Second 128-bit SIMD&amp;FP source register (field &quot;M:Vm&quot;)">&lt;Qm&gt;</a><text>, #</text><a link="sa_imm" hover="Location of extracted result in the concatenation of the operands (field &quot;imm4&quot;)">&lt;imm&gt;</a></asmtemplate>
      </encoding>
      <ps_section howmany="1">
        <ps name="aarch32/instrs/VEXT/T1A1_A.txt" mylink="aarch32.instrs.VEXT.T1A1_A.txt" enclabels="" sections="1" secttype="noheading">
          <pstext mayhavelinks="1" section="Decode" rep_section="decode">if Q == '1' &amp;&amp; (Vd&lt;0&gt; == '1' || Vn&lt;0&gt; == '1' || Vm&lt;0&gt; == '1') then UNDEFINED;
if Q == '0' &amp;&amp; imm4&lt;3&gt; == '1' then UNDEFINED;
quadword_operation = (Q == '1');  position = 8 * <a link="impl-shared.UInt.1" file="shared_pseudocode.xml" hover="function: integer UInt(bits(N) x)">UInt</a>(imm4);
d = <a link="impl-shared.UInt.1" file="shared_pseudocode.xml" hover="function: integer UInt(bits(N) x)">UInt</a>(D:Vd);  n = <a link="impl-shared.UInt.1" file="shared_pseudocode.xml" hover="function: integer UInt(bits(N) x)">UInt</a>(N:Vn);  m = <a link="impl-shared.UInt.1" file="shared_pseudocode.xml" hover="function: integer UInt(bits(N) x)">UInt</a>(M:Vm);</pstext>
        </ps>
      </ps_section>
    </iclass>
  </classes>
  <explanations scope="all">
    <explanation enclist="VEXT_A1_Q" symboldefcount="1">
      <symbol link="sa_c_1">&lt;c&gt;</symbol>
      <account encodedin="">
        <docvars>
          <docvar key="armarmheading" value="A1" />
          <docvar key="isa" value="A32" />
        </docvars>
        <intro>
          <para>For encoding A1: see <xref linkend="Babbefhf">Standard assembler syntax fields</xref>. This encoding must be unconditional.</para>
        </intro>
      </account>
    </explanation>
    <explanation enclist="VEXT_T1_Q" symboldefcount="2">
      <symbol link="sa_c">&lt;c&gt;</symbol>
      <account encodedin="">
        <docvars>
          <docvar key="armarmheading" value="T1" />
          <docvar key="isa" value="T32" />
        </docvars>
        <intro>
          <para>For encoding T1: see <xref linkend="Babbefhf">Standard assembler syntax fields</xref>.</para>
        </intro>
      </account>
    </explanation>
    <explanation enclist="VEXT_A1_Q, VEXT_T1_Q" symboldefcount="1">
      <symbol link="sa_q">&lt;q&gt;</symbol>
      <account encodedin="">
        <intro>
          <para>See <xref linkend="Babbefhf">Standard assembler syntax fields</xref>.</para>
        </intro>
      </account>
    </explanation>
    <explanation enclist="VEXT_A1_Q, VEXT_T1_Q" symboldefcount="1">
      <symbol link="sa_qd">&lt;Qd&gt;</symbol>
      <account encodedin="D:Vd">
        <intro>
          <para>Is the 128-bit name of the SIMD&amp;FP destination register, encoded in the "D:Vd" field as &lt;Qd&gt;*2.</para>
        </intro>
      </account>
    </explanation>
    <explanation enclist="VEXT_A1_Q, VEXT_T1_Q" symboldefcount="1">
      <symbol link="sa_qn">&lt;Qn&gt;</symbol>
      <account encodedin="N:Vn">
        <intro>
          <para>Is the 128-bit name of the first SIMD&amp;FP source register, encoded in the "N:Vn" field as &lt;Qn&gt;*2.</para>
        </intro>
      </account>
    </explanation>
    <explanation enclist="VEXT_A1_Q, VEXT_T1_Q" symboldefcount="1">
      <symbol link="sa_qm">&lt;Qm&gt;</symbol>
      <account encodedin="M:Vm">
        <intro>
          <para>Is the 128-bit name of the second SIMD&amp;FP source register, encoded in the "M:Vm" field as &lt;Qm&gt;*2.</para>
        </intro>
      </account>
    </explanation>
    <explanation enclist="VEXT_A1_D, VEXT_T1_D" symboldefcount="1">
      <symbol link="sa_dd">&lt;Dd&gt;</symbol>
      <account encodedin="D:Vd">
        <intro>
          <para>Is the 64-bit name of the SIMD&amp;FP destination register, encoded in the "D:Vd" field.</para>
        </intro>
      </account>
    </explanation>
    <explanation enclist="VEXT_A1_D, VEXT_T1_D" symboldefcount="1">
      <symbol link="sa_dn">&lt;Dn&gt;</symbol>
      <account encodedin="N:Vn">
        <intro>
          <para>Is the 64-bit name of the first SIMD&amp;FP source register, encoded in the "N:Vn" field.</para>
        </intro>
      </account>
    </explanation>
    <explanation enclist="VEXT_A1_D, VEXT_T1_D" symboldefcount="1">
      <symbol link="sa_dm">&lt;Dm&gt;</symbol>
      <account encodedin="M:Vm">
        <intro>
          <para>Is the 64-bit name of the second SIMD&amp;FP source register, encoded in the "M:Vm" field.</para>
        </intro>
      </account>
    </explanation>
    <explanation enclist="VEXT_A1_D, VEXT_T1_D" symboldefcount="1">
      <symbol link="sa_imm_1">&lt;imm&gt;</symbol>
      <account encodedin="imm4">
        <docvars>
          <docvar key="simdvectorsize" value="double" />
        </docvars>
        <intro>
          <para>For the 64-bit SIMD vector variant: is the location of the extracted result in the concatenation of the operands, as a number of bytes from the least significant end, in the range 0 to 7, encoded in the "imm4" field.</para>
        </intro>
      </account>
    </explanation>
    <explanation enclist="VEXT_A1_Q, VEXT_T1_Q" symboldefcount="2">
      <symbol link="sa_imm">&lt;imm&gt;</symbol>
      <account encodedin="imm4">
        <docvars>
          <docvar key="simdvectorsize" value="quad" />
        </docvars>
        <intro>
          <para>For the 128-bit SIMD vector variant: is the location of the extracted result in the concatenation of the operands, as a number of bytes from the least significant end, in the range 0 to 15, encoded in the "imm4" field.</para>
        </intro>
      </account>
    </explanation>
  </explanations>
  <aliastablehook anchor="aliasconditions">Alias Conditions</aliastablehook>
  <ps_section howmany="1">
    <ps name="aarch32/instrs/VEXT/Op_A.txt" mylink="execute" enclabels="" sections="1" secttype="Operation">
      <pstext mayhavelinks="1" section="Execute" rep_section="execute">if <a link="impl-aarch32.ConditionPassed.0" file="shared_pseudocode.xml" hover="function: boolean ConditionPassed()">ConditionPassed</a>() then
    EncodingSpecificOperations();  <a link="impl-aarch32.CheckAdvSIMDEnabled.0" file="shared_pseudocode.xml" hover="function: CheckAdvSIMDEnabled()">CheckAdvSIMDEnabled</a>();
    if quadword_operation then
        <a link="impl-aarch32.Q.write.1" file="shared_pseudocode.xml" hover="accessor: Q[integer n] = bits(128) value">Q</a>[d&gt;&gt;1] = (<a link="impl-aarch32.Q.read.1" file="shared_pseudocode.xml" hover="accessor: bits(128) Q[integer n]">Q</a>[m&gt;&gt;1]:<a link="impl-aarch32.Q.read.1" file="shared_pseudocode.xml" hover="accessor: bits(128) Q[integer n]">Q</a>[n&gt;&gt;1])&lt;position+127:position&gt;;
    else
        <a link="impl-aarch32.D.write.1" file="shared_pseudocode.xml" hover="accessor: D[integer n] = bits(64) value">D</a>[d] = (<a link="impl-aarch32.D.read.1" file="shared_pseudocode.xml" hover="accessor: bits(64) D[integer n]">D</a>[m]:<a link="impl-aarch32.D.read.1" file="shared_pseudocode.xml" hover="accessor: bits(64) D[integer n]">D</a>[n])&lt;position+63:position&gt;;</pstext>
    </ps>
  </ps_section>
</instructionsection>
