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<instructionsection id="VLD2_1" title="VLD2 (single 2-element structure to one lane) -- AArch32" type="instruction">
  <docvars>
    <docvar key="instr-class" value="fpsimd" />
    <docvar key="mnemonic" value="VLD2" />
  </docvars>
  <heading>VLD2 (single 2-element structure to one lane)</heading>
  <desc>
    <brief>
      <para>Load single 2-element structure to one lane of two registers</para>
    </brief>
    <authored>
      <para>Load single 2-element structure to one lane of two registers loads one 2-element structure from memory into corresponding elements of two registers. Elements of the registers that are not loaded are unchanged. For details of the addressing mode, see <xref linkend="Cjaefebe">Advanced SIMD addressing mode</xref>.</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>
    <encodingnotes>
      <para>For more information about the <arm-defined-word>constrained unpredictable</arm-defined-word> behavior of this instruction, see <xref linkend="CJAEGDJC">Architectural Constraints on UNPREDICTABLE behaviors</xref>, and particularly <xref linkend="CEGEDHDB">VLD2 (single 2-element structure to one lane)</xref>.</para>
    </encodingnotes>
    <syntaxnotes>
      <para>For more information about the variants of this instruction, see <xref linkend="Cjaefebe">Advanced SIMD addressing mode</xref>.</para>
    </syntaxnotes>
  </desc>
  <operationalnotes>
    <para>If CPSR.DIT is 1, the timing of this instruction is insensitive to the value of the data being loaded or stored.</para>
  </operationalnotes>
  <alias_list howmany="0"></alias_list>
  <classes>
    <classesintro count="6">
      <txt>It has encodings from the following instruction sets:</txt>
      <txt> A32 (</txt>
      <a href="#iclass_a1">A1</a>
      <txt>, </txt>
      <a href="#iclass_a2">A2</a>
      <txt> and </txt>
      <a href="#iclass_a3">A3</a>
      <txt>)</txt>
      <txt> and </txt>
      <txt> T32 (</txt>
      <a href="#iclass_t1">T1</a>
      <txt>, </txt>
      <a href="#iclass_t2">T2</a>
      <txt> and </txt>
      <a href="#iclass_t3">T3</a>
      <txt>)</txt>
      <txt>.</txt>
    </classesintro>
    <iclass name="A1" oneof="6" id="iclass_a1" no_encodings="3" isa="A32">
      <docvars>
        <docvar key="armarmheading" value="A1" />
        <docvar key="instr-class" value="fpsimd" />
        <docvar key="isa" value="A32" />
        <docvar key="mnemonic" value="VLD2" />
      </docvars>
      <iclassintro count="3"></iclassintro>
      <regdiagram form="32" psname="aarch32/instrs/VLD2_1/T1A1_A.txt" tworows="1">
        <box hibit="31" width="9" settings="9">
          <c>1</c>
          <c>1</c>
          <c>1</c>
          <c>1</c>
          <c>0</c>
          <c>1</c>
          <c>0</c>
          <c>0</c>
          <c>1</c>
        </box>
        <box hibit="22" name="D" usename="1">
          <c></c>
        </box>
        <box hibit="21" name="L" settings="1">
          <c>1</c>
        </box>
        <box hibit="20" settings="1">
          <c>0</c>
        </box>
        <box hibit="19" width="4" name="Rn" 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="2" name="size" usename="1" settings="2">
          <c>0</c>
          <c>0</c>
        </box>
        <box hibit="9" width="2" name="N" settings="2">
          <c>0</c>
          <c>1</c>
        </box>
        <box hibit="7" width="4" name="index_align" usename="1">
          <c colspan="4"></c>
        </box>
        <box hibit="3" width="4" name="Rm" usename="1">
          <c colspan="4"></c>
        </box>
      </regdiagram>
      <encoding name="VLD2_1_A1_nowb" oneofinclass="3" oneof="18" label="Offset" bitdiffs="Rm == 1111">
        <docvars>
          <docvar key="address-form" value="base-plus-offset" />
          <docvar key="armarmheading" value="A1" />
          <docvar key="instr-class" value="fpsimd" />
          <docvar key="isa" value="A32" />
          <docvar key="mnemonic" value="VLD2" />
        </docvars>
        <box hibit="3" width="4" name="Rm">
          <c>1</c>
          <c>1</c>
          <c>1</c>
          <c>1</c>
        </box>
        <asmtemplate><text>VLD2</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>.</text><a link="sa_size" hover="Data size (field &quot;size&quot;) [8,16,32]">&lt;size&gt;</a><text> </text><a link="sa_list" hover="List containing the 64-bit names of two SIMD&amp;FP registers holding element (field &quot;index_align&lt;1&gt;&quot;)">&lt;list&gt;</a><text>, [</text><a link="sa_rn" hover="General-purpose base register (field &quot;Rn&quot;)">&lt;Rn&gt;</a><text>{</text><text>:</text><a link="sa_align" hover="Optional alignment (field &quot;index_align&lt;0&gt;&quot;)">&lt;align&gt;</a><text>}</text><text>]</text></asmtemplate>
      </encoding>
      <encoding name="VLD2_1_A1_posti" oneofinclass="3" oneof="18" label="Post-indexed" bitdiffs="Rm == 1101">
        <docvars>
          <docvar key="address-form" value="post-indexed" />
          <docvar key="armarmheading" value="A1" />
          <docvar key="instr-class" value="fpsimd" />
          <docvar key="isa" value="A32" />
          <docvar key="mnemonic" value="VLD2" />
        </docvars>
        <box hibit="3" width="4" name="Rm">
          <c>1</c>
          <c>1</c>
          <c>0</c>
          <c>1</c>
        </box>
        <asmtemplate><text>VLD2</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>.</text><a link="sa_size" hover="Data size (field &quot;size&quot;) [8,16,32]">&lt;size&gt;</a><text> </text><a link="sa_list" hover="List containing the 64-bit names of two SIMD&amp;FP registers holding element (field &quot;index_align&lt;1&gt;&quot;)">&lt;list&gt;</a><text>, [</text><a link="sa_rn" hover="General-purpose base register (field &quot;Rn&quot;)">&lt;Rn&gt;</a><text>{</text><text>:</text><a link="sa_align" hover="Optional alignment (field &quot;index_align&lt;0&gt;&quot;)">&lt;align&gt;</a><text>}</text><text>]!</text></asmtemplate>
      </encoding>
      <encoding name="VLD2_1_A1_postr" oneofinclass="3" oneof="18" label="Post-indexed" bitdiffs="Rm != 11x1">
        <docvars>
          <docvar key="address-form" value="post-indexed" />
          <docvar key="address-offset" value="reg-offset" />
          <docvar key="armarmheading" value="A1" />
          <docvar key="instr-class" value="fpsimd" />
          <docvar key="isa" value="A32" />
          <docvar key="mnemonic" value="VLD2" />
        </docvars>
        <box hibit="3" width="4" name="Rm">
          <c>N</c>
          <c>N</c>
          <c></c>
          <c>N</c>
        </box>
        <asmtemplate><text>VLD2</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>.</text><a link="sa_size" hover="Data size (field &quot;size&quot;) [8,16,32]">&lt;size&gt;</a><text> </text><a link="sa_list" hover="List containing the 64-bit names of two SIMD&amp;FP registers holding element (field &quot;index_align&lt;1&gt;&quot;)">&lt;list&gt;</a><text>, [</text><a link="sa_rn" hover="General-purpose base register (field &quot;Rn&quot;)">&lt;Rn&gt;</a><text>{</text><text>:</text><a link="sa_align" hover="Optional alignment (field &quot;index_align&lt;0&gt;&quot;)">&lt;align&gt;</a><text>}</text><text>], </text><a link="sa_rm" hover="General-purpose index register containing an offset applied after the access (field &quot;Rm&quot;)">&lt;Rm&gt;</a></asmtemplate>
      </encoding>
      <ps_section howmany="1">
        <ps name="aarch32/instrs/VLD2_1/T1A1_A.txt" mylink="aarch32.instrs.VLD2_1.T1A1_A.txt" enclabels="" sections="1" secttype="noheading">
          <pstext mayhavelinks="1" section="Decode" rep_section="decode">if size == '11' then SEE "VLD2 (single 2-element structure to all lanes)";
ebytes = 1;  index = <a link="impl-shared.UInt.1" file="shared_pseudocode.xml" hover="function: integer UInt(bits(N) x)">UInt</a>(index_align&lt;3:1&gt;);  inc = 1;
alignment = if index_align&lt;0&gt; == '0' then 1 else 2;
d = <a link="impl-shared.UInt.1" file="shared_pseudocode.xml" hover="function: integer UInt(bits(N) x)">UInt</a>(D:Vd);  d2 = d + inc;  n = <a link="impl-shared.UInt.1" file="shared_pseudocode.xml" hover="function: integer UInt(bits(N) x)">UInt</a>(Rn);  m = <a link="impl-shared.UInt.1" file="shared_pseudocode.xml" hover="function: integer UInt(bits(N) x)">UInt</a>(Rm);
wback = (m != 15);  register_index = (m != 15 &amp;&amp; m != 13);
if n == 15 || d2 &gt; 31 then UNPREDICTABLE;</pstext>
        </ps>
      </ps_section>
      <constrained_unpredictables encoding="A1" ps_block="Decode">
        <cu_case>
          <cu_cause>
            <pstext mayhavelinks="1">d2 &gt; 31</pstext>
          </cu_cause>
          <cu_type constraint="Constraint_UNDEF" />
          <cu_type constraint="Constraint_NOP" />
          <cu_type>
            <cu_type_text>One or more of the SIMD and floating-point registers are <arm-defined-word>unknown</arm-defined-word>. If the instruction specifies writeback, the base register becomes <arm-defined-word>unknown</arm-defined-word>. This behavior does not affect any general-purpose registers.</cu_type_text>
          </cu_type>
        </cu_case>
      </constrained_unpredictables>
    </iclass>
    <iclass name="A2" oneof="6" id="iclass_a2" no_encodings="3" isa="A32">
      <docvars>
        <docvar key="armarmheading" value="A2" />
        <docvar key="instr-class" value="fpsimd" />
        <docvar key="isa" value="A32" />
        <docvar key="mnemonic" value="VLD2" />
      </docvars>
      <iclassintro count="3"></iclassintro>
      <regdiagram form="32" psname="aarch32/instrs/VLD2_1/T2A2_A.txt" tworows="1">
        <box hibit="31" width="9" settings="9">
          <c>1</c>
          <c>1</c>
          <c>1</c>
          <c>1</c>
          <c>0</c>
          <c>1</c>
          <c>0</c>
          <c>0</c>
          <c>1</c>
        </box>
        <box hibit="22" name="D" usename="1">
          <c></c>
        </box>
        <box hibit="21" name="L" settings="1">
          <c>1</c>
        </box>
        <box hibit="20" settings="1">
          <c>0</c>
        </box>
        <box hibit="19" width="4" name="Rn" 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="2" name="size" usename="1" settings="2">
          <c>0</c>
          <c>1</c>
        </box>
        <box hibit="9" width="2" name="N" settings="2">
          <c>0</c>
          <c>1</c>
        </box>
        <box hibit="7" width="4" name="index_align" usename="1">
          <c colspan="4"></c>
        </box>
        <box hibit="3" width="4" name="Rm" usename="1">
          <c colspan="4"></c>
        </box>
      </regdiagram>
      <encoding name="VLD2_1_A2_nowb" oneofinclass="3" oneof="18" label="Offset" bitdiffs="Rm == 1111">
        <docvars>
          <docvar key="address-form" value="base-plus-offset" />
          <docvar key="armarmheading" value="A2" />
          <docvar key="instr-class" value="fpsimd" />
          <docvar key="isa" value="A32" />
          <docvar key="mnemonic" value="VLD2" />
        </docvars>
        <box hibit="3" width="4" name="Rm">
          <c>1</c>
          <c>1</c>
          <c>1</c>
          <c>1</c>
        </box>
        <asmtemplate><text>VLD2</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>.</text><a link="sa_size" hover="Data size (field &quot;size&quot;) [8,16,32]">&lt;size&gt;</a><text> </text><a link="sa_list" hover="List containing the 64-bit names of two SIMD&amp;FP registers holding element (field &quot;index_align&lt;1&gt;&quot;)">&lt;list&gt;</a><text>, [</text><a link="sa_rn" hover="General-purpose base register (field &quot;Rn&quot;)">&lt;Rn&gt;</a><text>{</text><text>:</text><a link="sa_align" hover="Optional alignment (field &quot;index_align&lt;0&gt;&quot;)">&lt;align&gt;</a><text>}</text><text>]</text></asmtemplate>
      </encoding>
      <encoding name="VLD2_1_A2_posti" oneofinclass="3" oneof="18" label="Post-indexed" bitdiffs="Rm == 1101">
        <docvars>
          <docvar key="address-form" value="post-indexed" />
          <docvar key="armarmheading" value="A2" />
          <docvar key="instr-class" value="fpsimd" />
          <docvar key="isa" value="A32" />
          <docvar key="mnemonic" value="VLD2" />
        </docvars>
        <box hibit="3" width="4" name="Rm">
          <c>1</c>
          <c>1</c>
          <c>0</c>
          <c>1</c>
        </box>
        <asmtemplate><text>VLD2</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>.</text><a link="sa_size" hover="Data size (field &quot;size&quot;) [8,16,32]">&lt;size&gt;</a><text> </text><a link="sa_list" hover="List containing the 64-bit names of two SIMD&amp;FP registers holding element (field &quot;index_align&lt;1&gt;&quot;)">&lt;list&gt;</a><text>, [</text><a link="sa_rn" hover="General-purpose base register (field &quot;Rn&quot;)">&lt;Rn&gt;</a><text>{</text><text>:</text><a link="sa_align" hover="Optional alignment (field &quot;index_align&lt;0&gt;&quot;)">&lt;align&gt;</a><text>}</text><text>]!</text></asmtemplate>
      </encoding>
      <encoding name="VLD2_1_A2_postr" oneofinclass="3" oneof="18" label="Post-indexed" bitdiffs="Rm != 11x1">
        <docvars>
          <docvar key="address-form" value="post-indexed" />
          <docvar key="address-offset" value="reg-offset" />
          <docvar key="armarmheading" value="A2" />
          <docvar key="instr-class" value="fpsimd" />
          <docvar key="isa" value="A32" />
          <docvar key="mnemonic" value="VLD2" />
        </docvars>
        <box hibit="3" width="4" name="Rm">
          <c>N</c>
          <c>N</c>
          <c></c>
          <c>N</c>
        </box>
        <asmtemplate><text>VLD2</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>.</text><a link="sa_size" hover="Data size (field &quot;size&quot;) [8,16,32]">&lt;size&gt;</a><text> </text><a link="sa_list" hover="List containing the 64-bit names of two SIMD&amp;FP registers holding element (field &quot;index_align&lt;1&gt;&quot;)">&lt;list&gt;</a><text>, [</text><a link="sa_rn" hover="General-purpose base register (field &quot;Rn&quot;)">&lt;Rn&gt;</a><text>{</text><text>:</text><a link="sa_align" hover="Optional alignment (field &quot;index_align&lt;0&gt;&quot;)">&lt;align&gt;</a><text>}</text><text>], </text><a link="sa_rm" hover="General-purpose index register containing an offset applied after the access (field &quot;Rm&quot;)">&lt;Rm&gt;</a></asmtemplate>
      </encoding>
      <ps_section howmany="1">
        <ps name="aarch32/instrs/VLD2_1/T2A2_A.txt" mylink="aarch32.instrs.VLD2_1.T2A2_A.txt" enclabels="" sections="1" secttype="noheading">
          <pstext mayhavelinks="1" section="Decode" rep_section="decode">if size == '11' then SEE "VLD2 (single 2-element structure to all lanes)";
ebytes = 2;  index = <a link="impl-shared.UInt.1" file="shared_pseudocode.xml" hover="function: integer UInt(bits(N) x)">UInt</a>(index_align&lt;3:2&gt;);
inc = if index_align&lt;1&gt; == '0' then 1 else 2;
alignment = if index_align&lt;0&gt; == '0' then 1 else 4;
d = <a link="impl-shared.UInt.1" file="shared_pseudocode.xml" hover="function: integer UInt(bits(N) x)">UInt</a>(D:Vd);  d2 = d + inc;  n = <a link="impl-shared.UInt.1" file="shared_pseudocode.xml" hover="function: integer UInt(bits(N) x)">UInt</a>(Rn);  m = <a link="impl-shared.UInt.1" file="shared_pseudocode.xml" hover="function: integer UInt(bits(N) x)">UInt</a>(Rm);
wback = (m != 15);  register_index = (m != 15 &amp;&amp; m != 13);
if n == 15 || d2 &gt; 31 then UNPREDICTABLE;</pstext>
        </ps>
      </ps_section>
      <constrained_unpredictables encoding="A2" ps_block="Decode">
        <cu_case>
          <cu_cause>
            <pstext mayhavelinks="1">d2 &gt; 31</pstext>
          </cu_cause>
          <cu_type constraint="Constraint_UNDEF" />
          <cu_type constraint="Constraint_NOP" />
          <cu_type>
            <cu_type_text>One or more of the SIMD and floating-point registers are <arm-defined-word>unknown</arm-defined-word>. If the instruction specifies writeback, the base register becomes <arm-defined-word>unknown</arm-defined-word>. This behavior does not affect any general-purpose registers.</cu_type_text>
          </cu_type>
        </cu_case>
      </constrained_unpredictables>
    </iclass>
    <iclass name="A3" oneof="6" id="iclass_a3" no_encodings="3" isa="A32">
      <docvars>
        <docvar key="armarmheading" value="A3" />
        <docvar key="instr-class" value="fpsimd" />
        <docvar key="isa" value="A32" />
        <docvar key="mnemonic" value="VLD2" />
      </docvars>
      <iclassintro count="3"></iclassintro>
      <regdiagram form="32" psname="aarch32/instrs/VLD2_1/T3A3_A.txt" tworows="1">
        <box hibit="31" width="9" settings="9">
          <c>1</c>
          <c>1</c>
          <c>1</c>
          <c>1</c>
          <c>0</c>
          <c>1</c>
          <c>0</c>
          <c>0</c>
          <c>1</c>
        </box>
        <box hibit="22" name="D" usename="1">
          <c></c>
        </box>
        <box hibit="21" name="L" settings="1">
          <c>1</c>
        </box>
        <box hibit="20" settings="1">
          <c>0</c>
        </box>
        <box hibit="19" width="4" name="Rn" 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="2" name="size" usename="1" settings="2">
          <c>1</c>
          <c>0</c>
        </box>
        <box hibit="9" width="2" name="N" settings="2">
          <c>0</c>
          <c>1</c>
        </box>
        <box hibit="7" width="4" name="index_align" usename="1">
          <c colspan="4"></c>
        </box>
        <box hibit="3" width="4" name="Rm" usename="1">
          <c colspan="4"></c>
        </box>
      </regdiagram>
      <encoding name="VLD2_1_A3_nowb" oneofinclass="3" oneof="18" label="Offset" bitdiffs="Rm == 1111">
        <docvars>
          <docvar key="address-form" value="base-plus-offset" />
          <docvar key="armarmheading" value="A3" />
          <docvar key="instr-class" value="fpsimd" />
          <docvar key="isa" value="A32" />
          <docvar key="mnemonic" value="VLD2" />
        </docvars>
        <box hibit="3" width="4" name="Rm">
          <c>1</c>
          <c>1</c>
          <c>1</c>
          <c>1</c>
        </box>
        <asmtemplate><text>VLD2</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>.</text><a link="sa_size" hover="Data size (field &quot;size&quot;) [8,16,32]">&lt;size&gt;</a><text> </text><a link="sa_list" hover="List containing the 64-bit names of two SIMD&amp;FP registers holding element (field &quot;index_align&lt;1&gt;&quot;)">&lt;list&gt;</a><text>, [</text><a link="sa_rn" hover="General-purpose base register (field &quot;Rn&quot;)">&lt;Rn&gt;</a><text>{</text><text>:</text><a link="sa_align" hover="Optional alignment (field &quot;index_align&lt;0&gt;&quot;)">&lt;align&gt;</a><text>}</text><text>]</text></asmtemplate>
      </encoding>
      <encoding name="VLD2_1_A3_posti" oneofinclass="3" oneof="18" label="Post-indexed" bitdiffs="Rm == 1101">
        <docvars>
          <docvar key="address-form" value="post-indexed" />
          <docvar key="armarmheading" value="A3" />
          <docvar key="instr-class" value="fpsimd" />
          <docvar key="isa" value="A32" />
          <docvar key="mnemonic" value="VLD2" />
        </docvars>
        <box hibit="3" width="4" name="Rm">
          <c>1</c>
          <c>1</c>
          <c>0</c>
          <c>1</c>
        </box>
        <asmtemplate><text>VLD2</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>.</text><a link="sa_size" hover="Data size (field &quot;size&quot;) [8,16,32]">&lt;size&gt;</a><text> </text><a link="sa_list" hover="List containing the 64-bit names of two SIMD&amp;FP registers holding element (field &quot;index_align&lt;1&gt;&quot;)">&lt;list&gt;</a><text>, [</text><a link="sa_rn" hover="General-purpose base register (field &quot;Rn&quot;)">&lt;Rn&gt;</a><text>{</text><text>:</text><a link="sa_align" hover="Optional alignment (field &quot;index_align&lt;0&gt;&quot;)">&lt;align&gt;</a><text>}</text><text>]!</text></asmtemplate>
      </encoding>
      <encoding name="VLD2_1_A3_postr" oneofinclass="3" oneof="18" label="Post-indexed" bitdiffs="Rm != 11x1">
        <docvars>
          <docvar key="address-form" value="post-indexed" />
          <docvar key="address-offset" value="reg-offset" />
          <docvar key="armarmheading" value="A3" />
          <docvar key="instr-class" value="fpsimd" />
          <docvar key="isa" value="A32" />
          <docvar key="mnemonic" value="VLD2" />
        </docvars>
        <box hibit="3" width="4" name="Rm">
          <c>N</c>
          <c>N</c>
          <c></c>
          <c>N</c>
        </box>
        <asmtemplate><text>VLD2</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>.</text><a link="sa_size" hover="Data size (field &quot;size&quot;) [8,16,32]">&lt;size&gt;</a><text> </text><a link="sa_list" hover="List containing the 64-bit names of two SIMD&amp;FP registers holding element (field &quot;index_align&lt;1&gt;&quot;)">&lt;list&gt;</a><text>, [</text><a link="sa_rn" hover="General-purpose base register (field &quot;Rn&quot;)">&lt;Rn&gt;</a><text>{</text><text>:</text><a link="sa_align" hover="Optional alignment (field &quot;index_align&lt;0&gt;&quot;)">&lt;align&gt;</a><text>}</text><text>], </text><a link="sa_rm" hover="General-purpose index register containing an offset applied after the access (field &quot;Rm&quot;)">&lt;Rm&gt;</a></asmtemplate>
      </encoding>
      <ps_section howmany="1">
        <ps name="aarch32/instrs/VLD2_1/T3A3_A.txt" mylink="aarch32.instrs.VLD2_1.T3A3_A.txt" enclabels="" sections="1" secttype="noheading">
          <pstext mayhavelinks="1" section="Decode" rep_section="decode">if size == '11' then SEE "VLD2 (single 2-element structure to all lanes)";
if index_align&lt;1&gt; != '0' then UNDEFINED;
ebytes = 4;  index = <a link="impl-shared.UInt.1" file="shared_pseudocode.xml" hover="function: integer UInt(bits(N) x)">UInt</a>(index_align&lt;3&gt;);
inc = if index_align&lt;2&gt; == '0' then 1 else 2;
alignment = if index_align&lt;0&gt; == '0' then 1 else 8;
d = <a link="impl-shared.UInt.1" file="shared_pseudocode.xml" hover="function: integer UInt(bits(N) x)">UInt</a>(D:Vd);  d2 = d + inc;  n = <a link="impl-shared.UInt.1" file="shared_pseudocode.xml" hover="function: integer UInt(bits(N) x)">UInt</a>(Rn);  m = <a link="impl-shared.UInt.1" file="shared_pseudocode.xml" hover="function: integer UInt(bits(N) x)">UInt</a>(Rm);
wback = (m != 15);  register_index = (m != 15 &amp;&amp; m != 13);
if n == 15 || d2 &gt; 31 then UNPREDICTABLE;</pstext>
        </ps>
      </ps_section>
      <constrained_unpredictables encoding="A3" ps_block="Decode">
        <cu_case>
          <cu_cause>
            <pstext mayhavelinks="1">d2 &gt; 31</pstext>
          </cu_cause>
          <cu_type constraint="Constraint_UNDEF" />
          <cu_type constraint="Constraint_NOP" />
          <cu_type>
            <cu_type_text>One or more of the SIMD and floating-point registers are <arm-defined-word>unknown</arm-defined-word>. If the instruction specifies writeback, the base register becomes <arm-defined-word>unknown</arm-defined-word>. This behavior does not affect any general-purpose registers.</cu_type_text>
          </cu_type>
        </cu_case>
      </constrained_unpredictables>
    </iclass>
    <iclass name="T1" oneof="6" id="iclass_t1" no_encodings="3" isa="T32">
      <docvars>
        <docvar key="armarmheading" value="T1" />
        <docvar key="instr-class" value="fpsimd" />
        <docvar key="isa" value="T32" />
        <docvar key="mnemonic" value="VLD2" />
      </docvars>
      <iclassintro count="3"></iclassintro>
      <regdiagram form="16x2" psname="aarch32/instrs/VLD2_1/T1A1_A.txt" tworows="1">
        <box hibit="31" width="9" settings="9">
          <c>1</c>
          <c>1</c>
          <c>1</c>
          <c>1</c>
          <c>1</c>
          <c>0</c>
          <c>0</c>
          <c>1</c>
          <c>1</c>
        </box>
        <box hibit="22" name="D" usename="1">
          <c></c>
        </box>
        <box hibit="21" name="L" settings="1">
          <c>1</c>
        </box>
        <box hibit="20" settings="1">
          <c>0</c>
        </box>
        <box hibit="19" width="4" name="Rn" 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="2" name="size" usename="1" settings="2">
          <c>0</c>
          <c>0</c>
        </box>
        <box hibit="9" width="2" name="N" settings="2">
          <c>0</c>
          <c>1</c>
        </box>
        <box hibit="7" width="4" name="index_align" usename="1">
          <c colspan="4"></c>
        </box>
        <box hibit="3" width="4" name="Rm" usename="1">
          <c colspan="4"></c>
        </box>
      </regdiagram>
      <encoding name="VLD2_1_T1_nowb" oneofinclass="3" oneof="18" label="Offset" bitdiffs="Rm == 1111">
        <docvars>
          <docvar key="address-form" value="base-plus-offset" />
          <docvar key="armarmheading" value="T1" />
          <docvar key="instr-class" value="fpsimd" />
          <docvar key="isa" value="T32" />
          <docvar key="mnemonic" value="VLD2" />
        </docvars>
        <box hibit="3" width="4" name="Rm">
          <c>1</c>
          <c>1</c>
          <c>1</c>
          <c>1</c>
        </box>
        <asmtemplate><text>VLD2</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>.</text><a link="sa_size" hover="Data size (field &quot;size&quot;) [8,16,32]">&lt;size&gt;</a><text> </text><a link="sa_list" hover="List containing the 64-bit names of two SIMD&amp;FP registers holding element (field &quot;index_align&lt;1&gt;&quot;)">&lt;list&gt;</a><text>, [</text><a link="sa_rn" hover="General-purpose base register (field &quot;Rn&quot;)">&lt;Rn&gt;</a><text>{</text><text>:</text><a link="sa_align" hover="Optional alignment (field &quot;index_align&lt;0&gt;&quot;)">&lt;align&gt;</a><text>}</text><text>]</text></asmtemplate>
      </encoding>
      <encoding name="VLD2_1_T1_posti" oneofinclass="3" oneof="18" label="Post-indexed" bitdiffs="Rm == 1101">
        <docvars>
          <docvar key="address-form" value="post-indexed" />
          <docvar key="armarmheading" value="T1" />
          <docvar key="instr-class" value="fpsimd" />
          <docvar key="isa" value="T32" />
          <docvar key="mnemonic" value="VLD2" />
        </docvars>
        <box hibit="3" width="4" name="Rm">
          <c>1</c>
          <c>1</c>
          <c>0</c>
          <c>1</c>
        </box>
        <asmtemplate><text>VLD2</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>.</text><a link="sa_size" hover="Data size (field &quot;size&quot;) [8,16,32]">&lt;size&gt;</a><text> </text><a link="sa_list" hover="List containing the 64-bit names of two SIMD&amp;FP registers holding element (field &quot;index_align&lt;1&gt;&quot;)">&lt;list&gt;</a><text>, [</text><a link="sa_rn" hover="General-purpose base register (field &quot;Rn&quot;)">&lt;Rn&gt;</a><text>{</text><text>:</text><a link="sa_align" hover="Optional alignment (field &quot;index_align&lt;0&gt;&quot;)">&lt;align&gt;</a><text>}</text><text>]!</text></asmtemplate>
      </encoding>
      <encoding name="VLD2_1_T1_postr" oneofinclass="3" oneof="18" label="Post-indexed" bitdiffs="Rm != 11x1">
        <docvars>
          <docvar key="address-form" value="post-indexed" />
          <docvar key="address-offset" value="reg-offset" />
          <docvar key="armarmheading" value="T1" />
          <docvar key="instr-class" value="fpsimd" />
          <docvar key="isa" value="T32" />
          <docvar key="mnemonic" value="VLD2" />
        </docvars>
        <box hibit="3" width="4" name="Rm">
          <c>N</c>
          <c>N</c>
          <c></c>
          <c>N</c>
        </box>
        <asmtemplate><text>VLD2</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>.</text><a link="sa_size" hover="Data size (field &quot;size&quot;) [8,16,32]">&lt;size&gt;</a><text> </text><a link="sa_list" hover="List containing the 64-bit names of two SIMD&amp;FP registers holding element (field &quot;index_align&lt;1&gt;&quot;)">&lt;list&gt;</a><text>, [</text><a link="sa_rn" hover="General-purpose base register (field &quot;Rn&quot;)">&lt;Rn&gt;</a><text>{</text><text>:</text><a link="sa_align" hover="Optional alignment (field &quot;index_align&lt;0&gt;&quot;)">&lt;align&gt;</a><text>}</text><text>], </text><a link="sa_rm" hover="General-purpose index register containing an offset applied after the access (field &quot;Rm&quot;)">&lt;Rm&gt;</a></asmtemplate>
      </encoding>
      <ps_section howmany="1">
        <ps name="aarch32/instrs/VLD2_1/T1A1_A.txt" mylink="aarch32.instrs.VLD2_1.T1A1_A.txt" enclabels="" sections="1" secttype="noheading">
          <pstext mayhavelinks="1" section="Decode" rep_section="decode">if size == '11' then SEE "VLD2 (single 2-element structure to all lanes)";
ebytes = 1;  index = <a link="impl-shared.UInt.1" file="shared_pseudocode.xml" hover="function: integer UInt(bits(N) x)">UInt</a>(index_align&lt;3:1&gt;);  inc = 1;
alignment = if index_align&lt;0&gt; == '0' then 1 else 2;
d = <a link="impl-shared.UInt.1" file="shared_pseudocode.xml" hover="function: integer UInt(bits(N) x)">UInt</a>(D:Vd);  d2 = d + inc;  n = <a link="impl-shared.UInt.1" file="shared_pseudocode.xml" hover="function: integer UInt(bits(N) x)">UInt</a>(Rn);  m = <a link="impl-shared.UInt.1" file="shared_pseudocode.xml" hover="function: integer UInt(bits(N) x)">UInt</a>(Rm);
wback = (m != 15);  register_index = (m != 15 &amp;&amp; m != 13);
if n == 15 || d2 &gt; 31 then UNPREDICTABLE;</pstext>
        </ps>
      </ps_section>
      <constrained_unpredictables encoding="T1" ps_block="Decode">
        <cu_case>
          <cu_cause>
            <pstext mayhavelinks="1">d2 &gt; 31</pstext>
          </cu_cause>
          <cu_type constraint="Constraint_UNDEF" />
          <cu_type constraint="Constraint_NOP" />
          <cu_type>
            <cu_type_text>One or more of the SIMD and floating-point registers are <arm-defined-word>unknown</arm-defined-word>. If the instruction specifies writeback, the base register becomes <arm-defined-word>unknown</arm-defined-word>. This behavior does not affect any general-purpose registers.</cu_type_text>
          </cu_type>
        </cu_case>
      </constrained_unpredictables>
    </iclass>
    <iclass name="T2" oneof="6" id="iclass_t2" no_encodings="3" isa="T32">
      <docvars>
        <docvar key="armarmheading" value="T2" />
        <docvar key="instr-class" value="fpsimd" />
        <docvar key="isa" value="T32" />
        <docvar key="mnemonic" value="VLD2" />
      </docvars>
      <iclassintro count="3"></iclassintro>
      <regdiagram form="16x2" psname="aarch32/instrs/VLD2_1/T2A2_A.txt" tworows="1">
        <box hibit="31" width="9" settings="9">
          <c>1</c>
          <c>1</c>
          <c>1</c>
          <c>1</c>
          <c>1</c>
          <c>0</c>
          <c>0</c>
          <c>1</c>
          <c>1</c>
        </box>
        <box hibit="22" name="D" usename="1">
          <c></c>
        </box>
        <box hibit="21" name="L" settings="1">
          <c>1</c>
        </box>
        <box hibit="20" settings="1">
          <c>0</c>
        </box>
        <box hibit="19" width="4" name="Rn" 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="2" name="size" usename="1" settings="2">
          <c>0</c>
          <c>1</c>
        </box>
        <box hibit="9" width="2" name="N" settings="2">
          <c>0</c>
          <c>1</c>
        </box>
        <box hibit="7" width="4" name="index_align" usename="1">
          <c colspan="4"></c>
        </box>
        <box hibit="3" width="4" name="Rm" usename="1">
          <c colspan="4"></c>
        </box>
      </regdiagram>
      <encoding name="VLD2_1_T2_nowb" oneofinclass="3" oneof="18" label="Offset" bitdiffs="Rm == 1111">
        <docvars>
          <docvar key="address-form" value="base-plus-offset" />
          <docvar key="armarmheading" value="T2" />
          <docvar key="instr-class" value="fpsimd" />
          <docvar key="isa" value="T32" />
          <docvar key="mnemonic" value="VLD2" />
        </docvars>
        <box hibit="3" width="4" name="Rm">
          <c>1</c>
          <c>1</c>
          <c>1</c>
          <c>1</c>
        </box>
        <asmtemplate><text>VLD2</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>.</text><a link="sa_size" hover="Data size (field &quot;size&quot;) [8,16,32]">&lt;size&gt;</a><text> </text><a link="sa_list" hover="List containing the 64-bit names of two SIMD&amp;FP registers holding element (field &quot;index_align&lt;1&gt;&quot;)">&lt;list&gt;</a><text>, [</text><a link="sa_rn" hover="General-purpose base register (field &quot;Rn&quot;)">&lt;Rn&gt;</a><text>{</text><text>:</text><a link="sa_align" hover="Optional alignment (field &quot;index_align&lt;0&gt;&quot;)">&lt;align&gt;</a><text>}</text><text>]</text></asmtemplate>
      </encoding>
      <encoding name="VLD2_1_T2_posti" oneofinclass="3" oneof="18" label="Post-indexed" bitdiffs="Rm == 1101">
        <docvars>
          <docvar key="address-form" value="post-indexed" />
          <docvar key="armarmheading" value="T2" />
          <docvar key="instr-class" value="fpsimd" />
          <docvar key="isa" value="T32" />
          <docvar key="mnemonic" value="VLD2" />
        </docvars>
        <box hibit="3" width="4" name="Rm">
          <c>1</c>
          <c>1</c>
          <c>0</c>
          <c>1</c>
        </box>
        <asmtemplate><text>VLD2</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>.</text><a link="sa_size" hover="Data size (field &quot;size&quot;) [8,16,32]">&lt;size&gt;</a><text> </text><a link="sa_list" hover="List containing the 64-bit names of two SIMD&amp;FP registers holding element (field &quot;index_align&lt;1&gt;&quot;)">&lt;list&gt;</a><text>, [</text><a link="sa_rn" hover="General-purpose base register (field &quot;Rn&quot;)">&lt;Rn&gt;</a><text>{</text><text>:</text><a link="sa_align" hover="Optional alignment (field &quot;index_align&lt;0&gt;&quot;)">&lt;align&gt;</a><text>}</text><text>]!</text></asmtemplate>
      </encoding>
      <encoding name="VLD2_1_T2_postr" oneofinclass="3" oneof="18" label="Post-indexed" bitdiffs="Rm != 11x1">
        <docvars>
          <docvar key="address-form" value="post-indexed" />
          <docvar key="address-offset" value="reg-offset" />
          <docvar key="armarmheading" value="T2" />
          <docvar key="instr-class" value="fpsimd" />
          <docvar key="isa" value="T32" />
          <docvar key="mnemonic" value="VLD2" />
        </docvars>
        <box hibit="3" width="4" name="Rm">
          <c>N</c>
          <c>N</c>
          <c></c>
          <c>N</c>
        </box>
        <asmtemplate><text>VLD2</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>.</text><a link="sa_size" hover="Data size (field &quot;size&quot;) [8,16,32]">&lt;size&gt;</a><text> </text><a link="sa_list" hover="List containing the 64-bit names of two SIMD&amp;FP registers holding element (field &quot;index_align&lt;1&gt;&quot;)">&lt;list&gt;</a><text>, [</text><a link="sa_rn" hover="General-purpose base register (field &quot;Rn&quot;)">&lt;Rn&gt;</a><text>{</text><text>:</text><a link="sa_align" hover="Optional alignment (field &quot;index_align&lt;0&gt;&quot;)">&lt;align&gt;</a><text>}</text><text>], </text><a link="sa_rm" hover="General-purpose index register containing an offset applied after the access (field &quot;Rm&quot;)">&lt;Rm&gt;</a></asmtemplate>
      </encoding>
      <ps_section howmany="1">
        <ps name="aarch32/instrs/VLD2_1/T2A2_A.txt" mylink="aarch32.instrs.VLD2_1.T2A2_A.txt" enclabels="" sections="1" secttype="noheading">
          <pstext mayhavelinks="1" section="Decode" rep_section="decode">if size == '11' then SEE "VLD2 (single 2-element structure to all lanes)";
ebytes = 2;  index = <a link="impl-shared.UInt.1" file="shared_pseudocode.xml" hover="function: integer UInt(bits(N) x)">UInt</a>(index_align&lt;3:2&gt;);
inc = if index_align&lt;1&gt; == '0' then 1 else 2;
alignment = if index_align&lt;0&gt; == '0' then 1 else 4;
d = <a link="impl-shared.UInt.1" file="shared_pseudocode.xml" hover="function: integer UInt(bits(N) x)">UInt</a>(D:Vd);  d2 = d + inc;  n = <a link="impl-shared.UInt.1" file="shared_pseudocode.xml" hover="function: integer UInt(bits(N) x)">UInt</a>(Rn);  m = <a link="impl-shared.UInt.1" file="shared_pseudocode.xml" hover="function: integer UInt(bits(N) x)">UInt</a>(Rm);
wback = (m != 15);  register_index = (m != 15 &amp;&amp; m != 13);
if n == 15 || d2 &gt; 31 then UNPREDICTABLE;</pstext>
        </ps>
      </ps_section>
      <constrained_unpredictables encoding="T2" ps_block="Decode">
        <cu_case>
          <cu_cause>
            <pstext mayhavelinks="1">d2 &gt; 31</pstext>
          </cu_cause>
          <cu_type constraint="Constraint_UNDEF" />
          <cu_type constraint="Constraint_NOP" />
          <cu_type>
            <cu_type_text>One or more of the SIMD and floating-point registers are <arm-defined-word>unknown</arm-defined-word>. If the instruction specifies writeback, the base register becomes <arm-defined-word>unknown</arm-defined-word>. This behavior does not affect any general-purpose registers.</cu_type_text>
          </cu_type>
        </cu_case>
      </constrained_unpredictables>
    </iclass>
    <iclass name="T3" oneof="6" id="iclass_t3" no_encodings="3" isa="T32">
      <docvars>
        <docvar key="armarmheading" value="T3" />
        <docvar key="instr-class" value="fpsimd" />
        <docvar key="isa" value="T32" />
        <docvar key="mnemonic" value="VLD2" />
      </docvars>
      <iclassintro count="3"></iclassintro>
      <regdiagram form="16x2" psname="aarch32/instrs/VLD2_1/T3A3_A.txt" tworows="1">
        <box hibit="31" width="9" settings="9">
          <c>1</c>
          <c>1</c>
          <c>1</c>
          <c>1</c>
          <c>1</c>
          <c>0</c>
          <c>0</c>
          <c>1</c>
          <c>1</c>
        </box>
        <box hibit="22" name="D" usename="1">
          <c></c>
        </box>
        <box hibit="21" name="L" settings="1">
          <c>1</c>
        </box>
        <box hibit="20" settings="1">
          <c>0</c>
        </box>
        <box hibit="19" width="4" name="Rn" 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="2" name="size" usename="1" settings="2">
          <c>1</c>
          <c>0</c>
        </box>
        <box hibit="9" width="2" name="N" settings="2">
          <c>0</c>
          <c>1</c>
        </box>
        <box hibit="7" width="4" name="index_align" usename="1">
          <c colspan="4"></c>
        </box>
        <box hibit="3" width="4" name="Rm" usename="1">
          <c colspan="4"></c>
        </box>
      </regdiagram>
      <encoding name="VLD2_1_T3_nowb" oneofinclass="3" oneof="18" label="Offset" bitdiffs="Rm == 1111">
        <docvars>
          <docvar key="address-form" value="base-plus-offset" />
          <docvar key="armarmheading" value="T3" />
          <docvar key="instr-class" value="fpsimd" />
          <docvar key="isa" value="T32" />
          <docvar key="mnemonic" value="VLD2" />
        </docvars>
        <box hibit="3" width="4" name="Rm">
          <c>1</c>
          <c>1</c>
          <c>1</c>
          <c>1</c>
        </box>
        <asmtemplate><text>VLD2</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>.</text><a link="sa_size" hover="Data size (field &quot;size&quot;) [8,16,32]">&lt;size&gt;</a><text> </text><a link="sa_list" hover="List containing the 64-bit names of two SIMD&amp;FP registers holding element (field &quot;index_align&lt;1&gt;&quot;)">&lt;list&gt;</a><text>, [</text><a link="sa_rn" hover="General-purpose base register (field &quot;Rn&quot;)">&lt;Rn&gt;</a><text>{</text><text>:</text><a link="sa_align" hover="Optional alignment (field &quot;index_align&lt;0&gt;&quot;)">&lt;align&gt;</a><text>}</text><text>]</text></asmtemplate>
      </encoding>
      <encoding name="VLD2_1_T3_posti" oneofinclass="3" oneof="18" label="Post-indexed" bitdiffs="Rm == 1101">
        <docvars>
          <docvar key="address-form" value="post-indexed" />
          <docvar key="armarmheading" value="T3" />
          <docvar key="instr-class" value="fpsimd" />
          <docvar key="isa" value="T32" />
          <docvar key="mnemonic" value="VLD2" />
        </docvars>
        <box hibit="3" width="4" name="Rm">
          <c>1</c>
          <c>1</c>
          <c>0</c>
          <c>1</c>
        </box>
        <asmtemplate><text>VLD2</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>.</text><a link="sa_size" hover="Data size (field &quot;size&quot;) [8,16,32]">&lt;size&gt;</a><text> </text><a link="sa_list" hover="List containing the 64-bit names of two SIMD&amp;FP registers holding element (field &quot;index_align&lt;1&gt;&quot;)">&lt;list&gt;</a><text>, [</text><a link="sa_rn" hover="General-purpose base register (field &quot;Rn&quot;)">&lt;Rn&gt;</a><text>{</text><text>:</text><a link="sa_align" hover="Optional alignment (field &quot;index_align&lt;0&gt;&quot;)">&lt;align&gt;</a><text>}</text><text>]!</text></asmtemplate>
      </encoding>
      <encoding name="VLD2_1_T3_postr" oneofinclass="3" oneof="18" label="Post-indexed" bitdiffs="Rm != 11x1">
        <docvars>
          <docvar key="address-form" value="post-indexed" />
          <docvar key="address-offset" value="reg-offset" />
          <docvar key="armarmheading" value="T3" />
          <docvar key="instr-class" value="fpsimd" />
          <docvar key="isa" value="T32" />
          <docvar key="mnemonic" value="VLD2" />
        </docvars>
        <box hibit="3" width="4" name="Rm">
          <c>N</c>
          <c>N</c>
          <c></c>
          <c>N</c>
        </box>
        <asmtemplate><text>VLD2</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>.</text><a link="sa_size" hover="Data size (field &quot;size&quot;) [8,16,32]">&lt;size&gt;</a><text> </text><a link="sa_list" hover="List containing the 64-bit names of two SIMD&amp;FP registers holding element (field &quot;index_align&lt;1&gt;&quot;)">&lt;list&gt;</a><text>, [</text><a link="sa_rn" hover="General-purpose base register (field &quot;Rn&quot;)">&lt;Rn&gt;</a><text>{</text><text>:</text><a link="sa_align" hover="Optional alignment (field &quot;index_align&lt;0&gt;&quot;)">&lt;align&gt;</a><text>}</text><text>], </text><a link="sa_rm" hover="General-purpose index register containing an offset applied after the access (field &quot;Rm&quot;)">&lt;Rm&gt;</a></asmtemplate>
      </encoding>
      <ps_section howmany="1">
        <ps name="aarch32/instrs/VLD2_1/T3A3_A.txt" mylink="aarch32.instrs.VLD2_1.T3A3_A.txt" enclabels="" sections="1" secttype="noheading">
          <pstext mayhavelinks="1" section="Decode" rep_section="decode">if size == '11' then SEE "VLD2 (single 2-element structure to all lanes)";
if index_align&lt;1&gt; != '0' then UNDEFINED;
ebytes = 4;  index = <a link="impl-shared.UInt.1" file="shared_pseudocode.xml" hover="function: integer UInt(bits(N) x)">UInt</a>(index_align&lt;3&gt;);
inc = if index_align&lt;2&gt; == '0' then 1 else 2;
alignment = if index_align&lt;0&gt; == '0' then 1 else 8;
d = <a link="impl-shared.UInt.1" file="shared_pseudocode.xml" hover="function: integer UInt(bits(N) x)">UInt</a>(D:Vd);  d2 = d + inc;  n = <a link="impl-shared.UInt.1" file="shared_pseudocode.xml" hover="function: integer UInt(bits(N) x)">UInt</a>(Rn);  m = <a link="impl-shared.UInt.1" file="shared_pseudocode.xml" hover="function: integer UInt(bits(N) x)">UInt</a>(Rm);
wback = (m != 15);  register_index = (m != 15 &amp;&amp; m != 13);
if n == 15 || d2 &gt; 31 then UNPREDICTABLE;</pstext>
        </ps>
      </ps_section>
      <constrained_unpredictables encoding="T3" ps_block="Decode">
        <cu_case>
          <cu_cause>
            <pstext mayhavelinks="1">d2 &gt; 31</pstext>
          </cu_cause>
          <cu_type constraint="Constraint_UNDEF" />
          <cu_type constraint="Constraint_NOP" />
          <cu_type>
            <cu_type_text>One or more of the SIMD and floating-point registers are <arm-defined-word>unknown</arm-defined-word>. If the instruction specifies writeback, the base register becomes <arm-defined-word>unknown</arm-defined-word>. This behavior does not affect any general-purpose registers.</cu_type_text>
          </cu_type>
        </cu_case>
      </constrained_unpredictables>
    </iclass>
  </classes>
  <explanations scope="all">
    <explanation enclist="VLD2_1_A1_nowb, VLD2_1_A2_nowb, VLD2_1_A3_nowb" symboldefcount="1">
      <symbol link="sa_c_1">&lt;c&gt;</symbol>
      <account encodedin="">
        <docvars>
          <docvar key="isa" value="A32" />
        </docvars>
        <intro>
          <para>For encoding A1, A2 and A3: see <xref linkend="Babbefhf">Standard assembler syntax fields</xref>. This encoding must be unconditional.</para>
        </intro>
      </account>
    </explanation>
    <explanation enclist="VLD2_1_T1_nowb, VLD2_1_T2_nowb, VLD2_1_T3_nowb" symboldefcount="2">
      <symbol link="sa_c">&lt;c&gt;</symbol>
      <account encodedin="">
        <docvars>
          <docvar key="isa" value="T32" />
        </docvars>
        <intro>
          <para>For encoding T1, T2 and T3: see <xref linkend="Babbefhf">Standard assembler syntax fields</xref>.</para>
        </intro>
      </account>
    </explanation>
    <explanation enclist="VLD2_1_A1_nowb, VLD2_1_A2_nowb, VLD2_1_A3_nowb, VLD2_1_T1_nowb, VLD2_1_T2_nowb, VLD2_1_T3_nowb" 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="VLD2_1_A1_nowb, VLD2_1_A2_nowb, VLD2_1_A3_nowb, VLD2_1_T1_nowb, VLD2_1_T2_nowb, VLD2_1_T3_nowb" symboldefcount="1">
      <symbol link="sa_size">&lt;size&gt;</symbol>
      <definition encodedin="size">
        <intro>Is the data size, </intro>
        <table class="valuetable">
          <tgroup cols="2">
            <thead>
              <row>
                <entry class="bitfield">size</entry>
                <entry class="symbol">&lt;size&gt;</entry>
              </row>
            </thead>
            <tbody>
              <row>
                <entry class="bitfield">00</entry>
                <entry class="symbol">8</entry>
              </row>
              <row>
                <entry class="bitfield">01</entry>
                <entry class="symbol">16</entry>
              </row>
              <row>
                <entry class="bitfield">10</entry>
                <entry class="symbol">32</entry>
              </row>
            </tbody>
          </tgroup>
        </table>
      </definition>
    </explanation>
    <explanation enclist="VLD2_1_A1_nowb, VLD2_1_A2_nowb, VLD2_1_A3_nowb, VLD2_1_T1_nowb, VLD2_1_T2_nowb, VLD2_1_T3_nowb" symboldefcount="1">
      <symbol link="sa_list">&lt;list&gt;</symbol>
      <account encodedin="index_align&lt;1&gt;">
        <intro>
          <para>Is a list containing the 64-bit names of the two SIMD&amp;FP registers holding the element.</para>
          <para>The list must be one of:</para>
          <list type="param">
            <listitem>
              <param><syntax>{ &lt;Dd&gt;[&lt;index&gt;], &lt;Dd+1&gt;[&lt;index&gt;] }</syntax></param><content>Single-spaced registers, encoded as "spacing" = <binarynumber>0</binarynumber>.</content>
            </listitem>
            <listitem>
              <param><syntax>{ &lt;Dd&gt;[&lt;index&gt;], &lt;Dd+2&gt;[&lt;index&gt;] }</syntax></param><content>Double-spaced registers, encoded as "spacing" = <binarynumber>1</binarynumber>. Not permitted when <syntax>&lt;size&gt;</syntax> == 8.</content>
            </listitem>
          </list>
          <para>The encoding of "spacing" depends on <syntax>&lt;size&gt;</syntax>:</para>
          <list type="param">
            <listitem>
              <param><syntax>&lt;size&gt;</syntax> == 16</param><content>"spacing" is encoded in the "index_align&lt;1&gt;" field.</content>
            </listitem>
            <listitem>
              <param><syntax>&lt;size&gt;</syntax> == 32</param><content>"spacing" is encoded in the "index_align&lt;2&gt;" field.</content>
            </listitem>
          </list>
          <para>The register <syntax>&lt;Dd&gt;</syntax> is encoded in the "D:Vd" field.</para>
          <para>The permitted values and encoding of <syntax>&lt;index&gt;</syntax> depend on <syntax>&lt;size&gt;</syntax>:</para>
          <list type="param">
            <listitem>
              <param><syntax>&lt;size&gt;</syntax> == 8</param><content><syntax>&lt;index&gt;</syntax> is in the range 0 to 7, encoded in the "index_align&lt;3:1&gt;" field.</content>
            </listitem>
            <listitem>
              <param><syntax>&lt;size&gt;</syntax> == 16</param><content><syntax>&lt;index&gt;</syntax> is in the range 0 to 3, encoded in the "index_align&lt;3:2&gt;" field.</content>
            </listitem>
            <listitem>
              <param><syntax>&lt;size&gt;</syntax> == 32</param><content><syntax>&lt;index&gt;</syntax> is 0 or 1, encoded in the "index_align&lt;3&gt;" field.</content>
            </listitem>
          </list>
        </intro>
      </account>
    </explanation>
    <explanation enclist="VLD2_1_A1_nowb, VLD2_1_A2_nowb, VLD2_1_A3_nowb, VLD2_1_T1_nowb, VLD2_1_T2_nowb, VLD2_1_T3_nowb" symboldefcount="1">
      <symbol link="sa_rn">&lt;Rn&gt;</symbol>
      <account encodedin="Rn">
        <intro>
          <para>Is the general-purpose base register, encoded in the "Rn" field.</para>
        </intro>
      </account>
    </explanation>
    <explanation enclist="VLD2_1_A1_nowb, VLD2_1_A2_nowb, VLD2_1_A3_nowb, VLD2_1_T1_nowb, VLD2_1_T2_nowb, VLD2_1_T3_nowb" symboldefcount="1">
      <symbol link="sa_align">&lt;align&gt;</symbol>
      <account encodedin="index_align&lt;0&gt;">
        <intro>
          <para>Is the optional alignment.</para>
          <para>Whenever <syntax>&lt;align&gt;</syntax> is omitted, the standard alignment is used, see <xref linkend="Chdijihg">Unaligned data access</xref>, and the encoding depends on <syntax>&lt;size&gt;</syntax>:</para>
          <list type="param">
            <listitem>
              <param><syntax>&lt;size&gt;</syntax> == 8</param><content>Encoded in the "index_align&lt;0&gt;" field as <binarynumber>0</binarynumber>.</content>
            </listitem>
            <listitem>
              <param><syntax>&lt;size&gt;</syntax> == 16</param><content>Encoded in the "index_align&lt;0&gt;" field as <binarynumber>0</binarynumber>.</content>
            </listitem>
            <listitem>
              <param><syntax>&lt;size&gt;</syntax> == 32</param><content>Encoded in the "index_align&lt;1:0&gt;" field as <binarynumber>0b00</binarynumber>.</content>
            </listitem>
          </list>
          <para>Whenever <syntax>&lt;align&gt;</syntax> is present, the permitted values and encoding depend on <syntax>&lt;size&gt;</syntax>:</para>
          <list type="param">
            <listitem>
              <param><syntax>&lt;size&gt;</syntax> == 8</param><content><syntax>&lt;align&gt;</syntax> is 16, meaning 16-bit alignment, encoded in the "index_align&lt;0&gt;" field as <binarynumber>1</binarynumber>.</content>
            </listitem>
            <listitem>
              <param><syntax>&lt;size&gt;</syntax> == 16</param><content><syntax>&lt;align&gt;</syntax> is 32, meaning 32-bit alignment, encoded in the "index_align&lt;0&gt;" field as <binarynumber>1</binarynumber>.</content>
            </listitem>
            <listitem>
              <param><syntax>&lt;size&gt;</syntax> == 32</param><content><syntax>&lt;align&gt;</syntax> is 64, meaning 64-bit alignment, encoded in the "index_align&lt;1:0&gt;" field as <binarynumber>0b01</binarynumber>.</content>
            </listitem>
          </list>
          <para><value>:</value> is the preferred separator before the <syntax>&lt;align&gt;</syntax> value, but the alignment can be specified as <value>@&lt;align&gt;</value>, see <xref linkend="Cjaefebe">Advanced SIMD addressing mode</xref>.</para>
        </intro>
      </account>
    </explanation>
    <explanation enclist="VLD2_1_A1_postr, VLD2_1_A2_postr, VLD2_1_A3_postr, VLD2_1_T1_postr, VLD2_1_T2_postr, VLD2_1_T3_postr" symboldefcount="1">
      <symbol link="sa_rm">&lt;Rm&gt;</symbol>
      <account encodedin="Rm">
        <intro>
          <para>Is the general-purpose index register containing an offset applied after the access, encoded in the "Rm" field.</para>
        </intro>
      </account>
    </explanation>
  </explanations>
  <ps_section howmany="1">
    <ps name="aarch32/instrs/VLD2_1/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>();

    address = <a link="impl-aarch32.R.read.1" file="shared_pseudocode.xml" hover="accessor: bits(32) R[integer n]">R</a>[n];

    boolean nontemporal = FALSE;
    boolean tagchecked  = FALSE;
    <a link="AccessDescriptor" file="shared_pseudocode.xml" hover="type AccessDescriptor is ( AccessType acctype, bits(2) el, SecurityState ss, boolean acqsc, boolean acqpc, boolean relsc, boolean limitedordered, boolean exclusive, boolean atomicop, MemAtomicOp modop, boolean nontemporal, boolean read, boolean write, CacheOp cacheop, CacheOpScope opscope, CacheType cachetype, boolean pan, boolean transactional, boolean nonfault, boolean firstfault, boolean first, boolean contiguous, boolean streamingsve, boolean ls64, boolean mops, boolean rcw, boolean rcws, boolean toplevel, VARange varange, boolean a32lsmd, boolean tagchecked, boolean tagaccess, MPAMinfo mpam )">AccessDescriptor</a> accdesc = <a link="impl-shared.CreateAccDescASIMD.3" file="shared_pseudocode.xml" hover="function: AccessDescriptor CreateAccDescASIMD(MemOp memop, boolean nontemporal, boolean tagchecked)">CreateAccDescASIMD</a>(<a link="MemOp_LOAD" file="shared_pseudocode.xml" hover="enumeration MemOp {MemOp_LOAD, MemOp_STORE, MemOp_PREFETCH}">MemOp_LOAD</a>, nontemporal, tagchecked);
    if !<a link="impl-shared.IsAligned.2" file="shared_pseudocode.xml" hover="function: boolean IsAligned(integer x, integer y)">IsAligned</a>(address, alignment) then
        <a link="AArch32.Abort.2" file="shared_pseudocode.xml" hover="function: AArch32.Abort(bits(32) vaddress, FaultRecord fault)">AArch32.Abort</a>(address, <a link="impl-shared.AlignmentFault.1" file="shared_pseudocode.xml" hover="function: FaultRecord AlignmentFault(AccessDescriptor accdesc)">AlignmentFault</a>(accdesc));

    <a link="impl-shared.Elem.write.3" file="shared_pseudocode.xml" hover="accessor: Elem[bits(N) &amp;vector, integer e, integer size] = bits(size) value">Elem</a>[<a link="impl-aarch32.D.write.1" file="shared_pseudocode.xml" hover="accessor: D[integer n] = bits(64) value">D</a>[d], index,8*ebytes] = <a link="impl-aarch32.MemU.read.2" file="shared_pseudocode.xml" hover="accessor: bits(8*size) MemU[bits(32) address, integer size]">MemU</a>[address,ebytes];
    <a link="impl-shared.Elem.write.3" file="shared_pseudocode.xml" hover="accessor: Elem[bits(N) &amp;vector, integer e, integer size] = bits(size) value">Elem</a>[<a link="impl-aarch32.D.write.1" file="shared_pseudocode.xml" hover="accessor: D[integer n] = bits(64) value">D</a>[d2],index,8*ebytes] = <a link="impl-aarch32.MemU.read.2" file="shared_pseudocode.xml" hover="accessor: bits(8*size) MemU[bits(32) address, integer size]">MemU</a>[address+ebytes,ebytes];
    if wback then
        if register_index then
            <a link="impl-aarch32.R.write.1" file="shared_pseudocode.xml" hover="accessor: R[integer n] = bits(32) value">R</a>[n] = <a link="impl-aarch32.R.read.1" file="shared_pseudocode.xml" hover="accessor: bits(32) R[integer n]">R</a>[n] + <a link="impl-aarch32.R.read.1" file="shared_pseudocode.xml" hover="accessor: bits(32) R[integer n]">R</a>[m];
        else
            <a link="impl-aarch32.R.write.1" file="shared_pseudocode.xml" hover="accessor: R[integer n] = bits(32) value">R</a>[n] = <a link="impl-aarch32.R.read.1" file="shared_pseudocode.xml" hover="accessor: bits(32) R[integer n]">R</a>[n] + 2*ebytes;</pstext>
    </ps>
  </ps_section>
</instructionsection>
