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<instructionsection id="VSHL_r" title="VSHL (register) -- AArch32" type="instruction">
  <docvars>
    <docvar key="instr-class" value="fpsimd" />
    <docvar key="mnemonic" value="VSHL" />
  </docvars>
  <heading>VSHL (register)</heading>
  <desc>
    <brief>
      <para>Vector Shift Left (register)</para>
    </brief>
    <authored>
      <para>Vector Shift Left (register) takes each element in a vector, shifts them by a value from the least significant byte of the corresponding element of a second vector, and places the results in the destination vector. If the shift value is positive, the operation is a left shift. If the shift value is negative, it is a truncating right shift.</para>
      <para>For a rounding shift, see <xref linkend="A32T32-fpsimd.instructions.VRSHL">VRSHL</xref>.</para>
      <para>The first operand and result elements are the same data type, and can be any one of:</para>
      <list type="unordered">
        <listitem><content>8-bit, 16-bit, 32-bit, or 64-bit signed integers.</content></listitem>
        <listitem><content>8-bit, 16-bit, 32-bit, or 64-bit unsigned integers.</content></listitem>
      </list>
      <para>The second operand is always a signed integer of the same size.</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="0"></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="VSHL" />
      </docvars>
      <iclassintro count="2"></iclassintro>
      <regdiagram form="32" psname="aarch32/instrs/VSHL_r/T1A1_A.txt">
        <box hibit="31" width="7" settings="7">
          <c>1</c>
          <c>1</c>
          <c>1</c>
          <c>1</c>
          <c>0</c>
          <c>0</c>
          <c>1</c>
        </box>
        <box hibit="24" name="U" usename="1">
          <c></c>
        </box>
        <box hibit="23" settings="1">
          <c>0</c>
        </box>
        <box hibit="22" name="D" usename="1">
          <c></c>
        </box>
        <box hibit="21" width="2" name="size" usename="1">
          <c colspan="2"></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="opc" settings="4">
          <c>0</c>
          <c>1</c>
          <c>0</c>
          <c>0</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" name="o1" settings="1">
          <c>0</c>
        </box>
        <box hibit="3" width="4" name="Vm" usename="1">
          <c colspan="4"></c>
        </box>
      </regdiagram>
      <encoding name="VSHL_r_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="VSHL" />
          <docvar key="simdvectorsize" value="double" />
        </docvars>
        <box hibit="6" width="1" name="Q">
          <c>0</c>
        </box>
        <asmtemplate><text>VSHL</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_dt" hover="Data type for elements of vectors (field &quot;U:size&quot;) [S8,S16,S32,S64,U8,U16,U32,U64]">&lt;dt&gt;</a><text> </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_dm" hover="Second 64-bit SIMD&amp;FP source register (field &quot;M:Vm&quot;)">&lt;Dm&gt;</a><text>, </text><a link="sa_dn" hover="First 64-bit SIMD&amp;FP source register (field &quot;N:Vn&quot;)">&lt;Dn&gt;</a></asmtemplate>
      </encoding>
      <encoding name="VSHL_r_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="VSHL" />
          <docvar key="simdvectorsize" value="quad" />
        </docvars>
        <box hibit="6" width="1" name="Q">
          <c>1</c>
        </box>
        <asmtemplate><text>VSHL</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_dt" hover="Data type for elements of vectors (field &quot;U:size&quot;) [S8,S16,S32,S64,U8,U16,U32,U64]">&lt;dt&gt;</a><text> </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_qm" hover="Second 128-bit SIMD&amp;FP source register (field &quot;M:Vm&quot;)">&lt;Qm&gt;</a><text>, </text><a link="sa_qn" hover="First 128-bit SIMD&amp;FP source register (field &quot;N:Vn&quot;)">&lt;Qn&gt;</a></asmtemplate>
      </encoding>
      <ps_section howmany="1">
        <ps name="aarch32/instrs/VSHL_r/T1A1_A.txt" mylink="aarch32.instrs.VSHL_r.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' || Vm&lt;0&gt; == '1' || Vn&lt;0&gt; == '1') then UNDEFINED;
unsigned = (U == '1');
esize = 8 &lt;&lt; <a link="impl-shared.UInt.1" file="shared_pseudocode.xml" hover="function: integer UInt(bits(N) x)">UInt</a>(size);  elements = 64 DIV esize;
d = <a link="impl-shared.UInt.1" file="shared_pseudocode.xml" hover="function: integer UInt(bits(N) x)">UInt</a>(D:Vd);  m = <a link="impl-shared.UInt.1" file="shared_pseudocode.xml" hover="function: integer UInt(bits(N) x)">UInt</a>(M:Vm);  n = <a link="impl-shared.UInt.1" file="shared_pseudocode.xml" hover="function: integer UInt(bits(N) x)">UInt</a>(N:Vn);  regs = if Q == '0' then 1 else 2;</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="VSHL" />
      </docvars>
      <iclassintro count="2"></iclassintro>
      <regdiagram form="16x2" psname="aarch32/instrs/VSHL_r/T1A1_A.txt">
        <box hibit="31" width="3" settings="3">
          <c>1</c>
          <c>1</c>
          <c>1</c>
        </box>
        <box hibit="28" name="U" usename="1">
          <c></c>
        </box>
        <box hibit="27" width="5" settings="5">
          <c>1</c>
          <c>1</c>
          <c>1</c>
          <c>1</c>
          <c>0</c>
        </box>
        <box hibit="22" name="D" usename="1">
          <c></c>
        </box>
        <box hibit="21" width="2" name="size" usename="1">
          <c colspan="2"></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="opc" settings="4">
          <c>0</c>
          <c>1</c>
          <c>0</c>
          <c>0</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" name="o1" settings="1">
          <c>0</c>
        </box>
        <box hibit="3" width="4" name="Vm" usename="1">
          <c colspan="4"></c>
        </box>
      </regdiagram>
      <encoding name="VSHL_r_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="VSHL" />
          <docvar key="simdvectorsize" value="double" />
        </docvars>
        <box hibit="6" width="1" name="Q">
          <c>0</c>
        </box>
        <asmtemplate><text>VSHL</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_dt" hover="Data type for elements of vectors (field &quot;U:size&quot;) [S8,S16,S32,S64,U8,U16,U32,U64]">&lt;dt&gt;</a><text> </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_dm" hover="Second 64-bit SIMD&amp;FP source register (field &quot;M:Vm&quot;)">&lt;Dm&gt;</a><text>, </text><a link="sa_dn" hover="First 64-bit SIMD&amp;FP source register (field &quot;N:Vn&quot;)">&lt;Dn&gt;</a></asmtemplate>
      </encoding>
      <encoding name="VSHL_r_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="VSHL" />
          <docvar key="simdvectorsize" value="quad" />
        </docvars>
        <box hibit="6" width="1" name="Q">
          <c>1</c>
        </box>
        <asmtemplate><text>VSHL</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_dt" hover="Data type for elements of vectors (field &quot;U:size&quot;) [S8,S16,S32,S64,U8,U16,U32,U64]">&lt;dt&gt;</a><text> </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_qm" hover="Second 128-bit SIMD&amp;FP source register (field &quot;M:Vm&quot;)">&lt;Qm&gt;</a><text>, </text><a link="sa_qn" hover="First 128-bit SIMD&amp;FP source register (field &quot;N:Vn&quot;)">&lt;Qn&gt;</a></asmtemplate>
      </encoding>
      <ps_section howmany="1">
        <ps name="aarch32/instrs/VSHL_r/T1A1_A.txt" mylink="aarch32.instrs.VSHL_r.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' || Vm&lt;0&gt; == '1' || Vn&lt;0&gt; == '1') then UNDEFINED;
unsigned = (U == '1');
esize = 8 &lt;&lt; <a link="impl-shared.UInt.1" file="shared_pseudocode.xml" hover="function: integer UInt(bits(N) x)">UInt</a>(size);  elements = 64 DIV esize;
d = <a link="impl-shared.UInt.1" file="shared_pseudocode.xml" hover="function: integer UInt(bits(N) x)">UInt</a>(D:Vd);  m = <a link="impl-shared.UInt.1" file="shared_pseudocode.xml" hover="function: integer UInt(bits(N) x)">UInt</a>(M:Vm);  n = <a link="impl-shared.UInt.1" file="shared_pseudocode.xml" hover="function: integer UInt(bits(N) x)">UInt</a>(N:Vn);  regs = if Q == '0' then 1 else 2;</pstext>
        </ps>
      </ps_section>
    </iclass>
  </classes>
  <explanations scope="all">
    <explanation enclist="VSHL_r_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="VSHL_r_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="VSHL_r_A1_Q, VSHL_r_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="VSHL_r_A1_Q, VSHL_r_T1_Q" symboldefcount="1">
      <symbol link="sa_dt">&lt;dt&gt;</symbol>
      <definition encodedin="U:size">
        <intro>Is the data type for the elements of the vectors, </intro>
        <table class="valuetable">
          <tgroup cols="3">
            <thead>
              <row>
                <entry class="bitfield">U</entry>
                <entry class="bitfield">size</entry>
                <entry class="symbol">&lt;dt&gt;</entry>
              </row>
            </thead>
            <tbody>
              <row>
                <entry class="bitfield">0</entry>
                <entry class="bitfield">00</entry>
                <entry class="symbol">S8</entry>
              </row>
              <row>
                <entry class="bitfield">0</entry>
                <entry class="bitfield">01</entry>
                <entry class="symbol">S16</entry>
              </row>
              <row>
                <entry class="bitfield">0</entry>
                <entry class="bitfield">10</entry>
                <entry class="symbol">S32</entry>
              </row>
              <row>
                <entry class="bitfield">0</entry>
                <entry class="bitfield">11</entry>
                <entry class="symbol">S64</entry>
              </row>
              <row>
                <entry class="bitfield">1</entry>
                <entry class="bitfield">00</entry>
                <entry class="symbol">U8</entry>
              </row>
              <row>
                <entry class="bitfield">1</entry>
                <entry class="bitfield">01</entry>
                <entry class="symbol">U16</entry>
              </row>
              <row>
                <entry class="bitfield">1</entry>
                <entry class="bitfield">10</entry>
                <entry class="symbol">U32</entry>
              </row>
              <row>
                <entry class="bitfield">1</entry>
                <entry class="bitfield">11</entry>
                <entry class="symbol">U64</entry>
              </row>
            </tbody>
          </tgroup>
        </table>
      </definition>
    </explanation>
    <explanation enclist="VSHL_r_A1_Q, VSHL_r_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="VSHL_r_A1_Q, VSHL_r_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="VSHL_r_A1_Q, VSHL_r_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="VSHL_r_A1_D, VSHL_r_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="VSHL_r_A1_D, VSHL_r_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="VSHL_r_A1_D, VSHL_r_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>
  </explanations>
  <ps_section howmany="1">
    <ps name="aarch32/instrs/VSHL_r/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>();
    for r = 0 to regs-1
        for e = 0 to elements-1
            shift = <a link="impl-shared.SInt.1" file="shared_pseudocode.xml" hover="function: integer SInt(bits(N) x)">SInt</a>(<a link="impl-shared.Elem.read.3" file="shared_pseudocode.xml" hover="accessor: bits(size) Elem[bits(N) vector, integer e, integer size]">Elem</a>[<a link="impl-aarch32.D.read.1" file="shared_pseudocode.xml" hover="accessor: bits(64) D[integer n]">D</a>[n+r],e,esize]&lt;7:0&gt;);
            integer result;
            if shift &gt;= 0 then
                result = <a link="impl-shared.Int.2" file="shared_pseudocode.xml" hover="function: integer Int(bits(N) x, boolean unsigned)">Int</a>(<a link="impl-shared.Elem.read.3" file="shared_pseudocode.xml" hover="accessor: bits(size) Elem[bits(N) vector, integer e, integer size]">Elem</a>[<a link="impl-aarch32.D.read.1" file="shared_pseudocode.xml" hover="accessor: bits(64) D[integer n]">D</a>[m+r],e,esize], unsigned) &lt;&lt; shift;
            else
                result = <a link="impl-shared.Int.2" file="shared_pseudocode.xml" hover="function: integer Int(bits(N) x, boolean unsigned)">Int</a>(<a link="impl-shared.Elem.read.3" file="shared_pseudocode.xml" hover="accessor: bits(size) Elem[bits(N) vector, integer e, integer size]">Elem</a>[<a link="impl-aarch32.D.read.1" file="shared_pseudocode.xml" hover="accessor: bits(64) D[integer n]">D</a>[m+r],e,esize], unsigned) &gt;&gt; -shift;
            <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+r],e,esize] = result&lt;esize-1:0&gt;;</pstext>
    </ps>
  </ps_section>
</instructionsection>
