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<instructionsection id="sqdecp_z_p_z" title="SQDECP (vector)" type="instruction">
  <docvars>
    <docvar key="instr-class" value="sve" />
    <docvar key="isa" value="A64" />
    <docvar key="mnemonic" value="SQDECP" />
  </docvars>
  <heading>SQDECP (vector)</heading>
  <desc>
    <brief>Signed saturating decrement vector by count of true predicate elements</brief>
    <description>
      <para>Counts the number of true elements in the source predicate and then uses the result to decrement all destination vector elements. The results are saturated to the element signed integer range.</para>
      <para>The predicate size specifier may be omitted in assembler source code, but this is deprecated and will be prohibited in a future release of the architecture.</para>
    </description>
    <status>Green</status>
    <predicated>False</predicated>
    <takes_movprfx>True</takes_movprfx>
  </desc>
  <alias_list howmany="0"></alias_list>
  <classes>
    <iclass name="SVE" oneof="1" id="iclass_sve" no_encodings="1" isa="A64">
      <docvars>
        <docvar key="instr-class" value="sve" />
        <docvar key="isa" value="A64" />
        <docvar key="mnemonic" value="SQDECP" />
      </docvars>
      <iclassintro count="1"></iclassintro>
      <regdiagram form="32" psname="SQDECP-Z.P.Z-_" tworows="1">
        <box hibit="31" width="8" settings="8">
          <c>0</c>
          <c>0</c>
          <c>1</c>
          <c>0</c>
          <c>0</c>
          <c>1</c>
          <c>0</c>
          <c>1</c>
        </box>
        <box hibit="23" width="2" name="size" usename="1">
          <c colspan="2"></c>
        </box>
        <box hibit="21" width="4" settings="4">
          <c>1</c>
          <c>0</c>
          <c>1</c>
          <c>0</c>
        </box>
        <box hibit="17" name="D" usename="1" settings="1">
          <c>1</c>
        </box>
        <box hibit="16" name="U" usename="1" settings="1">
          <c>0</c>
        </box>
        <box hibit="15" width="5" settings="5">
          <c>1</c>
          <c>0</c>
          <c>0</c>
          <c>0</c>
          <c>0</c>
        </box>
        <box hibit="10" name="opc&lt;1&gt;" settings="1">
          <c>0</c>
        </box>
        <box hibit="9" name="opc&lt;0&gt;" settings="1">
          <c>0</c>
        </box>
        <box hibit="8" width="4" name="Pm" usename="1">
          <c colspan="4"></c>
        </box>
        <box hibit="4" width="5" name="Zdn" usename="1">
          <c colspan="5"></c>
        </box>
      </regdiagram>
      <encoding name="sqdecp_z_p_z_" oneofinclass="1" oneof="1" label="">
        <docvars>
          <docvar key="instr-class" value="sve" />
          <docvar key="isa" value="A64" />
          <docvar key="mnemonic" value="SQDECP" />
        </docvars>
        <asmtemplate><text>SQDECP  </text><a link="sa_zdn" hover="Source and destination scalable vector register (field &quot;Zdn&quot;)">&lt;Zdn&gt;</a><text>.</text><a link="sa_t" hover="Size specifier (field &quot;size&quot;) [D,H,S]">&lt;T&gt;</a><text>, </text><a link="sa_pm" hover="Source scalable predicate register (field &quot;Pm&quot;)">&lt;Pm&gt;</a><text>.</text><a link="sa_t" hover="Size specifier (field &quot;size&quot;) [D,H,S]">&lt;T&gt;</a></asmtemplate>
      </encoding>
      <ps_section howmany="1">
        <ps name="SQDECP-Z.P.Z-_" mylink="SQDECP-Z.P.Z-_" enclabels="" sections="1" secttype="noheading">
          <pstext mayhavelinks="1" section="Decode" rep_section="decode">if !<a link="impl-aarch64.HaveSVE.0" file="shared_pseudocode.xml" hover="function: boolean HaveSVE()">HaveSVE</a>() &amp;&amp; !<a link="impl-aarch64.HaveSME.0" file="shared_pseudocode.xml" hover="function: boolean HaveSME()">HaveSME</a>() then UNDEFINED;
if size == '00' then UNDEFINED;
constant integer esize = 8 &lt;&lt; <a link="impl-shared.UInt.1" file="shared_pseudocode.xml" hover="function: integer UInt(bits(N) x)">UInt</a>(size);
integer m = <a link="impl-shared.UInt.1" file="shared_pseudocode.xml" hover="function: integer UInt(bits(N) x)">UInt</a>(Pm);
integer dn = <a link="impl-shared.UInt.1" file="shared_pseudocode.xml" hover="function: integer UInt(bits(N) x)">UInt</a>(Zdn);
boolean unsigned = FALSE;</pstext>
        </ps>
      </ps_section>
    </iclass>
  </classes>
  <explanations scope="all">
    <explanation enclist="sqdecp_z_p_z_" symboldefcount="1">
      <symbol link="sa_zdn">&lt;Zdn&gt;</symbol>
      <account encodedin="Zdn">
        <intro>
          <para>Is the name of the source and destination scalable vector register, encoded in the "Zdn" field.</para>
        </intro>
      </account>
    </explanation>
    <explanation enclist="sqdecp_z_p_z_" symboldefcount="1">
      <symbol link="sa_t">&lt;T&gt;</symbol>
      <definition encodedin="size">
        <intro>Is the size specifier, </intro>
        <table class="valuetable">
          <tgroup cols="2">
            <thead>
              <row>
                <entry class="bitfield">size</entry>
                <entry class="symbol">&lt;T&gt;</entry>
              </row>
            </thead>
            <tbody>
              <row>
                <entry class="bitfield">00</entry>
                <entry class="symbol">RESERVED</entry>
              </row>
              <row>
                <entry class="bitfield">01</entry>
                <entry class="symbol">H</entry>
              </row>
              <row>
                <entry class="bitfield">10</entry>
                <entry class="symbol">S</entry>
              </row>
              <row>
                <entry class="bitfield">11</entry>
                <entry class="symbol">D</entry>
              </row>
            </tbody>
          </tgroup>
        </table>
      </definition>
    </explanation>
    <explanation enclist="sqdecp_z_p_z_" symboldefcount="1">
      <symbol link="sa_pm">&lt;Pm&gt;</symbol>
      <account encodedin="Pm">
        <intro>
          <para>Is the name of the source scalable predicate register, encoded in the "Pm" field.</para>
        </intro>
      </account>
    </explanation>
  </explanations>
  <ps_section howmany="1">
    <ps name="SQDECP-Z.P.Z-_" mylink="execute" enclabels="" sections="1" secttype="Operation">
      <pstext mayhavelinks="1" section="Execute" rep_section="execute"><a link="impl-aarch64.CheckSVEEnabled.0" file="shared_pseudocode.xml" hover="function: CheckSVEEnabled()">CheckSVEEnabled</a>();
constant integer VL = <a link="impl-aarch64.CurrentVL.read.none" file="shared_pseudocode.xml" hover="accessor: integer CurrentVL">CurrentVL</a>;
constant integer PL = VL DIV 8;
constant integer elements = VL DIV esize;
bits(VL) operand1 = <a link="impl-aarch64.Z.read.2" file="shared_pseudocode.xml" hover="accessor: bits(width) Z[integer n, integer width]">Z</a>[dn, VL];
bits(PL) operand2 = <a link="impl-aarch64.P.read.2" file="shared_pseudocode.xml" hover="accessor: bits(width) P[integer n, integer width]">P</a>[m, PL];
bits(VL) result;
integer count = 0;

for e = 0 to elements-1
    if <a link="impl-aarch64.ActivePredicateElement.3" file="shared_pseudocode.xml" hover="function: boolean ActivePredicateElement(bits(N) pred, integer e, integer esize)">ActivePredicateElement</a>(operand2, e, esize) then
        count = count + 1;

for e = 0 to elements-1
    integer element = <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>[operand1, e, esize], unsigned);
    (<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>[result, e, esize], -) = <a link="impl-shared.SatQ.3" file="shared_pseudocode.xml" hover="function: (bits(N), boolean) SatQ(integer i, integer N, boolean unsigned)">SatQ</a>(element - count, esize, unsigned);

<a link="impl-aarch64.Z.write.2" file="shared_pseudocode.xml" hover="accessor: Z[integer n, integer width] = bits(width) value">Z</a>[dn, VL] = result;</pstext>
    </ps>
  </ps_section>
</instructionsection>
