archived-ballistic/spec/arm64_xml/setf.xml

<?xml version="1.0" encoding="utf-8"?>
<?xml-stylesheet type="text/xsl" encoding="UTF-8" href="iform.xsl" version="1.0"?>
<!DOCTYPE instructionsection PUBLIC "-//ARM//DTD instructionsection //EN" "iform-p.dtd">
<!-- Copyright (c) 2010-2022 Arm Limited or its affiliates. All rights reserved. -->
<!-- This document is Non-Confidential. This document may only be used and distributed in accordance with the terms of the agreement entered into by Arm and the party that Arm delivered this document to. -->

<instructionsection id="SETF" title="SETF8, SETF16 -- A64" type="instruction">
  <docvars>
    <docvar key="instr-class" value="general" />
    <docvar key="isa" value="A64" />
  </docvars>
  <heading>SETF8, SETF16</heading>
  <desc>
    <brief>
      <para>Evaluation of 8 or 16 bit flag values</para>
    </brief>
    <authored>
      <para>Set the PSTATE.NZV flags based on the value in the specified general-purpose register. <instruction>SETF8</instruction> treats the value as an 8 bit value, and <instruction>SETF16</instruction> treats the value as an 16 bit value.</para>
      <para>The PSTATE.C flag is not affected by these instructions.</para>
    </authored>
  </desc>
  <operationalnotes>
    <para>If PSTATE.DIT is 1:</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>
    <iclass name="Integer" oneof="1" id="iclass_general" no_encodings="2" isa="A64">
      <docvars>
        <docvar key="instr-class" value="general" />
        <docvar key="isa" value="A64" />
      </docvars>
      <iclassintro count="2"></iclassintro>
      <arch_variants>
        <arch_variant name="ARMv8.4" feature="FEAT_FlagM" />
      </arch_variants>
      <regdiagram form="32" psname="aarch64/instrs/integer/flags/setf" tworows="1">
        <box hibit="31" name="sf" usename="1" settings="1" psbits="x">
          <c>0</c>
        </box>
        <box hibit="30" name="op" settings="1">
          <c>0</c>
        </box>
        <box hibit="29" name="S" settings="1">
          <c>1</c>
        </box>
        <box hibit="28" width="8" settings="8">
          <c>1</c>
          <c>1</c>
          <c>0</c>
          <c>1</c>
          <c>0</c>
          <c>0</c>
          <c>0</c>
          <c>0</c>
        </box>
        <box hibit="20" width="6" name="opcode2" settings="6">
          <c>0</c>
          <c>0</c>
          <c>0</c>
          <c>0</c>
          <c>0</c>
          <c>0</c>
        </box>
        <box hibit="14" name="sz" usename="1">
          <c></c>
        </box>
        <box hibit="13" width="4" settings="4">
          <c>0</c>
          <c>0</c>
          <c>1</c>
          <c>0</c>
        </box>
        <box hibit="9" width="5" name="Rn" usename="1">
          <c colspan="5"></c>
        </box>
        <box hibit="4" name="o3" settings="1">
          <c>0</c>
        </box>
        <box hibit="3" width="4" name="mask" settings="4">
          <c>1</c>
          <c>1</c>
          <c>0</c>
          <c>1</c>
        </box>
      </regdiagram>
      <encoding name="SETF8_only_setf" oneofinclass="2" oneof="2" label="SETF8" bitdiffs="sz == 0">
        <docvars>
          <docvar key="instr-class" value="general" />
          <docvar key="isa" value="A64" />
          <docvar key="mnemonic" value="SETF8" />
        </docvars>
        <box hibit="14" width="1" name="sz">
          <c>0</c>
        </box>
        <asmtemplate><text>SETF8  </text><a link="sa_wn" hover="32-bit general-purpose source register (field &quot;Rn&quot;)">&lt;Wn&gt;</a></asmtemplate>
      </encoding>
      <encoding name="SETF16_only_setf" oneofinclass="2" oneof="2" label="SETF16" bitdiffs="sz == 1">
        <docvars>
          <docvar key="instr-class" value="general" />
          <docvar key="isa" value="A64" />
          <docvar key="mnemonic" value="SETF16" />
        </docvars>
        <box hibit="14" width="1" name="sz">
          <c>1</c>
        </box>
        <asmtemplate><text>SETF16  </text><a link="sa_wn" hover="32-bit general-purpose source register (field &quot;Rn&quot;)">&lt;Wn&gt;</a></asmtemplate>
      </encoding>
      <ps_section howmany="1">
        <ps name="aarch64/instrs/integer/flags/setf" mylink="aarch64.instrs.integer.flags.setf" enclabels="" sections="1" secttype="noheading">
          <pstext mayhavelinks="1" section="Decode" rep_section="decode">if !<a link="impl-shared.HaveFlagManipulateExt.0" file="shared_pseudocode.xml" hover="function: boolean HaveFlagManipulateExt()">HaveFlagManipulateExt</a>() || sf != '0' then UNDEFINED;
integer msb = if sz=='1' then 15 else 7;
integer n = <a link="impl-shared.UInt.1" file="shared_pseudocode.xml" hover="function: integer UInt(bits(N) x)">UInt</a>(Rn);</pstext>
        </ps>
      </ps_section>
    </iclass>
  </classes>
  <explanations scope="all">
    <explanation enclist="SETF8_only_setf, SETF16_only_setf" symboldefcount="1">
      <symbol link="sa_wn">&lt;Wn&gt;</symbol>
      <account encodedin="Rn">
        <intro>
          <para>Is the 32-bit name of the general-purpose source register, encoded in the "Rn" field.</para>
        </intro>
      </account>
    </explanation>
  </explanations>
  <ps_section howmany="1">
    <ps name="aarch64/instrs/integer/flags/setf" mylink="execute" enclabels="" sections="1" secttype="Operation">
      <pstext mayhavelinks="1" section="Execute" rep_section="execute">bits(32) tmpreg = <a link="impl-aarch64.X.read.2" file="shared_pseudocode.xml" hover="accessor: bits(width) X[integer n, integer width]">X</a>[n, 32];
PSTATE.N = tmpreg&lt;msb&gt;;
PSTATE.Z = if (tmpreg&lt;msb:0&gt; == <a link="impl-shared.Zeros.1" file="shared_pseudocode.xml" hover="function: bits(N) Zeros(integer N)">Zeros</a>(msb+1)) then '1' else '0';
PSTATE.V = tmpreg&lt;msb+1&gt; EOR tmpreg&lt;msb&gt;;
//PSTATE.C unchanged;</pstext>
    </ps>
  </ps_section>
</instructionsection>