slonik/specs/vcvtb.xml

402 lines
22 KiB
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="VCVTB" title="VCVTB -- AArch32" type="instruction">
<docvars>
<docvar key="instr-class" value="fpsimd" />
<docvar key="mnemonic" value="VCVTB" />
</docvars>
<heading>VCVTB</heading>
<desc>
<brief>
<para>Convert to or from a half-precision value in the bottom half of a single-precision register</para>
</brief>
<authored>
<para>Convert to or from a half-precision value in the bottom half of a single-precision register does one of the following:</para>
<list type="unordered">
<listitem><content>Converts the half-precision value in the bottom half of a single-precision register to single-precision and writes the result to a single-precision register.</content></listitem>
<listitem><content>Converts the half-precision value in the bottom half of a single-precision register to double-precision and writes the result to a double-precision register.</content></listitem>
<listitem><content>Converts the single-precision value in a single-precision register to half-precision and writes the result into the bottom half of a single-precision register, preserving the other half of the destination register.</content></listitem>
<listitem><content>Converts the double-precision value in a double-precision register to half-precision and writes the result into the bottom half of a single-precision register, preserving the other half of the destination register.</content></listitem>
</list>
<para>Depending on settings in the <xref linkend="AArch32.cpacr">CPACR</xref>, <xref linkend="AArch32.nsacr">NSACR</xref>, <xref linkend="AArch32.hcptr">HCPTR</xref>, and <xref linkend="AArch32.fpexc">FPEXC</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>
<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="4" isa="A32">
<docvars>
<docvar key="armarmheading" value="A1" />
<docvar key="instr-class" value="fpsimd" />
<docvar key="isa" value="A32" />
<docvar key="mnemonic" value="VCVTB" />
</docvars>
<iclassintro count="4"></iclassintro>
<regdiagram form="32" psname="aarch32/instrs/VCVTB/T1A1_A.txt" tworows="1">
<box hibit="31" width="4" name="cond" usename="1" settings="4" constraint="!= 1111">
<c colspan="4">!= 1111</c>
</box>
<box hibit="27" width="5" settings="5">
<c>1</c>
<c>1</c>
<c>1</c>
<c>0</c>
<c>1</c>
</box>
<box hibit="22" name="D" usename="1">
<c></c>
</box>
<box hibit="21" width="2" settings="2">
<c>1</c>
<c>1</c>
</box>
<box hibit="19" name="o1" settings="1">
<c>0</c>
</box>
<box hibit="18" width="2" settings="2">
<c>0</c>
<c>1</c>
</box>
<box hibit="16" name="op" usename="1">
<c></c>
</box>
<box hibit="15" width="4" name="Vd" usename="1">
<c colspan="4"></c>
</box>
<box hibit="11" width="2" settings="2">
<c>1</c>
<c>0</c>
</box>
<box hibit="9" settings="1">
<c>1</c>
</box>
<box hibit="8" name="sz" usename="1">
<c></c>
</box>
<box hibit="7" name="T" usename="1" settings="1">
<c>0</c>
</box>
<box hibit="6" settings="1">
<c>1</c>
</box>
<box hibit="5" name="M" usename="1">
<c></c>
</box>
<box hibit="4" settings="1">
<c>0</c>
</box>
<box hibit="3" width="4" name="Vm" usename="1">
<c colspan="4"></c>
</box>
</regdiagram>
<encoding name="VCVTB_A1_SH" oneofinclass="4" oneof="8" label="Half-precision to single-precision" bitdiffs="op == 0 &amp;&amp; sz == 0">
<docvars>
<docvar key="armarmheading" value="A1" />
<docvar key="convert-type" value="half-to-single" />
<docvar key="instr-class" value="fpsimd" />
<docvar key="isa" value="A32" />
<docvar key="mnemonic" value="VCVTB" />
</docvars>
<box hibit="16" width="1" name="op">
<c>0</c>
</box>
<box hibit="8" width="1" name="sz">
<c>0</c>
</box>
<asmtemplate><text>VCVTB</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>.F32.F16 </text><a link="sa_sd" hover="32-bit SIMD&amp;FP destination register (field &quot;Vd:D&quot;)">&lt;Sd&gt;</a><text>, </text><a link="sa_sm" hover="32-bit SIMD&amp;FP source register (field &quot;Vm:M&quot;)">&lt;Sm&gt;</a></asmtemplate>
</encoding>
<encoding name="VCVTB_A1_DH" oneofinclass="4" oneof="8" label="Half-precision to double-precision" bitdiffs="op == 0 &amp;&amp; sz == 1">
<docvars>
<docvar key="armarmheading" value="A1" />
<docvar key="convert-type" value="half-to-double" />
<docvar key="instr-class" value="fpsimd" />
<docvar key="isa" value="A32" />
<docvar key="mnemonic" value="VCVTB" />
</docvars>
<box hibit="16" width="1" name="op">
<c>0</c>
</box>
<box hibit="8" width="1" name="sz">
<c>1</c>
</box>
<asmtemplate><text>VCVTB</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>.F64.F16 </text><a link="sa_dd" hover="64-bit SIMD&amp;FP destination register (field &quot;D:Vd&quot;)">&lt;Dd&gt;</a><text>, </text><a link="sa_sm" hover="32-bit SIMD&amp;FP source register (field &quot;Vm:M&quot;)">&lt;Sm&gt;</a></asmtemplate>
</encoding>
<encoding name="VCVTB_A1_HS" oneofinclass="4" oneof="8" label="Single-precision to half-precision" bitdiffs="op == 1 &amp;&amp; sz == 0">
<docvars>
<docvar key="armarmheading" value="A1" />
<docvar key="convert-type" value="single-to-half" />
<docvar key="instr-class" value="fpsimd" />
<docvar key="isa" value="A32" />
<docvar key="mnemonic" value="VCVTB" />
</docvars>
<box hibit="16" width="1" name="op">
<c>1</c>
</box>
<box hibit="8" width="1" name="sz">
<c>0</c>
</box>
<asmtemplate><text>VCVTB</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>.F16.F32 </text><a link="sa_sd" hover="32-bit SIMD&amp;FP destination register (field &quot;Vd:D&quot;)">&lt;Sd&gt;</a><text>, </text><a link="sa_sm" hover="32-bit SIMD&amp;FP source register (field &quot;Vm:M&quot;)">&lt;Sm&gt;</a></asmtemplate>
</encoding>
<encoding name="VCVTB_A1_HD" oneofinclass="4" oneof="8" label="Double-precision to half-precision" bitdiffs="op == 1 &amp;&amp; sz == 1">
<docvars>
<docvar key="armarmheading" value="A1" />
<docvar key="convert-type" value="double-to-half" />
<docvar key="instr-class" value="fpsimd" />
<docvar key="isa" value="A32" />
<docvar key="mnemonic" value="VCVTB" />
</docvars>
<box hibit="16" width="1" name="op">
<c>1</c>
</box>
<box hibit="8" width="1" name="sz">
<c>1</c>
</box>
<asmtemplate><text>VCVTB</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>.F16.F64 </text><a link="sa_sd" hover="32-bit SIMD&amp;FP destination register (field &quot;Vd:D&quot;)">&lt;Sd&gt;</a><text>, </text><a link="sa_dm" hover="64-bit SIMD&amp;FP source register (field &quot;M:Vm&quot;)">&lt;Dm&gt;</a></asmtemplate>
</encoding>
<ps_section howmany="1">
<ps name="aarch32/instrs/VCVTB/T1A1_A.txt" mylink="aarch32.instrs.VCVTB.T1A1_A.txt" enclabels="" sections="1" secttype="noheading">
<pstext mayhavelinks="1" section="Decode" rep_section="decode">uses_double = (sz == '1'); convert_from_half = (op == '0');
lowbit = (if T == '1' then 16 else 0);
integer d;
integer m;
if uses_double then
if convert_from_half then
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>(Vm:M);
else
d = <a link="impl-shared.UInt.1" file="shared_pseudocode.xml" hover="function: integer UInt(bits(N) x)">UInt</a>(Vd:D); m = <a link="impl-shared.UInt.1" file="shared_pseudocode.xml" hover="function: integer UInt(bits(N) x)">UInt</a>(M:Vm);
else
d = <a link="impl-shared.UInt.1" file="shared_pseudocode.xml" hover="function: integer UInt(bits(N) x)">UInt</a>(Vd:D); m = <a link="impl-shared.UInt.1" file="shared_pseudocode.xml" hover="function: integer UInt(bits(N) x)">UInt</a>(Vm:M);</pstext>
</ps>
</ps_section>
</iclass>
<iclass name="T1" oneof="2" id="iclass_t1" no_encodings="4" isa="T32">
<docvars>
<docvar key="armarmheading" value="T1" />
<docvar key="instr-class" value="fpsimd" />
<docvar key="isa" value="T32" />
<docvar key="mnemonic" value="VCVTB" />
</docvars>
<iclassintro count="4"></iclassintro>
<regdiagram form="16x2" psname="aarch32/instrs/VCVTB/T1A1_A.txt" tworows="1">
<box hibit="31" width="9" settings="9">
<c>1</c>
<c>1</c>
<c>1</c>
<c>0</c>
<c>1</c>
<c>1</c>
<c>1</c>
<c>0</c>
<c>1</c>
</box>
<box hibit="22" name="D" usename="1">
<c></c>
</box>
<box hibit="21" width="2" settings="2">
<c>1</c>
<c>1</c>
</box>
<box hibit="19" name="o1" settings="1">
<c>0</c>
</box>
<box hibit="18" width="2" settings="2">
<c>0</c>
<c>1</c>
</box>
<box hibit="16" name="op" usename="1">
<c></c>
</box>
<box hibit="15" width="4" name="Vd" usename="1">
<c colspan="4"></c>
</box>
<box hibit="11" width="2" settings="2">
<c>1</c>
<c>0</c>
</box>
<box hibit="9" settings="1">
<c>1</c>
</box>
<box hibit="8" name="sz" usename="1">
<c></c>
</box>
<box hibit="7" name="T" usename="1" settings="1">
<c>0</c>
</box>
<box hibit="6" settings="1">
<c>1</c>
</box>
<box hibit="5" name="M" usename="1">
<c></c>
</box>
<box hibit="4" settings="1">
<c>0</c>
</box>
<box hibit="3" width="4" name="Vm" usename="1">
<c colspan="4"></c>
</box>
</regdiagram>
<encoding name="VCVTB_T1_SH" oneofinclass="4" oneof="8" label="Half-precision to single-precision" bitdiffs="op == 0 &amp;&amp; sz == 0">
<docvars>
<docvar key="armarmheading" value="T1" />
<docvar key="convert-type" value="half-to-single" />
<docvar key="instr-class" value="fpsimd" />
<docvar key="isa" value="T32" />
<docvar key="mnemonic" value="VCVTB" />
</docvars>
<box hibit="16" width="1" name="op">
<c>0</c>
</box>
<box hibit="8" width="1" name="sz">
<c>0</c>
</box>
<asmtemplate><text>VCVTB</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>.F32.F16 </text><a link="sa_sd" hover="32-bit SIMD&amp;FP destination register (field &quot;Vd:D&quot;)">&lt;Sd&gt;</a><text>, </text><a link="sa_sm" hover="32-bit SIMD&amp;FP source register (field &quot;Vm:M&quot;)">&lt;Sm&gt;</a></asmtemplate>
</encoding>
<encoding name="VCVTB_T1_DH" oneofinclass="4" oneof="8" label="Half-precision to double-precision" bitdiffs="op == 0 &amp;&amp; sz == 1">
<docvars>
<docvar key="armarmheading" value="T1" />
<docvar key="convert-type" value="half-to-double" />
<docvar key="instr-class" value="fpsimd" />
<docvar key="isa" value="T32" />
<docvar key="mnemonic" value="VCVTB" />
</docvars>
<box hibit="16" width="1" name="op">
<c>0</c>
</box>
<box hibit="8" width="1" name="sz">
<c>1</c>
</box>
<asmtemplate><text>VCVTB</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>.F64.F16 </text><a link="sa_dd" hover="64-bit SIMD&amp;FP destination register (field &quot;D:Vd&quot;)">&lt;Dd&gt;</a><text>, </text><a link="sa_sm" hover="32-bit SIMD&amp;FP source register (field &quot;Vm:M&quot;)">&lt;Sm&gt;</a></asmtemplate>
</encoding>
<encoding name="VCVTB_T1_HS" oneofinclass="4" oneof="8" label="Single-precision to half-precision" bitdiffs="op == 1 &amp;&amp; sz == 0">
<docvars>
<docvar key="armarmheading" value="T1" />
<docvar key="convert-type" value="single-to-half" />
<docvar key="instr-class" value="fpsimd" />
<docvar key="isa" value="T32" />
<docvar key="mnemonic" value="VCVTB" />
</docvars>
<box hibit="16" width="1" name="op">
<c>1</c>
</box>
<box hibit="8" width="1" name="sz">
<c>0</c>
</box>
<asmtemplate><text>VCVTB</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>.F16.F32 </text><a link="sa_sd" hover="32-bit SIMD&amp;FP destination register (field &quot;Vd:D&quot;)">&lt;Sd&gt;</a><text>, </text><a link="sa_sm" hover="32-bit SIMD&amp;FP source register (field &quot;Vm:M&quot;)">&lt;Sm&gt;</a></asmtemplate>
</encoding>
<encoding name="VCVTB_T1_HD" oneofinclass="4" oneof="8" label="Double-precision to half-precision" bitdiffs="op == 1 &amp;&amp; sz == 1">
<docvars>
<docvar key="armarmheading" value="T1" />
<docvar key="convert-type" value="double-to-half" />
<docvar key="instr-class" value="fpsimd" />
<docvar key="isa" value="T32" />
<docvar key="mnemonic" value="VCVTB" />
</docvars>
<box hibit="16" width="1" name="op">
<c>1</c>
</box>
<box hibit="8" width="1" name="sz">
<c>1</c>
</box>
<asmtemplate><text>VCVTB</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>.F16.F64 </text><a link="sa_sd" hover="32-bit SIMD&amp;FP destination register (field &quot;Vd:D&quot;)">&lt;Sd&gt;</a><text>, </text><a link="sa_dm" hover="64-bit SIMD&amp;FP source register (field &quot;M:Vm&quot;)">&lt;Dm&gt;</a></asmtemplate>
</encoding>
<ps_section howmany="1">
<ps name="aarch32/instrs/VCVTB/T1A1_A.txt" mylink="aarch32.instrs.VCVTB.T1A1_A.txt" enclabels="" sections="1" secttype="noheading">
<pstext mayhavelinks="1" section="Decode" rep_section="decode">uses_double = (sz == '1'); convert_from_half = (op == '0');
lowbit = (if T == '1' then 16 else 0);
integer d;
integer m;
if uses_double then
if convert_from_half then
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>(Vm:M);
else
d = <a link="impl-shared.UInt.1" file="shared_pseudocode.xml" hover="function: integer UInt(bits(N) x)">UInt</a>(Vd:D); m = <a link="impl-shared.UInt.1" file="shared_pseudocode.xml" hover="function: integer UInt(bits(N) x)">UInt</a>(M:Vm);
else
d = <a link="impl-shared.UInt.1" file="shared_pseudocode.xml" hover="function: integer UInt(bits(N) x)">UInt</a>(Vd:D); m = <a link="impl-shared.UInt.1" file="shared_pseudocode.xml" hover="function: integer UInt(bits(N) x)">UInt</a>(Vm:M);</pstext>
</ps>
</ps_section>
</iclass>
</classes>
<explanations scope="all">
<explanation enclist="VCVTB_A1_SH, VCVTB_T1_SH" symboldefcount="1">
<symbol link="sa_c">&lt;c&gt;</symbol>
<account encodedin="">
<intro>
<para>See <xref linkend="Babbefhf">Standard assembler syntax fields</xref>.</para>
</intro>
</account>
</explanation>
<explanation enclist="VCVTB_A1_SH, VCVTB_T1_SH" 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="VCVTB_A1_SH, VCVTB_T1_SH" symboldefcount="1">
<symbol link="sa_sd">&lt;Sd&gt;</symbol>
<account encodedin="Vd:D">
<intro>
<para>Is the 32-bit name of the SIMD&amp;FP destination register, encoded in the "Vd:D" field.</para>
</intro>
</account>
</explanation>
<explanation enclist="VCVTB_A1_HD, VCVTB_T1_HD" symboldefcount="1">
<symbol link="sa_dm">&lt;Dm&gt;</symbol>
<account encodedin="M:Vm">
<intro>
<para>Is the 64-bit name of the SIMD&amp;FP source register, encoded in the "M:Vm" field.</para>
</intro>
</account>
</explanation>
<explanation enclist="VCVTB_A1_DH, VCVTB_T1_DH" 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="VCVTB_A1_SH, VCVTB_T1_SH" symboldefcount="1">
<symbol link="sa_sm">&lt;Sm&gt;</symbol>
<account encodedin="Vm:M">
<intro>
<para>Is the 32-bit name of the SIMD&amp;FP source register, encoded in the "Vm:M" field.</para>
</intro>
</account>
</explanation>
</explanations>
<ps_section howmany="1">
<ps name="aarch32/instrs/VCVTB/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.CheckVFPEnabled.1" file="shared_pseudocode.xml" hover="function: CheckVFPEnabled(boolean include_fpexc_check)">CheckVFPEnabled</a>(TRUE);
bits(16) hp;
if convert_from_half then
hp = <a link="impl-aarch32.S.read.1" file="shared_pseudocode.xml" hover="accessor: bits(32) S[integer n]">S</a>[m]&lt;lowbit+15:lowbit&gt;;
if uses_double then
<a link="impl-aarch32.D.write.1" file="shared_pseudocode.xml" hover="accessor: D[integer n] = bits(64) value">D</a>[d] = <a link="impl-shared.FPConvert.3" file="shared_pseudocode.xml" hover="function: bits(M) FPConvert(bits(N) op, FPCRType fpcr, integer M)">FPConvert</a>(hp, FPSCR[], 64);
else
<a link="impl-aarch32.S.write.1" file="shared_pseudocode.xml" hover="accessor: S[integer n] = bits(32) value">S</a>[d] = <a link="impl-shared.FPConvert.3" file="shared_pseudocode.xml" hover="function: bits(M) FPConvert(bits(N) op, FPCRType fpcr, integer M)">FPConvert</a>(hp, FPSCR[], 32);
else
if uses_double then
hp = <a link="impl-shared.FPConvert.3" file="shared_pseudocode.xml" hover="function: bits(M) FPConvert(bits(N) op, FPCRType fpcr, integer M)">FPConvert</a>(<a link="impl-aarch32.D.read.1" file="shared_pseudocode.xml" hover="accessor: bits(64) D[integer n]">D</a>[m], FPSCR[], 16);
else
hp = <a link="impl-shared.FPConvert.3" file="shared_pseudocode.xml" hover="function: bits(M) FPConvert(bits(N) op, FPCRType fpcr, integer M)">FPConvert</a>(<a link="impl-aarch32.S.read.1" file="shared_pseudocode.xml" hover="accessor: bits(32) S[integer n]">S</a>[m], FPSCR[], 16);
<a link="impl-aarch32.S.write.1" file="shared_pseudocode.xml" hover="accessor: S[integer n] = bits(32) value">S</a>[d]&lt;lowbit+15:lowbit&gt; = hp;</pstext>
</ps>
</ps_section>
</instructionsection>