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archived-ballistic/spec/arm64_xml/frintn_advsimd.xml
Ronald Caesar 26a677f8b4 decoder: Add ARM specification docs
Signed-off-by: Ronald Caesar <github43132@proton.me>
2025-12-12 18:11:36 -04:00

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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="FRINTN_advsimd" title="FRINTN (vector) -- A64" type="instruction">
<docvars>
<docvar key="advsimd-type" value="simd" />
<docvar key="instr-class" value="advsimd" />
<docvar key="isa" value="A64" />
<docvar key="mnemonic" value="FRINTN" />
</docvars>
<heading>FRINTN (vector)</heading>
<desc>
<brief>
<para>Floating-point Round to Integral, to nearest with ties to even (vector)</para>
</brief>
<authored>
<para>Floating-point Round to Integral, to nearest with ties to even (vector). This instruction rounds a vector of floating-point values in the SIMD&amp;FP source register to integral floating-point values of the same size using the Round to Nearest rounding mode, and writes the result to the SIMD&amp;FP destination register.</para>
<para>A zero input gives a zero result with the same sign, an infinite input gives an infinite result with the same sign, and a NaN is propagated as for normal arithmetic.</para>
<para>A floating-point exception can be generated by this instruction. Depending on the settings in <xref linkend="AArch64.fpcr">FPCR</xref>, the exception results in either a flag being set in <xref linkend="AArch64.fpsr">FPSR</xref>, or a synchronous exception being generated. For more information, see <xref linkend="BEIJDDAG">Floating-point exception traps</xref>.</para>
<para>Depending on the settings in the <xref linkend="AArch64.cpacr_el1">CPACR_EL1</xref>, <xref linkend="AArch64.cptr_el2">CPTR_EL2</xref>, and <xref linkend="AArch64.cptr_el3">CPTR_EL3</xref> registers, and the current Security state and Exception level, an attempt to execute the instruction might be trapped.</para>
</authored>
</desc>
<alias_list howmany="0"></alias_list>
<classes>
<classesintro count="2">
<txt>It has encodings from 2 classes:</txt>
<a href="#iclass_half">Half-precision</a>
<txt> and </txt>
<a href="#iclass_single_and_double">Single-precision and double-precision</a>
</classesintro>
<iclass name="Half-precision" oneof="2" id="iclass_half" no_encodings="1" isa="A64">
<docvars>
<docvar key="advsimd-datatype" value="simd-half" />
<docvar key="advsimd-type" value="simd" />
<docvar key="datatype" value="half" />
<docvar key="instr-class" value="advsimd" />
<docvar key="isa" value="A64" />
<docvar key="mnemonic" value="FRINTN" />
</docvars>
<iclassintro count="1"></iclassintro>
<arch_variants>
<arch_variant name="ARMv8.2" feature="FEAT_FP16" />
</arch_variants>
<regdiagram form="32" psname="aarch64/instrs/vector/arithmetic/unary/fp16/round" tworows="1">
<box hibit="31" settings="1">
<c>0</c>
</box>
<box hibit="30" name="Q" usename="1">
<c></c>
</box>
<box hibit="29" name="U" usename="1" settings="1" psbits="x">
<c>0</c>
</box>
<box hibit="28" width="5" settings="5">
<c>0</c>
<c>1</c>
<c>1</c>
<c>1</c>
<c>0</c>
</box>
<box hibit="23" name="o2" usename="1" settings="1" psbits="x">
<c>0</c>
</box>
<box hibit="22" width="6" settings="6">
<c>1</c>
<c>1</c>
<c>1</c>
<c>1</c>
<c>0</c>
<c>0</c>
</box>
<box hibit="16" width="4" name="opcode[4:1]" settings="4">
<c>1</c>
<c>1</c>
<c>0</c>
<c>0</c>
</box>
<box hibit="12" name="o1" usename="1" settings="1" psbits="x">
<c>0</c>
</box>
<box hibit="11" width="2" settings="2">
<c>1</c>
<c>0</c>
</box>
<box hibit="9" width="5" name="Rn" usename="1">
<c colspan="5"></c>
</box>
<box hibit="4" width="5" name="Rd" usename="1">
<c colspan="5"></c>
</box>
</regdiagram>
<encoding name="FRINTN_asimdmiscfp16_R" oneofinclass="1" oneof="2" label="">
<docvars>
<docvar key="advsimd-datatype" value="simd-half" />
<docvar key="advsimd-type" value="simd" />
<docvar key="datatype" value="half" />
<docvar key="instr-class" value="advsimd" />
<docvar key="isa" value="A64" />
<docvar key="mnemonic" value="FRINTN" />
</docvars>
<asmtemplate><text>FRINTN </text><a link="sa_vd" hover="SIMD&amp;FP destination register (field &quot;Rd&quot;)">&lt;Vd&gt;</a><text>.</text><a link="sa_t_1" hover="Arrangement specifier (field &quot;Q&quot;) [4H,8H]">&lt;T&gt;</a><text>, </text><a link="sa_vn" hover="SIMD&amp;FP source register (field &quot;Rn&quot;)">&lt;Vn&gt;</a><text>.</text><a link="sa_t_1" hover="Arrangement specifier (field &quot;Q&quot;) [4H,8H]">&lt;T&gt;</a></asmtemplate>
</encoding>
<ps_section howmany="1">
<ps name="aarch64/instrs/vector/arithmetic/unary/fp16/round" mylink="aarch64.instrs.vector.arithmetic.unary.fp16.round" enclabels="" sections="1" secttype="noheading">
<pstext mayhavelinks="1" section="Decode" rep_section="decode">if !<a link="impl-shared.HaveFP16Ext.0" file="shared_pseudocode.xml" hover="function: boolean HaveFP16Ext()">HaveFP16Ext</a>() then UNDEFINED;
integer d = <a link="impl-shared.UInt.1" file="shared_pseudocode.xml" hover="function: integer UInt(bits(N) x)">UInt</a>(Rd);
integer n = <a link="impl-shared.UInt.1" file="shared_pseudocode.xml" hover="function: integer UInt(bits(N) x)">UInt</a>(Rn);
integer esize = 16;
integer datasize = if Q == '1' then 128 else 64;
integer elements = datasize DIV esize;
boolean exact = FALSE;
<a link="FPRounding" file="shared_pseudocode.xml" hover="enumeration FPRounding {FPRounding_TIEEVEN, FPRounding_POSINF, FPRounding_NEGINF, FPRounding_ZERO, FPRounding_TIEAWAY, FPRounding_ODD}">FPRounding</a> rounding;
case U:o1:o2 of
when '0xx' rounding = <a link="impl-shared.FPDecodeRounding.1" file="shared_pseudocode.xml" hover="function: FPRounding FPDecodeRounding(bits(2) rmode)">FPDecodeRounding</a>(o1:o2);
when '100' rounding = <a link="FPRounding_TIEAWAY" file="shared_pseudocode.xml" hover="enumeration FPRounding {FPRounding_TIEEVEN, FPRounding_POSINF, FPRounding_NEGINF, FPRounding_ZERO, FPRounding_TIEAWAY, FPRounding_ODD}">FPRounding_TIEAWAY</a>;
when '101' UNDEFINED;
when '110' rounding = <a link="impl-shared.FPRoundingMode.1" file="shared_pseudocode.xml" hover="function: FPRounding FPRoundingMode(FPCRType fpcr)">FPRoundingMode</a>(FPCR[]); exact = TRUE;
when '111' rounding = <a link="impl-shared.FPRoundingMode.1" file="shared_pseudocode.xml" hover="function: FPRounding FPRoundingMode(FPCRType fpcr)">FPRoundingMode</a>(FPCR[]);</pstext>
</ps>
</ps_section>
</iclass>
<iclass name="Single-precision and double-precision" oneof="2" id="iclass_single_and_double" no_encodings="1" isa="A64">
<docvars>
<docvar key="advsimd-datatype" value="simd-single-and-double" />
<docvar key="advsimd-type" value="simd" />
<docvar key="datatype" value="single-and-double" />
<docvar key="instr-class" value="advsimd" />
<docvar key="isa" value="A64" />
<docvar key="mnemonic" value="FRINTN" />
</docvars>
<iclassintro count="1"></iclassintro>
<regdiagram form="32" psname="aarch64/instrs/vector/arithmetic/unary/float/round" tworows="1">
<box hibit="31" settings="1">
<c>0</c>
</box>
<box hibit="30" name="Q" usename="1">
<c></c>
</box>
<box hibit="29" name="U" usename="1" settings="1" psbits="x">
<c>0</c>
</box>
<box hibit="28" width="5" settings="5">
<c>0</c>
<c>1</c>
<c>1</c>
<c>1</c>
<c>0</c>
</box>
<box hibit="23" name="o2" usename="1" settings="1" psbits="x">
<c>0</c>
</box>
<box hibit="22" name="sz" usename="1">
<c></c>
</box>
<box hibit="21" width="5" settings="5">
<c>1</c>
<c>0</c>
<c>0</c>
<c>0</c>
<c>0</c>
</box>
<box hibit="16" width="4" name="opcode[4:1]" settings="4">
<c>1</c>
<c>1</c>
<c>0</c>
<c>0</c>
</box>
<box hibit="12" name="o1" usename="1" settings="1" psbits="x">
<c>0</c>
</box>
<box hibit="11" width="2" settings="2">
<c>1</c>
<c>0</c>
</box>
<box hibit="9" width="5" name="Rn" usename="1">
<c colspan="5"></c>
</box>
<box hibit="4" width="5" name="Rd" usename="1">
<c colspan="5"></c>
</box>
</regdiagram>
<encoding name="FRINTN_asimdmisc_R" oneofinclass="1" oneof="2" label="">
<docvars>
<docvar key="advsimd-datatype" value="simd-single-and-double" />
<docvar key="advsimd-type" value="simd" />
<docvar key="datatype" value="single-and-double" />
<docvar key="instr-class" value="advsimd" />
<docvar key="isa" value="A64" />
<docvar key="mnemonic" value="FRINTN" />
</docvars>
<asmtemplate><text>FRINTN </text><a link="sa_vd" hover="SIMD&amp;FP destination register (field &quot;Rd&quot;)">&lt;Vd&gt;</a><text>.</text><a link="sa_t" hover="Arrangement specifier (field &quot;sz:Q&quot;) [2D,2S,4S]">&lt;T&gt;</a><text>, </text><a link="sa_vn" hover="SIMD&amp;FP source register (field &quot;Rn&quot;)">&lt;Vn&gt;</a><text>.</text><a link="sa_t" hover="Arrangement specifier (field &quot;sz:Q&quot;) [2D,2S,4S]">&lt;T&gt;</a></asmtemplate>
</encoding>
<ps_section howmany="1">
<ps name="aarch64/instrs/vector/arithmetic/unary/float/round" mylink="aarch64.instrs.vector.arithmetic.unary.float.round" enclabels="" sections="1" secttype="noheading">
<pstext mayhavelinks="1" section="Decode" rep_section="decode">integer d = <a link="impl-shared.UInt.1" file="shared_pseudocode.xml" hover="function: integer UInt(bits(N) x)">UInt</a>(Rd);
integer n = <a link="impl-shared.UInt.1" file="shared_pseudocode.xml" hover="function: integer UInt(bits(N) x)">UInt</a>(Rn);
if sz:Q == '10' then UNDEFINED;
integer esize = 32 &lt;&lt; <a link="impl-shared.UInt.1" file="shared_pseudocode.xml" hover="function: integer UInt(bits(N) x)">UInt</a>(sz);
integer datasize = if Q == '1' then 128 else 64;
integer elements = datasize DIV esize;
boolean exact = FALSE;
<a link="FPRounding" file="shared_pseudocode.xml" hover="enumeration FPRounding {FPRounding_TIEEVEN, FPRounding_POSINF, FPRounding_NEGINF, FPRounding_ZERO, FPRounding_TIEAWAY, FPRounding_ODD}">FPRounding</a> rounding;
case U:o1:o2 of
when '0xx' rounding = <a link="impl-shared.FPDecodeRounding.1" file="shared_pseudocode.xml" hover="function: FPRounding FPDecodeRounding(bits(2) rmode)">FPDecodeRounding</a>(o1:o2);
when '100' rounding = <a link="FPRounding_TIEAWAY" file="shared_pseudocode.xml" hover="enumeration FPRounding {FPRounding_TIEEVEN, FPRounding_POSINF, FPRounding_NEGINF, FPRounding_ZERO, FPRounding_TIEAWAY, FPRounding_ODD}">FPRounding_TIEAWAY</a>;
when '101' UNDEFINED;
when '110' rounding = <a link="impl-shared.FPRoundingMode.1" file="shared_pseudocode.xml" hover="function: FPRounding FPRoundingMode(FPCRType fpcr)">FPRoundingMode</a>(FPCR[]); exact = TRUE;
when '111' rounding = <a link="impl-shared.FPRoundingMode.1" file="shared_pseudocode.xml" hover="function: FPRounding FPRoundingMode(FPCRType fpcr)">FPRoundingMode</a>(FPCR[]);</pstext>
</ps>
</ps_section>
</iclass>
</classes>
<explanations scope="all">
<explanation enclist="FRINTN_asimdmisc_R, FRINTN_asimdmiscfp16_R" symboldefcount="1">
<symbol link="sa_vd">&lt;Vd&gt;</symbol>
<account encodedin="Rd">
<intro>
<para>Is the name of the SIMD&amp;FP destination register, encoded in the "Rd" field.</para>
</intro>
</account>
</explanation>
<explanation enclist="FRINTN_asimdmiscfp16_R" symboldefcount="1">
<symbol link="sa_t_1">&lt;T&gt;</symbol>
<definition encodedin="Q">
<intro>For the half-precision variant: is an arrangement specifier, </intro>
<table class="valuetable">
<tgroup cols="2">
<thead>
<row>
<entry class="bitfield">Q</entry>
<entry class="symbol">&lt;T&gt;</entry>
</row>
</thead>
<tbody>
<row>
<entry class="bitfield">0</entry>
<entry class="symbol">4H</entry>
</row>
<row>
<entry class="bitfield">1</entry>
<entry class="symbol">8H</entry>
</row>
</tbody>
</tgroup>
</table>
</definition>
</explanation>
<explanation enclist="FRINTN_asimdmisc_R" symboldefcount="2">
<symbol link="sa_t">&lt;T&gt;</symbol>
<definition encodedin="sz:Q">
<intro>For the single-precision and double-precision variant: is an arrangement specifier, </intro>
<table class="valuetable">
<tgroup cols="3">
<thead>
<row>
<entry class="bitfield">sz</entry>
<entry class="bitfield">Q</entry>
<entry class="symbol">&lt;T&gt;</entry>
</row>
</thead>
<tbody>
<row>
<entry class="bitfield">0</entry>
<entry class="bitfield">0</entry>
<entry class="symbol">2S</entry>
</row>
<row>
<entry class="bitfield">0</entry>
<entry class="bitfield">1</entry>
<entry class="symbol">4S</entry>
</row>
<row>
<entry class="bitfield">1</entry>
<entry class="bitfield">0</entry>
<entry class="symbol">RESERVED</entry>
</row>
<row>
<entry class="bitfield">1</entry>
<entry class="bitfield">1</entry>
<entry class="symbol">2D</entry>
</row>
</tbody>
</tgroup>
</table>
</definition>
</explanation>
<explanation enclist="FRINTN_asimdmisc_R, FRINTN_asimdmiscfp16_R" symboldefcount="1">
<symbol link="sa_vn">&lt;Vn&gt;</symbol>
<account encodedin="Rn">
<intro>
<para>Is the name of the SIMD&amp;FP source register, encoded in the "Rn" field.</para>
</intro>
</account>
</explanation>
</explanations>
<ps_section howmany="1">
<ps name="aarch64/instrs/vector/arithmetic/unary/fp16/round" mylink="execute" enclabels="" sections="1" secttype="Operation">
<pstext mayhavelinks="1" section="Execute" rep_section="execute"><a link="impl-aarch64.CheckFPAdvSIMDEnabled64.0" file="shared_pseudocode.xml" hover="function: CheckFPAdvSIMDEnabled64()">CheckFPAdvSIMDEnabled64</a>();
bits(datasize) operand = <a link="impl-aarch64.V.read.2" file="shared_pseudocode.xml" hover="accessor: bits(width) V[integer n, integer width]">V</a>[n, datasize];
bits(datasize) result;
bits(esize) element;
for e = 0 to elements-1
element = <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>[operand, e, esize];
<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.FPRoundInt.4" file="shared_pseudocode.xml" hover="function: bits(N) FPRoundInt(bits(N) op, FPCRType fpcr, FPRounding rounding, boolean exact)">FPRoundInt</a>(element, FPCR[], rounding, exact);
<a link="impl-aarch64.V.write.2" file="shared_pseudocode.xml" hover="accessor: V[integer n, integer width] = bits(width) value">V</a>[d, datasize] = result;</pstext>
</ps>
</ps_section>
</instructionsection>