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archived-ballistic/spec/arm64_xml/frintx_float.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="FRINTX_float" title="FRINTX (scalar) -- A64" type="instruction">
<docvars>
<docvar key="instr-class" value="float" />
<docvar key="isa" value="A64" />
<docvar key="mnemonic" value="FRINTX" />
</docvars>
<heading>FRINTX (scalar)</heading>
<desc>
<brief>
<para>Floating-point Round to Integral exact, using current rounding mode (scalar)</para>
</brief>
<authored>
<para>Floating-point Round to Integral exact, using current rounding mode (scalar). This instruction rounds a floating-point value in the SIMD&amp;FP source register to an integral floating-point value of the same size using the rounding mode that is determined by the <xref linkend="AArch64.fpcr">FPCR</xref>, and writes the result to the SIMD&amp;FP destination register.</para>
<para>When the result value is not numerically equal to the input value, an Inexact exception is raised. 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>
<iclass name="Floating-point" oneof="1" id="iclass_float" no_encodings="3" isa="A64">
<docvars>
<docvar key="instr-class" value="float" />
<docvar key="isa" value="A64" />
<docvar key="mnemonic" value="FRINTX" />
</docvars>
<iclassintro count="3"></iclassintro>
<regdiagram form="32" psname="aarch64/instrs/float/arithmetic/round/frint" tworows="1">
<box hibit="31" name="M" settings="1">
<c>0</c>
</box>
<box hibit="30" settings="1">
<c>0</c>
</box>
<box hibit="29" name="S" settings="1">
<c>0</c>
</box>
<box hibit="28" width="5" settings="5">
<c>1</c>
<c>1</c>
<c>1</c>
<c>1</c>
<c>0</c>
</box>
<box hibit="23" width="2" name="ftype" usename="1">
<c colspan="2"></c>
</box>
<box hibit="21" settings="1">
<c>1</c>
</box>
<box hibit="20" width="3" name="opcode[5:3]" settings="3">
<c>0</c>
<c>0</c>
<c>1</c>
</box>
<box hibit="17" width="3" name="rmode" usename="1" settings="3" psbits="xxx">
<c>1</c>
<c>1</c>
<c>0</c>
</box>
<box hibit="14" width="5" settings="5">
<c>1</c>
<c>0</c>
<c>0</c>
<c>0</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="FRINTX_H_floatdp1" oneofinclass="3" oneof="3" label="Half-precision" bitdiffs="ftype == 11">
<docvars>
<docvar key="datatype" value="half" />
<docvar key="instr-class" value="float" />
<docvar key="isa" value="A64" />
<docvar key="mnemonic" value="FRINTX" />
</docvars>
<arch_variants>
<arch_variant name="ARMv8.2" feature="FEAT_FP16" />
</arch_variants>
<box hibit="23" width="2" name="ftype">
<c>1</c>
<c>1</c>
</box>
<asmtemplate><text>FRINTX </text><a link="sa_hd" hover="16-bit SIMD&amp;FP destination register (field &quot;Rd&quot;)">&lt;Hd&gt;</a><text>, </text><a link="sa_hn" hover="16-bit SIMD&amp;FP source register (field &quot;Rn&quot;)">&lt;Hn&gt;</a></asmtemplate>
</encoding>
<encoding name="FRINTX_S_floatdp1" oneofinclass="3" oneof="3" label="Single-precision" bitdiffs="ftype == 00">
<docvars>
<docvar key="datatype" value="single" />
<docvar key="instr-class" value="float" />
<docvar key="isa" value="A64" />
<docvar key="mnemonic" value="FRINTX" />
</docvars>
<box hibit="23" width="2" name="ftype">
<c>0</c>
<c>0</c>
</box>
<asmtemplate><text>FRINTX </text><a link="sa_sd" hover="32-bit SIMD&amp;FP destination register (field &quot;Rd&quot;)">&lt;Sd&gt;</a><text>, </text><a link="sa_sn" hover="32-bit SIMD&amp;FP source register (field &quot;Rn&quot;)">&lt;Sn&gt;</a></asmtemplate>
</encoding>
<encoding name="FRINTX_D_floatdp1" oneofinclass="3" oneof="3" label="Double-precision" bitdiffs="ftype == 01">
<docvars>
<docvar key="datatype" value="double" />
<docvar key="instr-class" value="float" />
<docvar key="isa" value="A64" />
<docvar key="mnemonic" value="FRINTX" />
</docvars>
<box hibit="23" width="2" name="ftype">
<c>0</c>
<c>1</c>
</box>
<asmtemplate><text>FRINTX </text><a link="sa_dd" hover="64-bit SIMD&amp;FP destination register (field &quot;Rd&quot;)">&lt;Dd&gt;</a><text>, </text><a link="sa_dn" hover="64-bit SIMD&amp;FP source register (field &quot;Rn&quot;)">&lt;Dn&gt;</a></asmtemplate>
</encoding>
<ps_section howmany="1">
<ps name="aarch64/instrs/float/arithmetic/round/frint" mylink="aarch64.instrs.float.arithmetic.round.frint" 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);
integer esize;
case ftype of
when '00' esize = 32;
when '01' esize = 64;
when '10' UNDEFINED;
when '11'
if <a link="impl-shared.HaveFP16Ext.0" file="shared_pseudocode.xml" hover="function: boolean HaveFP16Ext()">HaveFP16Ext</a>() then
esize = 16;
else
UNDEFINED;
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 rmode of
when '0xx' rounding = <a link="impl-shared.FPDecodeRounding.1" file="shared_pseudocode.xml" hover="function: FPRounding FPDecodeRounding(bits(2) rmode)">FPDecodeRounding</a>(rmode&lt;1:0&gt;);
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="FRINTX_D_floatdp1" symboldefcount="1">
<symbol link="sa_dd">&lt;Dd&gt;</symbol>
<account encodedin="Rd">
<intro>
<para>Is the 64-bit name of the SIMD&amp;FP destination register, encoded in the "Rd" field.</para>
</intro>
</account>
</explanation>
<explanation enclist="FRINTX_D_floatdp1" symboldefcount="1">
<symbol link="sa_dn">&lt;Dn&gt;</symbol>
<account encodedin="Rn">
<intro>
<para>Is the 64-bit name of the SIMD&amp;FP source register, encoded in the "Rn" field.</para>
</intro>
</account>
</explanation>
<explanation enclist="FRINTX_H_floatdp1" symboldefcount="1">
<symbol link="sa_hd">&lt;Hd&gt;</symbol>
<account encodedin="Rd">
<intro>
<para>Is the 16-bit name of the SIMD&amp;FP destination register, encoded in the "Rd" field.</para>
</intro>
</account>
</explanation>
<explanation enclist="FRINTX_H_floatdp1" symboldefcount="1">
<symbol link="sa_hn">&lt;Hn&gt;</symbol>
<account encodedin="Rn">
<intro>
<para>Is the 16-bit name of the SIMD&amp;FP source register, encoded in the "Rn" field.</para>
</intro>
</account>
</explanation>
<explanation enclist="FRINTX_S_floatdp1" symboldefcount="1">
<symbol link="sa_sd">&lt;Sd&gt;</symbol>
<account encodedin="Rd">
<intro>
<para>Is the 32-bit name of the SIMD&amp;FP destination register, encoded in the "Rd" field.</para>
</intro>
</account>
</explanation>
<explanation enclist="FRINTX_S_floatdp1" symboldefcount="1">
<symbol link="sa_sn">&lt;Sn&gt;</symbol>
<account encodedin="Rn">
<intro>
<para>Is the 32-bit 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/float/arithmetic/round/frint" mylink="execute" enclabels="" sections="1" secttype="Operation">
<pstext mayhavelinks="1" section="Execute" rep_section="execute"><a link="impl-aarch64.CheckFPEnabled64.0" file="shared_pseudocode.xml" hover="function: CheckFPEnabled64()">CheckFPEnabled64</a>();
<a link="FPCRType" file="shared_pseudocode.xml" hover="type FPCRType">FPCRType</a> fpcr = FPCR[];
boolean merge = <a link="impl-shared.IsMerging.1" file="shared_pseudocode.xml" hover="function: boolean IsMerging(FPCRType fpcr)">IsMerging</a>(fpcr);
bits(128) result = if merge then <a link="impl-aarch64.V.read.2" file="shared_pseudocode.xml" hover="accessor: bits(width) V[integer n, integer width]">V</a>[d, 128] else <a link="impl-shared.Zeros.1" file="shared_pseudocode.xml" hover="function: bits(N) Zeros(integer N)">Zeros</a>(128);
bits(esize) operand = <a link="impl-aarch64.V.read.2" file="shared_pseudocode.xml" hover="accessor: bits(width) V[integer n, integer width]">V</a>[n, 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, 0, 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>(operand, 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, 128] = result;</pstext>
</ps>
</ps_section>
</instructionsection>