slonik/specs/ldc_i.xml

382 lines
21 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="LDC_i" title="LDC (immediate) -- AArch32" type="instruction">
<docvars>
<docvar key="instr-class" value="general" />
<docvar key="mnemonic" value="LDC" />
</docvars>
<heading>LDC (immediate)</heading>
<desc>
<brief>
<para>Load data to System register (immediate)</para>
</brief>
<authored>
<para>Load data to System register (immediate) calculates an address from a base register value and an immediate offset, loads a word from memory, and writes it to the <xref linkend="AArch32.dbgdtrtxint">DBGDTRTXint</xref> System register. It can use offset, post-indexed, pre-indexed, or unindexed addressing. For information about memory accesses see <xref linkend="Chddjfjf">Memory accesses</xref>.</para>
<para>In an implementation that includes EL2, the permitted <instruction>LDC</instruction> access to <xref linkend="AArch32.dbgdtrtxint">DBGDTRTXint</xref> can be trapped to Hyp mode, meaning that an attempt to execute an <instruction>LDC</instruction> instruction in a Non-secure mode other than Hyp mode, that would be permitted in the absence of the Hyp trap controls, generates a Hyp Trap exception. For more information, see <xref linkend="BEICAABI">Trapping general Non-secure System register accesses to debug registers</xref>.</para>
<para>For simplicity, the <instruction>LDC</instruction> pseudocode does not show this possible trap to Hyp mode.</para>
</authored>
</desc>
<operationalnotes>
<para>If CPSR.DIT is 1, the timing of this instruction is insensitive to the value of the data being loaded or stored.</para>
</operationalnotes>
<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="general" />
<docvar key="isa" value="A32" />
<docvar key="mnemonic" value="LDC" />
</docvars>
<iclassintro count="4"></iclassintro>
<regdiagram form="32" psname="aarch32/instrs/LDC_i/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="3" settings="3">
<c>1</c>
<c>1</c>
<c>0</c>
</box>
<box hibit="24" name="P" usename="1">
<c></c>
</box>
<box hibit="23" name="U" usename="1">
<c></c>
</box>
<box hibit="22" name="D" settings="1">
<c>0</c>
</box>
<box hibit="21" name="W" usename="1">
<c></c>
</box>
<box hibit="20" name="L" settings="1">
<c>1</c>
</box>
<box hibit="19" width="4" name="Rn" usename="1" settings="4" constraint="!= 1111">
<c colspan="4">!= 1111</c>
</box>
<box hibit="15" width="4" name="CRd" settings="4">
<c>0</c>
<c>1</c>
<c>0</c>
<c>1</c>
</box>
<box hibit="11" width="3" settings="3">
<c>1</c>
<c>1</c>
<c>1</c>
</box>
<box hibit="8" name="cp15" settings="1">
<c>0</c>
</box>
<box hibit="7" width="8" name="imm8" usename="1">
<c colspan="8"></c>
</box>
</regdiagram>
<encoding name="LDC_i_A1_off" oneofinclass="4" oneof="8" label="Offset" bitdiffs="P == 1 &amp;&amp; W == 0">
<docvars>
<docvar key="address-form" value="base-plus-offset" />
<docvar key="address-offset" value="signed-offset" />
<docvar key="armarmheading" value="A1" />
<docvar key="instr-class" value="general" />
<docvar key="isa" value="A32" />
<docvar key="mnemonic" value="LDC" />
</docvars>
<box hibit="24" width="1" name="P">
<c>1</c>
</box>
<box hibit="21" width="1" name="W">
<c>0</c>
</box>
<asmtemplate><text>LDC</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> p14, c5, [</text><a link="sa_rn" hover="General-purpose base register (field &quot;Rn&quot;)">&lt;Rn&gt;</a><text>{</text><text>, #</text><a link="sa__plusminus_" hover="Specifies the offset is added to or subtracted from the base register (field &quot;U&quot;) [+,-]">{+/-}</a><a link="sa_imm" hover="Immediate offset used for forming the address (field &quot;imm8&quot;)">&lt;imm&gt;</a><text>}</text><text>]</text></asmtemplate>
</encoding>
<encoding name="LDC_i_A1_post" oneofinclass="4" oneof="8" label="Post-indexed" bitdiffs="P == 0 &amp;&amp; W == 1">
<docvars>
<docvar key="address-form" value="post-indexed" />
<docvar key="armarmheading" value="A1" />
<docvar key="instr-class" value="general" />
<docvar key="isa" value="A32" />
<docvar key="mnemonic" value="LDC" />
</docvars>
<box hibit="24" width="1" name="P">
<c>0</c>
</box>
<box hibit="21" width="1" name="W">
<c>1</c>
</box>
<asmtemplate><text>LDC</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> p14, c5, [</text><a link="sa_rn" hover="General-purpose base register (field &quot;Rn&quot;)">&lt;Rn&gt;</a><text>], #</text><a link="sa__plusminus_" hover="Specifies the offset is added to or subtracted from the base register (field &quot;U&quot;) [+,-]">{+/-}</a><a link="sa_imm" hover="Immediate offset used for forming the address (field &quot;imm8&quot;)">&lt;imm&gt;</a></asmtemplate>
</encoding>
<encoding name="LDC_i_A1_pre" oneofinclass="4" oneof="8" label="Pre-indexed" bitdiffs="P == 1 &amp;&amp; W == 1">
<docvars>
<docvar key="address-form" value="pre-indexed" />
<docvar key="armarmheading" value="A1" />
<docvar key="instr-class" value="general" />
<docvar key="isa" value="A32" />
<docvar key="mnemonic" value="LDC" />
</docvars>
<box hibit="24" width="1" name="P">
<c>1</c>
</box>
<box hibit="21" width="1" name="W">
<c>1</c>
</box>
<asmtemplate><text>LDC</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> p14, c5, [</text><a link="sa_rn" hover="General-purpose base register (field &quot;Rn&quot;)">&lt;Rn&gt;</a><text>, #</text><a link="sa__plusminus_" hover="Specifies the offset is added to or subtracted from the base register (field &quot;U&quot;) [+,-]">{+/-}</a><a link="sa_imm" hover="Immediate offset used for forming the address (field &quot;imm8&quot;)">&lt;imm&gt;</a><text>]!</text></asmtemplate>
</encoding>
<encoding name="LDC_i_A1_unind" oneofinclass="4" oneof="8" label="Unindexed" bitdiffs="P == 0 &amp;&amp; U == 1 &amp;&amp; W == 0">
<docvars>
<docvar key="address-form" value="unindexed" />
<docvar key="armarmheading" value="A1" />
<docvar key="instr-class" value="general" />
<docvar key="isa" value="A32" />
<docvar key="mnemonic" value="LDC" />
</docvars>
<box hibit="24" width="1" name="P">
<c>0</c>
</box>
<box hibit="23" width="1" name="U">
<c>1</c>
</box>
<box hibit="21" width="1" name="W">
<c>0</c>
</box>
<asmtemplate><text>LDC</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> p14, c5, [</text><a link="sa_rn" hover="General-purpose base register (field &quot;Rn&quot;)">&lt;Rn&gt;</a><text>], </text><a link="sa_option" hover="8-bit immediate [0-255 enclosed in { }] (field &quot;imm8&quot;)">&lt;option&gt;</a></asmtemplate>
</encoding>
<ps_section howmany="1">
<ps name="aarch32/instrs/LDC_i/T1A1_A.txt" mylink="aarch32.instrs.LDC_i.T1A1_A.txt" enclabels="" sections="1" secttype="noheading">
<pstext mayhavelinks="1" section="Decode" rep_section="decode">if Rn == '1111' then SEE "LDC (literal)";
if P == '0' &amp;&amp; U == '0' &amp;&amp; W == '0' then UNDEFINED;
n = <a link="impl-shared.UInt.1" file="shared_pseudocode.xml" hover="function: integer UInt(bits(N) x)">UInt</a>(Rn); cp = 14;
imm32 = <a link="impl-shared.ZeroExtend.2" file="shared_pseudocode.xml" hover="function: bits(N) ZeroExtend(bits(M) x, integer N)">ZeroExtend</a>(imm8:'00', 32); index = (P == '1'); add = (U == '1'); wback = (W == '1');</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="general" />
<docvar key="isa" value="T32" />
<docvar key="mnemonic" value="LDC" />
</docvars>
<iclassintro count="4"></iclassintro>
<regdiagram form="16x2" psname="aarch32/instrs/LDC_i/T1A1_A.txt" tworows="1">
<box hibit="31" width="7" settings="7">
<c>1</c>
<c>1</c>
<c>1</c>
<c>0</c>
<c>1</c>
<c>1</c>
<c>0</c>
</box>
<box hibit="24" name="P" usename="1">
<c></c>
</box>
<box hibit="23" name="U" usename="1">
<c></c>
</box>
<box hibit="22" name="D" settings="1">
<c>0</c>
</box>
<box hibit="21" name="W" usename="1">
<c></c>
</box>
<box hibit="20" name="L" settings="1">
<c>1</c>
</box>
<box hibit="19" width="4" name="Rn" usename="1" settings="4" constraint="!= 1111">
<c colspan="4">!= 1111</c>
</box>
<box hibit="15" width="4" name="CRd" settings="4">
<c>0</c>
<c>1</c>
<c>0</c>
<c>1</c>
</box>
<box hibit="11" width="3" settings="3">
<c>1</c>
<c>1</c>
<c>1</c>
</box>
<box hibit="8" name="cp15" settings="1">
<c>0</c>
</box>
<box hibit="7" width="8" name="imm8" usename="1">
<c colspan="8"></c>
</box>
</regdiagram>
<encoding name="LDC_i_T1_off" oneofinclass="4" oneof="8" label="Offset" bitdiffs="P == 1 &amp;&amp; W == 0">
<docvars>
<docvar key="address-form" value="base-plus-offset" />
<docvar key="address-offset" value="signed-offset" />
<docvar key="armarmheading" value="T1" />
<docvar key="instr-class" value="general" />
<docvar key="isa" value="T32" />
<docvar key="mnemonic" value="LDC" />
</docvars>
<box hibit="24" width="1" name="P">
<c>1</c>
</box>
<box hibit="21" width="1" name="W">
<c>0</c>
</box>
<asmtemplate><text>LDC</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> p14, c5, [</text><a link="sa_rn" hover="General-purpose base register (field &quot;Rn&quot;)">&lt;Rn&gt;</a><text>{</text><text>, #</text><a link="sa__plusminus_" hover="Specifies the offset is added to or subtracted from the base register (field &quot;U&quot;) [+,-]">{+/-}</a><a link="sa_imm" hover="Immediate offset used for forming the address (field &quot;imm8&quot;)">&lt;imm&gt;</a><text>}</text><text>]</text></asmtemplate>
</encoding>
<encoding name="LDC_i_T1_post" oneofinclass="4" oneof="8" label="Post-indexed" bitdiffs="P == 0 &amp;&amp; W == 1">
<docvars>
<docvar key="address-form" value="post-indexed" />
<docvar key="armarmheading" value="T1" />
<docvar key="instr-class" value="general" />
<docvar key="isa" value="T32" />
<docvar key="mnemonic" value="LDC" />
</docvars>
<box hibit="24" width="1" name="P">
<c>0</c>
</box>
<box hibit="21" width="1" name="W">
<c>1</c>
</box>
<asmtemplate><text>LDC</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> p14, c5, [</text><a link="sa_rn" hover="General-purpose base register (field &quot;Rn&quot;)">&lt;Rn&gt;</a><text>], #</text><a link="sa__plusminus_" hover="Specifies the offset is added to or subtracted from the base register (field &quot;U&quot;) [+,-]">{+/-}</a><a link="sa_imm" hover="Immediate offset used for forming the address (field &quot;imm8&quot;)">&lt;imm&gt;</a></asmtemplate>
</encoding>
<encoding name="LDC_i_T1_pre" oneofinclass="4" oneof="8" label="Pre-indexed" bitdiffs="P == 1 &amp;&amp; W == 1">
<docvars>
<docvar key="address-form" value="pre-indexed" />
<docvar key="armarmheading" value="T1" />
<docvar key="instr-class" value="general" />
<docvar key="isa" value="T32" />
<docvar key="mnemonic" value="LDC" />
</docvars>
<box hibit="24" width="1" name="P">
<c>1</c>
</box>
<box hibit="21" width="1" name="W">
<c>1</c>
</box>
<asmtemplate><text>LDC</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> p14, c5, [</text><a link="sa_rn" hover="General-purpose base register (field &quot;Rn&quot;)">&lt;Rn&gt;</a><text>, #</text><a link="sa__plusminus_" hover="Specifies the offset is added to or subtracted from the base register (field &quot;U&quot;) [+,-]">{+/-}</a><a link="sa_imm" hover="Immediate offset used for forming the address (field &quot;imm8&quot;)">&lt;imm&gt;</a><text>]!</text></asmtemplate>
</encoding>
<encoding name="LDC_i_T1_unind" oneofinclass="4" oneof="8" label="Unindexed" bitdiffs="P == 0 &amp;&amp; U == 1 &amp;&amp; W == 0">
<docvars>
<docvar key="address-form" value="unindexed" />
<docvar key="armarmheading" value="T1" />
<docvar key="instr-class" value="general" />
<docvar key="isa" value="T32" />
<docvar key="mnemonic" value="LDC" />
</docvars>
<box hibit="24" width="1" name="P">
<c>0</c>
</box>
<box hibit="23" width="1" name="U">
<c>1</c>
</box>
<box hibit="21" width="1" name="W">
<c>0</c>
</box>
<asmtemplate><text>LDC</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> p14, c5, [</text><a link="sa_rn" hover="General-purpose base register (field &quot;Rn&quot;)">&lt;Rn&gt;</a><text>], </text><a link="sa_option" hover="8-bit immediate [0-255 enclosed in { }] (field &quot;imm8&quot;)">&lt;option&gt;</a></asmtemplate>
</encoding>
<ps_section howmany="1">
<ps name="aarch32/instrs/LDC_i/T1A1_A.txt" mylink="aarch32.instrs.LDC_i.T1A1_A.txt" enclabels="" sections="1" secttype="noheading">
<pstext mayhavelinks="1" section="Decode" rep_section="decode">if Rn == '1111' then SEE "LDC (literal)";
if P == '0' &amp;&amp; U == '0' &amp;&amp; W == '0' then UNDEFINED;
n = <a link="impl-shared.UInt.1" file="shared_pseudocode.xml" hover="function: integer UInt(bits(N) x)">UInt</a>(Rn); cp = 14;
imm32 = <a link="impl-shared.ZeroExtend.2" file="shared_pseudocode.xml" hover="function: bits(N) ZeroExtend(bits(M) x, integer N)">ZeroExtend</a>(imm8:'00', 32); index = (P == '1'); add = (U == '1'); wback = (W == '1');</pstext>
</ps>
</ps_section>
</iclass>
</classes>
<explanations scope="all">
<explanation enclist="LDC_i_A1_off, LDC_i_T1_off" 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="LDC_i_A1_off, LDC_i_T1_off" 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="LDC_i_A1_off, LDC_i_T1_off" symboldefcount="1">
<symbol link="sa_rn">&lt;Rn&gt;</symbol>
<account encodedin="Rn">
<intro>
<para>Is the general-purpose base register, encoded in the "Rn" field. If the PC is used, see <xref linkend="A32T32-base.instructions.LDC_l">LDC (literal)</xref>.</para>
</intro>
</account>
</explanation>
<explanation enclist="LDC_i_A1_unind, LDC_i_T1_unind" symboldefcount="1">
<symbol link="sa_option">&lt;option&gt;</symbol>
<account encodedin="imm8">
<intro>
<para>Is an 8-bit immediate, in the range 0 to 255 enclosed in { }, encoded in the "imm8" field. The value of this field is ignored when executing this instruction.</para>
</intro>
</account>
</explanation>
<explanation enclist="LDC_i_A1_off, LDC_i_T1_off" symboldefcount="1">
<symbol link="sa__plusminus_">+/-</symbol>
<definition encodedin="U">
<intro>Specifies the offset is added to or subtracted from the base register, defaulting to + if omitted and </intro>
<table class="valuetable">
<tgroup cols="2">
<thead>
<row>
<entry class="bitfield">U</entry>
<entry class="symbol">+/-</entry>
</row>
</thead>
<tbody>
<row>
<entry class="bitfield">0</entry>
<entry class="symbol">-</entry>
</row>
<row>
<entry class="bitfield">1</entry>
<entry class="symbol">+</entry>
</row>
</tbody>
</tgroup>
</table>
</definition>
</explanation>
<explanation enclist="LDC_i_A1_off, LDC_i_T1_off" symboldefcount="1">
<symbol link="sa_imm">&lt;imm&gt;</symbol>
<account encodedin="imm8">
<intro>
<para>Is the immediate offset used for forming the address, a multiple of 4 in the range 0-1020, defaulting to 0 and encoded in the "imm8" field, as &lt;imm&gt;/4.</para>
</intro>
</account>
</explanation>
</explanations>
<ps_section howmany="1">
<ps name="aarch32/instrs/LDC_i/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();
offset_addr = if add then (<a link="impl-aarch32.R.read.1" file="shared_pseudocode.xml" hover="accessor: bits(32) R[integer n]">R</a>[n] + imm32) else (<a link="impl-aarch32.R.read.1" file="shared_pseudocode.xml" hover="accessor: bits(32) R[integer n]">R</a>[n] - imm32);
address = if index then offset_addr else <a link="impl-aarch32.R.read.1" file="shared_pseudocode.xml" hover="accessor: bits(32) R[integer n]">R</a>[n];
// System register write to DBGDTRTXint.
<a link="AArch32.SysRegWriteM.3" file="shared_pseudocode.xml" hover="function: AArch32.SysRegWriteM(integer cp_num, bits(32) instr, bits(32) address)">AArch32.SysRegWriteM</a>(cp, <a link="impl-shared.ThisInstr.0" file="shared_pseudocode.xml" hover="function: bits(32) ThisInstr()">ThisInstr</a>(), address);
if wback then <a link="impl-aarch32.R.write.1" file="shared_pseudocode.xml" hover="accessor: R[integer n] = bits(32) value">R</a>[n] = offset_addr;</pstext>
</ps>
</ps_section>
</instructionsection>