slonik/specs/bkpt.xml

191 lines
8.5 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="BKPT" title="BKPT -- AArch32" type="instruction">
<docvars>
<docvar key="instr-class" value="general" />
<docvar key="mnemonic" value="BKPT" />
</docvars>
<heading>BKPT</heading>
<desc>
<brief>
<para>Breakpoint</para>
</brief>
<authored>
<para>Breakpoint causes a Breakpoint Instruction exception.</para>
<para>Breakpoint is always unconditional, even when inside an IT block.</para>
</authored>
<encodingnotes>
<para>For more information about the <arm-defined-word>constrained unpredictable</arm-defined-word> behavior of this instruction, see <xref linkend="CJAEGDJC">Architectural Constraints on UNPREDICTABLE behaviors</xref>.</para>
</encodingnotes>
</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="1" isa="A32">
<docvars>
<docvar key="armarmheading" value="A1" />
<docvar key="instr-class" value="general" />
<docvar key="isa" value="A32" />
<docvar key="mnemonic" value="BKPT" />
</docvars>
<iclassintro count="1"></iclassintro>
<regdiagram form="32" psname="aarch32/instrs/BKPT/A1_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>0</c>
<c>0</c>
<c>0</c>
<c>1</c>
<c>0</c>
</box>
<box hibit="22" width="2" name="opc" settings="2">
<c>0</c>
<c>1</c>
</box>
<box hibit="20" settings="1">
<c>0</c>
</box>
<box hibit="19" width="12" name="imm12" usename="1">
<c colspan="12"></c>
</box>
<box hibit="7" width="4" settings="4">
<c>0</c>
<c>1</c>
<c>1</c>
<c>1</c>
</box>
<box hibit="3" width="4" name="imm4" usename="1">
<c colspan="4"></c>
</box>
</regdiagram>
<encoding name="BKPT_A1" oneofinclass="1" oneof="2" label="A1">
<docvars>
<docvar key="armarmheading" value="A1" />
<docvar key="instr-class" value="general" />
<docvar key="isa" value="A32" />
<docvar key="mnemonic" value="BKPT" />
</docvars>
<asmtemplate><text>BKPT</text><text>{</text><a link="sa_q" hover="See {xref{ARMARM_Babbefhf}{Standard assembler syntax fields}}">&lt;q&gt;</a><text>}</text><text> </text><a>{#}</a><a link="sa_imm_1" hover="16-bit unsigned immediate [0-65535] (field &quot;imm12:imm4&quot;)">&lt;imm&gt;</a></asmtemplate>
</encoding>
<ps_section howmany="1">
<ps name="aarch32/instrs/BKPT/A1_A.txt" mylink="aarch32.instrs.BKPT.A1_A.txt" enclabels="" sections="1" secttype="noheading">
<pstext mayhavelinks="1" section="Decode" rep_section="decode">imm16 = imm12:imm4;
if cond != '1110' then UNPREDICTABLE; // BKPT must be encoded with AL condition</pstext>
</ps>
</ps_section>
<constrained_unpredictables encoding="A1" ps_block="Decode">
<cu_case>
<cu_cause>
<pstext mayhavelinks="1">cond != '1110'</pstext>
</cu_cause>
<cu_type constraint="Constraint_UNDEF" />
<cu_type constraint="Constraint_NOP" />
<cu_type constraint="Constraint_UNCOND" />
<cu_type constraint="Constraint_COND" />
</cu_case>
</constrained_unpredictables>
</iclass>
<iclass name="T1" oneof="2" id="iclass_t1" no_encodings="1" isa="T32">
<docvars>
<docvar key="armarmheading" value="T1" />
<docvar key="instr-class" value="general" />
<docvar key="isa" value="T32" />
<docvar key="mnemonic" value="BKPT" />
</docvars>
<iclassintro count="1"></iclassintro>
<regdiagram form="16" psname="aarch32/instrs/BKPT/T1_A.txt">
<box hibit="31" width="8" settings="8">
<c>1</c>
<c>0</c>
<c>1</c>
<c>1</c>
<c>1</c>
<c>1</c>
<c>1</c>
<c>0</c>
</box>
<box hibit="23" width="8" name="imm8" usename="1">
<c colspan="8"></c>
</box>
</regdiagram>
<encoding name="BKPT_T1" oneofinclass="1" oneof="2" label="T1">
<docvars>
<docvar key="armarmheading" value="T1" />
<docvar key="instr-class" value="general" />
<docvar key="isa" value="T32" />
<docvar key="mnemonic" value="BKPT" />
</docvars>
<asmtemplate><text>BKPT</text><text>{</text><a link="sa_q" hover="See {xref{ARMARM_Babbefhf}{Standard assembler syntax fields}}">&lt;q&gt;</a><text>}</text><text> </text><a>{#}</a><a link="sa_imm" hover="8-bit unsigned immediate [0-255] (field &quot;imm8&quot;)">&lt;imm&gt;</a></asmtemplate>
</encoding>
<ps_section howmany="1">
<ps name="aarch32/instrs/BKPT/T1_A.txt" mylink="aarch32.instrs.BKPT.T1_A.txt" enclabels="" sections="1" secttype="noheading">
<pstext mayhavelinks="1" section="Decode" rep_section="decode">imm16 = <a link="impl-shared.ZeroExtend.2" file="shared_pseudocode.xml" hover="function: bits(N) ZeroExtend(bits(M) x, integer N)">ZeroExtend</a>(imm8, 16);</pstext>
</ps>
</ps_section>
</iclass>
</classes>
<explanations scope="all">
<explanation enclist="BKPT_A1, BKPT_T1" symboldefcount="1">
<symbol link="sa_q">&lt;q&gt;</symbol>
<account encodedin="">
<intro>
<para>See <xref linkend="Babbefhf">Standard assembler syntax fields</xref>. A <instruction>BKPT</instruction> instruction must be unconditional.</para>
</intro>
</account>
</explanation>
<explanation enclist="BKPT_A1" symboldefcount="1">
<symbol link="sa_imm_1">&lt;imm&gt;</symbol>
<account encodedin="imm12:imm4">
<docvars>
<docvar key="armarmheading" value="A1" />
<docvar key="isa" value="A32" />
</docvars>
<intro>
<para>For encoding A1: is a 16-bit unsigned immediate, in the range 0 to 65535, encoded in the "imm12:imm4" field. This value:</para>
<list type="unordered">
<listitem><content>Is recorded in the Comment field of ESR_ELx.ISS if the Software Breakpoint Instruction exception is taken to an exception level that is using AArch64.</content></listitem>
<listitem><content>Is ignored otherwise.</content></listitem>
</list>
</intro>
</account>
</explanation>
<explanation enclist="BKPT_T1" symboldefcount="2">
<symbol link="sa_imm">&lt;imm&gt;</symbol>
<account encodedin="imm8">
<docvars>
<docvar key="armarmheading" value="T1" />
<docvar key="isa" value="T32" />
</docvars>
<intro>
<para>For encoding T1: is a 8-bit unsigned immediate, in the range 0 to 255, encoded in the "imm8" field. This value:</para>
<list type="unordered">
<listitem><content>Is recorded in the Comment field of ESR_ELx.ISS if the Software Breakpoint Instruction exception is taken to an exception level that is using AArch64.</content></listitem>
<listitem><content>Is ignored otherwise.</content></listitem>
</list>
</intro>
</account>
</explanation>
</explanations>
<ps_section howmany="1">
<ps name="aarch32/instrs/BKPT/Op_A.txt" mylink="execute" enclabels="" sections="1" secttype="Operation">
<pstext mayhavelinks="1" section="Execute" rep_section="execute">EncodingSpecificOperations();
<a link="AArch32.SoftwareBreakpoint.1" file="shared_pseudocode.xml" hover="function: AArch32.SoftwareBreakpoint(bits(16) immediate)">AArch32.SoftwareBreakpoint</a>(imm16);</pstext>
</ps>
</ps_section>
</instructionsection>