mipsy.xml

<!-- This file is part of Mipsy, a tiny MIPS simulator -->
<!-- Copyright (C) 2003 Benoit Perrot (benoit@lrde.epita.fr) -->
<!-- Mipsy is free software; you can redistribute it and/or modify  -->
<!-- it under the terms of the GNU General Public License as published by -->
<!-- the Free Software Foundation; either version 2 of the License, or -->
<!-- (at your option) any later version. -->

<!-- Mipsy is distributed in the hope that it will be useful, -->
<!-- but WITHOUT ANY WARRANTY; without even the implied warranty of -->
<!-- MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the -->
<!-- GNU General Public License for more details. -->

<!-- You should have received a copy of the GNU General Public License -->
<!-- along with this program; if not, write to the Free Software -->
<!-- Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA -->

<instructions>

  <!-- Arithmetic instructions  -->

  <instruction opcode="add" level="native" kind="arithmetic">
    <description>To add 32-bit integers. If an overflow occurs, then trap.</description>
    <format>
      <attribute type="Register" name="dest" />
      <attribute type="Register" name="src1" />
      <attribute type="Register" name="src2" />
    </format>
    <syntax>
      <token kind="register" name="dest" />
      <token kind="register" default="@0" />
      <token kind="register" />
    </syntax>
    <syntax alias="addi">
      <token kind="register" name="dest" />
      <token kind="register" default="@0" />
      <token kind="immediate" />
    </syntax>
  </instruction>
  <instruction opcode="addu" level="native" kind="arithmetic">
    <description>To add 32-bit integers.</description>
    <format>
      <attribute type="Register" name="dest" />
      <attribute type="Register" name="src1" />
      <attribute type="Register" name="src2" />
    </format>
    <syntax>
      <token kind="register" name="dest" />
      <token kind="register" default="@0"/>
      <token kind="register" />
    </syntax>
    <syntax alias="addiu">
      <token kind="register" name="dest" />
      <token kind="register" default="@0" />
      <token kind="immediate" />
    </syntax>
  </instruction>

  <instruction opcode="addi" level="native" kind="arithmetic">
    <description>To add a constant to a 32-bit integer. If overflow occurs, then trap.</description>
    <format>
      <attribute type="Register" name="dest" />
      <attribute type="Register" name="src" />
      <attribute type="Exp" name="imm" />
    </format>
    <syntax>
      <token kind="register" name="dest" />
      <token kind="register" default="@0" />
      <token kind="immediate" />
    </syntax>
  </instruction>
  <instruction opcode="addiu" level="native" kind="arithmetic">
    <description>To add a constant to a 32-bit integer.</description>
    <format>
      <attribute type="Register" name="dest" />
      <attribute type="Register" name="src" />
      <attribute type="Exp" name="imm" />
    </format>
    <syntax>
      <token kind="register" name="dest" />
      <token kind="register" default="@0" />
      <token kind="immediate" />
    </syntax>
  </instruction>

  <instruction opcode="sub" level="native" kind="arithmetic">
    <description>To subtract 32-bit integers. If overflow occurs, then trap.</description>
    <format>
      <attribute type="Register" name="dest" />
      <attribute type="Register" name="src1" />
      <attribute type="Register" name="src2" />
    </format>
    <syntax>
      <token kind="register" />
      <token kind="register" />
      <token kind="register" />
    </syntax>
    <syntax alias="addi">
      <token kind="register" />
      <token kind="register" />
      <token kind="immediate" name="imm" value="*new OpExp(*new IntExp(0), OpExp::sub, @2)" />
    </syntax>
  </instruction>
  <instruction opcode="subu" level="native" kind="arithmetic">
    <description>To subtract 32-bit integers.</description>
    <format>
      <attribute type="Register" name="dest" />
      <attribute type="Register" name="src1" />
      <attribute type="Register" name="src2" />
    </format>
    <syntax>
      <token kind="register" />
      <token kind="register" />
      <token kind="register" />
    </syntax>
    <syntax alias="addiu">
      <token kind="register" />
      <token kind="register" />
      <token kind="immediate" name="imm" value="*new OpExp(*new IntExp(0), OpExp::sub, @2)" />
    </syntax>
  </instruction>

  <instruction opcode="neg" level="pseudo" kind="arithmetic">
    <description>FIXME</description>
    <syntax alias="sub">
      <token kind="register" name="dest" />
      <token kind="hidden" value="* new Register(Register::general, Cpu::zero)" />
      <token kind="register" default="@0" />
    </syntax>
  </instruction>
  <instruction opcode="negu" level="pseudo" kind="arithmetic">
    <description>FIXME</description>
    <syntax alias="subu">
      <token kind="register" name="dest" />
      <token kind="hidden" value="* new Register(Register::general, Cpu::zero)" />
      <token kind="register" default="@0" />
    </syntax>
  </instruction>

  <instruction opcode="abs" level="complex" kind="arithmetic">
    <description>FIXME</description>
    <syntax>
      <token kind="register" name="dest" />
      <token kind="register" default="@0" />
    </syntax>
  </instruction>

  <instruction opcode="mul" level="native" kind="arithmetic">
    <description>To multiply two words and write the result to a GPR.</description>
    <format>
      <attribute type="Register" name="dest" />
      <attribute type="Register" name="src1" />
      <attribute type="Register" name="src2" />
    </format>
    <syntax>
      <token kind="register" />
      <token kind="register" />
      <token kind="register" />
    </syntax>
    <syntax level="complex">
      <token kind="register" />
      <token kind="register" />
      <token kind="immediate" />
    </syntax>
  </instruction>

  <instruction opcode="div" level="native" kind="arithmetic">
    <description>To divide a 32-bit signed integers.</description>
    <format>
      <attribute type="Register" name="src1" />
      <attribute type="Register" name="src2" />
    </format>
    <syntax>
      <token kind="register" />
      <token kind="register" />
    </syntax>
    <syntax level="complex">
      <token kind="register" />
      <token kind="register" />
      <token kind="register" />
    </syntax>
    <syntax level="complex">
      <token kind="register" />
      <token kind="register" />
      <token kind="immediate" />
    </syntax>
  </instruction>
  <instruction opcode="divu" level="native" kind="arithmetic">
    <description>To divide a 32-bit unsigned integers.</description>
    <format>
      <attribute type="Register" name="src1" />
      <attribute type="Register" name="src2" />
    </format>
    <syntax>
      <token kind="register" />
      <token kind="register" />
    </syntax>
    <syntax level="complex">
      <token kind="register" />
      <token kind="register" />
      <token kind="register" />
    </syntax>
    <syntax level="complex">
      <token kind="register" />
      <token kind="register" />
      <token kind="immediate" />
    </syntax>
  </instruction>

  <instruction opcode="rem" level="complex" kind="arithmetic">
    <description>FIXME</description>
    <syntax>
      <token kind="register" />
      <token kind="register" />
      <token kind="register" />
    </syntax>
  </instruction>
  <instruction opcode="remu" level="complex" kind="arithmetic">
    <description>FIXME</description>
    <syntax>
      <token kind="register" />
      <token kind="register" />
      <token kind="register" />
    </syntax>
  </instruction>


  <!-- Binary instructions -->
  <instruction opcode="sll" level="native" kind="bitwise">
    <description>To left-shift a word by a fixed number of bits.</description>
    <format>
      <attribute type="Register" name="dest" />
      <attribute type="Register" name="src" />
      <attribute type="Exp" name="imm" />
    </format>
    <syntax>
      <token kind="register" />
      <token kind="register" />
      <token kind="immediate" />
    </syntax>
    <syntax alias="sllv">
      <token kind="register" />
      <token kind="register" />
      <token kind="register" />
    </syntax>
  </instruction>

  <instruction opcode="sllv" level="native" kind="bitwise">
    <description>To left-shift a word by a variable number of bits.</description>
    <format>
      <attribute type="Register" name="dest" />
      <attribute type="Register" name="src1" />
      <attribute type="Register" name="src2" />
    </format>
    <syntax>
      <token kind="register" />
      <token kind="register" />
      <token kind="register" />
    </syntax>
  </instruction>

  <instruction opcode="sra" level="native" kind="bitwise">
    <description>To execute an arithmetic right-shift of a word by a fixed number of bits.</description>
    <format>
      <attribute type="Register" name="dest" />
      <attribute type="Register" name="src" />
      <attribute type="Exp" name="imm" />
    </format>
    <syntax>
      <token kind="register" />
      <token kind="register" />
      <token kind="immediate" />
    </syntax>
    <syntax alias="srav">
      <token kind="register" />
      <token kind="register" />
      <token kind="register" />
    </syntax>
  </instruction>

  <instruction opcode="srav" level="native" kind="bitwise">
    <description>To execute an arithmetic right-shift of a word by a variable number of bits.</description>
    <format>
      <attribute type="Register" name="dest" />
      <attribute type="Register" name="src1" />
      <attribute type="Register" name="src2" />
    </format>
    <syntax>
      <token kind="register" />
      <token kind="register" />
      <token kind="register" />
    </syntax>
  </instruction>

  <instruction opcode="srl" level="native" kind="bitwise">
    <description>To execute a logical right-shift of a word by a fixed number of bits.</description>
    <format>
      <attribute type="Register" name="dest" />
      <attribute type="Register" name="src" />
      <attribute type="Exp" name="imm" />
    </format>
    <syntax>
      <token kind="register" />
      <token kind="register" />
      <token kind="immediate" />
    </syntax>
    <syntax alias="srlv">
      <token kind="register" />
      <token kind="register" />
      <token kind="register" />
    </syntax>
  </instruction>

  <instruction opcode="srlv" level="native" kind="bitwise">
    <description>To execute a logical right-shift of a word by a variable number of bits.</description>
    <format>
      <attribute type="Register" name="dest" />
      <attribute type="Register" name="src1" />
      <attribute type="Register" name="src2" />
    </format>
    <syntax>
      <token kind="register" />
      <token kind="register" />
      <token kind="register" />
    </syntax>
  </instruction>

  <instruction opcode="rol" level="complex" kind="bitwise">
    <syntax>
      <token kind="register" />
      <token kind="register" />
      <token kind="register" />
    </syntax>
    <syntax>
      <token kind="register" />
      <token kind="register" />
      <token kind="immediate" />
    </syntax>
  </instruction>

  <instruction opcode="ror" level="complex" kind="bitwise">
    <syntax>
      <token kind="register" />
      <token kind="register" />
      <token kind="register" />
    </syntax>
    <syntax>
      <token kind="register" />
      <token kind="register" />
      <token kind="immediate" />
    </syntax>
  </instruction>


  <instruction opcode="and" level="native" kind="bitwise">
    <format>
      <attribute type="Register" name="dest" />
      <attribute type="Register" name="src1" />
      <attribute type="Register" name="src2" />
    </format>
    <syntax>
      <token kind="register" name="dest" />
      <token kind="register" default="@0" />
      <token kind="register" />
    </syntax>
    <syntax alias="andi">
      <token kind="register" name="dest" />
      <token kind="register" default="@0" />
      <token kind="immediate" />
    </syntax>
  </instruction>

  <instruction opcode="andi" level="native" kind="bitwise">
    <format>
      <attribute type="Register" name="dest" />
      <attribute type="Register" name="src" />
      <attribute type="Exp" name="imm" />
    </format>
    <syntax>
      <token kind="register" />
      <token kind="register" />
      <token kind="immediate" />
    </syntax>
  </instruction>


  <instruction opcode="or" level="native" kind="bitwise">
    <format>
      <attribute type="Register" name="dest" />
      <attribute type="Register" name="src1" />
      <attribute type="Register" name="src2" />
    </format>
    <syntax>
      <token kind="register" name="dest" />
      <token kind="register" default="@0" />
      <token kind="register" />
    </syntax>
    <syntax alias="ori">
      <token kind="register" name="dest" />
      <token kind="register" default="@0" />
      <token kind="immediate" />
    </syntax>
  </instruction>

  <instruction opcode="ori" level="native" kind="bitwise">
    <format>
      <attribute type="Register" name="dest" />
      <attribute type="Register" name="src" />
      <attribute type="Exp" name="imm" />
    </format>
    <syntax>
      <token kind="register" />
      <token kind="register" />
      <token kind="immediate" />
    </syntax>
  </instruction>


  <instruction opcode="xor" level="native" kind="bitwise">
    <format>
      <attribute type="Register" name="dest" />
      <attribute type="Register" name="src1" />
      <attribute type="Register" name="src2" />
    </format>
    <syntax>
      <token kind="register" name="dest" />
      <token kind="register" default="@0" />
      <token kind="register" />
    </syntax>
    <syntax alias="xori">
      <token kind="register" name="dest" />
      <token kind="register" default="@0" />
      <token kind="immediate" />
    </syntax>
  </instruction>

  <instruction opcode="xori" level="native" kind="bitwise">
    <format>
      <attribute type="Register" name="dest" />
      <attribute type="Register" name="src" />
      <attribute type="Exp" name="imm" />
    </format>
    <syntax>
      <token kind="register" />
      <token kind="register" />
      <token kind="immediate" />
    </syntax>
  </instruction>


  <instruction opcode="nor" level="native" kind="bitwise">
    <format>
      <attribute type="Register" name="dest" />
      <attribute type="Register" name="src1" />
      <attribute type="Register" name="src2" />
    </format>
    <syntax>
      <token kind="register" name="dest" />
      <token kind="register" default="@0" />
      <token kind="register" />
    </syntax>
    <syntax level="complex">
      <token kind="register" name="dest" />
      <token kind="register" default="@0" />
      <token kind="immediate" />
    </syntax>
  </instruction>


  <instruction opcode="not" level="pseudo" kind="bitwise">
    <syntax alias="nor">
      <token kind="register" name="dest" />
      <token kind="register" default="@0"/>
      <token kind="hidden" value="* new Register(Register::general, Cpu::zero)" />
    </syntax>
  </instruction>


  <!-- Comparison instructions -->
  <instruction opcode="seq" level="complex" kind="comparison">
    <syntax>
      <token kind="register" />
      <token kind="register" />
      <token kind="register" />
    </syntax>
    <syntax>
      <token kind="register" />
      <token kind="register" />
      <token kind="immediate" />
    </syntax>
  </instruction>
  <instruction opcode="sne" level="complex" kind="comparison">
    <syntax>
      <token kind="register" />
      <token kind="register" />
      <token kind="register" />
    </syntax>
    <syntax>
      <token kind="register" />
      <token kind="register" />
      <token kind="immediate" />
    </syntax>
  </instruction>

  <instruction opcode="sge" level="complex" kind="comparison">
    <syntax>
      <token kind="register" />
      <token kind="register" />
      <token kind="register" />
    </syntax>
    <syntax>
      <token kind="register" />
      <token kind="register" />
      <token kind="immediate" />
    </syntax>
  </instruction>
  <instruction opcode="sgeu" level="complex" kind="comparison">
    <syntax>
      <token kind="register" />
      <token kind="register" />
      <token kind="register" />
    </syntax>
    <syntax>
      <token kind="register" />
      <token kind="register" />
      <token kind="immediate" />
    </syntax>
  </instruction>  

  <instruction opcode="sgt" level="complex" kind="comparison">
    <syntax alias="slt">
      <token kind="register" />
      <token kind="register" name="src1" value="@2"/>
      <token kind="register" name="src2" value="@1"/>
    </syntax>
    <syntax>
      <token kind="register" />
      <token kind="register" />
      <token kind="immediate" />
    </syntax>
  </instruction>
  <instruction opcode="sgtu" level="complex" kind="comparison">
    <syntax alias="sltu">
      <token kind="register" />
      <token kind="register" name="src1" value="@2"/>
      <token kind="register" name="src2" value="@1"/>
    </syntax>
    <syntax>
      <token kind="register" />
      <token kind="register" />
      <token kind="immediate" />
    </syntax>
  </instruction>  

  <instruction opcode="sle" level="complex" kind="comparison">
    <syntax>
      <token kind="register" />
      <token kind="register" />
      <token kind="register" />
    </syntax>
    <syntax>
      <token kind="register" />
      <token kind="register" />
      <token kind="immediate" />
    </syntax>
  </instruction>
  <instruction opcode="sleu" level="complex" kind="comparison">
    <syntax>
      <token kind="register" />
      <token kind="register" />
      <token kind="register" />
    </syntax>
    <syntax>
      <token kind="register" />
      <token kind="register" />
      <token kind="immediate" />
    </syntax>
  </instruction>  

  <instruction opcode="slt" level="native" kind="comparison">
    <format>
      <attribute type="Register" name="dest" />
      <attribute type="Register" name="src1" />
      <attribute type="Register" name="src2" />
    </format>
    <syntax>
      <token kind="register" />
      <token kind="register" />
      <token kind="register" />
    </syntax>
    <syntax alias="slti">
      <token kind="register" />
      <token kind="register" />
      <token kind="immediate" />
    </syntax>
  </instruction>
  <instruction opcode="slti" level="native" kind="comparison">
    <format>
      <attribute type="Register" name="dest" />
      <attribute type="Register" name="src" />
      <attribute type="Exp" name="imm" />
    </format>
    <syntax>
      <token kind="register" />
      <token kind="register" />
      <token kind="immediate" />
    </syntax>
  </instruction>
  <instruction opcode="sltu" level="native" kind="comparison">
    <format>
      <attribute type="Register" name="dest" />
      <attribute type="Register" name="src1" />
      <attribute type="Register" name="src2" />
    </format>
    <syntax>
      <token kind="register" />
      <token kind="register" />
      <token kind="register" />
    </syntax>
    <syntax alias="sltiu">
      <token kind="register" />
      <token kind="register" />
      <token kind="immediate" />
    </syntax>
  </instruction>
  <instruction opcode="sltiu" level="native" kind="comparison">
    <format>
      <attribute type="Register" name="dest" />
      <attribute type="Register" name="src" />
      <attribute type="Exp" name="imm" />
    </format>
    <syntax>
      <token kind="register" />
      <token kind="register" />
      <token kind="immediate" />
    </syntax>
  </instruction>


  <!-- Branch instructions -->
  <instruction opcode="beq" level="native" kind="branch">
    <format>
      <attribute type="Register" name="src1"/>
      <attribute type="Register" name="src2"/>
      <attribute type="Exp" name="label"/>
    </format>
    <syntax>
      <token kind="register" />
      <token kind="register" />
      <token kind="label" />
    </syntax>
    <syntax level="complex">
      <token kind="register" />
      <token kind="immediate" />
      <token kind="label" />
    </syntax>
  </instruction>
  <instruction opcode="beqz" level="pseudo" kind="branch">
    <syntax alias="beq">
      <token kind="register" />
      <token kind="hidden" value="* new Register(Register::general, Cpu::zero)"/>
      <token kind="label" />
    </syntax>
  </instruction>

  <instruction opcode="bne" level="native" kind="branch">
    <format>
      <attribute type="Register" name="src1"/>
      <attribute type="Register" name="src2"/>
      <attribute type="Exp" name="label"/>
    </format>
    <syntax>
      <token kind="register" />
      <token kind="register" />
      <token kind="label" />
    </syntax>
    <syntax level="complex">
      <token kind="register" />
      <token kind="immediate" />
      <token kind="label" />
    </syntax>
  </instruction>
  <instruction opcode="bnez" level="pseudo" kind="branch">
    <syntax alias="bne">
      <token kind="register" />
      <token kind="hidden" value="* new Register(Register::general, Cpu::zero)"/>
      <token kind="label" />
    </syntax>
  </instruction>


  <instruction opcode="bge" level="complex" kind="branch">
    <syntax>
      <token kind="register" />
      <token kind="register" />
      <token kind="label" />
    </syntax>
    <syntax>
      <token kind="register" />
      <token kind="immediate" />
      <token kind="label" />
    </syntax>
  </instruction>
  <instruction opcode="bgeu" level="complex" kind="branch">
    <syntax>
      <token kind="register" />
      <token kind="register" />
      <token kind="label" />
    </syntax>
    <syntax>
      <token kind="register" />
      <token kind="immediate" />
      <token kind="label" />
    </syntax>
  </instruction>
  <instruction opcode="bgez" level="native" kind="branch">
    <format>
      <attribute type="Register" name="src"/>
      <attribute type="Exp" name="label"/>
    </format>
    <syntax>
      <token kind="register" />
      <token kind="label" />
    </syntax>
  </instruction>
  <instruction opcode="bgezal" level="native" kind="branch">
    <format>
      <attribute type="Register" name="src"/>
      <attribute type="Exp" name="label"/>
    </format>
    <syntax>
      <token kind="register" />
      <token kind="label" />
    </syntax>
  </instruction>

  <instruction opcode="bgt" level="complex" kind="branch">
    <syntax>
      <token kind="register" />
      <token kind="register" />
      <token kind="label" />
    </syntax>
    <syntax>
      <token kind="register" />
      <token kind="immediate" />
      <token kind="label" />
    </syntax>
  </instruction>
  <instruction opcode="bgtu" level="complex" kind="branch">
    <syntax>
      <token kind="register" />
      <token kind="register" />
      <token kind="label" />
    </syntax>
    <syntax>
      <token kind="register" />
      <token kind="immediate" />
      <token kind="label" />
    </syntax>
  </instruction>
  <instruction opcode="bgtz" level="native" kind="branch">
    <format>
      <attribute type="Register" name="src"/>
      <attribute type="Exp" name="label"/>
    </format>
    <syntax>
      <token kind="register" />
      <token kind="label" />
    </syntax>
  </instruction>

  <instruction opcode="ble" level="complex" kind="branch">
    <syntax>
      <token kind="register" />
      <token kind="register" />
      <token kind="label" />
    </syntax>
    <syntax>
      <token kind="register" />
      <token kind="immediate" />
      <token kind="label" />
    </syntax>
  </instruction>
  <instruction opcode="bleu" level="complex" kind="branch">
    <syntax>
      <token kind="register" />
      <token kind="register" />
      <token kind="label" />
    </syntax>
    <syntax>
      <token kind="register" />
      <token kind="immediate" />
      <token kind="label" />
    </syntax>
  </instruction>
  <instruction opcode="blez" level="native" kind="branch">
    <format>
      <attribute type="Register" name="src"/>
      <attribute type="Exp" name="label"/>
    </format>
    <syntax>
      <token kind="register" />
      <token kind="label" />
    </syntax>
  </instruction>

  <instruction opcode="blt" level="complex" kind="branch">
    <syntax>
      <token kind="register" />
      <token kind="register" />
      <token kind="label" />
    </syntax>
    <syntax>
      <token kind="register" />
      <token kind="immediate" />
      <token kind="label" />
    </syntax>
  </instruction>
  <instruction opcode="bltu" level="complex" kind="branch">
    <syntax>
      <token kind="register" />
      <token kind="register" />
      <token kind="label" />
    </syntax>
    <syntax>
      <token kind="register" />
      <token kind="immediate" />
      <token kind="label" />
    </syntax>
  </instruction>
  <instruction opcode="bltz" level="native" kind="branch">
    <format>
      <attribute type="Register" name="src"/>
      <attribute type="Exp" name="label"/>
    </format>
    <syntax>
      <token kind="register" />
      <token kind="label" />
    </syntax>
  </instruction>
  <instruction opcode="bltzal" level="native" kind="branch">
    <format>
      <attribute type="Register" name="src"/>
      <attribute type="Exp" name="label"/>
    </format>
    <syntax>
      <token kind="register" />
      <token kind="label" />
    </syntax>
  </instruction>



  <instruction opcode="j" level="native" kind="branch">
    <format>
      <attribute type="Exp" name="label" />
    </format>
    <syntax>
      <token kind="label" />
    </syntax>
  </instruction>

  <instruction opcode="jr" level="native" kind="branch">
    <format>
      <attribute type="Register" name="dest" />
    </format>
    <syntax>
      <token kind="register" />
    </syntax>
  </instruction>

  <instruction opcode="jal" level="native" kind="branch">
    <format>
      <attribute type="Exp" name="label" />
    </format>
    <syntax>
      <token kind="label" />
    </syntax>
  </instruction>

  <instruction opcode="jalr" level="native" kind="branch">
    <format>
      <attribute type="Register" name="dest" />
    </format>
    <syntax>
      <token kind="register" />
    </syntax>
  </instruction>


  <!-- Load instructions -->
  <instruction opcode="lw" level="native" kind="load">
    <format>
      <attribute type="Register" name="dest" />
      <attribute type="Exp" name="offset" />
      <attribute type="Register" name="base" />
    </format>
    <syntax>
      <token kind="register" />
      <token kind="immediate" default="* new IntExp(0)" />
      <token kind="address" />
    </syntax>
  </instruction>

  <instruction opcode="lb" level="native" kind="load">
    <format>
      <attribute type="Register" name="dest" />
      <attribute type="Exp" name="offset" />
      <attribute type="Register" name="base" />
    </format>
    <syntax>
      <token kind="register" />
      <token kind="immediate" default="* new IntExp(0)" />
      <token kind="address" />
    </syntax>
  </instruction>

  <instruction opcode="lbu" level="native" kind="load">
    <format>
      <attribute type="Register" name="dest" />
      <attribute type="Exp" name="offset" />
      <attribute type="Register" name="base" />
    </format>
    <syntax>
      <token kind="register" />
      <token kind="immediate" default="* new IntExp(0)" />
      <token kind="address" />
    </syntax>
  </instruction>

  <instruction opcode="li" level="native" kind="load">
    <format>