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% !TEX program = xelatex
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Christian Urban <christian dot urban at kcl dot ac dot uk>
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\documentclass{article}
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Christian Urban <christian dot urban at kcl dot ac dot uk>
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\usepackage{../style}
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Christian Urban <christian dot urban at kcl dot ac dot uk>
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\usepackage{../langs}
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Christian Urban <christian dot urban at kcl dot ac dot uk>
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Christian Urban <christian dot urban at kcl dot ac dot uk>
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\begin{document}
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Christian Urban <christian dot urban at kcl dot ac dot uk>
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Christian Urban <christian dot urban at kcl dot ac dot uk>
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%https://github.com/Storyyeller/Krakatau
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Christian Urban <christian dot urban at kcl dot ac dot uk>
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%https://docs.oracle.com/javase/specs/jvms/se7/html/
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Christian Urban <christian dot urban at kcl dot ac dot uk>
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% Jasmin Tutorial
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%http://saksagan.ceng.metu.edu.tr/courses/ceng444/link/jvm-cpm.html
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\section*{Coursework 4}
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Christian Urban <christian dot urban at kcl dot ac dot uk>
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\noindent This coursework is worth 15\% and is due on \cwFOUR{}
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at 16:00. You are asked to implement a compiler for
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Christian Urban <christian dot urban at kcl dot ac dot uk>
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the WHILE language that targets the assembler language
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provided by Jasmin or Krakatau (both have a very similar
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syntax). Please submit your answers to the questions
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below as PDF. You can do the implementation in any programming
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Christian Urban <christian dot urban at kcl dot ac dot uk>
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language you like, but you need to submit the source code with
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Christian Urban <christian dot urban at kcl dot ac dot uk>
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which you answered the questions, otherwise a mark of 0\% will
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Christian Urban <christian dot urban at kcl dot ac dot uk>
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be awarded. You should use the lexer and parser from the
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previous courseworks. Implement your compiler in the file \texttt{cw04.sc}.
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%Please package \emph{everything}(!) in
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%a zip-file that creates a directory with the name
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%\texttt{YournameYourFamilyname} on my end.
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Christian Urban <christian dot urban at kcl dot ac dot uk>
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\subsection*{Disclaimer\alert}
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Christian Urban <christian dot urban at kcl dot ac dot uk>
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Christian Urban <christian dot urban at kcl dot ac dot uk>
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It should be understood that the work you submit represents
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Christian Urban <christian dot urban at kcl dot ac dot uk>
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your own effort. You have not copied from anyone else. An
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Christian Urban <christian dot urban at kcl dot ac dot uk>
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exception is the Scala code I showed during the lectures,
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Christian Urban <christian dot urban at kcl dot ac dot uk>
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which you can use. You can also use your own code from the
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CW~1, CW~2 and CW~3. But do not
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be tempted to ask Github Copilot for help or do any other
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shenanigans like this!
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Christian Urban <christian dot urban at kcl dot ac dot uk>
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Christian Urban <christian dot urban at kcl dot ac dot uk>
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Christian Urban <christian dot urban at kcl dot ac dot uk>
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\subsection*{Jasmin Assembler}
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Christian Urban <christian dot urban at kcl dot ac dot uk>
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For this coursework you will need an assembler.
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Christian Urban <christian dot urban at kcl dot ac dot uk>
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The Jasmin assembler is available from
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Christian Urban <christian dot urban at kcl dot ac dot uk>
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Christian Urban <christian dot urban at kcl dot ac dot uk>
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\begin{center}
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Christian Urban <christian dot urban at kcl dot ac dot uk>
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\url{http://jasmin.sourceforge.net}
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Christian Urban <christian dot urban at kcl dot ac dot uk>
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\end{center}
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Christian Urban <christian dot urban at kcl dot ac dot uk>
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Christian Urban <christian dot urban at kcl dot ac dot uk>
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\noindent
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This is a jar-file you can run on the commandline.
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Christian Urban <christian dot urban at kcl dot ac dot uk>
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There is a user guide for Jasmin
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Christian Urban <christian dot urban at kcl dot ac dot uk>
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Christian Urban <christian dot urban at kcl dot ac dot uk>
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\begin{center}
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Christian Urban <christian dot urban at kcl dot ac dot uk>
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\url{http://jasmin.sourceforge.net/guide.html}
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Christian Urban <christian dot urban at kcl dot ac dot uk>
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\end{center}
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Christian Urban <christian dot urban at kcl dot ac dot uk>
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Christian Urban <christian dot urban at kcl dot ac dot uk>
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\noindent and also a description of some of the instructions
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Christian Urban <christian dot urban at kcl dot ac dot uk>
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that the JVM understands
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Christian Urban <christian dot urban at kcl dot ac dot uk>
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Christian Urban <christian dot urban at kcl dot ac dot uk>
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\begin{center}
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Christian Urban <christian dot urban at kcl dot ac dot uk>
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\url{http://jasmin.sourceforge.net/instructions.html}
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Christian Urban <christian dot urban at kcl dot ac dot uk>
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\end{center}
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Christian Urban <christian dot urban at kcl dot ac dot uk>
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Christian Urban <christian dot urban at kcl dot ac dot uk>
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\noindent If you generated a correct assembler file for
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Christian Urban <christian dot urban at kcl dot ac dot uk>
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Jasmin, for example \texttt{loops.j}, you can use
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Christian Urban <christian dot urban at kcl dot ac dot uk>
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Christian Urban <christian dot urban at kcl dot ac dot uk>
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\begin{center}
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\texttt{java -jar jasmin.jar loops.j}
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Christian Urban <christian dot urban at kcl dot ac dot uk>
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\end{center}
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Christian Urban <christian dot urban at kcl dot ac dot uk>
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\noindent in order to translate it into Java Byte Code. If needed, you
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need to give the path to the Jasmin jar-file. The resulting class
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file can be run with
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Christian Urban <christian dot urban at kcl dot ac dot uk>
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Christian Urban <christian dot urban at kcl dot ac dot uk>
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\begin{center}
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Christian Urban <christian dot urban at kcl dot ac dot uk>
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\texttt{java loops}
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Christian Urban <christian dot urban at kcl dot ac dot uk>
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\end{center}
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Christian Urban <christian dot urban at kcl dot ac dot uk>
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Christian Urban <christian dot urban at kcl dot ac dot uk>
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\noindent where you might need to give the correct path to the
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Christian Urban <christian dot urban at kcl dot ac dot uk>
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class file. For example:
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Christian Urban <christian dot urban at kcl dot ac dot uk>
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Christian Urban <christian dot urban at kcl dot ac dot uk>
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\begin{center}
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Christian Urban <christian dot urban at kcl dot ac dot uk>
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\texttt{java -cp . loops/loops}
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Christian Urban <christian dot urban at kcl dot ac dot uk>
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\end{center}
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Christian Urban <christian dot urban at kcl dot ac dot uk>
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Christian Urban <christian dot urban at kcl dot ac dot uk>
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\noindent There are also other resources about Jasmin on the
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Christian Urban <christian dot urban at kcl dot ac dot uk>
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Internet, for example
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Christian Urban <christian dot urban at kcl dot ac dot uk>
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Christian Urban <christian dot urban at kcl dot ac dot uk>
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\begin{center}
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\small\url{https://saksagan.ceng.metu.edu.tr/courses/ceng444/link/f3jasmintutorial.html}
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Christian Urban <christian dot urban at kcl dot ac dot uk>
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\end{center}
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Christian Urban <christian dot urban at kcl dot ac dot uk>
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Christian Urban <christian dot urban at kcl dot ac dot uk>
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\noindent and
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Christian Urban <christian dot urban at kcl dot ac dot uk>
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Christian Urban <christian dot urban at kcl dot ac dot uk>
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\begin{center}
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\small\url{http://www.csc.villanova.edu/~tway/courses/csc4181/s2022/labs/finalproject/JVM.pdf}
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Christian Urban <christian dot urban at kcl dot ac dot uk>
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\end{center}
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Christian Urban <christian dot urban at kcl dot ac dot uk>
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\noindent
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If possible use Jasmin for the coursework. The Krakatau assembler
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below as a slightly different syntax.
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Christian Urban <christian dot urban at kcl dot ac dot uk>
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\subsection*{Krakatau Assembler}
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Christian Urban <christian dot urban at kcl dot ac dot uk>
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Christian Urban <christian dot urban at kcl dot ac dot uk>
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The Krakatau assembler is available from
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Christian Urban <christian dot urban at kcl dot ac dot uk>
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Christian Urban <christian dot urban at kcl dot ac dot uk>
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\begin{center}
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\url{https://github.com/Storyyeller/Krakatau/tree/master}
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Christian Urban <christian dot urban at kcl dot ac dot uk>
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\end{center}
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Christian Urban <christian dot urban at kcl dot ac dot uk>
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Christian Urban <christian dot urban at kcl dot ac dot uk>
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\noindent This assembler requires Python and a package called
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Christian Urban <christian dot urban at kcl dot ac dot uk>
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\pcode{ply} available from
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Christian Urban <christian dot urban at kcl dot ac dot uk>
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Christian Urban <christian dot urban at kcl dot ac dot uk>
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\begin{center}
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Christian Urban <christian dot urban at kcl dot ac dot uk>
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\url{https://pypi.python.org/pypi/ply}
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Christian Urban <christian dot urban at kcl dot ac dot uk>
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\end{center}
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Christian Urban <christian dot urban at kcl dot ac dot uk>
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Christian Urban <christian dot urban at kcl dot ac dot uk>
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\noindent This assembler is largely compatible with the Jasmin
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syntax---that means for the files we are concerned with here,
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Christian Urban <christian dot urban at kcl dot ac dot uk>
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it understands the same input syntax (no changes to your
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compiler need to be made; ok maybe some small syntactic
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adjustments are needed). You can generate Java Byte Code by
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Christian Urban <christian dot urban at kcl dot ac dot uk>
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using
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Christian Urban <christian dot urban at kcl dot ac dot uk>
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Christian Urban <christian dot urban at kcl dot ac dot uk>
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\begin{center}
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Christian Urban <christian dot urban at kcl dot ac dot uk>
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\texttt{python Krakatau-master/assemble.py loops.j}
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Christian Urban <christian dot urban at kcl dot ac dot uk>
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\end{center}
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Christian Urban <christian dot urban at kcl dot ac dot uk>
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Christian Urban <christian dot urban at kcl dot ac dot uk>
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\noindent where you may have to adapt the directory where
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Christian Urban <christian dot urban at kcl dot ac dot uk>
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Krakatau is installed (I just downloaded the zip file from
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Christian Urban <christian dot urban at kcl dot ac dot uk>
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Github and \pcode{Krakatau-master} was the directory where it
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was installed). Again the resulting class-file you can run with
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\texttt{java}. There is also a newer version of Krakatau available at
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\begin{center}
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\url{https://github.com/Storyyeller/Krakatau/tree/v2}
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\end{center}
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\noindent
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This is now a Rust program using Cargo as package manager (I have not tried this
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version---I assume it should produce the same output, but might be
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easier to install because it avoids Python's \emph{dependency hell}).
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Christian Urban <christian dot urban at kcl dot ac dot uk>
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Christian Urban <christian dot urban at kcl dot ac dot uk>
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Christian Urban <christian dot urban at kcl dot ac dot uk>
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%\noindent You need to submit a document containing the answers
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Christian Urban <christian dot urban at kcl dot ac dot uk>
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%for the two questions below. You can do the implementation in
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Christian Urban <christian dot urban at kcl dot ac dot uk>
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%any programming language you like, but you need to submit the
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Christian Urban <christian dot urban at kcl dot ac dot uk>
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%source code with which you answered the questions. Otherwise
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Christian Urban <christian dot urban at kcl dot ac dot uk>
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%the submission will not be counted. However, the coursework
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Christian Urban <christian dot urban at kcl dot ac dot uk>
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%will \emph{only} be judged according to the answers. You can
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Christian Urban <christian dot urban at kcl dot ac dot uk>
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%submit your answers in a txt-file or as pdf.\bigskip
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Christian Urban <christian dot urban at kcl dot ac dot uk>
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%\subsection*{Question 0 (Unmarked)}
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%
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%Please include in the PDF at the beginning your email address, your student
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%number and whether you are BSc / MSci student and for the latter in which
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%year your are in. Thanks!
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Christian Urban <christian dot urban at kcl dot ac dot uk>
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Christian Urban <christian dot urban at kcl dot ac dot uk>
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\subsection*{Question 1}
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Christian Urban <christian dot urban at kcl dot ac dot uk>
parents:
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Christian Urban <christian dot urban at kcl dot ac dot uk>
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You need to lex and parse WHILE programs, and then generate
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Christian Urban <christian dot urban at kcl dot ac dot uk>
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|
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Java Byte Code instructions for the Jasmin assembler (or
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Christian Urban <christian dot urban at kcl dot ac dot uk>
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Krakatau assembler). As solution you need to submit the
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Christian Urban <christian dot urban at kcl dot ac dot uk>
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assembler instructions for the Fibonacci and Factorial
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Christian Urban <christian dot urban at kcl dot ac dot uk>
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programs. Both should be so modified that a user can input on
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Christian Urban <christian dot urban at kcl dot ac dot uk>
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the console which Fibonacci number and which Factorial should
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Christian Urban <christian dot urban at kcl dot ac dot uk>
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be calculated. The Fibonacci program is given in
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Christian Urban <christian dot urban at kcl dot ac dot uk>
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Figure~\ref{fibs}. You can write your own program for
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calculating factorials. Submit your assembler code as
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a file that can be run, not as PDF-text.
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Christian Urban <christian dot urban at kcl dot ac dot uk>
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Christian Urban <christian dot urban at kcl dot ac dot uk>
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\begin{figure}[t]
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\lstinputlisting[language=while]{../cwtests/cw04/fib.while}
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Christian Urban <christian dot urban at kcl dot ac dot uk>
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\caption{The Fibonacci program in the WHILE language.\label{fibs}}
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Christian Urban <christian dot urban at kcl dot ac dot uk>
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\end{figure}
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Christian Urban <christian dot urban at kcl dot ac dot uk>
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Christian Urban <christian dot urban at kcl dot ac dot uk>
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\subsection*{Question 2}
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Christian Urban <christian dot urban at kcl dot ac dot uk>
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Christian Urban <christian dot urban at kcl dot ac dot uk>
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Extend the syntax of your language so that it contains also
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Christian Urban <christian dot urban at kcl dot ac dot uk>
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\texttt{for}-loops, like
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Christian Urban <christian dot urban at kcl dot ac dot uk>
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Christian Urban <christian dot urban at kcl dot ac dot uk>
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\begin{center}
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Christian Urban <christian dot urban at kcl dot ac dot uk>
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\lstset{language=While}
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Christian Urban <christian dot urban at kcl dot ac dot uk>
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\code{for} \;\textit{Id} \texttt{:=} \textit{AExp}\; \code{upto}
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Christian Urban <christian dot urban at kcl dot ac dot uk>
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\;\textit{AExp}\; \code{do} \textit{Block}
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Christian Urban <christian dot urban at kcl dot ac dot uk>
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\end{center}
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Christian Urban <christian dot urban at kcl dot ac dot uk>
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Christian Urban <christian dot urban at kcl dot ac dot uk>
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\noindent The intended meaning is to first assign the variable
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\textit{Id} the value of the first arithmetic expression, then test
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whether this value is less or equal than the value of the
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Christian Urban <christian dot urban at kcl dot ac dot uk>
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second arithmetic expression. If yes, go through the loop, and
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Christian Urban <christian dot urban at kcl dot ac dot uk>
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at the end increase the value of the loop variable by 1 and
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Christian Urban <christian dot urban at kcl dot ac dot uk>
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start again with the test. If no, leave the loop. For example
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Christian Urban <christian dot urban at kcl dot ac dot uk>
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the following instance of a \code{for}-loop is supposed to
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Christian Urban <christian dot urban at kcl dot ac dot uk>
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print out the numbers \pcode{2}, \pcode{3}, \pcode{4}.
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Christian Urban <christian dot urban at kcl dot ac dot uk>
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Christian Urban <christian dot urban at kcl dot ac dot uk>
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Christian Urban <christian dot urban at kcl dot ac dot uk>
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\begin{center}
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Christian Urban <christian dot urban at kcl dot ac dot uk>
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\begin{minipage}{12cm}
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Christian Urban <christian dot urban at kcl dot ac dot uk>
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\begin{lstlisting}[language=While, numbers=none]
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Christian Urban <christian dot urban at kcl dot ac dot uk>
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for i := 2 upto 4 do {
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Christian Urban <christian dot urban at kcl dot ac dot uk>
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write i
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Christian Urban <christian dot urban at kcl dot ac dot uk>
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}
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Christian Urban <christian dot urban at kcl dot ac dot uk>
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\end{lstlisting}
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Christian Urban <christian dot urban at kcl dot ac dot uk>
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\end{minipage}
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Christian Urban <christian dot urban at kcl dot ac dot uk>
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\end{center}
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Christian Urban <christian dot urban at kcl dot ac dot uk>
diff
changeset
|
210 |
|
390
Christian Urban <christian dot urban at kcl dot ac dot uk>
diff
changeset
|
211 |
\noindent There are two ways how this can be implemented: one
|
Christian Urban <christian dot urban at kcl dot ac dot uk>
diff
changeset
|
212 |
is to adapt the code generation part of the compiler and
|
391
Christian Urban <christian dot urban at kcl dot ac dot uk>
diff
changeset
|
213 |
generate specific code for \code{for}-loops; the other is to
|
Christian Urban <christian dot urban at kcl dot ac dot uk>
diff
changeset
|
214 |
translate the abstract syntax tree of \code{for}-loops into
|
390
Christian Urban <christian dot urban at kcl dot ac dot uk>
diff
changeset
|
215 |
an abstract syntax tree using existing language constructs.
|
Christian Urban <christian dot urban at kcl dot ac dot uk>
diff
changeset
|
216 |
For example the loop above could be translated to the
|
391
Christian Urban <christian dot urban at kcl dot ac dot uk>
diff
changeset
|
217 |
following \code{while}-loop:
|
203
Christian Urban <christian dot urban at kcl dot ac dot uk>
diff
changeset
|
218 |
|
Christian Urban <christian dot urban at kcl dot ac dot uk>
diff
changeset
|
219 |
\begin{center}
|
390
Christian Urban <christian dot urban at kcl dot ac dot uk>
diff
changeset
|
220 |
\begin{minipage}{12cm}
|
Christian Urban <christian dot urban at kcl dot ac dot uk>
diff
changeset
|
221 |
\begin{lstlisting}[language=While, numbers=none]
|
203
Christian Urban <christian dot urban at kcl dot ac dot uk>
diff
changeset
|
222 |
i := 2;
|
Christian Urban <christian dot urban at kcl dot ac dot uk>
diff
changeset
|
223 |
while (i <= 4) do {
|
Christian Urban <christian dot urban at kcl dot ac dot uk>
diff
changeset
|
224 |
write i;
|
905
|
225 |
i := i + 1
|
203
Christian Urban <christian dot urban at kcl dot ac dot uk>
diff
changeset
|
226 |
}
|
Christian Urban <christian dot urban at kcl dot ac dot uk>
diff
changeset
|
227 |
\end{lstlisting}
|
Christian Urban <christian dot urban at kcl dot ac dot uk>
diff
changeset
|
228 |
\end{minipage}
|
Christian Urban <christian dot urban at kcl dot ac dot uk>
diff
changeset
|
229 |
\end{center}
|
202
Christian Urban <christian dot urban at kcl dot ac dot uk>
diff
changeset
|
230 |
|
630
|
231 |
\subsection*{Question 3}
|
333
Christian Urban <christian dot urban at kcl dot ac dot uk>
diff
changeset
|
232 |
|
390
Christian Urban <christian dot urban at kcl dot ac dot uk>
diff
changeset
|
233 |
\noindent In this question you are supposed to give the
|
Christian Urban <christian dot urban at kcl dot ac dot uk>
diff
changeset
|
234 |
assembler instructions for the program
|
205
Christian Urban <christian dot urban at kcl dot ac dot uk>
diff
changeset
|
235 |
|
Christian Urban <christian dot urban at kcl dot ac dot uk>
diff
changeset
|
236 |
\begin{center}
|
390
Christian Urban <christian dot urban at kcl dot ac dot uk>
diff
changeset
|
237 |
\begin{minipage}{12cm}
|
Christian Urban <christian dot urban at kcl dot ac dot uk>
diff
changeset
|
238 |
\begin{lstlisting}[language=While, numbers=none]
|
333
Christian Urban <christian dot urban at kcl dot ac dot uk>
diff
changeset
|
239 |
for i := 1 upto 10 do {
|
Christian Urban <christian dot urban at kcl dot ac dot uk>
diff
changeset
|
240 |
for i := 1 upto 10 do {
|
Christian Urban <christian dot urban at kcl dot ac dot uk>
diff
changeset
|
241 |
write i
|
205
Christian Urban <christian dot urban at kcl dot ac dot uk>
diff
changeset
|
242 |
}
|
Christian Urban <christian dot urban at kcl dot ac dot uk>
diff
changeset
|
243 |
}
|
Christian Urban <christian dot urban at kcl dot ac dot uk>
diff
changeset
|
244 |
\end{lstlisting}
|
Christian Urban <christian dot urban at kcl dot ac dot uk>
diff
changeset
|
245 |
\end{minipage}
|
Christian Urban <christian dot urban at kcl dot ac dot uk>
diff
changeset
|
246 |
\end{center}
|
Christian Urban <christian dot urban at kcl dot ac dot uk>
diff
changeset
|
247 |
|
313
Christian Urban <christian dot urban at kcl dot ac dot uk>
diff
changeset
|
248 |
\noindent
|
Christian Urban <christian dot urban at kcl dot ac dot uk>
diff
changeset
|
249 |
Note that in this program the variable \pcode{i} is used
|
Christian Urban <christian dot urban at kcl dot ac dot uk>
diff
changeset
|
250 |
twice. You need to make a decision how it should be compiled?
|
390
Christian Urban <christian dot urban at kcl dot ac dot uk>
diff
changeset
|
251 |
Explain your decision and indicate what this program would
|
952
|
252 |
print out. Give your answer in the file \texttt{q3-answer.txt}.
|
202
Christian Urban <christian dot urban at kcl dot ac dot uk>
diff
changeset
|
253 |
|
920
|
254 |
\subsection*{Question 4}
|
|
255 |
|
943
|
256 |
Extend the lexer and parser to add a \textcolor{codepurple}{\pcode{break}} keyword. Modify
|
|
257 |
the compiler (including lexer and parser) such that when a \textcolor{codepurple}{\texttt{break}}-statement is encountered
|
920
|
258 |
the code should jump out of the ``enclosing'' for-loop, or in case it
|
|
259 |
is not inside a for-loop to the end of the program. For example the
|
|
260 |
program
|
|
261 |
|
|
262 |
\begin{center}
|
|
263 |
\begin{minipage}{12cm}
|
|
264 |
\begin{lstlisting}[language=While, numbers=none]
|
943
|
265 |
// should print 0 .. 10
|
920
|
266 |
for i := 0 upto 10 do {
|
|
267 |
write i;
|
|
268 |
write "\n"
|
|
269 |
};
|
910
|
270 |
|
943
|
271 |
// should print 0 .. 4
|
920
|
272 |
for i := 0 upto 10 do {
|
|
273 |
if i > 4 then break else skip;
|
|
274 |
write i;
|
|
275 |
write "\n"
|
|
276 |
};
|
910
|
277 |
|
920
|
278 |
write "Should print\n";
|
|
279 |
break;
|
|
280 |
write "Should not print\n"
|
|
281 |
\end{lstlisting}
|
|
282 |
\end{minipage}
|
|
283 |
\end{center}
|
|
284 |
|
|
285 |
\noindent
|
951
|
286 |
should print out 0 to 10 with the first for-loop, but only 0
|
920
|
287 |
to 4 in the second. Similarly it should print out \code{"Should print"},
|
|
288 |
but not \code{"Should not print"}. For this you need to add
|
|
289 |
a label to the end of every for-loop and also to the end of the
|
|
290 |
whole program just in case you need to jump to that label via a
|
952
|
291 |
\code{break}. The file you need to be able to process for this question
|
|
292 |
is called \texttt{break.while}.
|
920
|
293 |
|
910
|
294 |
|
204
Christian Urban <christian dot urban at kcl dot ac dot uk>
diff
changeset
|
295 |
\subsection*{Further Information}
|
Christian Urban <christian dot urban at kcl dot ac dot uk>
diff
changeset
|
296 |
|
390
Christian Urban <christian dot urban at kcl dot ac dot uk>
diff
changeset
|
297 |
The Java infrastructure unfortunately does not contain an
|
Christian Urban <christian dot urban at kcl dot ac dot uk>
diff
changeset
|
298 |
assembler out-of-the-box (therefore you need to download the
|
Christian Urban <christian dot urban at kcl dot ac dot uk>
diff
changeset
|
299 |
additional package Jasmin or Krakatau---see above). But it
|
Christian Urban <christian dot urban at kcl dot ac dot uk>
diff
changeset
|
300 |
does contain a disassembler, called \texttt{javap}. A
|
Christian Urban <christian dot urban at kcl dot ac dot uk>
diff
changeset
|
301 |
dissembler does the ``opposite'' of an assembler: it generates
|
Christian Urban <christian dot urban at kcl dot ac dot uk>
diff
changeset
|
302 |
readable assembler code from Java Byte Code. Have a look at
|
Christian Urban <christian dot urban at kcl dot ac dot uk>
diff
changeset
|
303 |
the following example: Compile using the usual Java compiler
|
Christian Urban <christian dot urban at kcl dot ac dot uk>
diff
changeset
|
304 |
the simple Hello World program below:
|
204
Christian Urban <christian dot urban at kcl dot ac dot uk>
diff
changeset
|
305 |
|
Christian Urban <christian dot urban at kcl dot ac dot uk>
diff
changeset
|
306 |
\begin{center}
|
390
Christian Urban <christian dot urban at kcl dot ac dot uk>
diff
changeset
|
307 |
\begin{minipage}{12cm}
|
313
Christian Urban <christian dot urban at kcl dot ac dot uk>
diff
changeset
|
308 |
\begin{lstlisting}[language=Java,numbers=none]
|
204
Christian Urban <christian dot urban at kcl dot ac dot uk>
diff
changeset
|
309 |
class HelloWorld {
|
Christian Urban <christian dot urban at kcl dot ac dot uk>
diff
changeset
|
310 |
public static void main(String[] args) {
|
Christian Urban <christian dot urban at kcl dot ac dot uk>
diff
changeset
|
311 |
System.out.println("Hello World!");
|
Christian Urban <christian dot urban at kcl dot ac dot uk>
diff
changeset
|
312 |
}
|
Christian Urban <christian dot urban at kcl dot ac dot uk>
diff
changeset
|
313 |
}
|
Christian Urban <christian dot urban at kcl dot ac dot uk>
diff
changeset
|
314 |
\end{lstlisting}
|
Christian Urban <christian dot urban at kcl dot ac dot uk>
diff
changeset
|
315 |
\end{minipage}
|
Christian Urban <christian dot urban at kcl dot ac dot uk>
diff
changeset
|
316 |
\end{center}
|
Christian Urban <christian dot urban at kcl dot ac dot uk>
diff
changeset
|
317 |
|
Christian Urban <christian dot urban at kcl dot ac dot uk>
diff
changeset
|
318 |
\noindent
|
Christian Urban <christian dot urban at kcl dot ac dot uk>
diff
changeset
|
319 |
You can use the command
|
Christian Urban <christian dot urban at kcl dot ac dot uk>
diff
changeset
|
320 |
|
Christian Urban <christian dot urban at kcl dot ac dot uk>
diff
changeset
|
321 |
\begin{center}
|
390
Christian Urban <christian dot urban at kcl dot ac dot uk>
diff
changeset
|
322 |
\begin{minipage}{12cm}
|
Christian Urban <christian dot urban at kcl dot ac dot uk>
diff
changeset
|
323 |
\begin{lstlisting}[language={},numbers=none]
|
951
|
324 |
javap -c HelloWorld
|
390
Christian Urban <christian dot urban at kcl dot ac dot uk>
diff
changeset
|
325 |
\end{lstlisting}
|
Christian Urban <christian dot urban at kcl dot ac dot uk>
diff
changeset
|
326 |
\end{minipage}
|
204
Christian Urban <christian dot urban at kcl dot ac dot uk>
diff
changeset
|
327 |
\end{center}
|
Christian Urban <christian dot urban at kcl dot ac dot uk>
diff
changeset
|
328 |
|
390
Christian Urban <christian dot urban at kcl dot ac dot uk>
diff
changeset
|
329 |
\noindent to see the assembler instructions of the Java Byte
|
Christian Urban <christian dot urban at kcl dot ac dot uk>
diff
changeset
|
330 |
Code that has been generated for this program. You can compare
|
313
Christian Urban <christian dot urban at kcl dot ac dot uk>
diff
changeset
|
331 |
this with the code generated for the Scala version of Hello
|
Christian Urban <christian dot urban at kcl dot ac dot uk>
diff
changeset
|
332 |
World.
|
204
Christian Urban <christian dot urban at kcl dot ac dot uk>
diff
changeset
|
333 |
|
Christian Urban <christian dot urban at kcl dot ac dot uk>
diff
changeset
|
334 |
\begin{center}
|
390
Christian Urban <christian dot urban at kcl dot ac dot uk>
diff
changeset
|
335 |
\begin{minipage}{12cm}
|
313
Christian Urban <christian dot urban at kcl dot ac dot uk>
diff
changeset
|
336 |
\begin{lstlisting}[language=Scala,numbers=none]
|
204
Christian Urban <christian dot urban at kcl dot ac dot uk>
diff
changeset
|
337 |
object HelloWorld {
|
951
|
338 |
def main(args: Array[String]) = {
|
204
Christian Urban <christian dot urban at kcl dot ac dot uk>
diff
changeset
|
339 |
println("Hello World!")
|
Christian Urban <christian dot urban at kcl dot ac dot uk>
diff
changeset
|
340 |
}
|
Christian Urban <christian dot urban at kcl dot ac dot uk>
diff
changeset
|
341 |
}
|
Christian Urban <christian dot urban at kcl dot ac dot uk>
diff
changeset
|
342 |
\end{lstlisting}
|
Christian Urban <christian dot urban at kcl dot ac dot uk>
diff
changeset
|
343 |
\end{minipage}
|
Christian Urban <christian dot urban at kcl dot ac dot uk>
diff
changeset
|
344 |
\end{center}
|
Christian Urban <christian dot urban at kcl dot ac dot uk>
diff
changeset
|
345 |
|
222
Christian Urban <christian dot urban at kcl dot ac dot uk>
diff
changeset
|
346 |
|
210
Christian Urban <christian dot urban at kcl dot ac dot uk>
diff
changeset
|
347 |
\subsection*{Library Functions}
|
Christian Urban <christian dot urban at kcl dot ac dot uk>
diff
changeset
|
348 |
|
313
Christian Urban <christian dot urban at kcl dot ac dot uk>
diff
changeset
|
349 |
You need to generate code for the commands \texttt{write} and
|
Christian Urban <christian dot urban at kcl dot ac dot uk>
diff
changeset
|
350 |
\texttt{read}. This will require the addition of some
|
Christian Urban <christian dot urban at kcl dot ac dot uk>
diff
changeset
|
351 |
``library'' functions to your generated code. The first
|
Christian Urban <christian dot urban at kcl dot ac dot uk>
diff
changeset
|
352 |
command even needs two versions, because you need to write out
|
Christian Urban <christian dot urban at kcl dot ac dot uk>
diff
changeset
|
353 |
an integer and string. The Java byte code will need two
|
Christian Urban <christian dot urban at kcl dot ac dot uk>
diff
changeset
|
354 |
separate functions for this. For writing out an integer, you
|
Christian Urban <christian dot urban at kcl dot ac dot uk>
diff
changeset
|
355 |
can use the assembler code
|
210
Christian Urban <christian dot urban at kcl dot ac dot uk>
diff
changeset
|
356 |
|
Christian Urban <christian dot urban at kcl dot ac dot uk>
diff
changeset
|
357 |
\begin{center}
|
Christian Urban <christian dot urban at kcl dot ac dot uk>
diff
changeset
|
358 |
\begin{minipage}{12cm}
|
313
Christian Urban <christian dot urban at kcl dot ac dot uk>
diff
changeset
|
359 |
\begin{lstlisting}[language=JVMIS, numbers=none]
|
210
Christian Urban <christian dot urban at kcl dot ac dot uk>
diff
changeset
|
360 |
.method public static write(I)V
|
859
|
361 |
.limit locals 1
|
|
362 |
.limit stack 2
|
|
363 |
getstatic java/lang/System/out Ljava/io/PrintStream;
|
|
364 |
iload 0
|
|
365 |
invokevirtual java/io/PrintStream/println(I)V
|
|
366 |
return
|
210
Christian Urban <christian dot urban at kcl dot ac dot uk>
diff
changeset
|
367 |
.end method
|
Christian Urban <christian dot urban at kcl dot ac dot uk>
diff
changeset
|
368 |
\end{lstlisting}
|
Christian Urban <christian dot urban at kcl dot ac dot uk>
diff
changeset
|
369 |
\end{minipage}
|
Christian Urban <christian dot urban at kcl dot ac dot uk>
diff
changeset
|
370 |
\end{center}
|
Christian Urban <christian dot urban at kcl dot ac dot uk>
diff
changeset
|
371 |
|
390
Christian Urban <christian dot urban at kcl dot ac dot uk>
diff
changeset
|
372 |
\noindent This function will invoke Java's \texttt{println}
|
Christian Urban <christian dot urban at kcl dot ac dot uk>
diff
changeset
|
373 |
function for integers. Then if you need to generate code for
|
Christian Urban <christian dot urban at kcl dot ac dot uk>
diff
changeset
|
374 |
\texttt{write x} where \texttt{x} is an integer variable, you
|
Christian Urban <christian dot urban at kcl dot ac dot uk>
diff
changeset
|
375 |
can generate
|
210
Christian Urban <christian dot urban at kcl dot ac dot uk>
diff
changeset
|
376 |
|
Christian Urban <christian dot urban at kcl dot ac dot uk>
diff
changeset
|
377 |
\begin{center}
|
390
Christian Urban <christian dot urban at kcl dot ac dot uk>
diff
changeset
|
378 |
\begin{minipage}{12cm}
|
313
Christian Urban <christian dot urban at kcl dot ac dot uk>
diff
changeset
|
379 |
\begin{lstlisting}[language=JVMIS, numbers=none]
|
210
Christian Urban <christian dot urban at kcl dot ac dot uk>
diff
changeset
|
380 |
iload n
|
Christian Urban <christian dot urban at kcl dot ac dot uk>
diff
changeset
|
381 |
invokestatic XXX/XXX/write(I)V
|
Christian Urban <christian dot urban at kcl dot ac dot uk>
diff
changeset
|
382 |
\end{lstlisting}
|
Christian Urban <christian dot urban at kcl dot ac dot uk>
diff
changeset
|
383 |
\end{minipage}
|
Christian Urban <christian dot urban at kcl dot ac dot uk>
diff
changeset
|
384 |
\end{center}
|
Christian Urban <christian dot urban at kcl dot ac dot uk>
diff
changeset
|
385 |
|
390
Christian Urban <christian dot urban at kcl dot ac dot uk>
diff
changeset
|
386 |
\noindent where \texttt{n} is the index where the value of the
|
Christian Urban <christian dot urban at kcl dot ac dot uk>
diff
changeset
|
387 |
variable \texttt{x} is stored. The \texttt{XXX/XXX} needs to
|
Christian Urban <christian dot urban at kcl dot ac dot uk>
diff
changeset
|
388 |
be replaced with the class name which you use to generate the
|
Christian Urban <christian dot urban at kcl dot ac dot uk>
diff
changeset
|
389 |
code (for example \texttt{fib/fib} in case of the Fibonacci
|
Christian Urban <christian dot urban at kcl dot ac dot uk>
diff
changeset
|
390 |
numbers).
|
210
Christian Urban <christian dot urban at kcl dot ac dot uk>
diff
changeset
|
391 |
|
390
Christian Urban <christian dot urban at kcl dot ac dot uk>
diff
changeset
|
392 |
Writing out a string is similar. The corresponding library
|
Christian Urban <christian dot urban at kcl dot ac dot uk>
diff
changeset
|
393 |
function uses strings instead of integers:
|
210
Christian Urban <christian dot urban at kcl dot ac dot uk>
diff
changeset
|
394 |
|
Christian Urban <christian dot urban at kcl dot ac dot uk>
diff
changeset
|
395 |
\begin{center}
|
Christian Urban <christian dot urban at kcl dot ac dot uk>
diff
changeset
|
396 |
\begin{minipage}{12cm}
|
313
Christian Urban <christian dot urban at kcl dot ac dot uk>
diff
changeset
|
397 |
\begin{lstlisting}[language=JVMIS, numbers=none]
|
210
Christian Urban <christian dot urban at kcl dot ac dot uk>
diff
changeset
|
398 |
.method public static writes(Ljava/lang/String;)V
|
Christian Urban <christian dot urban at kcl dot ac dot uk>
diff
changeset
|
399 |
.limit stack 2
|
390
Christian Urban <christian dot urban at kcl dot ac dot uk>
diff
changeset
|
400 |
.limit locals 1
|
210
Christian Urban <christian dot urban at kcl dot ac dot uk>
diff
changeset
|
401 |
getstatic java/lang/System/out Ljava/io/PrintStream;
|
Christian Urban <christian dot urban at kcl dot ac dot uk>
diff
changeset
|
402 |
aload 0
|
Christian Urban <christian dot urban at kcl dot ac dot uk>
diff
changeset
|
403 |
invokevirtual java/io/PrintStream/println(Ljava/lang/String;)V
|
Christian Urban <christian dot urban at kcl dot ac dot uk>
diff
changeset
|
404 |
return
|
Christian Urban <christian dot urban at kcl dot ac dot uk>
diff
changeset
|
405 |
.end method
|
Christian Urban <christian dot urban at kcl dot ac dot uk>
diff
changeset
|
406 |
\end{lstlisting}
|
Christian Urban <christian dot urban at kcl dot ac dot uk>
diff
changeset
|
407 |
\end{minipage}
|
Christian Urban <christian dot urban at kcl dot ac dot uk>
diff
changeset
|
408 |
\end{center}
|
Christian Urban <christian dot urban at kcl dot ac dot uk>
diff
changeset
|
409 |
|
390
Christian Urban <christian dot urban at kcl dot ac dot uk>
diff
changeset
|
410 |
\noindent The code that needs to be generated for \code{write
|
Christian Urban <christian dot urban at kcl dot ac dot uk>
diff
changeset
|
411 |
"some_string"} commands is
|
210
Christian Urban <christian dot urban at kcl dot ac dot uk>
diff
changeset
|
412 |
|
Christian Urban <christian dot urban at kcl dot ac dot uk>
diff
changeset
|
413 |
\begin{center}
|
390
Christian Urban <christian dot urban at kcl dot ac dot uk>
diff
changeset
|
414 |
\begin{minipage}{12cm}
|
313
Christian Urban <christian dot urban at kcl dot ac dot uk>
diff
changeset
|
415 |
\begin{lstlisting}[language=JVMIS,numbers=none]
|
210
Christian Urban <christian dot urban at kcl dot ac dot uk>
diff
changeset
|
416 |
ldc "some_string"
|
Christian Urban <christian dot urban at kcl dot ac dot uk>
diff
changeset
|
417 |
invokestatic XXX/XXX/writes(Ljava/lang/String;)V
|
Christian Urban <christian dot urban at kcl dot ac dot uk>
diff
changeset
|
418 |
\end{lstlisting}
|
Christian Urban <christian dot urban at kcl dot ac dot uk>
diff
changeset
|
419 |
\end{minipage}
|
Christian Urban <christian dot urban at kcl dot ac dot uk>
diff
changeset
|
420 |
\end{center}
|
Christian Urban <christian dot urban at kcl dot ac dot uk>
diff
changeset
|
421 |
|
390
Christian Urban <christian dot urban at kcl dot ac dot uk>
diff
changeset
|
422 |
\noindent Again you need to adjust the \texttt{XXX/XXX} part
|
Christian Urban <christian dot urban at kcl dot ac dot uk>
diff
changeset
|
423 |
in each call.
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Christian Urban <christian dot urban at kcl dot ac dot uk>
diff
changeset
|
424 |
|
390
Christian Urban <christian dot urban at kcl dot ac dot uk>
diff
changeset
|
425 |
The code for \texttt{read} is more complicated. The reason is
|
Christian Urban <christian dot urban at kcl dot ac dot uk>
diff
changeset
|
426 |
that inputting a string will need to be transformed into an
|
Christian Urban <christian dot urban at kcl dot ac dot uk>
diff
changeset
|
427 |
integer. The code in Figure~\ref{read} does this. It can be
|
Christian Urban <christian dot urban at kcl dot ac dot uk>
diff
changeset
|
428 |
called with
|
214
Christian Urban <christian dot urban at kcl dot ac dot uk>
diff
changeset
|
429 |
|
Christian Urban <christian dot urban at kcl dot ac dot uk>
diff
changeset
|
430 |
\begin{center}
|
390
Christian Urban <christian dot urban at kcl dot ac dot uk>
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changeset
|
431 |
\begin{minipage}{12cm}
|
313
Christian Urban <christian dot urban at kcl dot ac dot uk>
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changeset
|
432 |
\begin{lstlisting}[language=JVMIS,numbers=none]
|
214
Christian Urban <christian dot urban at kcl dot ac dot uk>
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changeset
|
433 |
invokestatic XXX/XXX/read()I
|
Christian Urban <christian dot urban at kcl dot ac dot uk>
diff
changeset
|
434 |
istore n
|
Christian Urban <christian dot urban at kcl dot ac dot uk>
diff
changeset
|
435 |
\end{lstlisting}
|
Christian Urban <christian dot urban at kcl dot ac dot uk>
diff
changeset
|
436 |
\end{minipage}
|
Christian Urban <christian dot urban at kcl dot ac dot uk>
diff
changeset
|
437 |
\end{center}
|
Christian Urban <christian dot urban at kcl dot ac dot uk>
diff
changeset
|
438 |
|
Christian Urban <christian dot urban at kcl dot ac dot uk>
diff
changeset
|
439 |
\noindent
|
951
|
440 |
where \texttt{n} is the index of the variable that requires an input.
|
|
441 |
%If you
|
|
442 |
%use Windows you need to take into account that a ``return'' is not just a newline,
|
|
443 |
%\code{'\\10'}, but \code{'\\13\\10'}. This means you need to change line~12 in
|
|
444 |
%Figure~\ref{read} to \pcode{ldc 13}.
|
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Christian Urban <christian dot urban at kcl dot ac dot uk>
diff
changeset
|
445 |
|
Christian Urban <christian dot urban at kcl dot ac dot uk>
diff
changeset
|
446 |
|
321
Christian Urban <christian dot urban at kcl dot ac dot uk>
diff
changeset
|
447 |
\begin{figure}[t]\small
|
540
|
448 |
\begin{lstlisting}[language=JVMIS,numbers=left]
|
214
Christian Urban <christian dot urban at kcl dot ac dot uk>
diff
changeset
|
449 |
.method public static read()I
|
859
|
450 |
.limit locals 10
|
|
451 |
.limit stack 10
|
214
Christian Urban <christian dot urban at kcl dot ac dot uk>
diff
changeset
|
452 |
|
859
|
453 |
ldc 0
|
|
454 |
istore 1 ; this will hold our final integer
|
214
Christian Urban <christian dot urban at kcl dot ac dot uk>
diff
changeset
|
455 |
Label1:
|
859
|
456 |
getstatic java/lang/System/in Ljava/io/InputStream;
|
|
457 |
invokevirtual java/io/InputStream/read()I
|
|
458 |
istore 2
|
|
459 |
iload 2
|
951
|
460 |
ldc 10 ; test for the newline delimiter for Unix
|
859
|
461 |
isub
|
951
|
462 |
ifeq Label2
|
|
463 |
iload 2
|
|
464 |
ldc 13 ; test for the carriage-return in Windows
|
|
465 |
isub
|
|
466 |
ifeq Label2
|
859
|
467 |
iload 2
|
|
468 |
ldc 32 ; the space delimiter
|
|
469 |
isub
|
|
470 |
ifeq Label2
|
|
471 |
iload 2
|
|
472 |
ldc 48 ; we have our digit in ASCII, have to subtract it from 48
|
|
473 |
isub
|
|
474 |
ldc 10
|
|
475 |
iload 1
|
|
476 |
imul
|
|
477 |
iadd
|
|
478 |
istore 1
|
|
479 |
goto Label1
|
214
Christian Urban <christian dot urban at kcl dot ac dot uk>
diff
changeset
|
480 |
Label2:
|
859
|
481 |
; when we come here we have our integer computed
|
|
482 |
; in local variable 1
|
|
483 |
iload 1
|
|
484 |
ireturn
|
214
Christian Urban <christian dot urban at kcl dot ac dot uk>
diff
changeset
|
485 |
.end method
|
Christian Urban <christian dot urban at kcl dot ac dot uk>
diff
changeset
|
486 |
\end{lstlisting}\normalsize
|
951
|
487 |
\caption{Assembler code for reading an integer from the console.
|
|
488 |
This code is portable for Unix and Windows (see Lines 11--18 for 2 separate
|
|
489 |
tests for the various end-of-line markers). Thanks to Harry
|
|
490 |
Dilnot to make it portable.\label{read}}
|
214
Christian Urban <christian dot urban at kcl dot ac dot uk>
diff
changeset
|
491 |
\end{figure}
|
Christian Urban <christian dot urban at kcl dot ac dot uk>
diff
changeset
|
492 |
|
200
Christian Urban <christian dot urban at kcl dot ac dot uk>
parents:
diff
changeset
|
493 |
\end{document}
|
Christian Urban <christian dot urban at kcl dot ac dot uk>
parents:
diff
changeset
|
494 |
|
Christian Urban <christian dot urban at kcl dot ac dot uk>
parents:
diff
changeset
|
495 |
%%% Local Variables:
|
Christian Urban <christian dot urban at kcl dot ac dot uk>
parents:
diff
changeset
|
496 |
%%% mode: latex
|
Christian Urban <christian dot urban at kcl dot ac dot uk>
parents:
diff
changeset
|
497 |
%%% TeX-master: t
|
Christian Urban <christian dot urban at kcl dot ac dot uk>
parents:
diff
changeset
|
498 |
%%% End:
|