Lab 0

• to give you a feeling for the final product of all the labs,
• to introduce you to some of the system tools that you will need later, and
• to quickly review some of the CIS 210 concepts.

The Duck Machine

• Go to http://www.cs.uoregon.edu/~sabry/duckMachine/index.html

• I assume that most of you have already navigated javadoc documentation but just in case ... use the javadoc documentation to find out the instruction set of the Duck Machine.

• The implementation of the machine consists of a large number of class files organized in four packages. Java provides a tool "jar" that archives an entire system into one file for easy transmission.

  Download the jar file to your machine and save it as a file called "duckMachine.jar". Change your CLASSPATH setting so that it includes this jar file. Using the jar file, you can immediately run the machine by typing:

  java duckMachine.Window
  

• A green and yellow window should have popped. The leftmost panel shows the state of the processor including the contents of each register and the values of the flags of the arithmetic and logic unit. The middle panel is the input/output port of the machine. The right panel displays the contents of the memory. Collectively the top three panels display the machine itself. The bottom panel is a miniature "operating system shell" to interact with the machine. There are four buttons which correspond to common machine commands and a window to display status and error messages.

• Initially the machine components are initialized to some arbitrary values. To use the machine, one writes a program in the "machine language", loads it in memory, and runs it. There are a few test programs that you can download from http://www.cs.uoregon.edu/~sabry/duckMachine/index.html

  Download the program "test4.o" and save it on your machine. Load that program in the memory of the duck machine by clicking on "Load Object File" and selecting "test4.o" when the file dialog window pops.

  Initially the machine is waiting at the first instruction "CLEAR 9". The "Step" command executes one instruction at a time, the "Run" command executes the entire program until it encounters a "HALT" instruction.

• If you have a computer at home, download the "duckMachine.jar" file. You might also find it useful to un-archive the system. The command:

  jar xf duckMachine.jar
  

  will extracts all the files from the archive. It will create a directory "duckMachine" in the current directory and several subdirectories (one for each package).

CIS 210 Review

public int length ()
public int indexOf (int ch)
public int lastIndexOf (int ch)
public String replace (char oldChar, char newChar)
public String trim ()
public String toString ()