CSE 2312 - Assignments - Assignment 7

The assignment will be graded out of 100 points. Submit a file called answers.xxx (where you replace xxx with whatever extension is appropriate, depending on the file format you use), that contains contains answers for all tasks. Acceptable file formats are plain text, Word document, OpenOffice document, and PDF. Put your name and UTA ID on the first line of the document.

Submit your answers.xxx file to Blackboard before the deadline. You will be able to revise your answers until the deadline with no penalty.

IMPORTANT: By submitting your answers, you are certifying that you have followed the UTA standards of academic integrity, and that these answers have been exclusively your own work. All students enrolled in this course are expected to adhere to the UT Arlington Honor Code:

I pledge, on my honor, to uphold UT Arlington's tradition of academic integrity, a tradition that values hard work and honest effort in the pursuit of academic excellence. I promise that I will submit only work that I personally create or contribute to group collaborations, and I will appropriately reference any work from other sources. I will follow the highest standards of integrity and uphold the spirit of the Honor Code.

Task 1 (10 points)

Design an expanding opcode scheme to allow all the following to be encoded in a 32-bit instruction:

• 15 instructions with two 12-bit addresses and one 4-bit register number.
• 650 instructions with one 12-bit address and one 4-bit register number.
• 80 instructions with no addresses or registers.

Task 2 (10 points)

A certain machine has 16-bit instructions and 6-bit addresses. Some instructions have one address and others have two. If there are N two-address instructions, what is the maximum number of one-address instructions?

Task 3 (10 points)

(This is Problem 5 from Chapter 5 of the textbook).

Is it possible to design an expanding opcode scheme to allow the following to be encoded in a 12-bit instruction? A register address takes 3 bits to specify.

• 4 instructions with three registers.
• 255 instructions with one register.
• 16 instructions with zero registers.

Task 4 (10 points)

Consider the machine whose instruction formats are given in Fig. 5-24. What is the maximum possible number of registers that that machine can have? Assume that DEST, SRC1, and SRC2 have enough bits to refer to any existing register.

Task 5 (10 points)

One of your friends has just come bursting into your room at 3 AM, out of breath, to tell you about his brilliant new idea: an instruction with two opcodes. Should you send your friend off to the patent office or back to the drawing board? In other words, is your friend's idea useful or useless? Justify your answer

Task 6 (50 points)

This task is to introduce you to the Quick Emulator (QEMU) and ARM assembly programming. The task is to take a screenshot of a running QEMU example, then include this screenshot as a picture in your answers.xxx document. Your name must be visible on the screenshot (type it somewhere visibly if your username does not display). An example screenshot is shown below. If your name is not visible, you will not receive credit. If the output of the program is not visible, you will not receive credit.

QEMU Installation and Execution Instructions

Install Virtual Box (free) from this link: http://www.oracle.com/technetwork/server-storage/virtualbox/downloads/index.html.

Step 2. Download and installation images for 32-bit Ubuntu.

Download an ISO for 32-bit Ubuntu for free from here: http://www.ubuntu.com/download/desktop.

1. In the "choose your flavor" menu choose 32-bit.
2. Click on the icon labeled Ubuntu 12.04 LTS.
3. The next page will "offer" you an opportunity to donate. To skip , scroll down to the end of the page and click "not now, take me to the download".
4. At that point you computer will start downloading a 731-MB file called ubuntu-12.04.4-desktop-i386.iso. When it finishes downloading, move that file to a place that you will remember (for example, your desktop). We will be referring to this file as the Ubuntu installation image.

Step 3. Create a virtual 32-bit Ubuntu machine in Virtual Box.

1. Start Virtual Box.
2. On the top left you will see a button labeled "New". Click on that button.
3. Here you will create the Ubuntu virtual machine. Put in whatever name you want, specify "Linux" for the type and Ubuntu (32-bit) for the version.
4. Select the defaults for the next few choices:
   • 512MB as the memory size.
   • Select "Create a virtual hard drive".
   • Select "VDI (VirtualBox Disk Image).
   • Select "Dynamically allocated" in the next menu.
   • Select 8.0GB for the size of the virtual hard drive.

After completing the previous step, you should now see some machine information displayed on the screen, and on the left you should see text that says "Powered Off".

1. On the top menu, click on Machine->Start.
2. You will be asked to select a startup disk. There should be a menu that says "Empty". To the right of the menu there should be a little yellow and green icon. Click on that.
3. A file menu opens. Navigate to the place where you stored the Ubuntu installation image (the file called ubuntu-12.04.4-desktop-i386.iso), and select that file.
4. Click on the "Start" button.
5. After perhaps a minute, you will have the choice to either "Try Ubuntu" or "Install Ubuntu". Select "Install Ubuntu".
6. In the next screen, select "Download updates while installing", and click on "Continue".
7. Select the default options for the next few choices, and click "Install Now" when given the choice.
8. Select whatever you want for location, select English for the keyboard layout.
9. Enter your name when asked (this will be important as it will show up on the screenshot you submit).
10. Choose whatever you want for computer name, username, password.
11. You need to wait for a few minutes, while the system initializes. Restart the computer when prompted.

Step 5. Install Guest additions.

Guest additions is an add-on that needs to be installed so that you are able to copy and paste between your actual computer and the virtual machine. To install it, follow these steps:

1. On the virtual machine window, go to the top menu, and select Machine->Settings->General.
2. Select the Advanced tab.
3. In the "Shared Clipboard" menu, select "bidirectional".
4. From your host machine (i.e., your actual computer, not the virtual machine), download this file: http://download.virtualbox.org/virtualbox/4.3.8/VBoxGuestAdditions_4.3.8.iso. Save this file in a convenient place, such as your desktop.
5. From your virtual machine, go to Devices->choose a virtual CD/DVD this file, and select the ISO file you just downloaded.
6. Follow the installation instructions that you see on the screen.
7. Restart the virtual machine when done.

Step 6. Start a terminal.

From the buttons on the left side of the screen, select the top one, that is called "Dash home". That button is a white circle (with some shapes in it) in brownish background.

Type "terminal" in the search box. Double-click on the terminal icon that comes up.

Once you have a terminal window open, execute the following commands from the command line. Be careful about line breaks.

Step 7. Install the QEMU system.

Execute this on the command line:

sudo apt-get install qemu qemu-system qemu-user qemu-utils

We need a special version of GCC since we are not compiling for an x86/x86-64 architecture. Execute these commands:

wget https://launchpad.net/gcc-arm-embedded/4.7/4.7-2013-q3-update/+download/gcc-arm-none-eabi-4_7-2013q3-20130916-linux.tar.bz2

tar xjvf gcc-arm-none-eabi-4_7-2013q3-20130916-linux.tar.bz2

sudo mv gcc-arm-none-eabi-4_7-2013q3 /opt/ARM

echo "PATH=$PATH:/opt/ARM/bin" >> /home/"$(whoami)"/.bashrc

source /home/"$(whoami)"/.bashrc

arm-none-eabi-gcc --version

Execute these commands:

wget http://vlm1.uta.edu/~athitsos/courses/cse2312_spring2014/assignments/assignment7/hw07_package.zip

unzip hw07_package.zip

cd hw07_package

make

Step 10. Execute QEMU on the test application.

Execute this command:

qemu-system-arm -s -M versatilepb -daemonize -m 128M -d in_asm,cpu,exec -kernel hw07.bin

The following is an example screenshot of what you should submit for this task. Note that the name is visible on the upper right and the QEMU output window is displaying the sample application's output (printing 0 through 7 repeatedly).

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