EECE $3435$ Lab $01$: DOS Debug

A$.$ Objectives: to get familiar with the debug program and use the debug commands to examine registers and memory contents.

B$.$ Resources

Online resources

Textbook

C$.$ Lab Preparation

Read online guide or textbook to understand the debug commands used in the assignment.

Start the Debug Application.

Search "dos" for the DOSBox application;

Start the DOSBox application;

Execute "mount c c:ldebug";

Execute $"$c:$"$;

Execute "debug".

Note that in the lab report you will be required to show the results you obtained in your experiments. You thus need to take screenshots of your work.

D$.$ The Lab

You will practice some commands useful in debug, such as the dump, enter, and fill commands.

First, execute the following command to fill the memory with some data:

$-$f $0$ ffff ac cb f$54$e $658$d $238$f e$9$

Execute the command $r$ to examine the contents of registers.

You can change the value of a register by doing the following.

$r$ IP

IP $0100$

Now you can enter a new value for the IP register after the prompt.

$2.$ Display and modify memory contents.

Use the command $d$ to dump $($display$)$ the memory contents from the data segment.