Update $10/18/24$: refer to the demonstration in lecture; instructions below updated for clarification

Hello All,

For this assignment, you will be debugging the the following example:

Copy machine language $($binary$)$ program from Figure $5\mathrm{.}14/5\mathrm{.}15$ to your LC$-3$ simulator

Figure $5\mathrm{.}14$ is a flowchart of the "algorithm for adding integers using a sentinel for loop control". Figure $5\mathrm{.}15$ is the program you will running and testing.

Add improved comments for each line, overall program, and other important info $($like what each register does$)$; if you are unsure of something, write down your questions as comments in the code $($or a separate doc$)$

Create object file & load the simulator

Set values for $12$ integers as follows $($starting @ x$3100)$: $5,10,15,20,25,20,15,10,5,1,2,3$

For the first iteration, since everything is $"0",$ also set $x310C$ to the value specified in the course book

For following iterations, since we randomize the machine, let's just leave $x310C$ alone

Verify the initial & final values $($update code comments if things become more clear$)$

Do whatever other tasks you need to in order to verify that the program works as intended.

Choose "randomize machine" and run the program again $($go to step $4)$; do this several times $($up to $5$ times$).$ It should fail one of the times.

If it doesn't fail any of the times, consider what could happen to make the program fail

Write down any remaining questions concerns about this program $($either in comments in code or as a separate doc$)$

While it seemed to be working from first simulation & possibly even after randomizing, eventually it stopped working as expected after more randomize attempts.

You are allowed to work on this assignment in groups $(3$ students max$),$ please put all your names on your submission. Group submissions are enabled on Gradescope $($please email if there are issues submitting as a group$).$ If working on this assignment as a group, everyone on the team is responsible for making sure the submission is submitted correctly.

NOTE: each time your randomize the machine, be sure to set the $12$ integer values from $3100$ to $310B.$

Homework Template $($can submit handwritten version, make sure to include all questions in template$)$:

Small Assignment $8$ Template $($docx darr $)($pdf darr $)$

Be sure to verify$/$identify your solution location for each question in your submission

A template is available here

Recreate the problem & take a screenshot showing the simulator $($showing the incorrect register values$).$ Note: this may take several randomizations.

Step through the code $($using "step over"$)$ and identify the point where this problem occurs $($show the screenshot showing the incorrect register values$).$ List the line number that is being executed $(x3$dots $)$ as well as any other important information $($maybe the value located @ x$31\_).$

Briefly describe what the problem is and why it only happens sometimes.

Propose a fix$/$modification that will guarantee that we will get the expected result regardless of how many times we randomize the machine.Figure $5\mathrm{.}14$ An algorithm for adding integers using a sentinel for loop control.

R x$3100$

R

R M$[$R$1]$

BRn x$3008$

R R$3+$R$4$

R R$1+1$

R M$[$R$1]$

BRnzp x$3003$

Figure $5\mathrm{.}15$ A program that implements the algorithm of Figure $5\mathrm{.}14.$