Project 2B - LMC Programming
DAT 2343 - Fall 2000
Synopsis
- Write LMC mnemonic instructions for a program, using the supplied pseudo-code.
- Assemble by hand your mnemonic instructions into LMC numeric codes.
- Enter your codes and test your program in the LMC simulator under Windows.
- Hand in an envelope containing a diskette and printout of your working program.
Program Description and Sample Input
Your program should read a pair of numbers (after all, the LMC can only input numbers!) and then calculate and print the sum of all the numbers between and including the two numbers. Inside the loop in the program, the program should count the number of times the program looped and print that after the sum.
For example, the input pair 003 009 would output 042 and 006. The input pair 009 003 would also output 042 and 006. (The order of the numbers should not matter.)Let's look at the pseudo-code that implements this program.
Pseudo-Code Algorithm
Use the following pseudo-code to develop your LMC mnemonic assembler program.
Initialize a result total to zero
Initialize a loop counter to zero
input a first number
input a second number
exchange numbers if first number is bigger than the second number
do {
add second number to the result total
subtract one from second number
add one to the loop counter
} while ( the second number is greater than first number )
add the first number to the result total
output the result total
output the loop counter
stop
Translate the given pseudo-code into LMC mnemonic instructions. Pay attention to the details of the algorithm and the placement of each statement.
Your translated code must be in the usual labels/mnemonics/operands/comments format. Do not optimize your code! Translate each pseudo-code statement separately.
Important Notes
 | Pick proper names for your variables. Do not use poor names such as "first", "second", "A", "B", "number", "num1", "num2", or "value" (etc.). Use good names that reflect the functions of the variables in the algorithm. |
| Variable names and labels must start with a letter and may not contain blanks (same as in most programming languages). |
| No numeric arguments/operands are allowed when writing LMC mnemonic instruction assembly language - write mnemonic instructions with labels only. (For example, always write "LDA SUM" not "LDA 23". |
| When writing mnemonic assembly language code using labels, ensure that all labels used have defined locations. |
| You can't use the same name for two different variables and/or labels. All names must be unique (same as in most programming languages). |
| Do not use the ORG pseudo-instruction. Code should begin at mailbox location zero. |
Assembly and Debugging
Hand-assemble your LMC mnemonic instructions into the equivalent LMC numeric codes. (Assign locations to all the instructions; build a label table; translate the mnemonics into LMC numeric codes.)
Download the "son of LMC" Simulator program (see below) that simulates the "Little Man Computer". This program should be run from Windows 95/98. Run the simulator and enter your numeric codes into the correct mailboxes. Run, test, and debug your program using the simulator.
When your program works correctly, use the simulator to save the numeric codes on a diskette, using the file name given below.
Be sure to resave your modified numeric codes if you make changes to the codes while in the simulator, and remember to modify your mnemonic instructions to reflect any such changes before you hand in your project. The mnemonic instructions you hand in must match the numeric codes used in the simulator and saved on disk!
Submit an envelope containing a diskette containing a text file of your saved LMC numeric codes and a text file of your mnemonic instructions. Also include one printed copy of the mnemonic instructions file on a sheet of paper. Follow the Hand In format given below.
LMC Simulator under Windows
The simulator comes in two versions. The basic version, available on Alan Pinck's site, is known to work reasonably under Windows 95/98. The enhanced version was enhanced by Algonquin student Christopher Hyne and permits editing and other features. I recommend you try the enhanced simulator first; if it misbehaves, tell me what went wrong and return to the basic simulator.
The Enhanced Simulator can read the data files saved by the Basic Simulator; but, the Basic Simulator can only read files saved in "old format". (You will be asked which format you want when you use the "save" feature of the Enhanced Simulator.) You may submit files on diskette in either format. Enhanced format is easier to read, since it is one mailbox per line.
Enhanced Simulator (FoSoLMC.EXE)
Download: FriendOfSonOfLMC.EXE
If you have Visual Basic 6.0 on your computer, you should only need the actual program executable, given above. If you don't have Visual Basic 6.0 or the Visual Basic Runtime Libraries on your computer you will need to download and install them using the (large!) Setup Kit available here.
The above links are local Algonquin copies of the original files kept on Christopher Hyne's F.O.S.O.L.M.C. site.
Basic Simulator (SonOfLMC.EXE)
Use this Basic Simulator if you can't get the Enhanced Simulator to work.
Download: SonOfLMC.EXE
The Basic Simulator doesn't have editing and other enhancements built in. It requires certain Dynamic Link Libraries which are commonly installed on many systems (all Algonquin College lab computers should have these files). Specifically, this program was created using Visual Basic version 4 and needs VB40032.DLL.
If your computer does not have any of the required files, you can download a .ZIP version of the entire package including all support files from:
The available files include: SonOfLMC.ZIP... the complete executable package (4Mb) Son_P1.ZIP, Son_P2.ZIP, Son_P3.ZIP, Son_P4.ZIP... all the same files as the above but broken up into 4 collections, each of which should fit on a 1.4Mb disk.
Hand In
Submit your Project in a labelled, unsealed, but closed envelope. (If you seal an envelope, it becomes useless as an envelope after I unseal it!)Create and include in the envelope a copy of a diskette containing two text-only files:
- File 1: A PROGRAM.TXT text file containing my Assignment Submission label information followed by the five-column (plus comments) code and mnemonic instructions of your LMC program.
- File 2: A P2CODES.LMC "save" text file from the LMC simulator containing the LMC numeric codes of your assembled program. I accept both Enhanced and Basic save formats. I will load this code into my own simulator and test it.
Print the PROGRAM.TXT from the diskette and include the printout in the envelope:
- Printout: Print a clear paper copy of your PROGRAM.TXT file for submission in the envelope along with your diskette.
Please keep master copies of the diskette and printout; don't hand in your only copy.
Text Files Only
For full marks:
| Follow my Assignment Submission Standards. Put labels on everything! |
| All the submission files on the diskette must be plain text only. Plain text is readable in Windows Notepad or DOS EDIT (or Unix/Linux vi). Check the format of your files before you submit them. Do not submit Word, WordPerfect, or HTML documents. |
| Use the exact file names given. The automated program I use to mark these assignments will not find misspelled files on your diskette. Do not place files in a subdirectory on the diskette. |
| Ensure that the document prints neatly - pay attention to margins, line length, and consistent indentation. Align the columns carefully. |
