Project 2 - LMC Programming
DAT 2343 - Fall 2000
Synopsis
- Write mnemonic LMC instructions for a program that will input two numbers
and calculate and print the value of the first number raised to the power of
the second number. (Follow the supplied pseudocode algorithm, below.)
- Assemble by hand your mnemonic instructions into LMC numeric codes.
- Enter your codes and test your program in the LMC simulator under
Windows. (See LMC Simulator, below.)
- Hand in a diskette and printout containing your working program.
(See Hand In, below.)
Algorithm Details
Your LMC assembler program should input two numbers and calculate and print
the value of the first number (the base number) raised to the power of the
second number (the exponent number). An algorithm is given, below.
For example, if the two input numbers were 005 then 004, your code should
output 625, which is 005 x 005 x 005 x 005, that is: 005 multiplied by itself
004 times. Note that, by definition, any value raised to the power of 000 is
equal to 001.
Use the two-argument Multiplication subroutine developed in class (available on
the Web as well) to perform the multiplication. You must handle the
multiplication by passing two arguments in a call to a multiplication
subroutine and returning the result.
Your mnemonic instructions must use only label-style references in the
address/operand field. Do not use any mailbox numbers as addresses - use
labels only. (Also, do not use the ORG pseudo-instruction. Code
should begin at mailbox location zero.)
You may assume that the final result will be no greater than 999; there is no
need to check for overflow or other error conditions when doing the
arithmetic.
Pseudo-Code
Use the following pseudo-code to develop your LMC mnemonic assembler
program. Your code will have a MAIN program and one SUBROUTINE:
/* First is the code for the MAIN program.
*/
Input the first number
Input the second number
Initialize the answer to one
While the second number is greater than zero
Call the Multiply subroutine to multiply the answer by
the first number, giving a new value for the answer
Decrement the second number by one
Endwhile
Display the value of the answer
Stop the program /* Second is the MULTIPLY SUBROUTINE given in the Web notes.
* This subroutine takes two arguments and returns the result
* of the multiplication in the calculator.
*/
Subroutine Multiply (to be copied from class and web notes)
Multiply the two input arguments ARG1 and ARG2
Return the result in calculator
Endsubroutine
Translate the given pseudo-code into one single program as LMC mnemonic
instructions. (You will copy the code for the Multiply subroutine from
the class notes or the Web page.)
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). |
| Make sure you set up the two arguments ARG1 and ARG2 to
the Multiply subroutine with the correct values before you call the
subroutine. Follow the examples used in class and in
the Web notes. |
| Do not alter the code or variable names of the Multiply
subroutine. You must use it as written. |
Debugging
Hand-assemble your mnemonic instructions into the equivalent LMC numeric
codes.
Download the "son of LMC" Simulator program (see below) that
simulates the "Little Man Computer" with a couple of additional
operations. 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 given file name (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!
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)
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 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:
Alan
Pinck Little Man Computer FTP site
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.
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)
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.
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 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. |
Problems?
As with all questions and comments on course content, please post any
problems to the course discussion news group.
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