Project 2: Assembly language

Assembly language is a very low-level representation of programs, having a direct translation to what the machine actually executes. (Basically, a compiler translates from a high-level language like C++ to assembly language, which the computer can then interpret quickly and easily when it runs the program.) Knowing how assembly language looks is important to programmers interested in writing very efficient code.

For the project, you will write two short programs in an assembly language called DLX.

1. Implement the Dynamic-Fibonacci algorithm on page 103 of this year's text using DLX.
2. Now, for a bigger challenge, implement the recursive Fibonacci algorithm on page 102 using DLX. (Don't use procedure calls; instead, just implement the recursion stack explicitly in your program. This isn't entirely easy.)

Resources for learning about DLX:

An excerpt from last year's textbook (PDF)

This is a very quick introduction to assembly language and DLX that I included in the textbook last year. You'll probably want to look over Section 12.1 of this year's textbook before you read this.

The DLX assembler

A compiled version this for SUN machines is at /afs/cs/user/cburch/www/pgss/work/self/dlxsim This is a Unix-based command-line system, but it's not necessary to know Unix well to use it. I recommend that you edit your program from your computer (using CodeWarrior's built-in editor, perhaps) and save it in your AFS home directory. In another window, keep an open telnet connection to a Sun system (like sun4.andrew) in another window and run the simulator in it. A TA can help you with this.

DLX simulator manual (PDF)

This describes the commands you can use for the DLX simulator. The most important commands to understand are load, go, and get.

My Prime-Test-All implementation

The DLX assembler allows you to use labels instead of memory addresses, substantially simplifying address calculation. The on-line implementation (a translation of the example from last year's textbook) demonstrates how this works.

A list of DLX instructions

In addition to the instructions mentioned here, I added a few to my simulator. You'll probably not find them useful, but I mention them for completeness.

mul, muli, mulu, mului	multiply two integer registers
divp, divpi, divpu, divpui	divide two integer registers
mod, modi, modu, modui	remainder on dividing two integer registers

Computer architecture: A quantitative approach, by Hennessy and Patterson

This book is the primary definition of DLX, on pages 96-108. Since defining the language isn't a major goal of the book, it is not a very complete or accessible definition, but it appears to be the best available. (The library should have some copies of this; Carl Burch also has one.)

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