Projects

[ Chris Fallin ]

• my undergrad research codebase -- facial recognition, specifically, automatic fiducial point selection for Elastic Bunch Graph Matching. This served as the basis of my undergrad honors thesis, which is currently in draft form and will be posted here when completed. The codebase is about 3500 lines of ANSI C and is likely not too useful as a whole but may contain very useful pieces: data structures, K-means clustering, Gabor wavelets and convolution, image I/O, and the like.
• comparch, a pipelined CPU in Verilog, dynamic translation firmware for a custom ISA implementing a stack-based machine on RISC hardware, and some system-level tools (simulators, assemblers) from the Computer Architecture two-semester sequence at ND in 2007-2008. I'm including only my contributions to the group projects (though these are large, functional pieces). Mostly a curiosity, though the pipelined core might prove useful to someone.
• digilight, a microcontroller-based low voltage halogen lighting system controlled via DMX (in practice, using a USB adapter).
• speck, the small, portable, efficiently-coded kernel: a hobby in later middle and high school. Mostly useless except as a toy. It runs on bare Intel hardware.
• cflat, an implementation of the C-Flat language as specified in the Compilers class at Notre Dame in fall 2008. It is a very basic compiler, comprised of a flex-based scanner/lexer, a bison-based parser, very simple resolver and typechecker stages, and a nearly-braindead code generator. However, it works well, and I wrote most of the backend in a few hours at a coffeeshop (long live Lula's). Maybe this will be useful to someone.
• ubergame, a simple "game framework" (if it may be called that) that provides an OpenGL and Newtonian physics framework to a Lua (scripting language) environment. This was my final project in CSE 20212, Fundamentals of Computing II, in spring 2007. The point was not to develop a nifty game but to demonstrate the use of SWIG interface/wrapper generation and cross-language programming together with the capabilities of rapid prototyping provided by a dynamic scripting language. The included demo script sets up a few spheres, one of which the user can move, and provides for gravity and collision detection.
• pong (browse Verilog source), an implementation of the classic game of Pong in hardware for a Digilent FPGA board with a Xilinx Spartan3E FPGA. It displays to a VGA monitor and takes input from a PS/2 keyboard. The game logic for Pong is remarkably simple -- maintain ball and paddle coordinates, detect collisions, flip velocity on bounce -- and the real challenge was in getting the VGA timing right. I created this as a final project in an independent study in place of CSE 20221, Logic Design, over summer 2007.
• cfallinfs (browse source tree), a very (VERY) simple filesystem that runs as an userspace process on Linux, providing services through FUSE. Developed as the last project in CSE 30341, Operating Systems, in spring 2008. The filesystem is a linked-list allocation table design inspired by FAT that does not support subdirectories.
• sudoku solver (and tutorial-style writeup), a little toy in Python that took me a few hours. Circa junior year of high school (2005). It's a CGI script with a fairly primitive online interface; the source is linked. I use a simple recursive backtracking algorithm that alternates between reduction (finding the sets of possible values for each unknown cell with given knowns) and recursion. In practice, solves most puzzles instantaneously. The writeup was written as part of a mini-project for my high school math teacher, but I think it stands alone as a nice piece on the intuition and philosophy behind recursion.
• libcif, a collection of high-quality, well-tested data structures and basic routines in pure ANSI C. I use these as the basis of several codebases, most notably my research codebase. Yet Another C Data Structures Library, but this one is mine.
• pwtk, the Python web toolkit. This was my attempt at a continuation-based web application development before I knew about continuations. My intuition told me that the traditional GUI model could work a lot better for web apps than managing state manually; turns out a lot of other people had done this before me, and better. This is a fairly compact implementation of the idea that serializes a Python object hierarchy into a MySQL table on every request (yikes!). Hey, I was young (15) and clueless...
• my .emacs file. I thank several Emacs devotees at Cypress for making me a lifelong addict.
• STS, the Speech Tournament System. I wrote this in middle school (summer 2002) for my school's regional speech tournament: its most interesting component is a full room-scheduling algorithm for contestants that handles multiple constraints (such as minimizing the number of contestants in the room who have seen each other in prior rounds). The web interface is clunky and the whole thing is a mess of Perl that requires ActivePerl's ASP plugin and Microsoft Access (not my choice!), but it is a curiosity.
• Some corporate software bits that are actually pretty nifty, but that you can't see (nor can I, anymore!).
• A bunch of abandonware and toy projects. I'll spare you.