Hi. I just discovered The Elements of Computing Systems a few weeks ago, and I'm having fun working through it on my own. It is a fantastic book. I stumbled across this forum when I got stuck on PC.hdl. I probably got enough hints from you to figure it out.
I wanted to make sure that everyone here knows about Udacity. If you haven't heard, it's a free online school started by Sebastian Thrun and Peter Norvig, following the free A.I. course they gave a few months ago. I'm really excited about the new batch of classes starting tomorrow. One of them is Programming Languages, which looks like it will fit very well with the language chapters of TECS.
David A. Hale