Refactoring Firmware

At the behest of Steve Yegge, I began reading the book, Refactoring, by Martin Fowler. Click the previous link and read what he has to say about it and see if you aren't intrigued. That essay, and the fact that my manager had the book collecting dust on his bookshelf, really made me want to read this book.

I finally started reading it this weekend, and even though I'm only 52 pages into it (well, I've taken some excursion into other parts of it, so I've read more like 100 pages), I completely agree with Steve. This is a good book. The writing is direct, concise, unapologetic, and still somehow very friendly. It introduces new vocabulary (new to me at least) seamlessly. There are extensive code examples (yes, you have to read code, Martin doesn't apologize for that either), but the code is fairly simple and you get to witness it becoming simpler before your eyes.

Here are a couple salient quotes to whet your appetite for this book:

Any fool can write code that a computer can understand. Good programmers write code that humans can understand. (p. 15)
You may be concerned about performance in this case. As with other performance issues, let it slide for the moment. Nine times out of ten, it won't matter. (p. 121)

Some of things he does to clean up code totally made me stop and ask the same question as Steve, "Is this guy insane, or merely an idiot?" Actually, for me it was more like, "Sure this looks good for your desktop software application code, but does any of this apply to firmware?" The more I think about it, the more I think it can apply in a lot of places in our firmware. We have a lot of code that isn't exactly human readable, and I'm pretty sure it doesn't have to be that way. A lot of the refactorings in this book are things we all do here and there anyway.

I have a lot more of this to read, and I need to try some of it out on my code. This probably isn't the last you'll hear about it from me.

Comments

Post a Comment

Popular posts from this blog

SystemVerilog Fork Disable "Gotchas"

This is a long post with a lot of SystemVerilog code. The purpose of this entry is to hopefully save you from beating your head against the wall trying to figure out some of the subtleties of SystemVerilog processes (basically, threads). Subtleties like these are commonly referred to in the industry as "Gotchas" which makes them sound so playful and fun, but they really aren't either. I encourage you to run these examples with your simulator (if you have access to one) so that a) you can see the results first hand and better internalize what's going on, and b) you can tell me in the comments if this code works fine for you and I'll know I should go complain to my simulator vendor. OK, I'll start with a warm-up that everyone who writes any Verilog or SystemVerilog at all should be aware of, tasks are static by default. If you do this: module top; task do_stuff ( int wait_time); #wait_time $display ( "waited %0d, then did stuff" , wa
Read more

'git revert' Is Not Equivalent To 'svn revert'

I just learned that if you have some changes in your working tree that you want to get rid of, you don't type 'git revert' like you might guess. No, that's what cvs, subversion, mercurial, and bazaar (to name a few) use revert to mean, but not git. With git, revert is used to undo actual commits. Thankfully, you can undo your revert with another 'git revert', I just learned. So let me repeat to be clear, if you have changes to your working files that you want to abandon, DO NOT do this: git revert HEAD That will undo your last commit. Do this instead: git reset --hard HEAD I'm glad I have that straightened out now. I'm wondering if /etc was really a good place for me to start out playing with git. UPDATE: Nearly two years later and I'm still getting comments on this. I'm glad I've been able to help people out this way. The discussion in the comments is good, and one thing I'd like to point out is that I now always use
Read more

Git Rebase Explained

Image
Introduction Rebase is a helpful git command that can be used to turn a branchy two-headed version history into an easy to follow linear one. A linear history is much easier for a human eye to follow and a human brain to understand. Rebase is a very safe command to use, despite some fear that people have about it. This post should explain how rebase works and clear up any misunderstandings about it. Rebase Basics The short summary of rebase is that it cuts commits out of the git history and reconnects them somewhere else. Let's say the common scenario comes up: you commit a change to the main branch of a repository, you then run  git fetch , and in come a couple changes that other people made on the main branch. If your commit is version 46f and the others that just came in on the fetch are versions ef9 and 4a2, your version history might look like this: The main branch now has two heads, 46f and 4a2. You can run  git rebase  to disconnect your commit from version d88 and connect i
Read more