This summer, I'm participating in Google's Summer of Code, attached to the NetBSD project and working on fixing certain misfeatures of the software RAID driver — more details on which later.
Various other SoCers have declared their intention of keeping a weblog on their work; and, since I'm not entirely unfamiliar with the concept, I thought I might do that as well. And this blog, being created for me to do Serious Technical Blogging (and then left to gather dust when I stopped being bothered with writing for it), and hosted by Google no less, seems like the best place.
Well. I briefly considered “blogging” by hand-writing an RSS file and giving out that URL — why, some web browsers even format RSS nicely when you browse to it — but then came to my senses. I also considered making a separate blog (as BlogSpot has a nice interface/ontology for that), but didn't really see the point. And, hey, tags; they're what Web 2.0 is all about, except when it's not, or something.
Showing posts with label meta. Show all posts
Showing posts with label meta. Show all posts
2009-05-21
2007-10-07
What's in a name?
Because somebody's going to wonder: rlwinm is a PowerPC machine instruction, the mnemonic standing for “Rotate Left Word Immediate then aNd with Mask”.
The mask in question isn't fully general, of course — this is RISC, so it wouldn't fit — but it can be any contiguous non-empty range of 1 bits, which can wrap around the beginning/end of the word, or not. Thus, things like left and right (logical) shifts, clearing the low or high N bits, and extracting a bitfield from a word are all just special cases of rlwinm.
In other words, it's a fairly elegant generalization of a bunch of related operations which are often considered as separate, and some of which usually require multiple instructions.
(It's also not a terribly common username, and perhaps more importantly it's six characters long.)
Ironically, I haven't really done any assembly or machine-language stuff on PowerPC, whereas I have on x86.
I might eventually decide in something different for the Blog Title, but the domain name will definitely stay.
The mask in question isn't fully general, of course — this is RISC, so it wouldn't fit — but it can be any contiguous non-empty range of 1 bits, which can wrap around the beginning/end of the word, or not. Thus, things like left and right (logical) shifts, clearing the low or high N bits, and extracting a bitfield from a word are all just special cases of rlwinm.
In other words, it's a fairly elegant generalization of a bunch of related operations which are often considered as separate, and some of which usually require multiple instructions.
(It's also not a terribly common username, and perhaps more importantly it's six characters long.)
Ironically, I haven't really done any assembly or machine-language stuff on PowerPC, whereas I have on x86.
I might eventually decide in something different for the Blog Title, but the domain name will definitely stay.
2007-10-06
Hello, World!
So I've finally gotten around to setting up a Serious Technical Blog, like I've been meaning to do for a while now.
(I do have another weblog-like object, but that's more of a personal thing, for people I know to keep track of my life and so on, and other arbitrary acts of self-indulgence, and much of it would probably bore other people at best. Notice how I'm not linking to it here.)
Basically, I felt like a place for just the computery stuff, formatted for more public consumption, might be a good thing to have. This, hopefully, will be that.
(I do have another weblog-like object, but that's more of a personal thing, for people I know to keep track of my life and so on, and other arbitrary acts of self-indulgence, and much of it would probably bore other people at best. Notice how I'm not linking to it here.)
Basically, I felt like a place for just the computery stuff, formatted for more public consumption, might be a good thing to have. This, hopefully, will be that.
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