Performance critical loops

[LordSloth]

ATI Mobility Radeon HD 5870, which in this particular case uses 3 GB RAM.

But you're right, there isn't any performance hit from the units with lines off. Since it happens with just a caps worth of mark one units, it'd probably drop my FPS to the single digits if it was on for just the AI too. I've got a decent enough feel for the appearance of the symbol of a booster unit, so I just presume from that point on that things are boosted, anyways.

[keith.lamothe]

I think for sufficiently awkward and big divisors, you will eventually hit a point where a division algorithm will take less cycles than their equivalent bunch of shifts and additions.

But for many small cases, yea they can be expressed as a nice small sum of bit shifts.

Yea, I've only ever used them for when I was literally multiplying or dividing by a power of 2, and only when handling non-negative integers.  With the parasite thing I wound up doing the *48 with the sum of two shifts.  That's significantly less efficient than finding a way to do it in one shift, but as I said about that particular part of code it wasn't nearly as common-case as the areas where we really have to prune mul and div instructions.

In theory, the compiler should be able to optimize something like "x = x * 2" to "x = x << 1" but in practice it has to be careful about the sign of x (and the signedness of x's type), and if I'm using a variable that happens to store 2 (and I happen to know it only stores powers of 2, like our image side lengths), the compiler simply can't assume that.  Etc.

[Nalgas]

ATI Mobility Radeon HD 5870, which in this particular case uses 3 GB RAM.

Wow, really?  It's not nearly as smooth as on my desktop, but I haven't noticed that big of a hit on the sad excuse for a GPU that the GeForce 9400M in my MacBook is.  Really large fights get kind of choppy at times, not surprisingly, but I haven't had obvious/significant problems jump out at me with just individual ship types like munitions/armor boosters, like having those as my starting bonus ship type didn't seem any worse for performance than cutlasses or whatever.