Re: [stella] Lord of the Rings optimizations

Subject: Re: [stella] Lord of the Rings optimizations
From: "B. Watson" <urchlay@xxxxxxxxxxxxxxxx>
Date: Mon, 17 Dec 2001 13:53:34 -0500 (EST)
On Mon, 17 Dec 2001, Thomas Jentzsch wrote:

> Hi,
> now, this is something for the hard core coders! (like me :-)
> While disassembling LOTR I found an interesting way of coding.


> So this is another (rather complicated) way for something like:
>    ldy     #value
>    jsr     Subroutine
> But it saves 3 bytes with each call! And the overhead is only 8 bytes,
> so after only 3 subroutine calls (LOTR has about 20) you are winning
> ROM space! Cool, isn't it?

How horribly abstruse... but, I'm going to count my subroutine calls in
Poker Squares and see if I can free up some ROM by er, borrowing this
technique. The 8 bytes of overhead aren't even really an issue, since I
have a few small chunks of empty ROM at the end of various data tables
(where the table is <256 bytes, and the next table must start on a page
boundary for timing reasons)...

but this may not be worth it, since I don't have any subroutines that
take a parameter in a register, so I won't be saving the 2 bytes for
the LDY #blah, and I think I only have maybe 3 JSR's in all the code. So
I'd only save 3 bytes or so... maybe I won't bother after all. Still,
it's an interesting technique.

Out of curiosity, has anyone spent more than 5 minutes playing LoTR? I
couldn't quite figure out what I was supposed to be doing there...


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