Subject: Re: [stella] VCS 101 (was: Linux makewav 4.1 text file) From: "B. Watson" <atari@xxxxxxxxxxxxxx> Date: Sun, 19 Aug 2001 18:44:03 -0400 (EDT) |
On Sun, 19 Aug 2001, Eckhard Stolberg wrote: > > I'm a brand-new list subscriber, it's good to meet you all. > > Welcome to the wonderfull world of classic console programming. ;-) > And a bizarre world it is, compared to the Atari 800 programming I used to do when I was a kid... Most of the games I wrote then were in BASIC with little assembly helper routines, and the one thing they all had in common was that I never finished any of them :) > > Then you'll now discover one of the key points in VCS programming: > cycle counting. Your code to display the player probably takes longer > than the VCS needs to get to the 40th pixel in the scanline. When your > change to the graphics register happens, the VCS is already past that > point, so that the change will only take effect in the next scanline. > You'll have to restructure your code in such a way that the write > access to the graphics register will happen during the horizontal > blank period. > Yes, I'm learning all about cycle counting... looks like I'm just trying to do too much in one scanline. > > Of course you can use the assembler that you like best. However, > since most of us are most familar with DASM sysntax, you'll probably > get more responses to your questions, if you post your code in that > format too. And since you probably haven't build up a large code base > in ca65 yet, and since you also haven't chosen ca65 for any special > reason, it might still be possible to switch assemblers without too > many problems. That's basically the conclusion I came to... the syntaxes (syntaces? syntaux?) aren't all that different anyway, ca65 uses .byte instead of just byte, etc., and requires a : after a label... and lets me use ASL A as a synonym for ASL... and is less picky about whitespace. But they're both nicer than MAC/65, which is what I learned on (actually, I once wrote some scripts to let me run MAC/65 under Atari800 in text mode directly from the Unix command line.. I'd write my code using vi, then type `make' and the Makefile would create a floppy image with the code on it, run MAC/65 within Atari800, then extract the binary... but I digress.) Anyway I've got the code assembling properly under dasm now, so that's what I'll stick with from now on. When posting code, which is better: include it inline in the message or as an attachment? (or both?).. more people would be likely to actually read it if I paste it into the message, but if they actually want to assemble & run it, it'd be better to have as an attachment, I'd think. But what I actually will do, is follow existing customs of this list, as soon as somebody lets me know what they are :) Later, B. --- If a trainstation is the place where trains stop, what is a workstation? - Archives (includes files) at http://www.biglist.com/lists/stella/archives/ Unsub & more at http://www.biglist.com/lists/stella/
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