Re: [stella] POLL

Subject: Re: [stella] POLL
From: emooney@xxxxxxxxxxxxxxxx (Erik Mooney)
Date: Wed, 05 Mar 1997 04:42:40 GMT
>It also helps to have a print reference of some kind for when you're
>confused on a certain point.
>
>Luckily, there's not much to the 6502.  Three registers and only a
>handful of opcodes that all pretty much work the same.
>
>And you have to understand both binary and hexadecimal.

</lurk>
FWIW, I've got a solid grounding in 80x86 assembly (I understand binary and
hex), and have done compact 80x86 assembly too (mainly coding a few BBS
adverts in <2k). As for the 2600, I understand the parts about cycle
counting, and that you're syncing to the horizontal scans and updating the
playfield graphics, sprite positions, etc each scanline (or each 2
scanlines to get more time for calculations), and I've even done that in
x86 assembler.. minimal cycle counting, but I've synced with the horizontal
rescan and updated stuff every scanline.  I also followed Nick's "How to
draw a Playfield" pretty well (thanks!)

I've also been trying to figure out how some other games draw their stuff..
some are pretty obvious, like Combat, Breakout, Pac-man (one sprite
recycled for the ghosts and one for Pac-man, playfield graphics for "dots"
and walls.. possibly ball graphics for the energizers and vitamins).
Asteroids (looks like playfield graphics for the rocks, at least the big
ones.. maybe a reused sprite for the small ones?), Defender (lots of sprite
reuse and flicker), Millipede (playfield for the "mushrooms", TONS of
sprite reuse), Missile Command (this one I'm not sure of - playfield
graphics for the missile trails and explosions?, multiple copies of one
sprite for the cities?), River Raid (tons of sprite reuse), Berzerk
(playfield for the playfield, reused sprites for robots, missile graphics
for missiles).

Hmm.. I knew I had a point here somewhere.. oh yeah.. Anyways, the missing
part here for me is a 6502 reference and development tools (like an
assembler).  I have no Supercharger, but should be able to test code on one
of the emulators.  Are there any good (free) references for the 6502, and
any 6502 assemblers that run on DOS-based systems?  Also, the contents of
the "vcs.h" referred to in "How to Draw a Playfield" would be pretty
helpful.  Any help appreciated.. thanks.

I'll worry about stuff like production, distribution method, pricing, and
so on when I actually make something that works =)
<lurk>

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