Overview
Welcome to the EmulAtar home page.
EmulAtar is (going to be) an Atari 2600 emulator for Linux. It was made
just for the hell of it by me, Phillip Powers. Right now, it is in very
early (Alpha? :) stage of development. So don't download this thinking
you're gonna be able to play River-Raid! I only get to work on this thing
about an hour a night, and it's usually LATE at night when I should be
sound asleep! This project was made purely as an educational experience
for myself. I have always been interested in the technical aspects of emulation
(as opposed to the piracy aspect) and have always been a fan of the Atari2600.
I have had an incredible surge of energy for coding lately, and am anticipating
a release rather soon :)
Status
The emulation has been progressing
nicely. I have become quite adept at disassembling ROMS and seeing where
bugs in the emulator are. There are quite a few games that are "viewable"
and "movable" and have great interaction. As to "playable" games, I'm not
quite sure. Tetris (demo) seems to work wonderfully. Pacman is great! Defender
is great! There are, of course, many others. However, until missile gfx,
ball gfx, and collision detection has been implemented I will not dubb
_ANY_ game "playable." Here's more...
Basically, there are three (3) main
points to any VCS emulator. (Technically)
These are:
-
6502 Emulation. (Main CPU)
-
6532 Emulation. (Switches/Timer/Ram)
-
TIA Emulation. (Gfx/Sound)
Number 1, the 6502 processor, has been
pretty well implemented. That's not to say it's 100% complete. Actually
6507 emulation would be more accurate in describing what is emulated. My
6502 core does not contain any support for interrupts, therefore not a
true 6502. There are some bugs in it, I know. For example, BCD subtraction
isn't working correctly. I'm not 100% sure on BCD addition, either. I think
that there could almost be a number 4 up there: Memory Emulation. However,
I think this ties in too much with the 6502 to give it its own category.
Number 2, the 6532, is pretty much
completely emulated. The timer has been implemented and I am pretty sure
it works correctly. It seems to on all the Atari demos I have gotten to
work thus far. IO ports have been partially emulated. Basically, there
is support for player0 joysticks and fire buttons. No support for player1
joystick or paddles have been implemented yet.
Number 3, the TIA, is a nastly little
chip! Emulating it is actually proving to be quite a task, since this is
where all the action for the Atari occurs. I mean, come on! MANUALLY drawing
out the frame for EVERY frame!! Playfield emulation is great. Player graphics
are pretty good. Missile and ball graphics are there. There are some issues
here, however. IE, Not all games work! :)
Contact
Please feel free to send any suggestions,
flames, marriage proposals,
improvements, patches, etc. to
THE
NAKEDMAN.
