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Amiga Format CD 24
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Amiga Format AFCD24 (Feb 1998, Issue 108).iso
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emulation
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v2600
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v2600.readme
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Amiga Virtual 2600 (v2600), An Atari 2600 Emulator
==================================================
Amiga version 0.82. This is BETA software. Please report any bugs.
DESCRIPTION
===========
Amiga Virtual 2600 is an emulation of the Atari 2600 video game system,
otherwise known as the Atari VCS, or Video Computer System. It can take
cartridge ROMs as .bin binary images (2K or 4K), Commodore .prg format
files, Activision Action Pack .bin files, and the new .c26 Common 2600 file
format files. It uses regular Amiga joysticks, and can use the mouse to
emulate paddles. Many existing Atari 2600 cartridges can be used with this
emulator. Even sound is supported, more or less...
REQUIREMENTS
============
Any fast Amiga, 020 or better, OS 3.0 or better.
Fast RAM recommended.
The faster the Amiga, the better.
Atari 2600 ROMs
USAGE
=====
Double-click on the v2600 icon to bring up the window. The Command Line
Interface has been removed. Too bad, eh? ;^)
Load ROM
Click on the "Load ROM" button to bring up a file requester. It will only
display files that are valid with v2600. When you select a ROM, the
filename and path will be shown in the box next to the "Load ROM" button.
You can just type in the name of a ROM you want to load in this box if you
don't care to use the file requester. Be careful what you load, since
there is no way to thoroughly check that you are using a real Atari ROM.
Loading other files will most likely crash your computer.
Refresh Rate
This will set how often the screen will be updated. For example, if you
set the Refresh Rate to 2, it will only refresh every-other-frame. This
can speed up the graphics rendering, but can also cause some games to look
pretty bad.
System Type
This will allow you to emulate either a PAL or NTSC Atari.
Left Controller
Right Controller
Paddle Control
This allows you to select what type of controller the left and right
players will use. If you select "Joystick", then a standard Amiga joystick
may be used. In case you didn't already know, Amiga joysticks are
compatible with Atari joysticks, so you can use the original Atari
joysticks for a really authentic (not to mention uncomfortable) experience.
The "Left Controller", which is used by "Player 1" in most games, uses the
joystick port (Port 1) on your Amiga. To use the "Right Controller", you
must remove your mouse from the mouse port (Port 0), and replace it with a
joystick. If you want to play a paddle game, you can change to "Paddle".
The Amiga mouse is used to emulate an Atari paddle. Real Atari paddles are
not supported at this time. If you set the "Paddle Control" to "Use Mouse
X", then you can move the mouse left and right (along the X-axis) to
emulate a paddle. If you change the "Paddle Control" to "Use Mouse Y",
then you can move the mouse up and down (along the Y-axis) to emulate a
paddle. Atari racing paddles and keyboard controllers are not supported at
this time.
Bank Switching
The Atari could only address about 6k from a cartridge ROM, so for games
requiring more memory, special hardware is used to "switch banks" of ROM
memory. Since this is done with hardware, emulating this can be tricky,
because there is no way to determine if a ROM requires this. It was up to
the game manufacturer to decide what type of bank switching hardware they
wanted to use. Thankfully there were a few companies that stuck with a
standard chip. The bank switching schemes emulated are Atari 8k, for most
8k Atari-manufactured ROMs, Atari 16k for most 16k Atari-manufactured ROMs,
Parker 8k for most 8k Parker-Brothers-manufactured ROMs, CBS for most
CBS-manufactured ROMs, and Atari Super Chip for Atari-manufactured ROMs
that use it. If the ROM you want to play is 6k or less, you can most
likely choose NONE for no banking, since it's not necessary for small ROMs.
It's a guessing game for other ROMs, though. Unfortunately, large
Activision ROMs are not yet supported. Currently, bank switching is fairly
unstable.
Video Output
This allows you to select the video output mode of the emulator.
"Workbench Screen" opens a window on the Workbench. The more colors your
Workbench can display, the better. "Custom Screen" opens a separate screen
for output. Both modes now use the WritePixelArray8() chunky-to-planar
routine. The custom c2p routines have been removed. This is for
compatibility reasons.
Sound Output
If you check this box, Atari sound will be emulated. This will slow down
the emulator considerably, so only use it if you have a really beefy
machine. Only pure sounds are supported. White noise, which is used in
explosions and other sound effects, is not emulated. This will make some
games sound bad. Sorry.
Start
Press the "Start" button to play the selected ROM. If you haven't selected
a ROM, the "Start" button will be "greyed-out", and won't function.
KEYBOARD CONTROL
================
For the sake of faster emulation and cleaner code, keyboard emulation of
the joystick has been removed. It will only be added if there is a big
demand for it.
CONSOLE SWITCHES
================
The Atari 2600 has several switches on the console which perform various
functions. The keyboard equivalents are:
F1 or R Reset
F2 or S Select
F3 or B Color/BW
F4 Left Player Amateur (B on some Ataris)
F5 Left Player Pro (A on some Ataris)
F6 Right Player Amateur (B on some Ataris)
F7 Right Player Pro (A on some Ataris)
ESC or F10 Quit
COPY POLICY
===========
The original Virtual 2600 is copyright 1995/96 Alex Hornby.
Amiga Virtual 2600 is copyright 1998 Matthew Stroup.
Virtual 2600 is free software distributed under the terms of the GNU
General Public License. This means that the source code needs to be
available. To cut down on archive size, I will make the source available
on my web page in a separate archive.
AUTHORS
=======
Amiga Virtual 2600:
Matthew Stroup
stroupm@jps.net
http://www.jps.net/stroupm/v2600.htm
When I saw that the Virtual 2600 code was available to be ported, I thought
it would be a challenging project. Unfortunately, it runs about 4 fps on
my 50MHz 68030. Most of the speed problems stem from the fact that Virtual
2600 was intended to run on PC hardware. A great deal of time is spent
emulating PC hardware, not an Atari 2600. Both my code and Alex Hornby's
original code are in beta stages. Later versions will hopefully be faster.
Amiga v2600 was compiled using SAS/C 6.57. All source for the Amiga
version is available on my web page, as per the GNU public license. To get
the original source code, or source code for other platforms, check the
Virtual 2600 home page.
Original Virtual 2600:
Alex Hornby
ahornby@zetnet.co.uk
http://www.users.zetnet.co.uk/ahornby/v2600.html
The original Virtual 2600 is the result of Alex Hornby's 3rd year
university project. His aim is to preserve old computer games that would
otherwise be lost to the world.
IMPORTANT NOTES
===============
Please don't e-mail me asking for ROMs, because I won't give them to you.
Anyone can find them by using a web search tool. I highly recommend only
getting the ROMs that you actually own. Doing otherwise can be copyright
infringement, although most of the copyrights for Atari 2600 software have
expired long ago. I have included a freeware game, OkieDokie, with the
permission of Bob Colbert and Retroware.
If you have any comments, suggestions, or bug reports, please send me
e-mail at stroupm@jps.net. I'll try to get back to you as soon as
possible. I no longer receive e-mail at stroupm@inreach.com or
stroupm@csus.edu.
TROUBLESHOOTING
===============
If a game doesn't seem to be working, it's probably because you selected
the wrong banking type. It is possible that your memory is getting
trashed, and v2600 may freeze up, requiring a reset. This is apparently
caused by faulty bank switching, which has been noted by the original
author. I have not, however, had any Enforcer hits. It would be a good
idea to reset your Amiga after using v2600, though, and don't do anything
important in the background. You've been warned! ;^)
Some games, such as Activision's Pitfall II, had custom hardware in the
cartridge, which makes emulation impossible. Although many games work,
there are quite a few that won't. Your best bet is to just experiment.
Have fun!
THINGS TO COME (MAYBE)
======================
* Support for real Atari paddles.
* Support (real or emulated) for Atari racing controllers.
* Support (real or emulated) for Atari keyboard controllers.
* Faster graphics. Kill chunky-to-planar altogether if possible.
* Improve sound emulation.
* Eliminate hardware banging for compatibility with future Amigas.