Atari 800 Emulator

[Agalia Valcin]

TheAtari 2600 Video Computer System (VCS), introduced in 1977,was the most popular home video game system of the early 1980's. Now you can enjoy all of your favorite Atari 2600 games on your PCthanks to Stella!

Stella is a multi-platform Atari 2600 VCS emulator released underthe GNU General Public License (GPL). Stella was originally developedfor Linux by Bradford W. Mott,and is currently maintained by Stephen Anthony.Since its original release several people have joined thedevelopment team to port Stella to other operating systems such asAcornOS, AmigaOS, DOS, FreeBSD, IRIX, Linux, OS/2, MacOS, Unix, andWindows. The development team is working hard to perfect the emulatorand we hope you enjoy our effort.

I had access to a number of 8-bit computers in my childhood, but my most favorite was the Atari 800, a 1.79MHz 6502-based computer with color graphics and a disk drive, and which as the predecessor to the Amiga, another favorite of mine. Over a decade later, I was struck by both nostalgia and ambition and started to write a new 8-bit Atari emulator from scratch. This is the result.

At this point, I've learned a lot more about the Atari and Altirra now emulates more than I ever had or did years ago, but I still work on it periodically. It also serves as a modularity test for the VirtualDub code base, from which Altirra shares some components. If you are struck by nostalgia too or have a desire to do some Atari development, perhaps it might be useful to you, too.

Note: Neither the author nor the software on this page is affiliated with Atari, and there is no code or software from Atari included in the downloads. All trademarks belong to their respective owners.

Altirra is designed with emulation quality in mind, sometimes over speed and polish. It's designed as a system emulator and debugger instead of a games machine, so there is some setup involved. There is a README file in the archive, but here are some quick tips:

First: Software. you need some actual 8-bit Atari (not Atari ST!) software to run. If you don't have any, it'll be a pretty boring experience. I can't give this to you for various reasons, but there are freely available demos, and if you have converted your Atari software to disk images for other emulators, those will work too. Specifically, disk images are supported in ATR, DCM, ATX, and PRO formats; some simple cartridge types are also supported, and you can directly load Atari executables as well (.obx/.xex).

Second: kernel ROMs. Altirra has an internal kernel that can be used to run Atari software, and thus you can run demos, games, and productivity software without needing any Atari ROM images. However, this kernel is reimplemented from scratch, and has some compatibility problems with software that depends on undocumented entry points or behavior. Therefore, you may want to consider hooking up real kernel ROM images, which will greatly increase Altirra's software compatibility. I'm afraid I can't offer these for download, but if you have downloaded ROM images from your Atari, Altirra uses the same format and filenames as most other popular Atari 8-bit system emulators.

Third: compatibility. Altirra is designed to emulate the actual Atari hardware as closely as possible. Its compatibility has been increasing over time, and at this point it should run most software correctly. However, there can still be problems, some of which may be emulation bugs, and some of which are related to hardware emulation settings. Tips:

Starting with 3.10, both x86/x64 and ARM64 versions are provided. Almost all computers should use the x86/x64 package. The ARM64 package is a native ARM64 build for systems running Windows 10 on ARM on a Snapdragon 835 or higher and will run faster on those systems.

Version 4.x binaries (local download):

Altirra 4.21: [4.21 (x86/x64)] [4.21 (ARM64)]

Altirra 4.20: [4.20 (x86/x64)] [4.20 (ARM64)]

Altirra 4.10: [4.10 (x86/x64)] [4.10 (ARM64)]

Altirra 4.01: [4.01 (x86/x64)] [4.01 (ARM64)]

Altirra 4.00: [4.00 (x86/x64)] [4.00 (ARM64)]

Version 3.x binaries (local download):

Altirra 3.91: [3.91 (x86/x64)] [3.91 (ARM64)]

Altirra 3.90: [3.90 (x86/x64)] [3.90 (ARM64)]

Altirra 3.20: [3.20 (x86/x64)] [3.20 (ARM64)]

Altirra 3.10: [3.10 (x86/x64)] [3.10 (ARM64)]

Altirra 3.00: [3.00 (x86/x64)]

Version 2.x binaries (local download): [2.90] [2.81] [2.80] [2.71] [2.70] [2.60] [2.50] [2.40] [2.30] [2.20] [2.10] [2.00]

Version 1.x binaries (local download): [1.9] [1.8] [1.7] [1.6] [1.5] [1.4] [1.3] [1.2]

Altirra 4.21 source code (local download)

Altirra 4.20 source code (local download)

Altirra 4.10 source code (local download)

Altirra 4.01 source code (local download)

Altirra 4.00 source code (local download)

Version 3.x source code (local download): [3.91] [3.90] [3.20] [3.10] [3.00]

Version 2.x source code (local download): [2.90] [2.81] [2.80] [2.71] [2.70] [2.60] [2.50] [2.40] [2.30] [2.20] [2.10] [2.00]

Version 1.x source code (local download): [1.9] [1.8] [1.7] [1.6] [1.5] [1.4] [1.3] [1.2]

Acid800 is a test suite designed to stress 8-bit Atari emulators. It tests a wide variety of program-visible hardware behaviors and reports any deviations from actual hardware behavior, such as missing features or incorrect timing. Acid800 can be run either as a full suite or as standalone tests, with symbols and source included. Also included are the Acid5200 test suite for the 5200 SuperSystem and the AcidSAP suite for SAP players.

On where it's going... I'll improve the emulation where possible, especially with regards to custom controllers. I'll also backport over any key improvements from MAME, though I'm not expecting any big ones that will improve the 7800 experience.

Thanks for replying. I understand that messing with the UI isn't really of much interest to you. Especially as, coding-wise, I'm sure it's pretty dull and when your time is limited you want to have fun in what you're creating.

I am just getting a bunch of errors Your video card does not fully support non power of two. If you click OK, I get another error saying textures It will just keep giving these errors forever until I force-quite from tash manager Windows 7 32 bit., with a g33/31 integrated Intel graphics chip.

It does not show up in the MAME menu. The aforementioned "mame.ini" file is not modified within the emulator. It typically resides in the same folder as the "a7800.exe" file, and can be opened and modified utilizing a simple application such as Notepad.

1. Double click A7800.exe.

2. Choose a console (Double click with mouse pointer or highlight with arrow keys and press 'Enter'), either NTSC or PAL, and the console temperature: Cold, Hot, or Warm. System temperature impacts the color palette.

3. Select a console configuration (Double click with mouse pointer or highlight with arrow keys and press 'Enter'): Standard Console, High Score Cartridge, XBoarD Expansion, XM Expansion Module.

What screen(s) are you seeing prior to attempting the "Selecting a ROM" section of the post? Was the "Starting an Atari 7800 console system", listed before it, performed entirely?

1. A7800 has been downloaded and files unzipped to a clean folder. BIOS file(s) were also downloaded and placed in a "bios" sub-folder. The folder should appear similar to the following capture:

5. Pressing 'Tab' at this point - where we now pick up at the "Selecting A ROM" instructions - will bring up a list of options, the topmost being "Load ROM File". The bottom option is "Return to Machine":

***If "Tab" is being pressed at the list of console screens above, and that is where "it highlights the "exit" button at the bottom" is experienced, then the issue is a console has not being started.

By utilizing the merged BIOS file from archive.org [Linked to previously under "Quick and easy portable install for Windows:], all that is required for every 7800 system and configuration to work, is placing the "bios" folder which contains a merged "a7800.zip" BIOS ROM set, as a subfolder under where the A7800 emulator was installed.

For those maintaining separate BIOS file archives, they may have both a "a7800.zip" file and a "a7800p.zip" file, among others; however, that is unnecessary when "Atari7800_mergedbios.zip" is leveraged.

A7800 emulator supports both zipped or unzipped BIOS file sets. Zipped is recommended (And illustrated above), as it is easier to manage and less steps to accomplish the same goal. If one chooses to unzip the "a7800.zip" BIOS file archive, the individual files should be stored inside a "a7800" subfolder within the "bios" folder.

3a8082e126