The Atari Jaguar console
The Atari Jaguar (AJ) was a console produced by Atari Corporation in 1993. Despite the common misconception that it was only listed as 64 bit for marketing purposes, the Atari Jaguar is IN FACT a 64 bit bussed console. It has a FULL WIDTH 64 bit read/write data bus, with two 64 bit graphics processors.
Emulation of the Atari Jaguar has been a hit or miss over these years, as its not sure if its great or not.
Technical Details[]
The blitter and the OPL are indeed full 64 bit bussed devices. This is where all the graphical work is done on the Jaguar and is the only part that needed to be 64 bits to justify Atari's claim. They read and write data to and from the bus at 64 bits and their very instructions are 64 bits wide. The RISC in the GPU die is only 32 bit wide internally and can read/write to the main 64 BIT BUS using the STOREP and LOADP instruction. The DSP is a 32 bit internal processor and a 16 bit external processor(which is more than enough for sound and inuput) due to the bad decision of using a 68000 as the system boot processor. The DSP follows the boot processor externally. Had they used a 68020, the DSP would have accessed the bus at 32 bits. The lackluster performance of the Atari Jaguar is NOT due to it's bitness but rather due to it's cheap design and its way overused, bus choking 68000 processor. This processor is only 32 bits internally and 16 bit externally and it ran at half the Jaguar system clock speed. All too many developers used this processor as a main processor when all it should have been used for is to bootstrap the system. The big chips in the Jaguar are more than capable of running with the 68000 halted after boot up. Another issue with the Jaguar design is its unified bus. Without careful coding, it was all too easy to choke system performance due to all 5 processors fighting over each other for bus time. Even though the two RISC processors had private memory, they were hardly large enough to make a difference. Each RISC should have had at least 64 kilobytes of private RAM, at very least externally and the 68000, with its own 64k of RAM would have made a LARGE difference. Instead it was like a cage match at a WWF event, fighting for bus face time. The developer tool kit was piss poor at best and only included a working assembler for the two RISC processors, the included C complier was a buggy unfinished pile of garbage that could not even properly compile if/then statments, nor could it handle the speacial case of running the GPU RISC out in main RAM properly. Many homebrewers came up with better ways of dealing with the shortcomings of the system via programming techniques such as GPU main ram workarounds, which allowed the RISC in the GPU to run in main without crashing, and many homebrew developer tool kits such at SMAC/SLN and Raptor made life much easier to develope apps for the black cat. The biggest problem of this console was Atari's carelessness at letting hardware bugs go without correcting them before release. In a nutshell, this system was not ready for market release and was essentially an unfinished buggy product, rushed out the door as a last ditch effort from Atari to remain in the hardware business.
Emulators[]
| Name | Operating System(s) | Latest version | AJ |
AJ-CD |
Recommended |
|---|---|---|---|---|---|
| MESS | Multi-platform | 0.150 | ✓ | ? | ✓ |
| Virtual Jaguar | Windows, Linux, OS X | Git | ✓ | ✗ | ✓ |
| Project Tempest | Windows | 0.95 | ✓ | ? | ✗ |
| Phoenix Project | Windows, Linux, Android | 2.8.JAG | ✓ | ✗ | ✓ |
- Project Tempest; This was the first ever working Atari Jaguar emulator. It emulates some games, but most have issues (bad/glitchy sound and/ or framerate). As it's name suggests it was primarily made for Tempest 2000, with other games as secondary goals. Project Tempest only supports two Jaguar CD games; Primal Rage and Baldies (the latter has sound distortion though). It haven't seen a update since 2004, so it's abandoned.
- Virtual Jaguar Is an open source emulator based on the original by the same name. It has excellent support and framerate. It is the most compatible jaguar emulator yet.
- Note; the builds for Virtual Jaguar from EmuCR doesn't seem to work, use the link given as "git" on this page and choose the most current version from there.