@ZbyniuR, post #240
@grikas, post #241
@grikas, post #239
@Gżegżółka, post #243
@grikas, post #244
@Gżegżółka, post #247
@grikas, post #248
I actually dug up all my old jaguar development hardware to give to these guys a year or two ago.
Unfortunately, it turned out that I had lost the C compiler that I had retargeted to the jaguar RISC engines, so DOOM was no longer buildable.
There is something noble about developing on a dead platform -- it is so completely for the joy of the development, without any commercial motivation.
The quick recap on the jaguar:
The memory, bus, blitter and video processor were 64 bits wide, but the processors (68k and two custom risc processors) were 32 bit.
The blitter could do basic texture mapping of horizontal and vertical spans, but because there wasn't any caching involved, every pixel caused two ram page misses and only used 1/4 of the 64 bit bus. Two 64 bit buffers would have easily trippled texture mapping performance. Unfortunate.
It could make better use of the 64 bit bus with Z buffered, shaded triangles, but that didn't make for compelling games.
It offered a usefull color space option that allowed you to do lighting effects based on a single channel, isntead of RGB.
The video compositing engine was the most innovative part of the console. All of the characters in Wolf3D were done with just the back end scalar instead of blitting. Still, the experience with the limitations and hard failure cases of that gave me good amunition to rail against microsoft's (thankfully aborted) talisman project.
The little risc engined were decent processors. I was surprised that they didn't use off the shelf designs, but they basically worked ok. They had some design hazards (write after write) that didn't get fixed, but the only thing truly wrong with them was that they had scratchpad memory instead of caches, and couldn't execute code from main memory. I had to chunk the DOOM renderer into nine sequentially loaded overlays to get it working (with hindsight, I would have done it differently in about three...).
The 68k was slow. This was the primary problem of the system. You options were either taking it easy, running everything on the 68k, and going slow, or sweating over lots of overlayed parallel asm chunks to make something go fast on the risc processors.
That is why playstation kicked so much ass for development -- it was programmed like a single serial processor with a single fast accelerator.
If the jaguar had dumped the 68k and offered a dynamic cache on the risc processors and had a tiny bit of buffering on the blitter, it could have put up a reasonable fight against sony.
Now the LYNX, on the other hand, was very much The Right Thing from a programming standpoint. A fast little processor (for its niche), a good color bitmapped display, and a general purpose blitter.
Price and form factor weighed too heavily against it.
John Carmack