I think a P96 driver for Minimig-AGA makes sense for us users, and here's why. Minimig-AGA gives us AGA, so we can run AGA software. A P96 driver for AGA lets us also run P96 (and most CGX too I guess) software that doesn't have an AGA/ECS equivalent. And it does that with far less effort than adding in a second graphics core that is compatible with an existing P96 driver.
I was originally excited in this thread to find out how Yaqube accomplished P96 compatibility. Since then, it's become apparent that his path really is the most efficient one to get us there. Efficient in usage of his time, and efficient in usage of FPGA resources.
You'd only need to make it work the same as the original graphics card, so it would be a zorro device.
No, it was a PCI graphics chip with a PCI->Zorro bridge in between. A PCI chip has a PCI register map. I guess in theory you could leave out PCI and also leave out Zorro and attach such a reinvented graphics core direct to the native 680x0 Minimig bus, but it's still a lot of work, even if you didn't have to reverse it to start. Since we're inside an FPGA now, there's no PCI or Zorro forced upon us, but it's still a ton of work any which way.
Now, I am not against Zorro or PCI. I have a slower than glaciers progress project to do a Zorro bridge myself. But my only goal is Zorro<->Wishbone. I suppose a Minimig<->Wishbone bridge would be required for Minimig, but AoOCS already has Wishbone, so I can start playing there and then see if someone ended up making Wishbone for Minimig by then. I've taken to thinking that desigining a couple bus bridges would be a good way for me to learn Verilog. (Or VHDL if we're taken there, as I think MikeJ has suggested may happen, or will we end up with both Verilog and VHDL ports tracking each other?)
I guess if you could use the AAA register layout then it would be cool, I like old hardware and adding new registers just seems wrong.
Who needs to add new registers? We can do things to improve AGA compared to Commodore's motherboard/chip design without changing registers. Make the bus faster clock. Maybe make the bus wider. Faster memory access. Things that can make Minimig's AGA implementation perform well enough for P96 driver to now be practical for the first time. We're not talking incompatible, we're talking fast enough to be worth doing a P96 driver. And Making an AGA clone that performs well is something that makes sense as a big goal for Minimig-AGA.
Now, if we can go beyond AGA (Natami anyone?) without breaking software, then why not? Add some true 24bit modes, and new registers or new bits previously undefined in old registers to support that. Add alpha blending. Add chunky modes. Add YUV and other color modes if you like. It doesn't have to break old stuff, and if you put your fingers over the new changes to the updated register map, you won't know the difference. If you want to get real crazy, add some hardware OpenGL.
And if someone wants to have fun putting an alien graphics chip in there too, that is OK to play around with. But for motivation of wanting to do that. Motivation to avoid writing a P96 driver is an odd one that I don't think makes sense. but do it for fun, for education, to show off, whatever. You're probably going to have to write a P96 driver anyway. (I think it would be fun to play with opengraphics and other free graphics cores, but I'd start on AmigaOnes and true Classics that have real PCI and real Zorro slots, rather than try to add PCI and Zorro into Minimig first. PCI, Zorro, and those other additional gfx cores will all take up space, and I don't have a huge FPGA chip)
