christos wrote:Unless you rework each game like Anima did with the x68k and the Neo Geo games there is no way you can emulate it on a standard Falcon. Megadrive should be unlikely on a CT60 without supervidel either way. Genecyst the oldest emulator needed a pentium with 8MB of RAM to work so it is within the CT60 capabilities but, converting the graphics format should be what would stop it. Still you could use the DSP for sound emulation so you'd gain some cycles there.
Either way, it should make for some good exercise for someone with lots of free time and willingness to convert the 68k emulator from x86 assembly to 68060.
I looked up some information about the Mega Drive video. I'd say it's just within the capabilities of the 68030 if you had an insane programmer. The Mega Drive is actually chunky, but it's four bits per pixel with two pixels in a byte. You could do the conversion in two ways. You could have a lookup table of longwords, take a byte from Mega Drive and convert to 16 bit truecolour (two pixels). Fast conversion, but truecolour mode slows the Falcon down.
Second way is to run in 4 bit planar. There's a little trick you can do. The Mega Drive has a tiny separate VRAM, but it doesn't have a frame buffer. It builds its picture out of small tiles like the SNES and NES. The VRAM isn't memory mapped, I doubt a game will change the contents of VRAM very often. You do your chunky to planar conversion when the contents of VRAM is changed. You store a copy of the contents of VRAM already converted into planar mode. Then you can draw the screen from the pre-converted pixels very quickly with movem or blitter.
I don't know if you can get 50fps, you can probably make it fast enough to play. Of course you don't emulate the 68000, you just run the code directly. I doubt Mega Drive games do any sync tricks, no need to be cycle exact.