SegaXtreme

Home	Forums	What's new	Resources

GEN Emulator on SS

Ratamahatta - Mar 7, 2002

< Prev

		IceDigger		Mar 12, 2002
			as far as I know, the PS Collection uses part of the roms (i.e. graphics), but doesn't actually emulate them.. kinda like the FF 4-6 on PSX.

		ExCyber		Mar 12, 2002
			Actually, I think FF4-6 on PSX are mostly emulated... I've ranted about this before in Eidolon's Tavern, but that's not important. The important thing is that it's rather likely that any emulation done on PSC was probably hacked up specifically for those games.

		slinga		Mar 12, 2002
			What about on Konami's MSX Museum Disk?

		ExCyber		Mar 13, 2002
			That's a lot of stuff to port, and I suspect that Saturn is powerful enough to do a basic MSX1 emulation. Hardly proof, but I'm leaning toward a generic (though probably not supporting most mappers and nothing above MSX1) emulator on this one...

		Fabrizo		Mar 13, 2002
			Would it be possible to incorperate the use of a 4meg ram cart for the saturn in an emus programing? I think that might help make the emu run at better speeds if it can be done.

ExCyber

Mar 13, 2002

	
	
		
		
			Would it be possible to incorperate the use of a 4meg ram cart for the saturn in an emus programing?

As long as the released docs are correct, yes.

	
	
		
		
			I think that might help make the emu run at better speeds if it can be done.

Why? CPU power is the primary bottleneck for a Saturn-hosted emulator. More memory would make it possible to support larger emulated games, though.

		Daniel Eriksson		Mar 13, 2002
			Also, there are many of those collections for Saturn: how about The Konami collections, Thunder Force Gold Pack, Salamander Deluxe Pack and Williams Arcade greatest hits. Do these also use that tecknique? It seems to be wideley used whatsoever. Lets not forget that there is a working (atleast it plays pong) Saturn emulator for Snes. Shure, Snes isn´t as fast as Genesis, but it does uses a 16 bit processor, and that is emulated. (i don´t know how fast it runs thought).

slinga

Mar 13, 2002

	
	
		
		
			Quote: from Daniel Eriksson on 5:12 pm on Mar. 13, 2002



 Lets not forget that there is a working (atleast it plays pong) Saturn emulator for Snes.

Really? That's news to me. I haven't heard of any attempt to emulate an Snes on a Saturn. BTW what would really kick ass is Gameboy Advance emu on saturn...*drools*....somebody that wasn't very feasible though. Oh well.

ExCyber

Mar 13, 2002

	
	
		
		
			I haven't heard of any attempt to emulate an Snes on a Saturn.

It's Takashi's project, called Stardust. More info can be found here....

	
	
		
		
			BTW what would really kick ass is Gameboy Advance emu on saturn...*drools*....somebody that wasn't very feasible though.

I don't know. I'm not familiar enough with dynarec coding to know how much sustained overhead they generally have (and how many calls to memory handlers can be feasibly eliminated), but if it's not too much I think it might be possible. An interpretive core is out of the question. Still, due to the RAM issue you'd probably be limited to running demos and a few early commercial games (with a 4MB RAM cart). In general, it doesn't sound like a very promising project to me.

		slinga		Apr 17, 2003
			If this statement is true: "Is it true that the Saturn's Audio processor is the same as Genesis's CPU, the Motorola 68000? Yes." (http://trivilite.tripod.com/trivilitesultimatesega...) I don't see why it would be impossible to have a full speed genesis emulator running on the saturn. In fact you wouldn't really be emulating all that much since I guess you could just use the sound cpu. Of course I don't know anything about emulator writing but seems interesting.

		AntiPasta		Apr 17, 2003
			I think it can be done - for instance, the TI-89 calculator which runs on a 10mhz 68000 CPU can actually emulate the ZX spectrum! Moreover, it does grayscale which has to be done entirely in software because the display is 1bpp too! Now, that's about 3 68000 cycles for one Z80 cycle plus the grayscale thing. Right, the two SH2s both run at 28mhz or something, which actually leaves about 4 cycles to do one 68k cycle. As the SH2 is pipelined and can do more opcodes in a the same number of cycles than the 68000, and, there are TWO Sh2s I believe 68000 emulation can be run at decent speed - now just because this SMS thing, which is written in C with SGL afaik, runs slow doesn't mean that with some hardcore optimization and proper workload distribution it can't be done. Of course, not all games would fit in the 2mb of RAM so a memory expansion module would need to be used for some games...

ExCyber

Apr 17, 2003

	
	
		
		
			I don't see why it would be impossible to have a full speed genesis emulator running on the saturn. In fact you wouldn't really be emulating all that much since I guess you could just use the sound cpu.

It's not that easy, unfortunately. The memory map on the SCSP 68K is much different from the Genesis memory map, and it has no MMU. I won't say it can't be done, but there's probably a Master's thesis in there somewhere.

	
	
		
		
			As the SH2 is pipelined and can do more opcodes in a the same number of cycles than the 68000, and, there are TWO Sh2s I believe 68000 emulation can be run at decent speed

It may, but probably not with a traditional interpreter. The Spectrum emulator you mentioned uses some interesting tricks to speed up interpretation that might be worth looking into, though at least one of them is Z80-specific. One also depends on self-modifying code, which could potentially slow things down a bit on SH-2 (since you need to invalidate the cache when changing instructions), but there's only one way to be sure whether or not it's a net benefit. As for using both SH-2s for 68K emulation, I believe this is only feasible with a recompiler/translator (i.e. have one SH-2 do the translation and the other SH-2 run the translated code). Otherwise you'd probably end up spending at least as much time making sure that the instructions execute in order as you could save by using both CPUs.

		AntiPasta		Apr 17, 2003
			well, I wasn't thinking to have them both execute 68k opcodes in parallel - just one running the instruction scheduler and controlling all the peripherals, and one doing ONLY mc68k emulation.

< Prev