Yabause 0.9.0 Released

[BlueCrab]

A new version of the multi-platform Sega Saturn emulator Yabause has been released today. As usual, this release contains binaries for Dreamcast, Linux, Mac OS X, and Windows. The main fixes involve emulation of VDP1 Lines and VDP2 Rotation Screens that apply to most of those ports listed above. Other than that, several ports had UI issues corrected or new UI features added.

Get it from here.

[RockinB]

I like to see yabause evolving. Why isn't there a port of yabause for XBox? I think it's a great opportunity to have an open source Saturn emu, with ports to modern consoles, we can keep Saturn in peoples minds. But why are there no console ports, other than Dreamcast port?

[BlueCrab]

The amin reason that there's not an Xbox version is that nobody has stepped up to do it. A secondary reason is that there is not a legal hombrew development kit that can actually access the 3d hardware in any useful way (OpenXDK doesn't support the 3d hardware the last time I checked). If the 3d hardware isn't used, Yabause would probably run slower than the Dreamcast port (software rendering takes a lot more work to do).

[Maturion]

[quote]OpenXDK doesn't support the 3d hardware the last time I checked[/url]

It does now. Check out pbKit!
I haven't used this library yet.

I couldn't test Yabause on my DC yet (I'm still wating for my new DC). So does Yabause-DC work fast? How fast does it emulate?

[PSmonkey]

The amin reason that there's not an Xbox version is that nobody has stepped up to do it. A secondary reason is that there is not a legal hombrew development kit that can actually access the 3d hardware in any useful way (OpenXDK doesn't support the 3d hardware the last time I checked). If the 3d hardware isn't used, Yabause would probably run slower than the Dreamcast port (software rendering takes a lot more work to do).

Does the dreamcast version even use any hw rendering? It seems to be based on the software rendering code (i looked over it 2 versions back because i was currious).

[BlueCrab]

I couldn't test Yabause on my DC yet (I'm still wating for my new DC). So does Yabause-DC work fast? How fast does it emulate?

Its pretty slow at the moment. Only 2-7 FPS or so.

Does the dreamcast version even use any hw rendering? It seems to be based on the software rendering code (i looked over it 2 versions back because i was currious).

The VDP1 emulation is done in hardware, as much as I could anyway. VDP2 is done in software, rendered to a texture, and blit to the screen by the hardware.

[RockinB]

Hardware accelerated emulation is very interesting and impresses me quite a lot. Vbt made it for his sms plus port to Saturn, I'd like to do it one day, too, maybe for the snes9x-port for Saturn.

Is it ever planned to make/use a dynarec cpu core in yabause? The interpreter is already so fast on pc, that I could even guess it's a dynarec. How much speedup do you think can be expected from a dynarec cpu core on Dreamcast? What are the main bottlenecks on Dreamcast?

Please keep the Dreamcast port updated, that would mean a lot to me.

[BlueCrab]

Is it ever planned to make/use a dynarec cpu core in yabause?

It is in my plans, but I don't have the time lately to do much coding at all, more or less something like that. As I get the time, I'll attempt to do it. It is high up on my list of stuff to do for Yabause. As a side note, there was one for the Linux version, but it was actually slower than the interpreter in most situations.

How much speedup do you think can be expected from a dynarec cpu core on Dreamcast?

A lot, to put it simply. Many instructions would be able to be emulated by a chain of one or two instructions, and that's a heck of a lot better than what GCC dumps out for some of the instructions in the interpreter core.

What are the main bottlenecks on Dreamcast?

If I had to guess, I'd say the top 4 bottlenecks (in no particular order) are:

• SH2 Core
• 68k Core
• SCSP Emulation (yes it is emulating it, just not outputting anything)
• VDP2 Emulation

Please keep the Dreamcast port updated, that would mean a lot to me.

I'm glad that everyone still believes in the project. It truly makes me feel like I'm doing something important by maintaining it.

[quzar]

One of the biggest problems I remember from the interrpeter (back from yabause-c) was that it deals with pointers to malloc'd sh contexts. On the DC it probably ends up doing silly stuff like having to read it in from memory on every instruction since the cache is $#@! and the cotexts are fairly large. Of course, emulating both procs without doing this could be quite challenging.

Anyways, the biggest thing that makes the SH interpreter so fast is the idle cycle detection. That thing is amazing.

I guess another question would be if you've given up on the idea of trying to have the DC run the saturn code (semi) natively. The way I understand it, to do this would probably require you to butcher KOS so that it doesn't get in your way, but what do I know anyways =P

[BlueCrab]

I guess another question would be if you've given up on the idea of trying to have the DC run the saturn code (semi) natively. The way I understand it, to do this would probably require you to butcher KOS so that it doesn't get in your way, but what do I know anyways =P

Basically, that's how a dynarec would sorta work for it. Optimally, I'd use the MMU to map all the memory out, and then I wouldn't have to deal with memory mapping either. It'd be a pain in the butt, but when I actually have the time, its something I certainly want to experiment with.