The awesome speed of MAME....

Post by **mahlemiut** » Sun Apr 04, 2004 10:54 pm

Yeah. 6GHz PCs better start appearing real soon. That or a dynarec R3000 CPU core. If that would help much.

Guess I'll be using Zinc to actually play the game still.

Post by **mahlemiut** » Sun May 16, 2004 8:42 pm

Some more examples

Buttermaker · Post by **Buttermaker** » Sun May 16, 2004 8:50 pm

Why don't you bitch on mame.net? :D

Post by **mahlemiut** » Sun May 16, 2004 9:36 pm

Because I know smf will eventually do a dynarec R3000 CPU core (although I get the feeling the possible 50% speed gain mentioned might be pushing it a bit) and probably some other optimisations too. He's mentioned it a couple of times on the mame.net forums. More games should be working before that will be done anyway.

LN2 · Post by **LN2** » Mon May 17, 2004 1:54 pm

Barry, I don't get the above..cuz you are still using fskp 0!!!

Show some stats at fskp 6 or 9. i'd bet you are at 100% speed except for maybe the last example where you are getting only 18fps at fskp 0.

Post by **mahlemiut** » Mon May 17, 2004 6:05 pm

No clue...

Frameskip does not have any effect on these games - it can actually make them go slower. The video rendering code is NOT the bottleneck, it's the CPU emulation and the amount of RAM it writes.

Post by **mahlemiut** » Mon May 17, 2004 8:44 pm

Hopefully this shot will explain it better:

You cannot skip CPU cycles, and you cannot skip memory reading/writing.

But it gives me another excuse to post a Bloody Roar 2 screen shot

LN2 · Post by **LN2** » Tue May 18, 2004 1:30 pm

well, a screenshot showing the frame rate at fskp 6 and 9 would have helped more.

yes, I see the video is a small part there....very odd.

I don't get give how much faster RAM throughput is nowadays compared to even 5 years ago how that could be the bottleneck.

The fact it's emulated can't be adding that much extra RAM throughput requirement can it?

How much RAM is being used for these games? How much is MAME using?

Post by **mahlemiut** » Tue May 18, 2004 7:46 pm

Are we happy now?

And also, Windows reports MAME uses 50MB when running this game. Some of this will, of course, be swapped out to disk (MAME is one large executable).

LN2 · Post by **LN2** » Wed May 19, 2004 1:39 am

yep...happy.....I would never attempt playing any of these on my older, slower system anyway.

It's why I hadn't seen that effect until your screenshots above.

Post by **mahlemiut** » Wed May 19, 2004 4:10 am

This has been well known since when Killer Instinct 1 and 2 were first emulated in MAME. Fast emulated CPU (100MHz MIPS R4600) takes up all the emulation time. The video hardware is very simple, no 3D or anything.
Cruisin' USA/World are similar.

Chad · Post by **Chad** » Wed May 19, 2004 11:46 am

If the 3d emulation is all in software (running on cpu only), i guess it would then be a mame-crime to change the emulation to convert it to using the latest 3d api's? since then it wouldn't be authentic but it would speed it up.

Post by **mahlemiut** » Wed May 19, 2004 5:53 pm

Chad wrote:If the 3d emulation is all in software (running on cpu only), i guess it would then be a mame-crime to change the emulation to convert it to using the latest 3d api's? since then it wouldn't be authentic but it would speed it up.

That would be right. Although I doubt there would be much of a speed up. A dynarec MIPS R3000 CPU core would probably give a better speed improvement - like it did with Killer Instinct.

Of course, there's nothing stopping you from adding Direct3D/OpenGL support for 3D games... it'll just never be an official part of the MAME core.

LordGaz · Post by **LordGaz** » Wed May 19, 2004 6:42 pm

Chad wrote:If the 3d emulation is all in software (running on cpu only), i guess it would then be a mame-crime to change the emulation to convert it to using the latest 3d api's? since then it wouldn't be authentic but it would speed it up.

From what I know about emulation engines, this would be just about an impossible task. You'd have to look at the disassembled ROM and see where it calls it's own 3D graphics handling routines. The emulator would then have to reinterpret this to a Direct 3D routine. Even this is very unlikely to work because the game's own graphics routine and the corresponding DirectX routine would have to match precisely, same parameters etc.

For example, game reaches a point where it calls 'Plot Triangle'. The emulator stops CPU emulation, skips the 'jsr' instruction and calls the necessary DirectX 'Plot Triangle' routine instead (if there is one) with the necessary parameters, then resumes normal CPU emulation.

This would be a miracle if it worked not to mention the amount of work involved to implement it! Gaz.

Post by **mahlemiut** » Wed May 19, 2004 7:38 pm

uhh... so how do all those PSX emulators (as well as Zinc/Impact/whatever) work then?

I'm no expert on how the PSX GPU works though...