FAME SH4 is here!

***quzar*** · January 14th, 2005, 02:20

1.6 times faster is still a very significant amount! and smaller size is always nice. will you be designing an easy wrapper like you did with c68k? also, is it API compliant with any other core? last question: when do you think it will be ready for download?

**Stef** · January 14th, 2005, 03:51

[quote author=quzar link=board=dcemu;num=1097277534;start=75#80 date=01/14/05 at 03:20:04]1.6 times faster is still a very significant amount! and smaller size is always nice. will you be designing an easy wrapper like you did with c68k? also, is it API compliant with any other core? last question: when do you think it will be ready for download?[/quote]

I already done the CPU interface to switch easily from an other core. Overall structure looks like C68K and is close from the z80 core currently used in Genesis Plus.
By the way, i just found a C Z80 core which should be quite fast beware the implementation, it's the core used in Generator, you can see it here : http://www.squish.net/cgi-bin/cvsweb...nerator/cmz80/

CZ80 needs some debug, i think it will be ready in 2 weeks (or more)... i'll anyway provide some beta version for tests.

**RockinB** · January 14th, 2005, 13:10

You're joking, right? 1.6 time faster is more one could expect.
I agree, the memory consumption of some CPU cores is really a pain. Some take LUT wherever they can, although most entries are the same.

You CZ80 would be very welcome for emus on SEGA Saturn, the performance gain and the smaller size will have a more significant impact than on Dreamcast.

This sh4 Z80 core needs to be published, that's for sure. Couldn't yet find Ishmairs sources on my own...

I really wonder, why there is noone making a dynarec core. On Saturn, this is the ultimate option to choose. I will start an SH2 dynamic recompiler and see, how far I get.

***quzar*** · January 14th, 2005, 13:28

[quote author=Stef link=board=dcemu;num=1097277534;start=75#81 date=01/14/05 at 04:51:43]

I already done the CPU interface to switch easily from an other core. Overall structure looks like C68K and is close from the z80 core currently used in Genesis Plus.
By the way, i just found a C Z80 core which should be quite fast beware the implementation, it's the core used in Generator, you can see it here : http://www.squish.net/cgi-bin/cvsweb...nerator/cmz80/

CZ80 needs some debug, i think it will be ready in 2 weeks (or more)... i'll anyway provide some beta version for tests.
[/quote]

you are the second person in the past day to link me to cmz80. currently NeoDC uses mz80 (and old version, which is why its broken), and I plan on trying to replace it with cmz80. How do you think the speed of CZ80 compares to that of cmz80?

**BlackAura** · January 15th, 2005, 22:10

As for a DBT (aka dynamic recompiler) CPU emulator... For systems as old as these, it's probably not a good idea unless you have no other choice. Most MegaDrive games don't rely on cycle-accurate timing from the 68k, so that might be a candidate for a DBT, but it doesn't run particularly fast (around 8MHz). The overhead of generating native code blocks, caching them, and maintaining that cache might be more than you'd gain by switching over. Even then, it would require writing yet another new CPU core, which would take a long time. We may not actually need to do that at all.

For a Z80, I wouldn't even consider it. Not on a Dreamcast.

**Stef** · January 16th, 2005, 09:55

You're joking, right? 1.6 time faster is more one could expect.
I agree, the memory consumption of some CPU cores is really a pain. Some take LUT wherever they can, although most entries are the same.

You CZ80 would be very welcome for emus on SEGA Saturn, the performance gain and the smaller size will have a more significant impact than on Dreamcast.

Well 1.6 time faster Â*isn't really much, i was expecting 2.0 but err, my optimisations wereÂ*done first for dreamcast, i hope to have better results on this architecture

AboutÂ*SEGA saturn, i'm Â*not sure than a simple C Z80Â*can be fast enough to be usable... i believe that only a strongly optimised assembly core can achieve acceptable speed. Anyway i would be interested to know how CZ80 runs on that system

[quote author=quzar link=board=dcemu;num=1097277534;start=75#83 date=01/14/05 at 14:28:18]

you are the second person in the past day to link me to cmz80. currently NeoDC uses mz80 (and old version, which is why its broken), and I plan on trying to replace it with cmz80. How do you think the speed of CZ80 compares to that of cmz80?
[/quote]

I can't be sure without tests but CMZ80 implement alls bases stuff to make a fast core. It even does the unbase PC trick on SP (stack pointer) which can make it possibily faster than CZ80 (lacks it for now) but i guess speed to be almost the same since optimisation on SP has far less impact. That deserves some tests i guess