|
AWJ |
|
|
|
|
|
|
|
Reged: 03/08/05
|
|
Posts: 936
|
|
Loc: Ottawa, Ontario
|
|
|
|
Send PM
|
|
Re: Performace drop in Sega System 24 driver recently?
05/23/11 09:52 PM
|
|
|
> > Does S24 do a lot of dynamic memory mapping? That slowed down a while back and I
> > haven't yet dug into why exactly.
>
> No, it doesn't do much, only some rom banking. It has a bunch of shared ram areas and
> mirrors because 95% of the memory map is shared between the two 68ks.
>
> Perhaps the decryption is less efficient than it should? That's rather intricate code
> I haven't really looked at, and iirc the sega 68ks can't be pre-decrypted.
>
> OG.
The FD1094s can't be predecrypted because the encryption is stateful, but the decrypted opcodes are cached.
Also, if the FD1094 decryption was a bottleneck, toutrun wouldn't be faster than outrun:
$ ./mame64 -video none -nosound -nothrottle -str 30 outrun
Average speed: 263.04% (29 seconds)
$ ./mame64 -video none -nosound -nothrottle -str 30 toutrun
Average speed: 269.63% (29 seconds)
|
|
Index 
Flat 
Re: Performace drop in Sega System 24 driver recently?
Reply
