[Scummvm-devel] PORTERS: AdLib emulator changes

[Max Horn]

Am 06.05.2009 um 16:21 schrieb Johannes Schickel:

> Lars Persson wrote:
>> Ok.. Then I understand. So actually this precision is what costs, in
>> the MAME FM OPL emulation, you can reduce the quality of the
>> audiogeneration, something which is generally done for lowend  
>> devices,
>> i.e number of bits used for envelopes etc, to get "good enough"  
>> sound,
>> whilst still getting a performance which is acceptable.i
>>
>> I think adding such configuration option to the DosBox implementation
>> is something that should be done, specially if it is planned to get
>> rid of the mame impl. in the longrun.
>
> For now we will probably stick with the MAME OPL for low end devices
> though. I'm not really sure how much is still to be done on the DOSBox
> code, so starting to change parts of it could make problems later on
> when merging fixes from DOSBox. Of course for the long run we might
> really want to try speeding up the code for lowend devices, for  
> example
> I think currently some sound generation parts are still relying on
> floating point maths (it's only one thing, namely operator generation,
> though AFAIK).

The DOSBox OPL code seems to heavily rely on floating point  
calculations, which makes it a big no-no for many small devices which  
often lack a (full) FPU. IIRC they were working on an integer based  
version, though? I think you mentioned something like that in the  
past. Might be good to check that out. I could look into trying to  
tweak things for performance, too, but it would be best to coordinate  
this with the DOSBox devs, I would say. I.e., maybe they already have  
similar plans?


Max