Jurrasic Park AGA (WHDLoad) - slow scrolling

[PopoCop]

I just tried Jurassic Park AGA (WHDLoad) on my A1200+040 and scrolling is very slow. ECS version works fine and scrolling is OK.
I tried nocache and nommu tooltypes but it didn't help.


Is there any way to fix this?

[dodke]

Same on Blizzard PPC 060. ChipNoCache tooltype helps with quite a few games but still isn't perfect. As far as I know the issue is that some accelerators (040/060 at least) work extremely slowly if the code resides in chip memory. At least on BPPC with caches enabled for chip it's even worse.
The difference with OCS versions is that the a1200 came with chip ram only so AGA version might not be placing code sections in fast memory and might even contain code in large sections that are also accessed by the chipset like blitter or for playing audio or something. OCS games require less speed but are also generally designed to utilise the 512k (fake) fast memory.

I suppose the whdload patches could in theory fix some of the slowness if someone wanted to look into it. I'd imagine some games have been patched to work better on this kind of setups.
For games that don't run well I simply write them to floppies and boot with the accelerator disabled to play them.
Also sometimes I swap the accelerator with a B1230 MK 4 which has better compatibility with old games and demos.

[jotd]

that's a good summary. For instance Chaos Engine ECS uses fastmem whereas the AA version doesn't...

And it's pretty difficult to move code to fastmem, specially if it's not an executable, because of relocations and also copperlists and all data that come with the code and need NOT to be relocated.

I've done that in the past (Chaos Engine CD32, Ultimate Bodyblows CD32) but that was a lot of work, and those were executable files (with hunks, relocs...), not trackloader. I'm currently failing despite multiple attempts on RedZone.

Another local solution would be to figure out where the code runs often and relocate only a part of the code. Easier. We usually do that with decrunchers for instance (that's easy).

[PopoCop]

Thanks for your replies. It seems that I have to choose another game to play. Fortunately those slowdowns are very rare (as far as I remember Jurassic Park is the first one I've encountered ever).

[jotd]

I think SWOS is another victim of that issue. It seems that the guys who designed accelerator boards didn't care too much about code running in chipmem.