WarpOS, PPC and ChipRAM

[Karlos]

Hi,

Can anybody confirm what the default cache setup is supposed to for the 603/604 with respect to the chip ram area?

I discovered recently (quite by accident whilst talking to Patrik about screwy performance results) that on my system it seems to be cached (copyback too), rather than non-cacheable. For writes, this slowed it down a *lot*. Allocating chip memory with AllocVecPPC() using MEMF_WRITETRHOUGH or MEMF_CACHEOFF corrected this.

This seems odd to me as I cannot think of any reason why the chip ram should be copyback enabled.

Is my installation screwy?

[Karlos]

I'm using warpup 5.1 as found on aminet. I'll need to check after work to get the exact powerpc.library version. I think it's v16, but I am not completely sure.

[Karlos]

Framiga wrote:

btw . . . it eats about 2 MB of fastram.

Trust me, that is not a problem ;-)

[Karlos]

The library uses 2MB you mean?

It probably allocates some memory for book keeping and what not. I also know that the PPC MMU tables can use up quite a lot of ram, but I think these are already allocated even before you start WarpOS (at least on BPPC)