[openbeos] Re: app_server: MMX/SSE help wanted
- From: "Axel Dörfler" <axeld@xxxxxxxxxxxxxxxx>
- To: openbeos@xxxxxxxxxxxxx
- Date: Fri, 13 Aug 2004 02:45:19 +0200 CEST
"shatty" <shatty@xxxxxxxxxxxxx> wrote:
> I've got a question about aligning bitmaps. Why do we
> need a new constructor or flag at all? Why not simply
> align all bitmaps? Also because bitmaps have this
> sort of property that they can possibly be arbitrarily
> large, it seems reasonable to be thinking about
> allocating the memory in a way that would help the VM
> to deal with them. (page boundary anyone?)
>
> I suppose there might be an issue with performing the
> alignment on a graphics card (depending on the driver
> API) but we can always simply make a best effort,
> can't we?
It's not always needed to align them that much. They could be aligned
at smaller byte ranges like 32 or 64 byte.
AFAICT, aligning on values like 64 kB can help as well with SIMD stuff,
depending on how the cache works. We'll have to see if that's so
beneficial, though.
Bye,
Axel.
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