[openbeos] Re: app_server: MMX/SSE help wanted
- From: "François Revol" <revol@xxxxxxx>
- To: openbeos@xxxxxxxxxxxxx
- Date: Wed, 11 Aug 2004 18:18:31 +0200 CEST
> Adi Oanca <e2joseph@xxxxxxxxxx> wrote:
> > > So from the SIMD coders perspective, it would be very good if
> > > Haiku
> > > would
> > > offer some control over data alignment for bitmap allocations.
> > > This includes not only the base address of the bitmap, but should
> > > ideally
> > > extend to each bitmap row, in cases where each row has to be
> > > processed
> > > separately (e.g. by blur routines:).
> > >
> > > Of course there'd be some 'waste', but I don't think this would
> > > matter too
> > > much on modern systems. Binary compatibility shouldn't be a
> > > problem
> > > either,
> > > as the BeBook already says that BytesPerRow() are decisive on
> > > determing a
> > > bitmaps actual size.
> > >
> > > This might be implemented by an additional constructor without
> > > too
> > > much
> > > fuss, I'd guess. It would be great if you could implement this,
> > > as
> > > this
> > > would make SIMD coding much easier and less bug-prone.
> > OK, you'll have that. Now, I have to see how. :-) Axel, can you
> > help?
>
> What he means is: we would need a change of the public API, that is
> add
> another BBitmap constructor that allows an alignment. What we could
> also do is to add another bitmap flag to force an ideal alignment for
> the current CPU.
>
Yeah, just #define B_BITMAP_CACHE_ALIGNED 0x00000100
...
François.
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