Re: SS20 cg14 help

[der Mouse <mouse%Rodents-Montreal.ORG@localhost>]

>> Not quite as nice as it would be if we knew, for example, how to use
>> the blitter, but still substantially faster than 24bpp by itself.
> The 'blitter' is actually half of a SIMD CPU nailed to the mainboard
> - 'half' as in 'no jumps, branches and related stuff'.

I'd heard it said it was a DMA engine - which of course is not very
inconsistent with what you wrote.

I've also seen it said it has access to all of host RAM, not just
framebuffer RAM, and that this is why it shouldn't be accessible to
userland in general.

> You're supposed to feed it instructions through an IO port, it has a
> bunch of registers, it could probably be used to do stuff like alpha
> blending but we have no docs at all on the actual instruction set.

Yeah. :(  Like the cg6.  (I know how to use the cg6 for things like
lines and polygons and rectangular blits, but I understand there's a
lot more in there, including full 3D perspective transform....)

>> I'm a little surprised at the implication that nobody has already
>> done a both-depths-on-the-screen-at-once cg14 layer for recent X;
> I guess nobody cares enough.

Sounds that way.  Oh well, it works for me, and if anyone does decide
to do it, the offer of my code as a starting point is still open. :)

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