Re: [f-cpu] Winograd DCT on my seul.org account

[Yann Guidon <whygee@f-cpu.org>]

hi !

Juergen Goeritz wrote:
> Hi!
> 
> this is indeed a very, very  convincing idea! Provide the
> 'fitter' for the processor with the processor. YESSS!

i'm happy to see that this idea is not so hallucinating for
at least someone ;-) maybe you like it because you're also
a "HW guy" but the important thing is to have the benefits
and let people understand how that works.

> <compare to vhdl>
> It would be similar to todays FPGAs tool chains!
> You can use a 'global tool' like synplicity or whatever
> and run the device fitter from the vendor to create
> fpga netlist.
> </compare to vhdl>

very nice comparison, even though i didn't think about it :-)

However this creates a new kind of problems : gcc should export
the whole Intermediate Representation instead of just register-wise
code, because register reallocation works best on program-wise
working sets. Usually, FPGA/ASIC synthesiser + fitter exchange data
in the form of a flattened netlist, but GCC outputs code
that almost looks like already-fitted code.

> Now you take gcc (or the ones for ada, f, pas and so on)
> and run the f-cpu optimization fitter as a second step.
> And I would love to see the optimization procedure as a
> part of the loader...
that's ADA/VHDL-like, no ? :-P

> Then there were the chance for portability at maxperf.
> And you wouldn't have to worry about f-cpu type during
> compilation...
but then your "distibuted binaries" would be some kind of IR, 
not executable code. what happens if you want to compile
a boot loader or a boot kernel ? (i guess the answer but
i ask you anyway)

> And the hardware guys must think about how software is
> to be optimized - what amount of synergy effects :-)
> 
> And finally I don't see problems using gcc as a frontend
> tool only.

me either : that's what it simply is.

> JG
WHYGEE
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