[Libre-soc-dev] [RFC] REMAP, SHAPE, complex (full) FFT
Luke Kenneth Casson Leighton
lkcl at lkcl.net
Sun Jul 11 21:40:06 BST 2021
crowd-funded eco-conscious hardware: https://www.crowdsupply.com/eoma68
On Sat, Jul 10, 2021 at 11:46 PM Luke Kenneth Casson Leighton
<lkcl at lkcl.net> wrote:
> 1) the current svremap, create a new "setvl-with-remap-butterfly-for-FFT"
> instruction, to be merged with the functionality of setvl.
still TODO. should be easy now that the SVSHAPEs are independent from
> 2) a new SPR, called SVREMAP, whose format and purpose would be to set
> what is currently established in REMAP "propagation"
done, very simple, stores its immediates into the SVREMAP SPR:
the principle here is:
* there are 5 registers - 3 input ([F]RA, [F]RB, [F]RC) 2 output
* there are 4 SVSHAPEs (0-3)
* REMAP is a dead-simple table "FRA uses SVSHAPEn, FRB uses SVSHAPEm ..."
that's now implemented and the unit tests for FFT and Matrix-Mul updated.
the next important step will be to check that temporary (scalar)
registers can be
used in a full complex FFT, with the "REMAPped" vector registers not needing
too many "remap" instructions.
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