[Libre-soc-dev] DCT/FFT augmentations

Luke Kenneth Casson Leighton lkcl at lkcl.net
Fri Jul 2 23:27:33 BST 2021

On 7/2/21, Hendrik Boom <hendrik at topoi.pooq.com> wrote:

> Just a note:  interpreting + as 'or', and * as 'and',
> operating on Boolean matrices,
> and having result, X, and Y be the exact same matrix,
> updated while being used,
> gives the traditional Warshall transitive-closure
> algorithm, if the loops are nested exactly in thie order.


we'd need a triple boolean logic
instruction to do it... oh wait! the ternary instruction!

this can handle 3 operands in with all possible permutations of all
possible boolean logic combinations between 3 operands.

> And probably a truckload of read-write conflicts.

the priority is i j on the result as inner loops, so it's ok.

read is fine, it's writes that you have to be careful about.

my other favourite one is GF(2^N) equivalent of mul-and-add.

this is how Rijndael MixColumns can be done in its original
mathematical form, with GF(2^8)

i'll make a note about the Warshall algorithm.

thank you Hendrik.


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