[Libre-soc-dev] planning next OPF ISA WG RFC: ls003, biginteger?

Jacob Lifshay programmerjake at gmail.com
Tue Oct 11 01:07:25 BST 2022

On Mon, Oct 10, 2022 at 4:59 PM Jacob Lifshay <programmerjake at gmail.com> wrote:
> I'd like to *not* submit double-wide shift instructions just yet, as
> part of writing the toom-cook algorithm generator I'm realizing that
> as currently defined the shift instructions are quite difficult to use
> as currently defined and they need some more thought/proposals.

added as TODO item in https://bugs.libre-soc.org/show_bug.cgi?id=937#c0

> I also just realized that sv.divmod2du used for divmod(bigint, word)
> can use a similar ultra-wide 320/64->256-bit divide trick (with 64-bit
> remainder) as sv.maddeu does for bigint*word mul where the SIMD
> backend can do a 256*64+64->320-bit mul add.

added as TODO item in https://bugs.libre-soc.org/show_bug.cgi?id=817#c0


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