[libre-riscv-dev] Libre RISC-V Requirements Specification document

Daniel Benusovich flyingmonkeys1996 at gmail.com
Thu Jan 10 08:09:16 GMT 2019


> i added a bit about exceeding the requirements "just because we can",
> just for the hell of it :)
>


we need a document that synthesises the design requirements in one
> place, such that it becomes clear what needs to be implemented, based
> on the analysis done over the past.... mm.... couple of months (ish).
>


i'm going to augment it with diagrams from mitch alsup's book,
> specifically and definitely the ones on how to do branch speculation
> and the way to do memory hazards that involve the TLB table.


neat. For progress!
Requirements look nice though the more specific set would be very helpful.

i'm *not* going to rush ahead with this (like i would have done in the
> past): i'm experimenting with this project to run it along "unanimous"
> decision-making lines.
>

Understood.


> daniel: given that you're on this part-time, once we've agreed that
> migen/nmigen is ok - or not - (jacob's fine with it, i'm fine with
> it), it *may* be a good idea to find a suitable self-contained
> "needed-in-the-future" task that you could do, which would not hold up
> the main development / iteration.
>
> candidates that i can immediately think of include a L1/L2 SMP-aware
> cache, a TLB table (virtual memory), a 64/32/16-bit IEEE754
> Floating-Point ALU (or at least starting one) - there's probably
> plenty of others that we can think of along the way (integer
> multiplier unit for example, for compliance with the optional RV "M"
> in "IMAFD").
>
> thoughts appreciated.
>

Those all sound and sound tantalizingly delicious!
 I have been reading up on virtual memory recently (coincidence has it), so
I would be happy to start there. If something else is more pressing than I
am happy to jump on that as well.

 Let me know where to get started with that task.

I will also be reading through the CDC 6600 documents you sent me this
weekend. If any part in that would be useful across from all of it let me
know what to focus on.

Hope you are having a good one and I hope to hear back soon

Daniel B.


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