[libre-riscv-dev] Why The Dual ISA

[Luke Kenneth Casson Leighton]

On Sunday, January 19, 2020, Adam Van Ymeren <adam at vany.ca> wrote:

>
> On 2020-01-19 04:07 AM, Luke Kenneth Casson Leighton wrote:
> > On Sun, Jan 19, 2020 at 3:50 AM Immanuel, Yehowshua U <
> yimmanuel3 at gatech.edu>
> > wrote:
> >
> >> So just throwing it out there?
> >>
> > ya man :)
> >
> >
> >> Why are we using the Dual ISA?
> >>
> > because as i said in the update, we have committments to users and to
> > sponsors.
> >
>
> How firm are these commitments?


one is USD 500 a month and as it is unconditional it is a big deal.  they
very specifically gave us that donation on the basis of RISCV compatibility.

their users are expecting to see a RISCV Libre processor.

the conversation i had to have with them about the RISCV Foundation's
intransigence, and the lack of action that had been taken by someone in
SiFive who continues with defamation of the project despite formal
complaints, was... difficult.



>   The crowd funding campaign hasn't start
> yet has it?


there is more than the crowdfunding campaign.


>  Although it sounds like you have a solid plan for dual-ISA,
> I wouldn't want to jeopardize the success of the project by including
> unnecessary complexity.


we don't exactly have a choice.  committments have been made.

now, if those turn out to be too difficult, after we have made every
effort, i am fine with explaining why.

but, "not trying" is definitely not ok.

 I'm reminded of the saga that was the mini-HDMI
> connector on EOMA68 and how much pain and delays that were caused by
> even a seemingly simple part.


good attempt at an analogy, bad example :) Mid Mount Micro HDMI connectors
are insanely difficult to get hold of.


> This is such a critically important

project, the world needs a commercially viable libre processor.
>
> I'm assuming that the sponsor commitments are some of the NLnet proposals?


 no, a separate backer (Purism)


> This is also a good illustration of how seemingly innocuous early
> decisions can have significant impact later in the project.  The goal
> really isn't, or shouldn't have been to make a libre RISC-V SoC, but to
> make just a libre SoC.


sigh, hindsight.  if we had known what we know, we wouldn't have started
from there.


> RISC-V seemed like such an obvious choice early
> on, and I'm sure the name helped raise the profile of this project to
> begin with, but in the end was not the right choice.
>
> Unrelated question, are you up here in Canada?


i was, i'm in cambridge uk now.



>
> _______________________________________________
> libre-riscv-dev mailing list
> libre-riscv-dev at lists.libre-riscv.org
> http://lists.libre-riscv.org/mailman/listinfo/libre-riscv-dev
>


-- 
---
crowd-funded eco-conscious hardware: https://www.crowdsupply.com/eoma68