anon.1 (abc.delete@this.def.com) on November 7, 2019 5:39 pm wrote:
> Ronald Maas (ronaldjmaas.delete@this.gmail.com) on November 6, 2019 11:53 pm wrote:
> > anon.1 (abc.delete@this.def.com) on November 6, 2019 9:36 pm wrote:
> > > Doug S (foo.delete@this.bar.bar) on November 6, 2019 11:47 am wrote:
> > > > anon.1 (abc.delete@this.def.com) on November 6, 2019 11:19 am wrote:
> > > > > The whole point of RISC was to make
> > > > > decode simple. Now they want to add complexity in decode because, well, the ISA is oversimplified.
> > > >
> > > >
> > > > The RISC concept was created 40 years ago. Things have changed, designers have a transistor
> > > > budget orders of magnitude larger today so what was appropriate for a decoder in 1980
> > > > shouldn't be a limitation on what is appropriate for a decoder in 2020.
> > >
> > > Pretty damning then that an ISA produced in this decade is
> > > based on design principles aimed at solving problems
> > > dating back 40 years. Seems like the memo didn’t travel into the academic ivory towers. Also, note that
> > > RISC was concerned with pipelining for frequency. They wanted minimum gates in the critical paths. Area
> > > is somewhat of a contributor to it but not the main one. ISA decode complexity is. The more encodings you
> > > have, the more information you store per instruction and the more work you have to do in decode.
> >
> > 5000 year ago we used wheels for transportation. And today we still use wheels
> > for transportation. Does not necessarily means every old idea is bad.
> >
> > Once implementation complexity exceeds a certain level and RISC-V implementations start to
> > implement a full spectrum of extensions, caches, branch prediction, etc. the differences between
> > ARMv8 vs RISC-V start to become less relevant from a technology perspective. Performance,
> > energy efficiency, die area, design and validation efforts for processor implementations targeting
> > higher transistor budgets will be closely matched regardless of the ISA.
> >
> > Because of that, claiming that ARM is superior compared to RISC-V or vice versa, is meaningless.
> > Both are excellent ISAs. It will be the other factors that will drive the implementation choice.
> > Such as licensing terms, maturity of the eco-system, familiarity with certain ISAs, etc. etc.
> >
> > Ronald
>
> The modern wheel bears no resemblance to the mesapotamian wheel other than its shape. The solid wood/stone
> wheel was obsolete centuries ago. Meaningless analogies aside, this old idea (RISC) was a good idea
> for a small window of time. To have the option of designing an ISA from scratch and make decisions
> rooted in constraints from that era reflect ignorance, intransigence, or incompetence. There were plenty
> of lessons to be learned if only one looked hard enough. The excuse of it being a pedagogical tool
> will not fly. This isn’t pedagogy, but indoctrination into the fundamentalist RISC cult. I have the
> same complaint of hennessy and patterson textbooks, but that’s an orthogonal issue.

The insane babbling robot is back.