[libre-riscv-dev] [Bug 209] spectre-proof speculative execution

Luke Kenneth Casson Leighton lkcl at lkcl.net
Mon May 18 20:38:52 BST 2020

On Mon, May 18, 2020 at 8:25 PM Yehowshua <yimmanuel3 at gatech.edu> wrote:

> > so basically this extends the Dependency Matrix "Shadow" concept actually
> > right down into the Caches.
> Exactly - keep in mind that this is only for variant 1.
> I’ll read up on the other variants later.
> Why do CPUs have to be so complicated...

Hugh said on one of the Virtual Coffee Calls, he's been in touch with
the IBM engineers for many years.  back when they first met, they told
him - straight up - that CPU design is hard.  however - it took
several years for him to properly and actually appreciate that when
they said "hard" they did not mean it in the ordinary sense of
"certain kinds of software engineering problems are hard", they meant,
like, REALLY hard.

this is why i recommended that we go with python, because not only can
we apply OO (Object-Orientated) techniques, we tap directly into the
"default mindset" behind python, which is that you *do not* write code
- ever - without having an adequate unit test.

this in combination with patiently following Mitch's advice of
drilling down to first principles, i am confident that we'll do fine.


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