Re: [TUHS] Encoding an ISA: Random Logic vs. Control Stores

[Henry Bent <henry.r.bent@gmail.com>]

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On Tue, 30 Nov 2021 at 18:10, Jon Steinhart <jon@fourwinds.com> wrote:

> Humm writes:
> > Quoth Jon Steinhart:
> > >arnold@skeeve.com writes:
> > >> Can someone please explain why it's called "random" logic? Discrete
> > >> logic I understand (more or less), but I've not heard the term
> "random"
> > >> used in this context before now.
> > >
> > >Well, as a recovered random logic designer, I think that the name comes
> > >from there being no particular structure to the logic.  Many parts of
> > >logic design are very regular, think memory.  But that regularity
> doesn't
> > >exist when, for example, decoding irregular instructions.
> >
> > Now that’s a “random” definition.
> >
> > --
> > Humm
>
> OK, I'll try again.  For anybody familiar with Portland, Oregon, it's the
> difference between driving in Northwest where there's a rectangular grid
> numbered in one direction and alphabetical in the other, and approaching
> the Ross Island Bridge from the west side which appears to be designed by
> someone following a goat while tripping their brains out.  One can address
> Northwest Portland quite easily unlike getting onto the Ross Island Bridge.
>

So - and as I say this as someone who has no direct experience with this
level of logic - everything is directly addressable but the difference is
in how you get there?

-Henry

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