CPU design at the gate level

From: Tom Uban <uban_at_ubanproductions.com>
Date: Sat Sep 22 09:12:24 2001

At 02:35 AM 9/22/01 +0100, you wrote:
>> The book: "Computer Organization & Design, The Hardware/Software
>> by David A. Patterson and John L. Hennessy is a pretty thorough modern
>Yes, unfortunately it is a 'modern book'. I read some of Hennessy and
>Patterson once, and found it was great at telling me how to analyse a
>processor design, and optimise it, and things like that, but it didn't
>really tell me how to do the design in the first place.
>It seems to have been written for the modern 'engineer' -- the sort that
>couldn't design an engine (in the original meaning of 'ingenious
>mechanism') if his life depended on it. And as you might have guessed by
>now, I have little time for 'engineers' who can't design and build
>examples of the things they claim to understand.
>You couldn't take that book and learn enough to start wiring up gates and
>flip-flops to make a processor :-(

I beg to differ. I feel that the book does a fairly good job of covering
all aspects of processor design to date. It does in fact describe how the
ALU is implemented along with the data paths necessary to feed it. It
also importantly covers the hows and whys of the control plane needed to
make the data path function. The book teaches all of the various arithmetic
concepts (like floating point) which are now expected in modern designs.
With these more basic concepts, it also covers the hows and whys of

While it does not teach you how to use a wire wrap tool, it does cover
basic logic design concepts (in an appendix) as well. Perhaps in your
case it just has too many references to the popular processors of the
day for your taste. But, just because they are popular today, does not
mean that they cannot be powerful learning tools, even for those who
are interested in the processors of yesteryear...

What it does not do is give you a schematic of a processor and hold your
hand while describing each gate. If this is what you want, then perhaps
the set of (KB11-A central processor unit maintenance manual, PDP-11/45
and PDP-11/50 system maintenance manual, and 11/45-0 engineering drawings)
would be a better instructional set.

Let's face it. No one book is going to teach someone everything that they
need to know to be able to design the next "great" processor. There is
also nothing better to teach a subject than to learn from what others
have done in the past.

Received on Sat Sep 22 2001 - 09:12:24 BST

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