Re: The 1802 microprocessor

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#621646

From: timcaf...
Date: Mon, 26 Mar 2018 17:27

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On Sunday, March 25, 2018 at 7:33:55 AM UTC-4, Gareth's Downstairs Computer wrote:
> Insofar as it is a radiation hardened device and can
> withstand the hostile environment of outer space does not
> imply that it is a well thought out instruction set
> architecture.
> 
> ISTR that it is doubly equipped with both conditional
> skip and conditional branch instructions, possibly showing
> that the designer had (limited) software experience of the
> PDP8 but that indicates that the eye was taken off the ball
> for the more essential operations of moving data and performing
> arithmetic and logical operations on it, and, especially,
> making subroutine calls!
> 
> YMMV, it is 40 years this year since dabbling with one.

While the 1802 was not a traditional architecture, I was 
fascinated by it.  Wrote a bunch of little programs for it.
It seemed like the thing to do was implement Forth on it, 
and then use that :).  It wasn't fast, but it used, AFAICT,
a 1 bit ALU.  I remember being at a trade show and the
demo used a lemon to power the system; very low power.
You could slow down the clock to DC if you needed to.

Ironically, considering your post, there was a CMOS PDP-8
chip (the Intersil 6100) available at the same time.

       - Tim

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