Groups > sci.electronics.design > #740359

Re: cheap analog square function?

From	Gerhard Hoffmann <dk4xp@arcor.de>
Newsgroups	sci.electronics.design
Subject	Re: cheap analog square function?
Date	2026-02-13 00:38 +0100
Message-ID	<10mloa4$34pk$1@solani.org> (permalink)
References	(5 earlier) <mv8pokd00bkmt0lebhc0fgokd7bjs2d27a@4ax.com> <10mjsd5$183og$1@dont-email.me> <np5sokhs2210slg8lnh71olithhaauileu@4ax.com> <10mlbr1$1o5b9$1@dont-email.me> <v4jsokl3hi6d9g90tucq3klb7gkh1et7rp@4ax.com>

Show all headers | View raw

Am 12.02.26 um 23:12 schrieb john larkin:
> On Thu, 12 Feb 2026 21:05:53 +0100, Lasse Langwadt <llc@fonz.dk>
> wrote:
> 
>> On 2/12/26 19:19, john larkin wrote:
>>> The internal stack-oriented architecture of Focal-8 inspired the cool
>>> PDP-11 architecture which in turn inspired the 68K.
>>
>> how did stack-oriented inspire architectures with lots of orthogonal
>> registers, by showing how it should not be done?
>>
> 
> Stack-oriented inspired stack-oriented. In the PDP-11, any of the
> registers could be used as a stack pointer.

That does not make it stack-oriented. It had registers and nice
addressing modes with pre-decrement and post increment etc.
Nice for string handling, too.

The PDP11/40e in our group was the 1st Unix machine on this side
of the pond.

Stack-oriented was Burroughs(sp?) B1700 or the p-code machines like
UCSD or Andrew Tanenbaum's EM. I wrote a Z8000 version of the EM.

We had to do a 1 semester group project for VLSI design and I
persuaded the group to do a somewhat dumbed-down version of
Tanenbaums Experimental Machine in HP's full custom dynamic n-mos
process.

Unluckily, another working group donated us a large metal square
across all of the ALU, so testing was not needed.    :-(
The design rule checker had its limitations for the multi
project wafer.

> It could do fun things like
> 
> NEG PC
> 
> negate the program counter.
> 
> There was the land mine opcode
> 
> MOV -(PC), -(PC)
> 
> (014747 octal)
> 
> which copied itself one location below itself and re-executed that.

OpCodes are precious!!!

cheers,   Gerhard

Back to sci.electronics.design | Previous | Next — Previous in thread | Next in thread | Find similar

Thread

cheap analog square function? Christopher Howard <christopher@librehacker.com> - 2026-02-09 14:52 -0900
  Re: cheap analog square function? john larkin <jl@glen--canyon.com> - 2026-02-09 16:47 -0800
  Re: cheap analog square function? Don Y <blockedofcourse@foo.invalid> - 2026-02-09 17:50 -0700
  Re: cheap analog square function? "Edward Rawde" <invalid@invalid.invalid> - 2026-02-09 20:03 -0500
  Re: cheap analog square function? Phil Hobbs <pcdhSpamMeSenseless@electrooptical.net> - 2026-02-10 02:05 +0000
  Re: cheap analog square function? Jan Panteltje <alien@comet.invalid> - 2026-02-10 05:50 +0000
    Re: cheap analog square function? bitrex <user@example.net> - 2026-02-10 03:39 -0500
  Re: cheap analog square function? Bill Sloman <bill.sloman@ieee.org> - 2026-02-10 18:05 +1100
    Re: cheap analog square function? John R Walliker <jrwalliker@gmail.com> - 2026-02-10 08:41 +0000
      Re: cheap analog square function? bitrex <user@example.net> - 2026-02-10 03:46 -0500
        Re: cheap analog square function? bitrex <user@example.net> - 2026-02-10 03:49 -0500
  Re: cheap analog square function? antispam@fricas.org (Waldek Hebisch) - 2026-02-10 14:12 +0000
    Re: cheap analog square function? Christopher Howard <christopher@librehacker.com> - 2026-02-10 07:49 -0900
      Re: cheap analog square function? Don Y <blockedofcourse@foo.invalid> - 2026-02-10 11:40 -0700
      Re: cheap analog square function? john larkin <jl@glen--canyon.com> - 2026-02-10 11:39 -0800
        Re: cheap analog square function? Bill Sloman <bill.sloman@ieee.org> - 2026-02-11 23:38 +1100
          Re: cheap analog square function? john larkin <jl@glen--canyon.com> - 2026-02-11 07:56 -0800
            Re: cheap analog square function? Buzz McCool <buzz_mccool@yahoo.com> - 2026-02-11 09:30 -0800
              Re: cheap analog square function? john larkin <jl@glen--canyon.com> - 2026-02-11 09:38 -0800
                Re: cheap analog square function? liz@poppyrecords.invalid.invalid (Liz Tuddenham) - 2026-02-11 18:52 +0000
                Re: cheap analog square function? bitrex <user@example.net> - 2026-02-11 14:22 -0500
                Re: cheap analog square function? john larkin <jl@glen--canyon.com> - 2026-02-11 12:14 -0800
                Re: cheap analog square function? bitrex <user@example.net> - 2026-02-11 15:35 -0500
                Re: cheap analog square function? john larkin <jl@glen--canyon.com> - 2026-02-11 13:04 -0800
                Re: cheap analog square function? bitrex <user@example.net> - 2026-02-11 16:35 -0500
                Re: cheap analog square function? Lasse Langwadt <llc@fonz.dk> - 2026-02-11 21:41 +0100
                Re: cheap analog square function? Jeroen Belleman <jeroen@nospam.please> - 2026-02-11 22:49 +0100
            Re: cheap analog square function? Lasse Langwadt <llc@fonz.dk> - 2026-02-11 21:37 +0100
            Re: cheap analog square function? Bill Sloman <bill.sloman@ieee.org> - 2026-02-12 17:36 +1100
              Re: cheap analog square function? john larkin <jl@glen--canyon.com> - 2026-02-12 10:19 -0800
                Re: cheap analog square function? Lasse Langwadt <llc@fonz.dk> - 2026-02-12 21:05 +0100
                Re: cheap analog square function? john larkin <jl@glen--canyon.com> - 2026-02-12 14:12 -0800
                Re: cheap analog square function? Lasse Langwadt <llc@fonz.dk> - 2026-02-12 23:39 +0100
                Re: cheap analog square function? john larkin <jl@glen--canyon.com> - 2026-02-12 15:19 -0800
                Re: cheap analog square function? Don Y <blockedofcourse@foo.invalid> - 2026-02-12 18:13 -0700
                Re: cheap analog square function? Gerhard Hoffmann <dk4xp@arcor.de> - 2026-02-13 00:38 +0100
                Re: cheap analog square function? john larkin <jl@glen--canyon.com> - 2026-02-12 16:09 -0800
                Re: cheap analog square function? Gerhard Hoffmann <dk4xp@arcor.de> - 2026-02-13 02:42 +0100
                Re: cheap analog square function? john larkin <jl@glen--canyon.com> - 2026-02-13 09:30 -0800
                Re: cheap analog square function? Jan Panteltje <alien@comet.invalid> - 2026-02-14 06:14 +0000
                Re: cheap analog square function? Glen Walpert <nospam@null.void> - 2026-02-14 14:18 +0000
                Re: cheap analog square function? john larkin <jl@glen--canyon.com> - 2026-02-14 07:51 -0800
                Re: cheap analog square function? Jan Panteltje <alien@comet.invalid> - 2026-02-15 06:27 +0000
                Re: cheap analog square function? john larkin <jl@glen--canyon.com> - 2026-02-14 07:47 -0800
                Re: cheap analog square function? Jan Panteltje <alien@comet.invalid> - 2026-02-15 06:50 +0000
                Re: cheap analog square function? mas@example.com - 2026-02-16 07:38 +0000
                Re: cheap analog square function? Jan Panteltje <alien@comet.invalid> - 2026-02-16 08:49 +0000
              Re: cheap analog square function? legg <legg@nospam.magma.ca> - 2026-02-14 08:57 -0500
  Re: cheap analog square function? piglet <erichpwagner@hotmail.com> - 2026-02-12 21:37 +0000
    Re: cheap analog square function? Christopher Howard <christopher@librehacker.com> - 2026-02-13 06:40 -0900
      Re: cheap analog square function? john larkin <jl@glen--canyon.com> - 2026-02-13 08:34 -0800
        Re: cheap analog square function? bitrex <user@example.net> - 2026-02-13 13:00 -0500
          Re: cheap analog square function? john larkin <jl@glen--canyon.com> - 2026-02-13 10:52 -0800
        Re: cheap analog square function? bitrex <user@example.net> - 2026-02-13 13:01 -0500
      Re: cheap analog square function? piglet <erichpwagner@hotmail.com> - 2026-02-13 19:36 +0000
        Re: cheap analog square function? john larkin <jl@glen--canyon.com> - 2026-02-13 12:06 -0800
          Re: cheap analog square function? piglet <erichpwagner@hotmail.com> - 2026-02-13 20:42 +0000
            Re: cheap analog square function? john larkin <jl@glen--canyon.com> - 2026-02-15 12:43 -0800
        Re: cheap analog square function? Christopher Howard <christopher@librehacker.com> - 2026-02-16 09:36 -0900
          Re: cheap analog square function? Bill Sloman <bill.sloman@ieee.org> - 2026-02-18 00:03 +1100
            Re: cheap analog square function? john larkin <jl@glen--canyon.com> - 2026-02-17 08:06 -0800
        Re: cheap analog square function? Christopher Howard <christopher@librehacker.com> - 2026-02-16 13:08 -0900
          Re: cheap analog square function? piglet <erichpwagner@hotmail.com> - 2026-02-17 11:40 +0000
            Re: cheap analog square function? Phil Hobbs <pcdhSpamMeSenseless@electrooptical.net> - 2026-02-17 12:34 -0500
              Re: cheap analog square function? Gerhard Hoffmann <dk4xp@arcor.de> - 2026-02-17 18:57 +0100
                Re: cheap analog square function? Phil Hobbs <pcdhSpamMeSenseless@electrooptical.net> - 2026-02-17 18:18 +0000
                Re: cheap analog square function? Gerhard Hoffmann <dk4xp@arcor.de> - 2026-02-17 19:39 +0100
                Re: cheap analog square function? Phil Hobbs <pcdhSpamMeSenseless@electrooptical.net> - 2026-02-17 14:00 -0500
                Re: cheap analog square function? Bill Sloman <bill.sloman@ieee.org> - 2026-02-18 15:10 +1100
              Re: cheap analog square function? Bill Sloman <bill.sloman@ieee.org> - 2026-02-18 14:43 +1100
          Re: cheap analog square function? Bill Sloman <bill.sloman@ieee.org> - 2026-02-18 01:43 +1100
      Re: cheap analog square function? Jan Panteltje <alien@comet.invalid> - 2026-02-14 05:53 +0000

csiph-web