[Oberon] Hennessy.Mod 64kB limit

Frans-Pieter Vonck fp at vonck.nl
Tue Feb 18 19:34:09 CET 2020


A few days ago I posted a comment on an item on Andreas Spiess youtube 
channel, "What we should NOT do in 2020"
Spiess is an 'influencer' for programming ESP32 chips in arduino, "The 
guy with the Swiss accent".
https://youtu.be/zFVM9xZR8KI


Me.
Quote from Edsger Dijkstra:

" [..]before really embarking on a sizable project, in particular before 
starting the large investment of coding, try to kill the project first, 
and
(ii) start with the most difficult, most risky parts first."
https://www.cs.utexas.edu/users/EWD/transcriptions/EWD13xx/EWD1308.html

Andreas Spiess
2 dagen geleden
Killing the projet means say "no" ;-)  To start with the most difficult 
part is no more in fashion these days with "agile" and "low hanging 
fruits". But I tend to agree with Dijkstra.
1
Oberoid Droidus
2 dagen geleden (bewerkt)
@Andreas Spiess Unfortunately trial and error tinkering with IOT is 
impossible while following Dijkstra's adagia. I feel more comfortable 
with the ideas of Niklaus Wirth, a electronic engineer, not a 
mathematician. He has developped an elegant language called Oberon07. 
Oberon7  has an interesting approach to setting bits by using SET 
operations. There is a commercial implementation of Oberon07 
https://www.astrobe.com/  .  At ETHZ the development of Oberon for 
micro-controllers is undertaken by Paul Reed.
Andreas Spiess
2 dagen geleden
Nicklaus Wirth was one of my professors at ETH ;-)
1
Oberoid Droidus
2 dagen geleden
@Andreas Spiess The best! Hope there will be an Oberon Day at ETHZ soon. 
A reason to visit Zwitserland and to check on my VM that is hosted 
somewhere in the Alps. https://datacenterlight.ch/


I had this document in mind when I wrote the comment.
SET: A neglected data type, and its compilation for the ARM
https://people.inf.ethz.ch/wirth/Oberon/SETs.pdf

I think that bitwise manipulations by set operations is elegant.

Greets,
F.P. Vonck


Pablo Cayuela schreef op 2020-02-18 19:09:
> I'm on your side Wojtek, as a professor and a former student, I'm
> always praising Wirth's School but struggle with code, despite being
> Oberon, LoLa or Verilog in ETHZ repositories and followers.
> Too many parts of the codes are full of idioms known to an already
> involved developer of the tools, but hard for outsiders and newbies.
> I hope for they will follow the preached way.
> 
> Prof. Pablo Cayuela
> 
> On Tue, Feb 18, 2020 at 1:26 PM Skulski, Wojciech
> <skulski at pas.rochester.edu> wrote:
> 
>> Joerg:
>> 
>> I am not questioning the code. I am questioning the coding
>> practice: avoiding any comments and writing bit masks explicitly in
>> hex.
>> 
>> I have learned how to clearly code bit masks from Cypress EZ-SB
>> Frameworks originally written by Anchor Chips. Translated to Oberon
>> it would look like this:
>> 
>> CONST Bit0 = 1; Bit1 = 2; Bit3 = 4; (* and so on, the same can be
>> written in hex *)
>> 
>> mno := inst DIV Bit20 MOD Bit4; (*  inst DIV 100000H MOD 10H; *)
>> 
>> So now we at least see which bit is being used without parsing hex
>> in mind. The intent of DIV and MOD can be explained in a comment.
>> All your explanations can be written in a comment. As a minimum, a
>> reference to NW papers could be given, with the paper title and
>> page.
>> 
>> I have written references to NW papers in my SysDef.Mod. I am
>> asking, why I could do in Rochester what has not been done in
>> Zurich, where this whole School of NW supposedly originated?
>> 
>> I do not want to present public speeches on the merits of NW
>> programming. I only want to see it done, in order for the code to
>> become clear rather than confusing.
>> 
>> W
>> 
>> --
>> Oberon at lists.inf.ethz.ch mailing list for ETH Oberon and related
>> systems
>> https://lists.inf.ethz.ch/mailman/listinfo/oberon
> --
> Oberon at lists.inf.ethz.ch mailing list for ETH Oberon and related 
> systems
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