October 2021 - Oberon - mailman3.inf.ethz.ch

Re: [Oberon] Emulators
by Jörg 14 Feb '22

14 Feb '22

Wojtek > How can I proceed, in practical terms, to use your JS emulator for development? Perhaps we should start discussing, WHAT you want to change. At the moment I see three different levels of HW modifications: easy, more difficult, impossible. Basically, see an emulator as virtualization. In virtualization you have a host machine (where the emulator runs on) and a guest machine (this is the FPGA board). I ignore „containers“ at the moment Easy: if you want to extend the RISC-5 instruction set in Verilog (eg add an autoincrement instruction) the modification of the emulator is rather straight forward. I neglect the fact that you have to modify the Oberon-07 compiler to use this new instruction, because this is not important for the emulator. More difficult: if you want to add IO mapped HW (eg Ethernet or Wifi) or memory mapped HW (eg color display) to your FPGA and the host machine has an equivalent of this HW, with a little bit of effort the emulator can be modified to map the IO register commands or new memory layout to the corresponding host HW. Impossible: if you want to add HW to your FPGA and the host machine does not have an equivalent HW (eg a neutrino sensor) then it‘s impossible for the emulator to mimic the new FPGA HW. br Jörg

7 33

Wanted: Oberon Syntax in TextMate, Sublime Text or Atom Grammar
by Treutwein Bernhard 01 Jan '22

01 Jan '22

Does somebody have grammars for Oberon / Oberon-2 / Component Pascal / Active Oberon as grammar for TextMate / Sublime Text / Atom Background: Github wrongly classifies Oberon / Oberon-2 / Component Pascal / Active Oberon as Modula-2. I opened quite some tiome ago an issue in the github/linguist project (https://github.com/github/linguist/issues/3888) and they don't accept EBNF grammars. -- Bernhard Treutwein

6 9

Re: [Oberon] _Compiler_Construction_ by Niklaus Wirth
by peter＠easthope.ca 17 Nov '21

17 Nov '21

P.s. for interest. From: peter(a)easthope.ca Date: Thu, 07 Jan 2021 08:37:22 -0800 > Currently the cheapest copy of _Compiler_Construction_ is 43.09 US$, > delivery in the USA included. Appears the copy posted at 43.09 US$ was sold that day. Subsequently the vendor listed another copy at 105.61 $US. The book market can be as volatile as the stock market. Regards, ... P. L. -- Tel: +1 604 670 0140 Bcc: peter at easthope. ca

8 21

The Radiar A2 Swiss industrial controller.
by peter＠easthope.ca 02 Nov '21

02 Nov '21

Jörg joerg.straube at iaeth.ch, Sun Oct 10 21:03:44 CEST 2021: > ... company Radiar http://www.radiar.ch/page_en.html still uses Oberon. Mention of a variety of applications in the Details PDF suggests the "controller" is a general purpose computer. Has anyone made ETH Oberon, A2 or V5 work on ite? Thanks, ... P.L. -- mobile: +1 778 951 5147 VoIP: +1 604 670 0140 48.7693 N 123.3053 W

3 2

Modules in C++20
by Hans Klaver 25 Oct '21

25 Oct '21

Recently in a local bookstore I was browsing through (the Dutch translation of) a book by Bjarne Stroustrup, 'A Tour of C++'. Somewhat surprised I read that C++20 has (or will have) modules à la Wirth (complete with import and export) as a better alternative for header files and #include. Stroustrup writes that using #include in a wrong order is the biggest and most expensive source of bugs since 1972, when this mechanism was introduced in C. Well, I guess that after nearly 40 years Stroustrup & al. saw the light... Ofcourse they make modules much more convoluted than Wirth, with multiple 'module units', one of them being the 'module interface unit', and with 'module partitions'. And for the time being C++ will be using these modules next to #include; and then there are also namespaces in C++. Must give Niklaus Wirth some joy and satisfaction that he did these things the right way from the start (when designing Modula around 1976, Modula-2 around 1979, and Oberon around 1986). Regards, Hans Klaver The Netherlands

1 0

Array Index Out Of Range in ORG.FindPtrFlds
by Andreas Pirklbauer 24 Oct '21

24 Oct '21

> Ich bin mir nicht ganz sicher, aber sollte es nicht so heissen? > > > ELSIF typ.form = ORB.Array THEN FindPtrFlds(typ.base, off, dcw) END Nope. You need *all* pointer locations across *all* array elements .. otherwise the garbage collector will not find find all pointer locations. So for an array of N=3 records with pointer offsets 3, 37, 62 within each record, and a record size of S = 100 bytes, one needs the offsets 3, 37, 62, 103, 137, 162, 203, 237, 262. Obviously, for large arrays the number of pointer locations can quickly exceed the value of ORG.maxTD. One way to avoid storing the *same* offsets *N times* would be to store them in compact form, for example as [N = 3, S = 100, 3, 37, 62]. But then one also needs to adapt Kernel.Mark so it can interpret this format. Due to the possibility of recursive data structures, this is complex. Been there. Doable. But not recommendable.. PS: An alternative is to extend the intrinsic procedure NEW to allow NEW(p), where p is an array of pointers. That’s what I use in Extended Oberon. In the PO 2013 2013 version I have found no better solution than to (temporarily) increase ORG.maxTD :-(

3 2

Array Index Out Of Range in ORG.FindPtrFlds
by Andreas Pirklbauer 23 Oct '21

23 Oct '21

The following program compilers correctly in FPGA Oberon MODULE M1; TYPE P = POINTER TO R; R = RECORD a: ARRAY 160 OF INTEGER END ; (*compiles correctly*) END M1. but the following program leads to a trap 1 = array index out of range error in ORG.FindPtrFlds MODULE M2; TYPE P = POINTER TO R; R = RECORD a: ARRAY 160 OF P END ; (*trap 1 = array index out of range*) END M2. The reason is, of course, that ORG.data is an ARRAY maxTD (=160) OF INTEGER and ORG.FindPtrFlds traverses each array element individually to compute the offsets ELSIF typ.form = ORB.Array THEN s := typ.base.size; FOR i := 0 TO typ.len-1 DO FindPtrFlds(typ.base, i*s + off, dcw) END (*<--------*) Any suggestions how to address that in program M2 (or in the compiler, other than increasing maxTD)?

3 2

Array Index Out Of Range in ORG.FindPtrFlds
by Andreas Pirklbauer 18 Oct '21

18 Oct '21

> > MODULE M2; > > TYPE P = POINTER TO R; > > R = RECORD a: ARRAY 160 OF P END ; (*trap 1*) > > END M2. > > > > Any suggestions how to address that in program M2? > > > > What practical problem are you trying to solve with example M2? > > If I just wanted a list of pointers I would use a static array e.g. > > MODULE M3; > TYPE P = POINTER TO R; > R = RECORD a: ARRAY 160 OF INTEGER END ; > A = ARRAY 200 OF P; > END M3. > > — > Regards, > Chris Burrows > I have adapted the inner core to allow for *arbitrary* file sizes, using a Unix-like inode structure both on disk and in-memory. On disk, it’s easy as all reference are simply (integer) disk addresses. But in-memory, I want to dynamically allocate *intermediate* nodes (nodes containing “just” 256 pointers to other index nodes which then contain actual disk addresses of data sectors) *only when needed*. In Extended Oberon, the modification in Files.Mod is straightforward, as one can just allocate a dynamic array of pointers whenever needed: MODULE Files; TYPE IndexTable = ARRAY FileDir.IndexSize OF Index; (*<---*) FileDesc* = RECORD … sec: FileDir.SectorTable; (*direct data blocks*) ext: ARRAY FileDir.ExTabSize OF Index; (*single indirect blocks*) ind: POINTER TO IndexTable; (*<--- double indirect blocks*) ... END PROCEDURE Old*(name: ARRAY OF CHAR): File; … IF k > FileDir.ExTabSize THEN NEW(f.ind); (*<--- allocate an array of pointers on the heap*) Disk.GetSector(F.ind, f.ind^) END but in the FPGA Oberon version, I currently need to resort to either a) or b): a) allocate a record containing an array of INTEGER using NEW, but do plus some type casting back to pointers (=> ugly) b) just increase the constant ORG.maxTD to e.g. 300 (which actually works and which is what I currently use). PS: I have played with a “compressed” representation of the pointer locations in records containing arrays of pointers (noting that the offsets simply repeat themselves N times in an array) in ORG, but the result is just too cumbersome, as such data structures can be defined recursively => not pursued. In any case, I’ll use b) for now. Regards, Andreas

1 0

Re: [Oberon] Array Index Out Of Range in ORG.FindPtrFlds
by Chris Burrows 18 Oct '21

18 Oct '21

> -----Original Message----- > From: Oberon [mailto:oberon-bounces@lists.inf.ethz.ch] On Behalf Of Andreas > Pirklbauer > Sent: Monday, 18 October 2021 5:09 PM > To: Oberon List > Subject: [Oberon] Array Index Out Of Range in ORG.FindPtrFlds > > The following program compilers correctly in FPGA Oberon > > MODULE M1; > TYPE P = POINTER TO R; > R = RECORD a: ARRAY 160 OF INTEGER END ; (*compiles correctly*) > END M1. > > but the following program leads to a trap 1 = array index out of range error > in ORG.FindPtrFlds > > MODULE M2; > TYPE P = POINTER TO R; > R = RECORD a: ARRAY 160 OF P END ; (*trap 1 = array index out of > range*) > END M2. ... ... > Any suggestions how to address that in program M2 (or in the compiler, other > than increasing maxTD)? > What practical problem are you trying to solve with example M2? If I just wanted a list of pointers I would use a static array e.g. MODULE M3; TYPE P = POINTER TO R; R = RECORD a: ARRAY 160 OF INTEGER END ; A = ARRAY 200 OF P; END M3. -- Regards, Chris Burrows CFB Software https://www.astrobe.com/RISC5

1 0

Re (2): Andre's Watson.html.
by peter＠easthope.ca 11 Oct '21

11 Oct '21

From: Liam Proven <lproven(a)gmail.com> Date: Mon, 11 Oct 2021 13:14:36 +0200 > Small correction: > "below" -- located underneath; opposite of "above" > "bellow" -- to speak at maximum volume, to shout Acknowledged. Unfortunately I can't correct the mail archive. > This also looks strange: http://easthope.ca/Watson2.gif Gadgets implementation of V4 fold? Used to store multiple revisions in one file. https://en.wikibooks.org/wiki/Oberon#Glossary Never used it and don't know the correct terminology. > You mean this? http://easthope.ca/Watson3.gif Yes. Meant to have the appearance of an eye? I don't understand the purpose. > You might ask him directly, via Jörg's suggestion? ?? Joerg referred to OMEGA or Omega. To my understanding, not related to the Watson{2,3}.gif active entities. Thanks, ... P. -- mobile: +1 778 951 5147 VoIP: +1 604 670 0140 48.7693 N 123.3053 W

1 0