March 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

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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

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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

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Usenet group comp.lang.oberon is no longer accessible
by Chris Burrows 30 May '21

30 May '21

The Usenet group 'comp.lang.oberon' which I normally access through Google Groups has recently become unavailable with the message: "Banned content warning: comp.lang.oberon has been identified as containing spam, malware, or other malicious content." https://groups.google.com/g/comp.lang.oberon While it is true that spammers occasionally attacked this group (I usually reported such attacks - maybe I shouldn't have?) there was about 30 years' worth of historically significant discussions about Oberon contained in the archived messages so it is an extreme case of 'throwing the baby out with the bathwater'. I reported the access problem to Google Groups about a week ago but haven't heard back yet. Does anybody know how to restore access to this group? If you are unfamiliar with what I'm talking about, see the similar Usenet discussion group comp.lang.modula2 which is still active and accessible: https://groups.google.com/g/comp.lang.modula2 Thanks, Chris Burrows CFB Software https://www.astrobe.com

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Oberon board, 2021
by Aubrey McIntosh 10 Apr '21

10 Apr '21

I have a windfall that will allow me to buy a hardware system that will support the Oberon / FPGA environment. I don't know the current status of board recommendation and such, and anyway it is a moving target. My last reasonably current status was in the Spartan board era. I would like to build some custom peripherals that are deeply coupled with my software. A representative example would be a 32-bit adder. An even more aggressive example would be a sha-256 stamper. I was somewhat active with Bitcoin long ago when a FPGA board was powerful enough for Bitcoin. I have also previously built a board with various A/D converters, with a view of using them in an undergraduate chemistry curriculum. The one restriction I can think of, I want to be able to program the hardware with homebrew and/or freeware. Previously, I have produced a board that could "in circuit program" a clone of itself. So, while not a professional, I am able to work at a level that pleases me. I think a group buy always makes sense. -- Aubrey McIntosh, PhD

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Re: [Oberon] How to use SYSTEM.VAL safely?
by Jeff Maggio 31 Mar '21

31 Mar '21

Thanks! I'm actually using binary-coded decimal, which is a little different. I'm writing two separate 4bit decimal digits alongside each other. Each 4bit field drives a separate seven segment display on our embedded board best, Jeff Jeff For bitwise operations SYSTEM.VAL is safe. > The hint to the garbage collection is rather meant in case you manipulate > POINTERs by doing calculations on them using INTEGERs. > Common low-level programming practice BTW: If I understand correctly what > you want to do with SetVal is, interprete the decimal input value as hex > nbr. SetVal(73) will store value 115 at address SEVENSEGADR. If so, I would > code it as follows: > SYSTEM.PUT(SEVENSEGADR, > val DIV 10*16 + val MOD 10); Perhaps an other method would be to call > SetVal with the hex value in the first place: > SetValue(73H); > and SerVal just does > SYSTEM.PUT(SEVENSEGADR, val) br > Jörg

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How to use SYSTEM.VAL safely?
by Jeff Maggio 31 Mar '21

31 Mar '21

Hi All! I'm new to the world of RISC5 and Oberon I'm curious about the dangers of using SYSTEM.VAL for casting or type conversion. I need to do bitwise operations on Integers and was planning on converting them to SETs using SYSTEM.VAL. However, this webpage <https://en.wikibooks.org/wiki/Oberon/ETH_Oberon/faqlang#bitwise> warns me to avoid using SYSTEM.VAL because it can break garbage collection, but I wasn't able to find any of Wirth's own documentation about it. I'm assuming that means that there is a potential for a memory leak if not used properly? How can I make sure I'm using SYSTEM.VAL safely? Is the following example "safe"? PROCEDURE SetVal*(val : INTEGER); > (* only values between 0 and 99 are valid*) > VAR digit1, digit2 : SET; > BEGIN > (* Convert the integer into 2 binary-coded decimal digits*) > digit1 := SYSTEM.VAL(SET, val DIV 10); > digit2 := SYSTEM.VAL(SET, val MOD 10); > digit1 := LSL(digit1, 4); > SYSTEM.PUT(SEVENSEGADR, digit1 + digit2); > END SetVal;

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Re (2): Emulating interrupts in oberon-risc-emu as in the RISC5 specification
by peter＠easthope.ca 31 Mar '21

31 Mar '21

>From Charles Perkins, Tue Mar 30 23:45:07 CEST 2021 > I wanted to explore interrupt handling in Oberon ... LDPSR is now in the glossary. https://en.wikibooks.org/wiki/Oberon#Glossary Review can be helpful. Feedback is welcome, here or in a private message. Or edit directly. (It's a wiki.) Regards, ... P. -- cell: +1 236 464 1479 Bcc: peter at easthope. ca VoIP: +1 604 670 0140

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Emulating interrupts in oberon-risc-emu as in the RISC5 specification
by Charles Perkins 31 Mar '21

31 Mar '21

Hello Everybody, I wanted to explore interrupt handling in Oberon and I discovered that Peter De Wachter's excellent emulator did not implement them, which is not surprising, as the current Project Oberon source doesn't use them as far as I can tell and the only example source code showing how to use interrupts is the TestInt module on Professor Wirth's own 2018 update to RISC5: https://people.inf.ethz.ch/wirth/ProjectOberon/RISC5.Update.pdf Since I wanted to compile and run that small example I forked Peter's emulator and added support for Interrupts in a branch here: https://github.com/io-core/oberon-risc-emu (only a few small changes were needed.) With those changes I am able to compile the TestInt module and execute it in the emulator using the 2019 disk image in the repo. Emulated LEDs update once per second as expected. I don't intend to maintain a fork of Peter's emulator, I just wanted to experiment with interrupts and share the implementation in case anyone else is interested. Best Regards, Chuck

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A network connection for ETHO on QEMU.
by peter＠easthope.ca 15 Mar '21

15 Mar '21

No problem running ETHO on QEMU in Debian 10. Creation of a network connection from the ETHO guest system to the QEMU host is giving difficulty. I expect to use the NetNe2000 driver. This qemu command fails as follows. alias etho='qemu-system-i386 \ -drive file=/dev/KingstonCF,media=disk,format=raw \ -vga std \ -boot order=c \ -netdev bridge,id=bridge0,br=br0 \ -device ne2k_pci,netdev=bridge0 \ ' peter@joule:/home/peter$ etho failed to parse default acl file `/etc/qemu/bridge.conf' qemu-system-i386: bridge helper failed Ideas? Thanks, ... P. L. -- cell: +1 236 464 1479 Bcc: peter at easthope. ca VoIP: +1 604 670 0140

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