January 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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Re: [Oberon] SD Card File Exchange (was: Why is RSC string data word-aligned?)
by Chris Burrows 01 Feb '21

01 Feb '21

> -----Original Message----- > From: Oberon [mailto:oberon-bounces@lists.inf.ethz.ch] On Behalf Of > Skulski, Wojciech > Sent: Monday, 1 February 2021 7:00 AM > To: ETH Oberon and related systems > Subject: Re: [Oberon] Why is RSC string data word-aligned? > > From my user perspective the file system speed optimizations are not > even secondary. I would rather want to see a convenient file exchange > between the RISC5 Oberon and Windows workstations. I would like to > plug the Oberon SD into an SD card reader and easily copy files under > Windows, from the V4 directory to the SD and vice versa, using the > usual Windows drag and drop. I would like to do the same between the > Oberon SD and the emulator. > As you are aware, our HCFiler (high-capacity) software allows you to plug the Oberon SD card into an SD card reader and copy files to Windows. For the benefit of others, the original announcement is here: "HCFiler - An efficient embedded SDHC FileSystem" https://www.astrobe.com/forum/viewtopic.php?f=4&t=534 The source code that is available to copy the files from the Project Oberon partition to the HCFiler partition (ALL of the SD card, no matter how big) is available. It would not be difficult to adapt this to copy files from Windows to the Project Oberon partition. I would recommend using Gardens Point Component Pascal as the compiler to do this: https://www.cfbsoftware.com/gpcp GPCP and CPIde is what I use daily for all of my Oberon development under Windows 10. > I would like to use the entire SD card rather than a small portion of > it. I do not mind "partitions", if partitions are visible and easily > used under the emulator, the Windows host, and the Oberon > workstation. > I would like to add Linux and Mac to the list of hosts, > though I am not using either. > I'll leave it to others to recommend solutions for emulators and Linux and Mac. > Present PC link is fine for small files or for the SW development. > But it is not great for massive file exchange between Oberon and > hosts, or Oberon and emulators. > Copying files from Windows using HCFiler has not been a high priority for me as nobody apart from you has asked me for it to date. Is there anybody else here who is interested? > Concerning the speed under the Oberon, a boost would be provided with > the QSPI interface rather than the present SPI interface. Point me to documentation on how to access SDHC cards using QSPI and I'll look into it. I was only aware of MMC as a faster access method. If anybody has any experience of using MMC with RISC5 I'd be very interested. Regards, Chris Burrows CFB Software https://www.astrobe.com/RISC5

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List of extensions for Project Oberon compiler
by August Karlstrom 01 Feb '21

01 Feb '21

Does anyone know if the language extensions that the Project Oberon compiler provides in relation to the Oberon report (from 2016) is documented somewhere? I'm thinking of features such as dynamic arrays and structural equivalence of arrays used in assignments. -- August

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Why is RSC string data word-aligned?
by Andreas Pirklbauer 31 Jan '21

31 Jan '21

> The unaligned data in a .rsc file is, I agree, unfortunate, as it could > have been aligned relatively easily and then data could have been > copied into memory a word at a time. Isn’t any data - including string data . already word-aligned in the compiler (and therefore also in the .rsc file)? 1. The array ORG.str itself is word-aligned, because... - Modules.AllocPtr is word-aligned (see Modules.Load) - Modules.DescSize is a multiple of 4, so mod.data is word-aligned - All type descriptors are word-aligned (see ORG.BuildTD) - All variables are word-aligned (see ORG.Declarations) - All strings are word-aligned (see ORG.MakeStringItem) 2. ORG.MakeStringItem WHILE strx MOD 4 # 0 DO str[strx] := 0X; INC(strx) END 3. ORP.Declarations IF sym = ORS.var THEN ... IF tp.size > 1 THEN varsize := (varsize + 3) DIV 4 * 4 (*align*) END ; … END ; varsize := (varsize + 3) DIV 4 * 4;

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Why is RSC string data word-aligned?
by Colby Russell 31 Jan '21

31 Jan '21

I'm returning to some of the code that deals with Oberon's RSC binary file format. The first time I went through this exercise, I noticed that ORG pads string data, so individual strings begin on word boundaries, and I didn't think much about it. Presumably it was done for efficiency. Now, though, I'm wondering. Does anyone have a breakdown comparing the two approaches--where strings don't get padded with NUL bytes and may begin anywhere, versus what happens if with word alignment? If there are some string handling routines where this makes a material difference, can someone point to them? I've already looked around, but I realize that string representation is a cross-cutting concern, and there's just too much material to exhaustively scour it all again. If there was a call out on this topic in the explanation of the the simple compiler that's documented in Compiler Construction, then I wasn't able to find it. I looked at a few sections in the Oberon book as well, hoping to see if it was explained (e.g. the module loader chapter), but didn't spot anything there, either. -- Colby Russell

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Why is RSC string data word-aligned?
by Andreas Pirklbauer 31 Jan '21

31 Jan '21

> However, the whole object file is read in when the module is loaded. Hence, > the module loader is only slowed down by 1% because of those extra nulls. Perhaps not even 1% slower, because consecutive bytes are read from in-memory buffers.

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Re: [Oberon] Why is RSC string data word-aligned?
by Jörg 31 Jan '21

31 Jan '21

Hi Colby > No. To repeat: I'm talking about CPU instructions and memory reads--i.e. Okay. So, what exactly do you want to optimize? - write IO commands - read IO commands - memory accesses - CPU cycles All of the above is not equivalent. And might result in different code. Normally, such kind of micro optimization is done in the inner most part of a loop that is called million of times. (ray tracing or so) rsc file writing and reading does not happen very often. >> To optimize the File IO you would turn this [...] into something like this >I'm not sure where that sample comes from. It doesn't match the code in the module loader (and it wouldn't make sense; the module loader is doing a file read, not a write). This is the code in the compiler, where strings are written to the rsc file. And my attempt to optimize file write IO in the compiler, when writing the rsc file. My code does for sure less file write IO but is longer than the original. I can't immediately judge whether overall less CPU cycles are the result of my code compared to the original simple FOR. File write is buffered and is very efficient as it normally involves only two IFs and 3 assignments per Write() call. The read in the module loader would obviously be the opposite: when reading the eos (=0X), we have to expand it to consecutive 0X to be word-aligned. br Jörg

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Re (2): Oberon genealogy graph
by peter＠easthope.ca 23 Jan '21

23 Jan '21

The genealogy diagram is revised again, primarily to remove ambiguous arrow crossings and to represent chronology better. https://en.wikibooks.org/wiki/Oberon#Historical_Perspective I think of two potential criticisms. (1) The diagram is too complex and bulky. Visualization is hampered. (2) Out of respect for original work, development beyond Oberon-07 and V5 should not be included. Both can be addressed by dividing the diagram into smaller diagrams. For example, derivatives beyond Oberon-07 and V5 can be in a second graph. Feedback in the list or in personal email is welcome. Regards, ... P. L. -- Tel: +1 604 670 0140 Bcc: peter at easthope. ca

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