September 2019 - Oberon - mailman3.inf.ethz.ch

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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Debugging FPGA oberon via serial line?
by Michael Schierl 29 May '20

29 May '20

Hello, while I was adding UTF-8 support to Fonts and Texts (and almost rewriting Fonts so that a font can be loaded partially and not all glyphs at once), I noticed that debugging such a system can be cumbersome (as you cannot read the TRAP output any more, as well as you have to reset the system to a previous state to be able to fix your mistakes if the screen is too garbled to be useful, or if the system TRAPs during boot). By the way, here is Oberon running in the browser with UTF-8 support for Texts (and Tahoma font): http://schierlm.github.io/OberonEmulator/emu.html?image=UnicodeDiskImage >From other (older) systems, I know it is possible to debug them via serial line, so I was thinking how much the FPGA oberon system needs to be changed (hardware side/software side) to accommodate this. RS232 is supported, so you could use one FPGA system (or emulator) to debug the other one. And I was wondering if anybody already tried doing something like this. I know that Colby Russell worked on debug support in the emulator, but no idea about how far he got. A minimal feature set to be useful (in my opinion) would be - Read and write memory and disk via serial port while the system is running/idle (already possible today via ORC / PCLink) - Set and remove software breakpoints while the system is running/idle - When software breakpoint or trap is hit, save processor state and allow debugging via serial port (-> suspended) - Read and write registers and memory while the system is suspended - Set and remove software breakpoints while the system is suspended - Continue execution when the system is suspended More advanced features would be single stepping (can be emulated by having a look at the instruction and setting software breakpoints at all following locations), or memory breakpoints. Also to be able to enter the debugger by pressing a hardware button on the FPGA (similar to the current reset functionality, but not resetting). And of course symbolic debugging :) Software breakpoints should be easy, just replace instruction by BL to a fixed address. Restore the instruction before returning. For catching TRAPs, overwrite the TRAP address. Saving processor state might be tricky, especially SYSTEM.H and the flags, and maybe you have problems since you need at least one spare register to be able to save the registers to a fixed location in memory. You will also need to switch stack to a second stack before the stack is accessed by the code. Probably solvable by using a special compiler that leaves a register or two unused. Restoring SYSTEM.H and Flags is also not supported (except by searching for instructions that will result in the desired flags or results). Also the question is whether returning to the code will not destroy some flags again. And you need to make sure not to set breakpoints or break at points where a BL has happened but the link register has not been saved yet. So (similar to interrupt) probably some hardware support is needed for this. Entering the debugger by button also needs hardware support (since the current Reset button forgets the PC and some other state). Once in suspend mode, it might be hard to avoid allocating memory, since you cannot run the GC which might collect objects that are still used by the suspended program. But that should be feasible if the functions are basic enough to work with a fixed buffer (e.g. number of breakpoints is limited). I guess memory breakpoints are only possible with hardware support for them (I have no idea how to emulate them except emulating or setting breakpoints at all LOAD/STORE instructions). For symbolic debugging, the compiler would have to write some more debug symbols. For a start, <https://github.com/schierlm/OberonXref/blob/master/ORG.Mod.patch> annotates the code position for every instruction; I currently use it for creating combined source/assembly listings like <https://schierlm.github.io/OberonXref/ProjectOberon2013/ORP.html#both>. But you would probably also need some information about the stack layout (variable names and types) and register contents for every code locatoin, as well as information about module/global variables, and not-exported record types and record members. And you would also need some client to utilize all this information so that you can do something like "Debugger.Inspect F.vwr.dsc" :) So I guess for my own needs, that's too much work for the benefit (especially since I don't know if I will ever try to rewrite any of the core modules again). But perhaps I'm missing something? Any better ideas? Regards, Michael

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Re: [Oberon] Oberon online (code snippets sharing)
by peter＠easthope.ca 19 Dec '19

19 Dec '19

From: Erik Terpstra <erterpstra(a)gmail.com> Date: Tue, 13 Aug 2019 10:00:04 +0200 > I have asked the maintainer of tio.run (Try It Online, a code snippet > sharing site) if Oberon-07 could be added, he agreed and added support for > it (using the OBNC compiler). Thanks Erik. > You can see a Hello world snippet here: > > https://bit.ly/2Mic0NN A click on Oberon-07 in the list of languages leads to https://tio.run/#oberon-07 . Is there any harm in referring to that URL? Thanks, ... Lyall E. -- https://en.wikibooks.org/wiki/Oberon Tel: +1 604 670 0140 Bcc: peter at easthope. ca

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Importing more than 15 modules
by Andreas Pirklbauer 27 Sep '19

27 Sep '19

> > Has anyone by any chance adapted the FPGA Oberon system to use a > > *separate* fixup list for each imported module … > > > Wish I could tackle such project but too ambitious for me at present. Never mind. It turned out to be only a few lines of code. Here is a proof-of-principle (for EO): https://github.com/andreaspirklbauer/Oberon-allow-importing-any-number-of-m…

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Local procedures.
by peter＠easthope.ca 27 Sep '19

27 Sep '19

From: Andreas Pirklbauer <andreas_pirklbauer(a)yahoo.com> Date: Thu, 26 Sep 2019 22:34:12 +0200 > Has anyone by any chance adapted the FPGA Oberon system to use a > *separate* fixup list for each imported module ... Wish I could tackle such project but too ambitious for me at present. >From andreas_pirklbauer at yahoo.com Sat Feb 10 15:37:23 2018 > I believe eliminating local procedures would not do much harm. In rewriting Mail.Wrap ( https://en.wikibooks.org/wiki/Oberon/A2/Oberon.Mail.Mod ) I globalized procedures which might have been local to Wrap. WCopySeparator(), for example. Rather than introduce a long parameter list I invented global type WrapData allowing parameter data bundled in one variable. If there is a negative concensus for what I've done, procedures can be localized easily enough. To the extent of my experience, Wrap is error-free when applied to Oberon Text. When applied to Text in a Document there can be some breakage. I need to understand and fix that. Given my limited expertise, feedback is certainly welcome. Thanks, ... Lyall E. -- https://en.wikibooks.org/wiki/Medical_Machines Tel: +1 604 670 0140 Bcc: peter at easthope. ca

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Importing more than 15 modules
by Andreas Pirklbauer 26 Sep '19

26 Sep '19

Has anyone by any chance adapted the FPGA Oberon system to use a *separate* fixup list for each imported module (similar to how it is done in A2) rather than using a single fixup list for all imported modules (as is currently the case in FPGA Oberon e.g. for the list headed by fixorgP)? I.e. has anyone played with implementing the list structure shown in Figure 15.8.(b) on p.97 of the book https://inf.ethz.ch/personal/wirth/CompilerConstruction/CompilerConstructio… ? This would allow one to lift the restriction of putting only 4 bits in place for a module number (mno) in a BL instruction generated for an external procedure call, which in turn would mean that one could import more than 15 modules in FPGA Oberon.

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OFSFATTools.
by peter＠easthope.ca 22 Sep '19

22 Sep '19

Hi again, I have the impression that a disk or diskette image mounted to imitate a real device is termed a ramdisk. An Oberon ramdisk is used in the Oberon0 diskette for installing S3. The section of Native.Tool for building the Dummies CD includes these lines. OFSFATTools.CreateFile FAT:/Oberon.Dsk 25 OFSFileBasedDeviceTools.Open VIRT FAT /Oberon.Dsk ~ # mount the file as a virual device In my understanding, a FAT ramdisk is created; but S3 Alpha has CreateFile commented out. Does anyone happen to know why that is? (I've never needed the Dummies CD but a FAT ramdisk still has some uses.) Thanks, ... Lyall E. -- https://en.wikibooks.org/wiki/Medical_Machines Tel: +1 604 670 0140 Bcc: peter at easthope. ca

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Q: Why bother with Mail.Show?
by peter＠easthope.ca 14 Sep '19

14 Sep '19

A: In S3 and in A2 Oberon (A2O) the Mail.Panel works well. Nevertheless Mail.Show can display a message without the Mail.Panel. Somewhat similar to Mutt or Alpine in Linux, although Mail.Show is better of course! =8~) A constraint with Mail.Show is that the message number n must be known to allow activation of Mail.Show n . Also, the user might want to search through senders or recipients or subjects without searching through a multi-MiB MsgFile (MailMessages). With S3 Mail.Mod and A2O Oberon.Mail.Mod, Mail.Show ~ does nothing. So my thought is to have Mail.Show ~ list messages. Ie. make a roster with message number, sender, recipient, subject per line. At least, I don't see any harm. (?) Also it's a chance to understand Gadgets just a little. The distributed source is at https://svn-dept.inf.ethz.ch/svn/lecturers/a2/trunk/source/ Userid is infsvn.anonymous, password is anonymous . The proposed revision follows. Apologies for the bulky message and any comment or criticism is welcome. Thanks! ... Lyall E. (* Show the message by activating in the Mail.Panel. Otherwise show the message identified by number. Show 13 ~ Otherwise, with no message identified, show a list of messages. Mail.Show ~ *) PROCEDURE Show*; VAR S: Attributes.Scanner; T: Texts.Text; D: Documents.Document; obj: Objects.Object; F: Texts.Finder; no: LONGINT; plain: BOOLEAN; line: ListGadgets.Line; strm: Streams.Stream; h: MIME.Header; cont: MIME.Content; len, pos: LONGINT; str: ARRAY BufLen OF CHAR; BEGIN IF Desktops.IsInMenu(Gadgets.context) THEN D := Desktops.CurDoc(Gadgets.context); Links.GetLink(D.dsc, "Model", obj); IF (obj # NIL) & (obj IS Texts.Text) THEN Texts.OpenFinder(F, obj(Texts.Text), 0); Texts.FindObj(F, obj); IF (obj # NIL) & (obj IS TextGadgets.Style) THEN Attributes.SetString(Gadgets.executorObj, "Caption", "Text"); Attributes.GetInt(obj, "Message", no); plain := TRUE ELSE Attributes.SetString(Gadgets.executorObj, "Caption", "Source"); Attributes.GetInt(Gadgets.executorObj, "Message", no); plain := FALSE END; IF (no >= 0) & (no < noMsgs) THEN decodeMessage(no, T, plain); Attributes.SetInt(Gadgets.executorObj, "Message", no); Links.SetLink(D.dsc, "Model", T) END; Gadgets.Update(Gadgets.executorObj) END ELSE Attributes.OpenScanner(S, Oberon.Par.text, Oberon.Par.pos); Attributes.Scan(S); IF S.class = Attributes.Int THEN IF (S.i >= 0) & (S.i < noMsgs) THEN (* Message identified. *) obj := FindObj("MailList"); IF obj # NIL THEN WITH obj: ListGadgets.Frame DO line := obj.lines; REPEAT line.sel := msgs[S.i].pos = line.key; line := line.next UNTIL line = obj.lines; obj.sel := TRUE; obj.time := Oberon.Time(); Gadgets.Update(obj) END END; decodeMessage(S.i, T, FALSE); ShowText("Mail.Text", T, TRUE) END ELSE (* No message identified. *) IF 0 < noMsgs THEN Texts.WriteString(W, "Msg no. From To Subject"); Texts.WriteLn(W); no := 0; WHILE no < noMsgs DO Texts.WriteInt(W, no, 0); Texts.Write(W, " "); strm := Streams.OpenFileReader(msgsF, msgs[no].pos); strm.mode := Streams.binary; MIME.ReadHeader(strm, NIL, h, len); ParseContent(h, cont); pos := MIME.FindField(h, "From"); MIME.ExtractEMail(h, pos, str); Texts.WriteString(W, str); Texts.WriteString(W, " "); pos := MIME.FindField(h, "To"); MIME.ExtractEMail(h, pos, str); Texts.WriteString(W, str); Texts.WriteString(W, " "); pos := MIME.FindField(h, "Subject"); MIME.ExtractValue(h, pos, str); Texts.WriteString(W, str); Texts.WriteLn(W); INC(no) END; NEW(T); Texts.Open(T, ""); Texts.Append(T, W.buf); ShowText("Messages", T, TRUE) END END END END Show; -- https://en.wikibooks.org/wiki/Medical_Machines https://en.wikibooks.org/wiki/Oberon Tel: +1 604 670 0140 Bcc: peter at easthope. ca

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Re (2): A case in S3 Mail.Show.
by peter＠easthope.ca 14 Sep '19

14 Sep '19

From: =?utf-8?Q?J=C3=B6rg?= <joerg.straube(a)iaeth.ch> Date: Sat, 14 Sep 2019 00:37:01 +0200 > The REPEAT/UNTIL loops through all lines in the ListGadget and only > selects (line.sel := TRUE) the line that corresponds to line 13 by > comparing the starting position of mail 13 to the „line.key“ > stored in the gadget. OK. > The final Gadgets.Update() displays the change of the line selection. OK, but the Mail.Panel isn't changed. For example, suppose message 10 is selected in the Mail.Panel; the line for message 10 is in reverse video. The message itself can be displayed or not. Mail.Show 13 will leave the line for message 10 in the panel in reverse video. What harm can occur if Gadgets.Update(obj) is omitted? Ie. the line list and the displayed message are left inconsistent. Thanks, ... Lyall E. -- https://en.wikibooks.org/wiki/Medical_Machines https://en.wikibooks.org/wiki/Oberon Tel: +1 604 670 0140 Bcc: peter at easthope. ca

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Re (2): A case in S3 Mail.Show.
by peter＠easthope.ca 14 Sep '19

14 Sep '19

From: =?utf-8?Q?J=C3=B6rg?= <joerg.straube(a)iaeth.ch> Date: Sat, 14 Sep 2019 00:37:01 +0200 > The REPEAT/UNTIL loops through all lines in the ListGadget and only > selects (line.sel := TRUE) the line that corresponds to line 13 by > comparing the starting position of mail 13 to the „line.key“ > stored in the gadget. OK. > The final Gadgets.Update() displays the change of the line selection. OK, but the Mail.Panel isn't changed. For example, suppose message 10 is selected in the Mail.Panel; the line for message 10 is in reverse video. The message itself can be displayed or not. Mail.Show 13 will leave the line for message 10 in the panel in reverse video. What harm can occur if Gadgets.Update(obj) is omitted? Ie. the line list and the displayed message are left inconsistent. Thanks, ... Lyall E. -- https://en.wikibooks.org/wiki/Medical_Machines https://en.wikibooks.org/wiki/Oberon Tel: +1 604 670 0140 Bcc: peter at easthope. ca

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