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</o:shapelayout></xml><![endif]--></head><body lang=EN-AU link=blue vlink=purple><div class=WordSection1><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D;mso-fareast-language:EN-US'>Before even thinking about embarking on a major project like that I would recommend spending a few months experimenting with GNU Modula-2 (a frontend to GCC) to get an idea of the effort involved in such an exercise and to gain some hands-on experience of how useful the end-product might be. <o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D;mso-fareast-language:EN-US'><o:p> </o:p></span></p><p class=MsoNormal><span class=MsoHyperlink><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";mso-fareast-language:EN-US'><a href="http://nongnu.org/gm2/download.html">http://nongnu.org/gm2/download.html</a><o:p></o:p></span></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D;mso-fareast-language:EN-US'><o:p> </o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D;mso-fareast-language:EN-US'>This work has been actively maintained by Gaius Mulley at the University of Glamorgan for many years now. The Modula-2 mailing list archives are evidence of this:<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D;mso-fareast-language:EN-US'><o:p> </o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D;mso-fareast-language:EN-US'><a href="https://lists.nongnu.org/archive/html/gm2/">https://lists.nongnu.org/archive/html/gm2/</a><o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D;mso-fareast-language:EN-US'><o:p> </o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D;mso-fareast-language:EN-US'>He has published some related papers on his website. e.g. “A report on the progress of GNU Modula-2 and its potential integration into GCC”<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D;mso-fareast-language:EN-US'><o:p> </o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D;mso-fareast-language:EN-US'><a href="http://floppsie.comp.glam.ac.uk/">http://floppsie.comp.glam.ac.uk/</a><o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D;mso-fareast-language:EN-US'><o:p> </o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D;mso-fareast-language:EN-US'>Regards,<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D;mso-fareast-language:EN-US'>Chris Burrows<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D;mso-fareast-language:EN-US'>CFB Software<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D;mso-fareast-language:EN-US'><a href="https://www.astrobe.com">https://www.astrobe.com</a><o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D;mso-fareast-language:EN-US'><o:p> </o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D;mso-fareast-language:EN-US'><o:p> </o:p></span></p><div style='border:none;border-left:solid blue 1.5pt;padding:0cm 0cm 0cm 4.0pt'><div><div style='border:none;border-top:solid #E1E1E1 1.0pt;padding:3.0pt 0cm 0cm 0cm'><p class=MsoNormal><b><span lang=EN-US style='font-size:11.0pt;font-family:"Calibri","sans-serif"'>From:</span></b><span lang=EN-US style='font-size:11.0pt;font-family:"Calibri","sans-serif"'> Oberon [mailto:oberon-bounces@lists.inf.ethz.ch] <b>On Behalf Of </b>Jan de Kruyf<br><b>Sent:</b> Thursday, 30 April 2020 8:07 AM<br><b>To:</b> ETH Oberon and related systems<br><b>Subject:</b> Re: [Oberon] Interfacing with Foreign Systems (was: Negative integer literals in Oberon)<o:p></o:p></span></p></div></div><p class=MsoNormal><o:p> </o:p></p><div><p class=MsoNormal>guy,<o:p></o:p></p><div><p class=MsoNormal>when I was young, and still thinking girls were stupid, I also did a hacked Oberon compiler for some micro controller.<o:p></o:p></p></div><div><p class=MsoNormal>It was a wonderful learning experience, but although the end result worked, I now would be <o:p></o:p></p></div><div><p class=MsoNormal>ashamed to show it. It was ultimately a one off for a one off job.<o:p></o:p></p></div><div><p class=MsoNormal>Since then I have learned that girls are actually quite nice and worthwhile to spend some time on,<o:p></o:p></p></div><div><p class=MsoNormal>while computer fashions change like the weather.<o:p></o:p></p></div><div><p class=MsoNormal><o:p> </o:p></p></div><div><p class=MsoNormal>Now for the bigger picture after this digression:<o:p></o:p></p></div><div><p class=MsoNormal>As you also did find out, I guess: <o:p></o:p></p></div><div><p class=MsoNormal>Oberon is a niche language sitting somewhere in an obscure corner. I maintain that one of the causes is <o:p></o:p></p></div><div><p class=MsoNormal>that there is no compiler like gcc that has an oberon front end but that could have many different back ends.<o:p></o:p></p></div><div><p class=MsoNormal>(Joerg does not agree with me I know <span style='font-family:"Segoe UI Symbol","sans-serif"'>🙄</span>)<o:p></o:p></p></div><div><p class=MsoNormal>If we would stick our heads together and see if an Oberon frontend to gcc is manageable then <o:p></o:p></p></div><div><p class=MsoNormal>Oberon becomes a useful tool for many embedded controllers since there are already many back-ends.<o:p></o:p></p></div><div><p class=MsoNormal>And the building of a toolchain for cross-compilation is a well documented task, I have done it in Ada.<o:p></o:p></p></div><div><p class=MsoNormal>A binding with the hardware / libraries of a new controller can then be whipped up in a matter of days.<o:p></o:p></p></div><div><p class=MsoNormal><o:p> </o:p></p></div><div><p class=MsoNormal>What you are proposing has been done in the past. People have constructed Oberon to C translators <o:p></o:p></p></div><div><p class=MsoNormal>(but without modifying the language), but for one reason or another none of those made it into a <o:p></o:p></p></div><div><p class=MsoNormal>productive tool that is used much. Lack of a well documented way to use foreign libraries and lack of <o:p></o:p></p></div><div><p class=MsoNormal>an easy debugging mechanism come to mind.<o:p></o:p></p></div><div><p class=MsoNormal><o:p> </o:p></p></div><div><p class=MsoNormal>hope this stimulates your grey matter a bit.<o:p></o:p></p></div><div><p class=MsoNormal><o:p> </o:p></p></div><div><p class=MsoNormal>j.<o:p></o:p></p></div><div><p class=MsoNormal><o:p> </o:p></p></div></div><p class=MsoNormal><o:p> </o:p></p><div><div><p class=MsoNormal>On Wed, Apr 29, 2020 at 2:45 PM Guy T. <<a href="mailto:turgu666@gmail.com">turgu666@gmail.com</a>> wrote:<o:p></o:p></p></div><blockquote style='border:none;border-left:solid #CCCCCC 1.0pt;padding:0cm 0cm 0cm 6.0pt;margin-left:4.8pt;margin-right:0cm'><div><p class=MsoNormal>The approach I’ve taken so far is very similar to the "Oberon-2 Programming with Windows”. Here is the modifications to the language I’ve done (from the syntax definition of Oberon-07):<o:p></o:p></p><div><p class=MsoNormal><o:p> </o:p></p></div><div><div><p class=MsoNormal><span style='font-size:8.5pt;font-family:"Menlo","serif"'>Module = OberonModule | CModule.<o:p></o:p></span></p></div><div><p class=MsoNormal><span style='font-size:8.5pt;font-family:"Menlo","serif"'>OberonModule = MODULE ident ";" [ImportList] DeclarationSequence<o:p></o:p></span></p></div><div><p class=MsoNormal><span style='font-size:8.5pt;font-family:"Menlo","serif"'> [BEGIN StatementSequence] END ident "." . (* No change here *)<o:p></o:p></span></p></div><div><p class=MsoNormal><span style='font-size:8.5pt;font-family:"Menlo","serif"'>CModule = MODULE "[" CDECL "]" ident ";" [ImportList]<o:p></o:p></span></p></div><div><p class=MsoNormal><span style='font-size:8.5pt;font-family:"Menlo","serif"'> CDeclarationSequence END ident "." .<o:p></o:p></span></p></div><div><p class=MsoNormal><span style='font-size:8.5pt;font-family:"Menlo","serif"'>CDeclarationSequence = DeclarationSequence =<o:p></o:p></span></p></div><div><p class=MsoNormal><span style='font-size:8.5pt;font-family:"Menlo","serif"'> [CONST {ConstDeclaration ";"}]<o:p></o:p></span></p></div><div><p class=MsoNormal><span style='font-size:8.5pt;font-family:"Menlo","serif"'> [TYPE {TypeDeclaration ";"}]<o:p></o:p></span></p></div><div><p class=MsoNormal><span style='font-size:8.5pt;font-family:"Menlo","serif"'> [VAR {VariableDeclaration ";"}]<o:p></o:p></span></p></div><div><p class=MsoNormal><span style='font-size:8.5pt;font-family:"Menlo","serif"'> {CProcedureDeclaration ";"}.<o:p></o:p></span></p></div><div><p class=MsoNormal><span style='font-size:8.5pt;font-family:"Menlo","serif"'><o:p> </o:p></span></p></div><div><p class=MsoNormal><span style='font-size:8.5pt;font-family:"Menlo","serif"'>ArrayType = ARRAY ["[" CDECL "]"] length {"," length} OF type.<o:p></o:p></span></p></div><div><p class=MsoNormal><span style='font-size:8.5pt;font-family:"Menlo","serif"'>PointerType = POINTER ["[" CDECL "]"] TO type.<o:p></o:p></span></p></div><div><p class=MsoNormal><span style='font-size:8.5pt;font-family:"Menlo","serif"'>ProcedureType = PROCEDURE ["[" CDECL "]"] [FormalParameters].<o:p></o:p></span></p></div><div><p class=MsoNormal><span style='font-size:8.5pt;font-family:"Menlo","serif"'><o:p> </o:p></span></p></div><div><p class=MsoNormal><span style='font-size:8.5pt;font-family:"Menlo","serif"'>ProcedureDeclaration = OberonProcedureDeclaration | CProcedureDeclaration.<o:p></o:p></span></p></div><div><p class=MsoNormal><span style='font-size:8.5pt;font-family:"Menlo","serif"'>OberonProcedureDeclaration = ProcedureHeading ";" ProcedureBody ident. (* No change here *)<o:p></o:p></span></p></div><div><p class=MsoNormal><span style='font-size:8.5pt;font-family:"Menlo","serif"'>CProcedureDeclaration = CProcedureHeading ";" .<o:p></o:p></span></p></div><div><p class=MsoNormal><span style='font-size:8.5pt;font-family:"Menlo","serif"'>CProcedureHeading = PROCEDURE ["[" CDECL "]"] identdef [FormalParameters].<o:p></o:p></span></p></div><div><p class=MsoNormal><span style='font-size:8.5pt;font-family:"Menlo","serif"'><o:p> </o:p></span></p></div><div><p class=MsoNormal><span style='font-size:8.5pt;font-family:"Menlo","serif"'>RecordType = OberonRecordType | CRecordType.<o:p></o:p></span></p></div><div><p class=MsoNormal><span style='font-size:8.5pt;font-family:"Menlo","serif"'>OberonRecordType = RECORD ["(" BaseType ")"] [FieldListSequence] END. (* No change here *)<o:p></o:p></span></p></div><div><p class=MsoNormal><span style='font-size:8.5pt;font-family:"Menlo","serif"'>CRecordType = RECORD ["[" CDECL "]"] [FieldListSequence] END.<o:p></o:p></span></p></div><div><p class=MsoNormal><span style='font-size:8.5pt;font-family:"Menlo","serif"'><o:p> </o:p></span></p></div></div><div><p class=MsoNormal><span style='font-size:8.5pt;font-family:"Menlo","serif"'>——<o:p></o:p></span></p></div><div><p class=MsoNormal><span style='font-size:8.5pt;font-family:"Menlo","serif"'><o:p> </o:p></span></p></div><div><p class=MsoNormal><span style='font-size:8.5pt;font-family:"Menlo","serif"'>The only change to the syntax is the use of a "[CDECL]” for elements that need to be internally managed as C elements. Internally, new forms are created for module, pointer, array procedure and record declared with "[CDECL]”. All basic Oberon types (CHAR, BYTE, BOOLEAN, SHORTINT (16 bits), INTEGER (32 bits), LONGINT (64 bits)) are the same as their equivalent in C. SET is mapped to C 32bits integer for bit-wise manipulations (0: LSB, 31: MSB). The ESP32 is using little-endian for memory addressing.<o:p></o:p></span></p></div><div><p class=MsoNormal><span style='font-size:8.5pt;font-family:"Menlo","serif"'><o:p> </o:p></span></p></div><div><p class=MsoNormal><span style='font-size:8.5pt;font-family:"Menlo","serif"'>A CModule is the equivalent of a header file in C. No code is produced so no statements are allowed in a CModule. All elements in a CModule are C related, so the use of [CDECL] for array, record, pointer and procedure is induced. A CModule can import other CModules.<o:p></o:p></span></p></div><div><p class=MsoNormal><span style='font-size:8.5pt;font-family:"Menlo","serif"'><o:p> </o:p></span></p></div><div><p class=MsoNormal><span style='font-size:8.5pt;font-family:"Menlo","serif"'>A CRecordType is the equivalent of a C struc. No RECORD extension is allowed.<o:p></o:p></span></p></div><div><p class=MsoNormal><span style='font-size:8.5pt;font-family:"Menlo","serif"'><o:p> </o:p></span></p></div><div><p class=MsoNormal><span style='font-size:8.5pt;font-family:"Menlo","serif"'>C Pointers can be declared to point to any simple types and C array, C record, C pointer and C procedure. They cannot be initialized through NEW() but can be initialized through assignation.<o:p></o:p></span></p></div><div><p class=MsoNormal><span style='font-size:8.5pt;font-family:"Menlo","serif"'><o:p> </o:p></span></p></div><div><p class=MsoNormal><span style='font-size:8.5pt;font-family:"Menlo","serif"'>C Array can be declared to point to any simple types and C array, C record, C pointer and C procedure.<o:p></o:p></span></p></div><div><p class=MsoNormal><span style='font-size:8.5pt;font-family:"Menlo","serif"'><o:p> </o:p></span></p></div><div><p class=MsoNormal><span style='font-size:8.5pt;font-family:"Menlo","serif"'>C Procedures don’t generate name mangling as for GCC and accept only parameters that are compatible (so no Oberon array, record, pointers and procedures but their [CDECL] equivalent).<o:p></o:p></span></p></div><div><p class=MsoNormal><span style='font-size:8.5pt;font-family:"Menlo","serif"'><o:p> </o:p></span></p></div><div><p class=MsoNormal><span style='font-size:8.5pt;font-family:"Menlo","serif"'>Guy<o:p></o:p></span></p></div><div><p class=MsoNormal><span style='font-size:8.5pt;font-family:"Menlo","serif"'><o:p> </o:p></span></p></div></div><p class=MsoNormal>--<br><a href="mailto:Oberon@lists.inf.ethz.ch" target="_blank">Oberon@lists.inf.ethz.ch</a> mailing list for ETH Oberon and related systems<br><a href="https://lists.inf.ethz.ch/mailman/listinfo/oberon" target="_blank">https://lists.inf.ethz.ch/mailman/listinfo/oberon</a><o:p></o:p></p></blockquote></div></div></div></body></html>