wibbe / oberon-experimental

Various experiments with the functionality, the module structure and the boot process of FPGA Oberon 2013

The Experimental Oberon Operating System

Experimental Oberon is a revision of the FPGA Oberon system and its compiler (www.projectoberon.com), featuring

• Smooth line scrolling with variable line spaces
• Multiple logical displays
• Safe module unloading
• System building and maintenance tools
• Revised Oberon-2 programming language, implementing a strict superset of Revised Oberon (Oberon-07)

Planned

• Unicode characters and fonts
• Larger maximum file sizes
• Multiple file system partitions
• Plug & Play Oberon images (automatically loaded onto dynamically created partitions)
• A variant of the Oberon-2 compiler that accepts programs written in Original Oberon-2 (as defined in 1991/1993)

REVISION: 1.9.2019

DOCUMENTATION

Topic	Documentation
Operating system	The-Experimental-Oberon-System.pdf
Programming language	The-Revised-Oberon2-Programming-Language.pdf
System building tools	The-Oberon-system-building-tools.pdf
Safe module unloading	Safe-module-unloading-in-Oberon.pdf
Symbol files	Streamlining-symbol-files-in-FPGA-Oberon.pdf

EMULATORS

Emulator	Link
Oberon emulator on the desktop (Linux, macOS, Windows)	Oberon emulator in C
Oberon emulator on the web (run in the browser)	Oberon emulator in Javascript

DEMOS

Demo	Link (click on "View raw" or "Download")
Smooth fractional line scrolling	DemoFractionalLineScrollVariableLineSpace.mov
Multiple logical displays (1/2)	DemoMultipleVirtualDisplays.mov
Multiple logical displays (2/2)	DemoCloningViewersIntoNewVirtualDisplays.mov

---

Instructions for converting an existing FPGA Oberon system to Experimental Oberon

PREREQUISITES: A current version of the FPGA Oberon 2013 system (see http://www.projectoberon.com).

NOTE: If you run Oberon in an emulator on the desktop (e.g., http://github.com/pdewacht/oberon-risc-emu), you can simply backup your existing S3RISCinstall directory, download the compressed archive S3RISCinstall.tar.gz from this repository (containing Experimental Oberon) to your emulator directory, run the command tar xvzf S3RISCinstall.tar.gz in that directory and then restart the emulator, instead of going through the instructions outlined below.

---

STEP 1: Build a slightly modified FPGA Oberon compiler on your FPGA Oberon system

Edit the file ORG.Mod on your Original system and set the following constants to the indicated new values:

 CONST ...
   maxCode = 8800; maxStrx = 3200; ...

Then recompile your FPGA Oberon compiler (and unload the old one):

 ORP.Compile ORS.Mod/s ORB.Mod/s ~
 ORP.Compile ORG.Mod/s ORP.Mod/s ~
 System.Free ORP ORG ORB ORS ~

This step is (unfortunately) necessary since the original Oberon-07 compiler has a tick too restrictive constants. To compile Experimental Oberon, one needs slightly more space (in the compiler) for both code and string constants.

---

STEP 2: Download and import the Experimental Oberon files to your FPGA Oberon system

Download all files from the Sources directory of this repository. Convert the source files to Oberon format (Oberon uses CR as line endings) using the command dos2oberon, also available in this repository (example shown for Linux or MacOS):

 for x in *.Mod *.Tool ; do ./dos2oberon $x $x ; done

Import the files to your Oberon system. If you use an emulator, click on the PCLink1.Run link in the System.Tool viewer, copy the files to the emulator directory, and execute the following command on the command shell of your host system:

 cd oberon-risc-emu
 for x in *.Mod *.Tool *.Scn.Fnt ; do ./pcreceive.sh $x ; sleep 0.5 ; done

Open the Experimental Oberon version of the System.Tool viewer in the system track of your FPGA Oberon system, so that you can directly activate the compilations needed to build Experimental Oberon:

 System.Open System.Tool

If you just follow the compilation sequence shown in System.Tool, you should be done with the remaining steps 3-5 in a few seconds!

---

STEP 3: Build a cross-development toolchain by compiling the "new" compiler and boot linker/loader on the "old" system

 ORP.Compile ORS.Mod/s ORB.Mod/s ~
 ORP.Compile ORG.Mod/s ORP.Mod/s ~
 ORP.Compile Boot.Mod/s ~
 System.Free ORP ORG ORB ORS Boot ~

---

STEP 4: Use the cross-development toolchain on your FPGA Oberon system to build Experimental Oberon

Compile the inner core of Experimental Oberon and load it onto the boot area of the local disk:

 ORP.Compile Kernel.Mod/s FileDir.Mod/s Files.Mod/s Modules.Mod/s ~    # modules for the "regular" boot file for Experimental Oberon
 Boot.Link Modules ~                                                   # generate a pre-linked binary file of the "regular" boot file (Modules.bin)
 Boot.Load Modules.bin ~                                               # load the "regular" boot file onto the boot area of the local disk

This step is possible, because module Boot is written such that it can be executed on both the FPGA Oberon 2013 and the Experimental Oberon system. It produces output using the Experimental Oberon module and object file format.

Compile the remaining modules of Experimental Oberon:

 ORP.Compile Input.Mod/s Display.Mod/s Viewers.Mod/s ~
 ORP.Compile Fonts.Mod/s Texts.Mod/s Oberon.Mod/s ~
 ORP.Compile MenuViewers.Mod/s TextFrames.Mod/s ~
 ORP.Compile System.Mod/s Edit.Mod/s Tools.Mod/s ~

Re-compile the Oberon compiler itself before (!) restarting the system:

ORP.Compile ORS.Mod/s ORB.Mod/s ORG.Mod/s ORP.Mod/s ORTool.Mod/s Boot.Mod/s ~

The last step is necessary because Experimental Oberon uses a different Oberon object file format (the currently loaded Experimental Oberon compiler runs under FPGA Oberon, but wouldn't be able to execute under Experimental Oberon).

---

STEP 5: Restart the Oberon system

You are now running Experimental Oberon. Re-compile any other modules that you may have on your system.