Why Oberon for the Prop2 ?

>David Betz Posts:
>1:07PM
>Your Oberon project sounds interesting. I'm looking forward to your new thread about it. Welcome!


My Initial post in "Status of P2 C/C++ Compiler?"

Hi all,

Cluso99 is correct, i have been lurking on these forums for some time, and thanks for the welcome !

To answer your questions, i have 30+ years of C experience, but not a lot of experience with implementing
C compilers. I have modified the back end of the gcc C compiler (and also gas) many years ago. I have
written linkers/loaders to run as the final stage of the gcc toolchain to load into various embedded boards that i used.

I have a mountain of experience with assembler (S360/390 thru to many modern cpus).

I do have a large amount of experience with writing/modifying compilers, but not C compilers.
Most of my compiler experience is with the Wirth type compilers. (eg: Pascal, Modula, Oberon family)

Long term i need a good C compiler on the Prop2, and am happy to work with others to achieve this.

Short term, i need experience on the Prop2, i never used the P1. To write a compiler backend requires
an intimate knowledge of the instruction set/architecture. I will get this experience with Prop2 by writing
a new back end for the latest version of the Oberon 07 Compiler to target the Prop2.

I plan to make all the source code available on github under a MIT license. The Oberon 07 Prop 2
compiler and tools will be written in C such that it will run on Windows, Linux, MacOS, BSD,Dos etc.

I wont post more in this thread about Oberon,i will make a new thread on the Forum eventually, or you can start an Oberon thread and i will answer any questions in that thread.

I am impressed by some of the posted assembly code that the fastspin/C compiler can produce ! Now if
that was combined with all the optimizations gcc can produce ...

And yes, my real name is actually mark.

Comments

  • Why Oberon for Propeller 2 ?

    For those not familiar with Project Oberon i suggest a quick look at the following github repo
    https://github.com/pdewacht/oberon-risc-emu - there are plenty of links there to follow.


    1. I need a learning exercise for the P2, and for me its a fun project.
    2. There is considerable similarity between Wirth's Risc5 cpu and the Prop2, making the Prop2
    and ideal target for the Oberon 07 compiler. Hopefully close to a 1 to 1 correspondence
    between Risc5 (NOT to be confused with Risc-V) and Prop2 machine instructions. Oberon 07
    code, while NOT optimized is typically quite fast.
    3. The Prop2 is capable of replacing all the hardware of "Project Oberon" using a single chip.
    (yes, it only has 512 Kb memory instead of the 1024Kb assumed by project oberon, but hopefully
    parallax will produce version of the Prop2 chip with more memory) .
    4. Project Oberon hardware on Risc5 runs typically at 25-50Mhz. Prop2 is WAY faster at 180Mhz.
    5. Some people still use Risc5 Oberon because they need the software to be deterministic. Whilst Oberon
    has been ported to ARM,MIPS etc etc - these platforms tend to loose their ability to be deterministic.
    More modern cpu's with big instruction and data caches can be fast until they get a cache miss and
    then your instruction may take hundreds of clock cycles to execute. Interrupts make this worse.
    This is a real problem for certain types of applications.
    Prop2 is FAR more deterministic than ARM, MIPS etc
    6. Prop2 hardware seems interesting, heaps of things i want to try !

    It is not my intention to have any debate about the relative merits of Oberon vs C vs C++ (or whatever).
    Feel free to ignore anything in this thread that you disagree with.
    I do unfortunately, have strong opinions on certain subjects, and its possible i could express them in this thread. Please feel free to ignore my opinions, because at the end of the day, they are only my opinions.

    Just so you know, things i believe

    C is ok (have written millions of lines of it, hate that its too easy not shoot yourself in the foot, hate the syntax)
    C++ is horrible (but i use it when i must)
    Assembler is great
    Debuggers are rarely needed, that what printf is for !
    Speed, efficiency and determinism is good.
    The smallest program to do the job is always best
    and my favorite editor is vim

    For any of you who are interested in Oberon 07, feel free to ask anything.

    My apologies for such a long post, i will keep them much shorter in future

    Mark
  • Welcome, @markmpx! Your project sounds pretty neat. Definitely porting a compiler is a good way to learn an instruction set :).

    I'm curious, does the Oberon compiler produce binary or assembly code as output? If the latter, you may want to take a look at Dave Hein's p2asm assembler for P2, which is a small and clean assembler. fastspin works too, but it's probably overkill to drag around the Spin/BASIC/C compilers just to parse assembly language :).
  • Welcome Mark!! : ]

    Oberon is a word that pops up around here from time to time.

    Also I 99.5% agree with the things you believe.

    C++ is horrible,
    Assembler is great!
    C can help you shoot your foot off faster. (but I like the syntax though) : P
    Smaller code is better code.
    VIM!

  • jmgjmg Posts: 13,918
    markmpx wrote: »
    ...

    I do have a large amount of experience with writing/modifying compilers, but not C compilers.
    Most of my compiler experience is with the Wirth type compilers. (eg: Pascal, Modula, Oberon family)
    ..
    Short term, i need experience on the Prop2, i never used the P1. To write a compiler backend requires
    an intimate knowledge of the instruction set/architecture. I will get this experience with Prop2 by writing
    a new back end for the latest version of the Oberon 07 Compiler to target the Prop2.
    ..
    I am impressed by some of the posted assembly code that the fastspin/C compiler can produce ! Now if
    that was combined with all the optimizations gcc can produce ...
    ...

    markmpx wrote: »

    I expect to port Wirth's Oberon compiler to Nim and then modify it to produce P2 object code directly. (google nim-lang)
    My preferred development environment is Ubuntu, but Nim is available on windows, mac etc, (ie: almost anything)
    The Nim compiler produces C/C++ source code and a C compiler produces the object code, so effectively the Oberon P2
    compiler is a C program. I expect to port a minimal set of the Oberon runtime and i expect i will have to write a linker
    (as the oberon system does this dynamically at runtime).

    That seems like many steps, and many on rarely or not-yet travelled pathways ?

    Since you mention fastspin, why not target one of the languages that the fastspin language suite does support, as a 'stepping stone' ?

    http://forums.parallax.com/discussion/168913/new-basic-compiler-for-prop1-and-prop2/p1
    http://forums.parallax.com/discussion/164187/fastspin-compiler-for-p2/p1

    You could look at using any subset of those as a cleaner assembler for P2 - I think they all allow in-line ASM too, so you can start easy, and optimize as needed.
    You also then piggy-back on the optimize that fastspin does.

    Most generated-language code is a severe subset of the language, so you could also try the C side of fastspin, it might be good enough already, for gode generator use ?

    Other work that may be usable :
    https://forums.parallax.com/discussion/164401/porting-the-oberon-compiler-orp-to-the-p2


  • jmg:

    Thanks for your comments, i shall read thru the other threads and comment after
    i have digested them in full.

    Thanks also for the link to a previous attempt at this.
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