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Re: PAF: a Portable Assembly Language

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hughaguilar96@gmail.com wrote:

> On Friday, January 23, 2015 at 11:01:42 AM UTC-7, Aliaksei Chapyzhenka
> wrote:
>> Hi All,
>> 
>> I have discovered great paper from Anton Ertl about Forth based Portable
>> Assembly Language (PAF):
>> 
>> http://www.complang.tuwien.ac.at/anton/euroforth/ef13/papers/ertl-paf.pdf
>> 
>> I plan using it in the tool chain for my processor project, and was
>> looking for more information about PAF. Does anybody can help me with:
>> PAF wordlist? any open source PAF reference implementation?
>> any other papers, threads, information sources?
>> 
>> --Alexey
> 
> This has already been discussed in this thread:
> 
https://groups.google.com/forum/#!topic/comp.lang.forth/YVjtNQwSIH0%5B326-350-false%5D
> Is that where you discovered it? Anton Ertl's paper isn't "great" --- I
> read the abstract, but didn't consider the paper worth reading.
> 
> Anton thinks that the register set size can be abstracted away, but this
> isn't true, as that is the one aspect of the target processor that has to
> be standardized. I don't think that Anton knows enough about assembly
> language to be the person who designs this portable-assembler.
> 
> The idea of a portable assembler is good, as this would allow Forth to be
> quickly ported to any processor that fits the basic profile (there is not
> much difference between the MIPS, ARM and ColdFire, for example) --- all
> that would be needed would be to rewrite the portable-assembler, and then
> the Forth system program would assemble for a new processor --- but the
> target processors have to be similar in that they all have the minimum
> number of registers and a reasonably orthogonal instruction set (there is
> a lot of difference between the 6502 and the Z80, or between the 6812 and
> the 8086, so a portable assembler wasn't realistic for them).
> 
> This is what I said in the thread mentioned previously:
> On Tuesday, January 20, 2015 at 9:40:31 PM UTC-7, hughag...@gmail.com
> wrote:
>> This is a good idea. This idea has been around since the 1980s though, so
>> you shouldn't take credit for it.
>> 
>> You can't abstract away the register set size --- you have to assume a
>> certain number of registers. This is why the idea is feasible now, and
>> wasn't feasible in the 1980s --- because you can assume 16 registers now
>> (this leaves out the 32-bit x86 though, but it is obsolete anyway) --- in
>> the old days, processors had very few registers, and juggling these few
>> registers was different on every processor (the 6812 and the 8086, for
>> example).
>> 
>> Your PAF won't work on the MiniForth though --- it will only work on
>> mainstream processors.
>> 
>> Anyway, what I'm doing right now is targeting the 8-bit AVR. This is the
>> smallest processor that I can imagine my Forth running on (16 registers
>> with 3 that can be used as pointers) --- porting it to a larger more
>> powerful processor should be easy (although going in the other direction,
>> from a powerful processor to a more limited one, would be difficult). I
>> don't actually consider the AVR to be very useful, because it is not
>> powerful enough for most applications and it is well on its way to being
>> obsolete --- I am just interested in the AVR as a proof-of-concept
>> platform.

There was an article in Forthwrite about the MAF and PAF implementations and 
maybe also mentioned in Forth Dimensions. The Forthwrite on-line resource 
didn't manage to get all the early paper versions scanned and on-line but I 
have many of the missing ones in my library. An email to Graham Dunbar might 
also be worthwhile.

-- 
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Paul E. Bennett IEng MIET.....<email://Paul_E.Bennett@topmail.co.uk>
Forth based HIDECS Consultancy.............<http://www.hidecs.co.uk>
Mob: +44 (0)7811-639972
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Thread

PAF: a Portable Assembly Language Aliaksei Chapyzhenka <alex.drom@gmail.com> - 2015-01-23 10:01 -0800
  Re: PAF: a Portable Assembly Language hughaguilar96@gmail.com - 2015-01-23 20:26 -0800
    Re: PAF: a Portable Assembly Language Paul E Bennett <Paul_E.Bennett@topmail.co.uk> - 2015-01-24 13:48 +0000
      Re: PAF: a Portable Assembly Language Aliaksei Chapyzhenka <alex.drom@gmail.com> - 2015-01-24 11:42 -0800
        Re: PAF: a Portable Assembly Language anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2015-01-25 15:26 +0000
          Re: PAF: a Portable Assembly Language Aliaksei Chapyzhenka <alex.drom@gmail.com> - 2015-01-25 11:57 -0800
          Re: PAF: a Portable Assembly Language Paul E Bennett <Paul_E.Bennett@topmail.co.uk> - 2015-01-26 10:42 +0000
  Re: PAF: a Portable Assembly Language anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2015-01-25 15:02 +0000
    Re: PAF: a Portable Assembly Language Aliaksei Chapyzhenka <alex.drom@gmail.com> - 2015-01-25 11:49 -0800
      Re: PAF: a Portable Assembly Language anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2015-01-26 12:01 +0000
        Re: PAF: a Portable Assembly Language Aliaksei Chapyzhenka <alex.drom@gmail.com> - 2015-01-27 15:33 -0800
          Re: PAF: a Portable Assembly Language anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2015-01-30 15:37 +0000
    Re: PAF: a Portable Assembly Language Aliaksei Chapyzhenka <alex.drom@gmail.com> - 2015-01-25 11:54 -0800
    Re: PAF: a Portable Assembly Language hughaguilar96@gmail.com - 2015-01-25 20:54 -0800
      Re: PAF: a Portable Assembly Language anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2015-01-26 12:21 +0000
        Re: PAF: a Portable Assembly Language hughaguilar96@gmail.com - 2015-01-26 16:21 -0800
    Re: PAF: a Portable Assembly Language Aliaksei Chapyzhenka <alex.drom@gmail.com> - 2015-01-25 23:44 -0800
      Re: PAF: a Portable Assembly Language anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2015-01-26 12:25 +0000

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