Open PowerPC Core?

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Does such an animal exist? I have looked around but
as of yet Ive not seen one. Saw reference to a couple
of non-open ones.

A x86 core would be nice too, but i doubt ill find
one of them due to IP rights...

I know performance would be dismal, but this is just
for some experimentation i want to do. ( and no, im
not up to 'rolling my own' version of something that
complex )

Re: Open PowerPC Core?
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There's probably a lot less problem with IP rights on the x86 than on
the PowerPC.  The x86 has been around long enough for the patents to
expire.  (Maybe not on things like MMX and SSE, but you didn't indicate
that you needed those.)

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I hadnt thought about the patents expiring on the older X86 stuff, which
would suit the bill fine. A reproduction of a 486 or base Pentium would
be plenty for what i want to do.

I also thought that PPC was more like ARM and SPARC, and the specs were
available openly, just that it would cost to be 'certified' ( which in
my case doesnt matter ). But ive been wrong before ;)

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I doubt it's a matter of patents, but more a matter of licening.  The two
are very different beasts.  Having said that, what you do in your own home
for your own amusement is your business... :)

--
 [100~Plax]sb16i0A2172656B63616820636420726568746F6E61207473754A[dZ1!=b]salax

Re: Open PowerPC Core?
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But if there isn't a patent on an architecture, you don't need a license
to implement it.  The purpose of the license is to grant you a right that
was taken away from the patent.  If there's no patent, you haven't been
denied the right.



Re: Open PowerPC Core?

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Since this topic has come up, maybe someone could answer this for me:

I've seen publicly available (often open source) cores for other
processors, such as the AVR.  Are these sort of cores legal to make,
distribute and use?  Supposing I made (from scratch) an msp430 compatible
core for an FPGA - any ideas whether that would be legal or not?  I'm
guessing that using the name "msp430" would be a trademark and/or
copyright violation, but if there are no patents involved it should be
okay?  Does it make any difference whether it is just used by the
developer, released as an inaccessible part of a closed design, or whether
it is released for free use by others?

mvh.,

David


Re: Open PowerPC Core?

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two
that

its done full soc based on MSP430 compatible core :)
http://bleyer.org /


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Re: Open PowerPC Core?

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I'd have been surprised if it hadn't been done, given that the msp430 core
is a solid 16-bit core with a good gcc port and a (relatively) clean
instruction set and programming model.  I was, however, more interested in
knowing where such a core stands legally (although I will also have a look
at the core sometime for curiosity - and the site you gave has a few other
interesting links).

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Re: Open PowerPC Core?
"David" wrote ...

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And the msp430 is a simplified version of the pdp-11.  Unlicensed?



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No, you are wrong.  I do not need a patent on my IP in order for me to
license it to you.  It's called copyright.

--
 [100~Plax]sb16i0A2172656B63616820636420726568746F6E61207473754A[dZ1!=b]salax

Re: Open PowerPC Core?
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["from the patent" was supposed to read "by the patent"]

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You can't copyright an idea.  You can only copyright a specific expression
of an idea.

If you invent a new processor architecture, and publish the architecture
specifications, copyright does not prevent me from designing my own
processor compatible with your specifications.  This is a very well-
established principle of US copyright law, and AFAIK the copyright
laws of most other countries work similarly.

If you published Verilog code for your core, that could be copyrighted,
and I wouldn't be able to use your Verilog code without a license,
though I could still write my own.

On the other hand, patents *do* protect ideas.  If you patent a feature
of your processor architecture, I can't use it without a license.  If
you have a patent that doesn't apply to the architecture, but only to
a feature of your implementation (e.g., your Verilog design), I could
either license that patent or try to figure out a different way to
implement the architecture that didn't infringe your patent.  For instance,
if your processor architecture had an (unpatented) multiply-by-37
instruction, but you have a very clever patented multiply-by-37 circuit,
and I didn't want to license your patent, I could still design my
own processor compatible with your architecture by using a different
(probably less clever) multiply-by-37 circuit.

Re: Open PowerPC Core?
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so precicely what do you claim is copyrightable in an ISA? instruction
names? thats not even handled by the implementation.

--
    Sander

+++ Out of cheese error +++

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Not being a top authority on soft core I'll still observeve that:

1. Implementing a CISC CPU is much more resource consuming than implementing
a RISC core.
2. x86 is way crazy because of the need to maintain compatibility with the
8086's real mode.

In late 80's Intel made a special version of 386 (385 if I remember right)
that was basically a 368 without  the real mode.
It was much cheaper than a 386 but there were no takers: x86 is used so much
only because of the huge volume of written code,
not because it is a good architecture.
If I had to go the CISC way, I'd much rather clone a 68000. Just as much
software written and a considerably better
instruction set.


--
-Alex.



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But in todays world, does anything actually use
the 'real mode' on an x86 chip?

Though i do agree that the 68k is a much better
chip, the x86 has a larger 'generic' software
base.

I think the 68k has been done however.. I just
dont remember where i saw that at.

Re: Open PowerPC Core?

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implementing
the
right)
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much

something is at opencores not sure how useabe it is

antti




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I think you saw the 6800 core.. i dont think there is a 68000 core
unless i missed something, which is always possible.

Re: Open PowerPC Core?
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much

http://www.opencores.com/projects.cgi/web/k68/overview

68K
but as said I have not evaluated it, so not sure how useable it is

antti





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Wonder how i missed it..  tks

Re: Open PowerPC Core?
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Careful with those quotes/attributions!  Eric Smith didn't say
any such thing!

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I wonder whether an x86 type replacement could be done in a different
way - instead of implementing an x86, implement a simpler RISC type
architecture, and translate the code off line in software.  At least
some of the x86 family used microcode AFAIK, so this could be feasible.

If the code is well written (no self modifying code), this might
actually do what a x86 soft-core would actually want to do.

Mind you, still a lot of functionality where that wouldn't work, but
from a purely instruction set point of view, this could maybe work.

Just an idea.

Jeremy

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