Re: [ZooLib-dev] zoolib/foundation/ZAtomic.cpp ZAtomic_Add segfault sparc

[Andrew G. <ag...@em...>]

James wrote:
> I downloaded Zoolib yesterday and compiled the demos on Linux 2.4.2
> (Intel) and Solaris 8 (UltraSPARC). The demos run (ostensibly) fine
> under Linux but crash (Segmentation fault) under Solaris. The problem
> seems to be when ZAtomic_Add tries to acquire the sMutexNR lock: the
> acquisition routine calls ZAtomic_Add...infinite recursion. It would
> seem that when compiled on an Intel platform the ASM is used and is
> correct (so the Linux build worked) but the C++ for non-PPC and
> non-Intel platforms is incorrect (so the Solaris build failed).


Hi James,

Mike's protestations (and associated complement):
>I would strongly disagree with you that there are logical errors in the C++
notwithstanding, you are correct that in the 0.8 source archive the 'dumb'
version of the atomic operators is incorrect. It was something I put
together as a placeholder as much as anything -- I didn't have a platform
that actually needed it, so I never actually ran it. On a subsequent
re-reading of the code my brain engaged: the implementation of sMutexNR is a
benaphore, relying on atomic add to shortcircuit non-contested non-recursive
mutex allocation. A fix is in place.
The most recent code  that I feel is in reasonable shape lives in
<http://www.zoolib.org/bleedingedge/>
I have not been posting announcements of updates to that directory, but in
looking back over it, I've been updating it about once a month.

Apps based on ZooLib have been built and run on Solaris, but it's been a
while and the full suite of atomic ops has grown up since then (about two
years ago). The atomic operations are fairly straightforward to port,
although sparc is probably the most awkward target architecture. I'd love to
work with you to get them in place.

I really appreciate the time you, and everyone, have taken to grab the
source and try it out. I encourage you all to post your findings to the
list. I can't promise to fix every problem that's found, but I'll do my best
to help out.

A
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Andrew Green                                  mailto:ag...@zo...
ZooLib Guy                                   http://www.zoolib.org
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