[rescue] compiling old software re: emacs on SunOS 4.1.4

[Romain Dolbeau]

2018-05-29 16:25 GMT+02:00 Doug McIntyre <merlyn at geeks.org>:
> I would say that 90% of the code out there could still compile on
> SunOS

Having tried to get a half-decent web browser in S7/S8 on v7 & v8
hardware, I strongly disagree.
Most OSS nowadays is heavily reliant on a multitude of libraries, many
of which are rife with linuxisms, or assume a much, much newer libc
with new functions.
They are also assuming that dereferencing a pointer is always OK,
without caring for data alignment - which is causing a lot of grief to
the Debian/sparc64 people among others.

Also - anything even indirectly reliant on recent C++ is pretty much a
no-go on v7/v8 HW, you need v8+/v9 - UltraSPARC, so no SunOS.
C++ requires some atomic updates, and the GCC interface (not sure
about the language itself) assumes an atomic fetch-and-add is
available.
Which doesn't exist in SPARC prior to v8+/v9. You can fake it with a
global lock (or a hashed lock, if you need ultimate speed on those hot
SM512 ;-) ) for intra-process locking (been there, done that), but for
inter-process it's a nightmare to emulate properly.

I love SPARC, but no matter how awesome the work of those who did make
parallel SPARC machine (yeah Solbourne!), the designer of SPARC didn't
properly specify the atomic instructions in v7/v8. You really, really
want atomic fetch-and-add in real life. Not that it was obvious at the
time - for a lock, SPARC has enough support.

Cordially,

-- 
Romain Dolbeau