[cpp-threads] Update

[Lawrence Crowl]

On 7/10/06, Boehm, Hans <hans.boehm at hp.com> wrote:
> I don't know whether platforms that don't support CAS will still be
> important.  I'm concerned about both embedded processors, which I think
> are sometimes weak there, and about older processor designs like PA-RISC
> and SPARC V8.  Those generally still give you atomic loads and stores,
> and those can be quite useful, even without CAS.

SPARC processors since circa 1996 have all implemented CAS in 32-bit
mode via the -xarch=v8plus compiler flag.  This flag has been the
default for the past couple of compiler releases, thus requiring the new
processors, and few users noticed.  Indeed, Solaris 10 requires the new
processors.  For any new C++ standard, my guess is that Sun would
require the v8plus instruction extension.

In the more general case, while I want C++ to run on embedded processors,
I do not want to make writing threaded code unnecessarily difficult.  One
possible solution is to simply accept that some processors will not be able
to implement the full proposed standard.

-- 
Lawrence Crowl