[dmd-concurrency] shared arrays

[Sean Kelly]

On Jan 15, 2010, at 12:54 PM, Brad Roberts wrote:

> On Fri, 15 Jan 2010, Sean Kelly wrote:
> 
>> On Jan 14, 2010, at 7:20 PM, Andrei Alexandrescu wrote:
>>> 
>>> Speaking of which: is it reasonable to assume that all 32-bit modern architectures have a 64-bit atomic assign? How about 64-bit atomic CAS?
>> 
>> For x86, I think this is reasonable today.  I recall there being an 
>> issue a while back with some CPUs (I can't recall if they were from 
>> Intel or AMD) that were missing this instruction, but I think those days 
>> are gone.  Here's a page about Windows and 8 byte CAS I ran across that 
>> seems relevant:
>> 
>> http://www.geoffchappell.com/viewer.htm?doc=studies/windows/km/cpu/cx8.htm
> 
> I'd have to go find the, but for my work environment, there's generations 
> of processors still in active use that don't support 2x32bit atomic word 
> stores.  Those processors are probably about 5 years old at this point 
> (again, from memory -- certainly less than 10).
> 
> 
> I don't think making the assumption that they're always available is 
> viable.  We're trying to run on all 32 bit platforms, right?

Maybe not all, but certainly all recent ones.