[fpc-devel] Apple M1 processor

[C Western]

On 07/02/2021 14:45, Jonas Maebe via fpc-devel wrote:
> On 02/02/2021 16:48, C Western via fpc-devel wrote:
>> My application works fine single threaded, but crashes occasionally when
>> multi threaded, with what I think is some sort of memory corruption, but
>> I haven't been able to pin this down yet, and fixing the above two
>> points would help.
> It's probably a data race. AArch64's memory model is much more relaxed
> than that of x86-64, so data races are much more likely to lead to
> errors. Additionally, while on x86 interlocked* routines implicitly act
> as memory barriers between them (due to an architectural idiosyncrasy),
> they don't on any other architecture.
>
I have located a possible fix; however I don't understand why I need to 
make the change I did. The variable reads/writes of concern currently 
use SetEvent in one thread and WaitFor in another - do these  not have 
implicit  memory barriers in them? Or is an explicit memory barrier 
required in AArch64? (or it could also be a different issue).

Colin