Plans for atomic instructions?

[alexrp]

At the moment, Epiphany only has the TESTSET instruction for atomic operations. This isn't quite enough to implement atomic increments/decrements, compare-and-swap, etc. On a related note, epiphany-elf-gcc doesn't support __sync_* intrinsics from the looks of it.

So are there any plans to improve on this situation or is it relatively low priority?

[over9000]

[alexrp]

[CIB]

Well, this is certainly an interesting topic. This stackoverflow question seems to explain the whole C++11 memory model nicely: http://stackoverflow.com/questions/6319 ... ow-is-it-g

Personally, I don't think that atomic operations make a lot of sense for the epiphany. Any halfway efficient program will be operating on core-local memory, and will be manually managing memory transactions between cores and to SDRAM. You won't really have "shared" memory, as much as you'll have a kind of message box, where each core operates on its own set of memory and communicates with others through messages.

Meanwhile, if you don't care about efficiency, and just want some C++11 program to get running on the epiphany while using SDRAM, emulating atomicity with mutexes should be good enough.

[ysapir]

[over9000]

[CIB]