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Parallella Community • View topic - "Inter-Workgroup" Communication

"Inter-Workgroup" Communication

Discussion about Parallella (and Epiphany) Software Development

Moderators: amylaar, jeremybennett, simoncook

"Inter-Workgroup" Communication

Postby laideybug » Thu Mar 31, 2016 12:23 pm

Hypothetically speaking, is there anything stopping an eCore reading or writing to/from the local memory of an eCore in a different workgroup?

I know it's bad practice and I'm aware that the eSDK is not set up in this way (in that, the majority of functions deal with eCores within the caller core's workgroup) but if you could calculate the local memory address space of an eCore in one particular workgroup, could you read or write to that eCore from an eCore in another, separate, workgroup?

My hunch is that you can but I just wanted to double check.
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Re: "Inter-Workgroup" Communication

Postby jar » Thu Mar 31, 2016 1:30 pm

No. The memory is not protected. Hack away.
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Re: "Inter-Workgroup" Communication

Postby laideybug » Thu Mar 31, 2016 4:21 pm

Nice! Any pointers on how you would calculate the address you would need to write to a core in another workgroup?

For example, I have a 1 x 3 workgroup (let's call it Group A) beginning at core (0,0) and a 1 x 1 workgroup (Group B) at core (0,3). What address would the cores in Group A need in order to write to the local address 0x4000 of the core in group B? How could I calculate that?

Any help would be much appreciated :) - this is on a Parallella-16 Microserver by the way.

EDIT: If I hardcode the address - 0x80B00000 as the base address for writes to Group B it works, but I'm interested to know if this address can be calculated on the fly from the another workgroup.
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Re: "Inter-Workgroup" Communication

Postby jar » Thu Mar 31, 2016 5:21 pm

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Re: "Inter-Workgroup" Communication

Postby laideybug » Thu Mar 31, 2016 11:20 pm

Thanks jar!
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