discussion with Roberto from PowerPC Notebook, 09 Apr 2020

basically, you remember EOMA68, i decided to go further down the rabbit hole after 10 years waiting for fabless semi manufacturers worldwide to FAIL to produce a modern SoC that has libre GPU and VPU drivers.

i therefore began designing a hybrid CPU GPU VPU which unlike a "normal" GPU which is totally separate and usually on a PCIe bus, you actually add GPU and VPU instructions to the main core's instruction set.

examples of this include ICubeCorp's IC3128 and the Broadcom Videocore IV which is actually an ARC Core (ARC was a competitor to ARM that didn't take off in the same way).

so we started with RISCV on the reasonable assumption that "Open" actually means "Open", only to find that they are "Fake Open Source".

we therefore had to scramble to find an alternative, which just happened to be right around when the OpenPOWER Foundation started kicking into gear.

we're therefore beginning to gear up to POWER9 V3.0B and tentatively negotiating and opening communications channels with the right (extremely busy) people, with the kind assistance of Hugh Blemings, Director of the OpenPOWER Foundation.

this does have to be done carefully because unlike a traditional GPU (which we do not want to do because the inter-processor communication is nuts and massively complicates drivers on both sides, CPU and GPU) we are using the same pipelines, the same L1 caches, everything, for all workloads and thus have to be very careful about resource utilisation.

however more than that, because we seek to extend (augment) the instruction set (add ATAN2 to POWER9 for example) this has to be managed extremely carefully.

normally in a proprietary product there would be absolutely no public evidence, documentation or publishing of the toolchain for such extensive custom modifications. they would definitely not be permitted to be upstreamed.

however here, with the business justification behind libre (see Intel Valve Steam collaboration) we have to extend the instruction set and document those augmentations and publish the toolchain and have it upstreamed and make sure that the entire OpenPOWER Community is ok with that, and all the implications and ramifications properly thought through.

so that's a potted version of why and what :)

it means that in say 12 to 18 months we will have a quad core SBC-style processor that you could use for a powerpc netbook. at last! :)