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Re: OpenACC in GCC - how does it not violate the license?

On 11/17/13 07:32, Jeff Hammond wrote:
On Nov 16, 2013, at 11:22 PM, Jeff Law <> wrote:

On 11/16/13 21:58, Alec Teal wrote:
Now while great, is this true!? Nvidia (IIRC, this was like a year ago
though) don't even give out the instruction set for their GPUs, can we
have GCC targeting closed things? Also there (must be and is) a Cuda
runtime, wouldn't we need an open runtime to link against?
The various projects looking at supporting OpenACC are, to the best of my knowledge, targeting PTX, which is a virtual ISA from NVidia which is published.

Going from PTX to the actual instructions for the particular GPU is the job of a runtime system which would be provided by NVidia.

If one wants to tilt at these windmills, we should belabor the lack of open documentation of the microcode corresponding to the x86 instruction set.
I certainly have in the context of PTX, HSA and Intel's integrated GPU support for GCC. Intel and AMD appear to me to be ahead of the curve here -- both in documentation and in terms of minimizing the size of the black box binary blob necessary to make this stuff work.

But in the end, my influence is limited for a variety of reasons. Regardless, I continue to raise these issues with the appropriate folks when the opportunities present themselves.


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