Re: QEMU for Qualcomm Hexagon - KVM Forum talk and code available

[Aleksandar Markovic]

On Friday, October 25, 2019, Taylor Simpson <address@hidden> wrote:

We would like inform the you that we will be doing a talk at the KVM Forum next week on QEMU for Qualcomm Hexagon.  Alessandro Di Federico, Niccolo Izzo, and I have been working independently on implementations of the Hexagon target.  We plan to merge the implementations, have a community review, and ultimately have Hexagon be an official target in QEMU.  Our code is available at the links below.

https://github.com/revng/qemu-hexagon

https://github.com/quic/qemu

If anyone has any feedback on the code as it stands today or guidance on how best to prepare it for review, please let us know.

 

Hi, Taylor, Niccolo (and Alessandro too).

I didn't have a chance to take a look at neither the code nor the docs, but I did attend you presentation at KVM Forum, and I found it superb and attractive, one of the best on the conference, if not the very best.

I just have a couple of general questions:

- Regarding the code you plan to upstream, are all SIMD instructions implemented via tcg API, or perhaps some of them remain being implemented using helpers?

- Most of SIMD instructions can be viewed simply as several paralel elementary operations. However, for a given SIMD instruction set, usually not all of them fit into this pattern. For example, "horizontal add" (addind data elements from the same SIMD register), various "pack/unpack/interleave/merge" operations, and more general "shuffle/permute" operations as well (here I am not sure which of these are included in Hexagon SIMD set, but there must be some). How did you deal with them?

- What were the most challenging Hexagon SIMD instructions you came accross while developing your solution?

Sincerely,

Aleksandar

 

Thanks,

Taylor