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XS3 Architecture released

Posted: Fri Sep 24, 2021 10:36 pm
by CousinItt
See here: https://www.xmos.ai/file/xmos-xs3-archi ... ion=latest

https://www.xmos.ai/xcore-ai/ also includes details of six variants of XU316, but no live datasheet links yet.

Re: XS3 Architecture released

Posted: Sun Sep 26, 2021 2:06 pm
by akp
Interesting. The vector unit and the FPU look to be fantastic additions for DSP just taking a quick glance at the new instructions. Clearly the FPU is pretty focused since it doesn't appear to have divider or other features like sqrt; but should be pretty good as long as you don't need ultrafast divide or those other things.

I didn't look deeply at it but is it true that the vector unit is the only thing that can use the full 256b of the bus? 256b memcpy would seems to be a 4x improvement on what is possible on XS2.

Re: XS3 Architecture released

Posted: Mon Sep 27, 2021 11:27 am
by CousinItt
The content regarding the 256-bit buffer for each thread and the two lanes for issuing two 16-bit instructions or a single 32-bit instruction seems pretty much identical to the XS2, so I'm not expecting much to change there. Not absolutely sure though.

Re: XS3 Architecture released

Posted: Mon Sep 27, 2021 11:40 am
by akp
Right, I meant the instructions to do 256b load and store to the vector unit

Re: XS3 Architecture released

Posted: Mon Sep 27, 2021 2:44 pm
by CousinItt
Sorry, wrong end of the stick. The document states the memory is 128 bits wide, but that doesn't square with the descriptions of the vector load/store operations. Usually multi-cycle instructions are noted. This diagram in the Linley document shows a 256-bit path.
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