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jrno
Visitor
Visitor
478 Views
Registered: ‎01-11-2021

sqrt, inv, invsqrt function clock cycles...

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Hello,
inside an AI Engine Tile, there is a 32b Scalar RISC Unit.

There is support for sqrt, inv, and invsqrt integer functions.

Is there hardware support for these functions or are they fully emulated by RISC instructions?

i guess that in the latter option, i couldn't start (i.e., pipeline) a new function, until the current function call is finished.

Is there somewhere mentioned, how many clock cycles these functions would approximately take?

Best wishes,
jarno

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derekh
Xilinx Employee
Xilinx Employee
463 Views
Registered: ‎08-06-2018

Hi,

The cycle counts for various AI Engine Scalar processor commands are listed in Architecture Manual AM009.
https://www.xilinx.com/support/documentation/architecture-manuals/am009-versal-ai-engine.pdf

See chapter 4, page 49-51 for details.
Note that the document update for 2020.2 is under review so check for new releases on xilinx.com or Xilinx Doc Nav.

Derek
SAE DSP and AI Engine, Xilinx Sweden/EMEA
**~ Don't forget to reply, give kudos, and accept as solution.~**

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derekh
Xilinx Employee
Xilinx Employee
464 Views
Registered: ‎08-06-2018

Hi,

The cycle counts for various AI Engine Scalar processor commands are listed in Architecture Manual AM009.
https://www.xilinx.com/support/documentation/architecture-manuals/am009-versal-ai-engine.pdf

See chapter 4, page 49-51 for details.
Note that the document update for 2020.2 is under review so check for new releases on xilinx.com or Xilinx Doc Nav.

Derek
SAE DSP and AI Engine, Xilinx Sweden/EMEA
**~ Don't forget to reply, give kudos, and accept as solution.~**

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jrno
Visitor
Visitor
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Registered: ‎01-11-2021

Hello,

and thanks for quick response! Actually, they are fast operations taking only 4 clock cycles!

Best wishes,

 jarno

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trissa
Xilinx Employee
Xilinx Employee
414 Views
Registered: ‎01-16-2020

Plus one cycle for fix2float and float2fix each, as most likely you're working on fixed point numbers.