sqrt, inv, invsqrt function clock cycles...

[jrno]

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

[derekh · Accepted solution]

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.

[jrno]

Hello,

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

Best wishes,

 jarno

[trissa]

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