CRC Tutorial

[Daniel B]

Hello,

I'm trying to follow this tutorial, provided on the PandA-Bambu website. I downloaded the Git repo to follow the tutorial but I'm using the latest App-image binary executable to actually execute Bambu (I linked bambu  to the AppImage). I successfully executed the first steps of the tutorial, but when I get to:

$ bambu ../spec.c --top-fname=icrc --generate-tb=../test_icrc.xml --simulate --simulator=VERILATOR

and execute $ cat results.txt, I get :

7|5457,5465|5809,
0

The tutorial says I shoud get:

      $ cat results.txt 

          1 2725 

          1 172

My questions are: 

• is this due to the tutorial being out of date ?
• if so, are those results normal ? How should I interpret them ?

Thank you,

Daniel B

PS: you might hear of me often as I'm doing an internship about HLS tools :)

[Michele Fiorito]

Hello Daniel,

The tutorial is pretty outdated with respect to the tool version you are using. The simulation environment has been completely changed, which is why you see different content in the results.txt file.

Currently, the results.txt reports a set of comma-separated start|stop half-cycle counts on the first line and the simulation process return value on the second line.

In your case, here is how you should read yours:

   7|5457,5465|5809,
   0

First kernel execution started at cycle 4 (computed as (7+1)/2) and ended at cycle 2729 (computed as (5457+1)/2), thus the execution time is 2725 (computed as 2729-4) cycles.

Second kernel execution started at cycle 2733 and ended at cycle 2905, thus the execution time is 172 cycles.
The simulation process returned a value of 0.

This computation is also performed by Bambu itself, but information on each execution is only printed if you raise the verbosity to 2 (passing -v2 through the command line).

Best,

Michele.