How to use tofino p4 program to read and write registers. For example, I want to store the first five packet sizes of the same stream in a register and read these values through the control plane (python). How can I write this program?
You can find a lot of useful information on this forum, especially if you use its search function ( 
). For example, a simple search on the “tofino” keyword will immediately produce this post , which contains the necessary recommendations.
Also, if you you haven’t done it already, I’d highly recommend you attend Intel Connectivity Academy by P4ica courses.
Happy hacking,
Vladimir