Unreachable condition in stoch_add

[nblei]

In stoch_add.sv you have, essentially

assign y = c >= 1;

But then in the comb block, you have

if (~|c & y) next_counter ...

This seemed strange to me, so I added a coverage check

cov_possable: cover property ((~|c & y));

and indeed, this is uncoverable. So simply replacing that procedural block with assign next_counter = c-y; will lead to better hardware implementation.

[darsnack]

Indeed that guard is not necessary and can be removed. Would you like to submit a PR? Otherwise I'll take care of it later.