I made an user function that I think could be useful:
neg(x;y) = hex(mask(min(-x;x);8))
Without it, I had to use windows calculator when I had a signed value for something I knew was supposed to be unsigned.
I also made this:
not_hex(x;y) = hex(mask(mod(not(x);2^y);y))
But didn't test it as much, so not sure how good it is.