Add more comments about missed features
Add more comments about missed features

Substraction between pointers is a valid operation,
and it generates the number of elements between
the pointers.

k0gaMSX/scc,8l/scc,k0gaMSX/scc,8l/scc,k0gaMSX/scc,k0gaMSX/kcc,8l/scc,k0gaMSX/kcc