Define operators for physaddr and virtaddr

[Timmmm]

The new physaddr and virtaddr types are quite nice, but they do make some code uglier. For example instead of

handle_mem_exception(vaddr - offset), e);

we have to do

handle_mem_exception(virtaddr(virtaddr_bits(vaddr) - offset), e);

I think we can overload + and - (and maybe others) so that they work with physaddr and virtaddr too.

[trdthg]

I tried this before, but due to the order of file dependencies, the result was not very ideal

The current compilation order is PRELUDE = prelude.sail ... prelude_mem.sail

- General overloads are defined in prelude.sail
- If you want to overload operator for physaddr and virtaddr, you must define it inprelude_mem.sail or after it, possibly in a new prelude_operator.sail which looks messy.

I wonder will sail support syntax like overload operator xxx += { }?

I found that overload runs in append way

[Timmmm]

Yeah it's described here. I think adding them just after the newtypes is fine.