Stack based machines generally need "variable space". This may be
quite via a symbol-to-word association a list, a hashmap, or some
other system. Here I decide to go for the simplest: extending the
register system to a dynamic/infinite number of them. This means, in
practice, that we may use a theoretically infinite number of indexed
words, hwords and bytes to act as variable space. This means that the
onus is on those who are targeting this virtual machine to create
their own association system to create syntactic variables: all the
machinery is technically installed within the VM, without the veneer
that causes extra cruft.
A negative number under 2s complement can never be equal to its
positive as the top bit *must* be on. If two numbers are equivalent
bit-by-bit then they are equal for both signed and unsigned numbers.
As it has no dependencies on vm specifically, and it's more necessary
for any vendors who wish to target the virtual machine, it makes more
sense for inst to be a lib module rather than a vm module.
