+ Unary plus. Returns the expression following the plus with no changes. The expression must be an absolute
immediate value.
- Unary minus. Returns the negated value of the expression following the minus. The expression must be an absolute
immediate value.
+ Addition. The expressions can be immediate values or memory references, but only one of the expressions can
be a relocatable value. If one of the expressions is a relocatable value, the result is also a relocatable value. If either
of the expressions is a memory reference, the result is also a memory reference.
