[Oberon] Negative integer literals in Oberon

[Guy T.]

In regard of the stack management procedure calls and parameters passing, the Oberon compiler is using the same method as for the C language. The ESP32 architecture defines a specific method of stack allocation that has been defined irrelevant of the programming language in use. Parameters are passed through registers pretty closed the Project Oberon RISC usage.

The only specific is the use of a base register for module variables that need to be managed differently than C (no base register in C).

Guy