Emulating actual DVK series would require changes to T11 core -- their microprocessors (1801VM1, 1801VM2 and 1801VM3) are ISA-compatible but have subtle differences.
Now that (almost?) all of the CPU cores have been converted to proper modern devices, implementing device-specific opcodes should be as simple as abstracting those opcodes behind member functions and then overriding them in a child class.
