@Override
	public ProgramLocation getProgramLocation(int row, int col, ListingField bf) {
		Object obj = bf.getProxy().getObject();
		if (obj instanceof Function) {
			Function function = (Function) obj;
			List<Register> setRegisters = getSetRegisters(function);
			String[] registerStrings = getRegisterStrings(function, setRegisters);
			String[] registerNames = getRegisterNames(setRegisters);
			return new RegisterFieldLocation(function.getProgram(), function.getEntryPoint(),
				registerNames, registerStrings, row, col);
		}
		return null;
	}
Field to show register values at the function entry point.
Ghidra/Features/Base/src/main/java/ghidra/app/util/viewer/field/RegisterFieldFactory.java