I am so stupid, it's unbelieveable...;-) I just found what I would have needed so much in the beginning: the description of the Self stack frame.
The port of NIC is making progress: I can call primitives now, '_Credits' works, '_Spy: true' works partially, it enters the C code with correct parameters but the window only opens in single step mode within the debugger (propably because of the turned off signals). '1 _IntAdd: 1' works as well as something like '( | x = 17. y = 18 | ) x'.
Assignable slots do not work yet, nor did I have a closer look at non local returns. The GC masks inside the SendDescs need to be fixed as well as the traversal of the stack frames. A lot of the primitive assembler code is also not yet written.
PS: I would like to get the group by email. The mail adress given on the web page to subscribe it does not work. What can I do?