User blog comment:ヌヌハラ/alice-tools v0.2.0/@comment-45214281-20200313112813/@comment-44256294-20200315181133

The DG instructions deal with delegates. A delegate is a kind of function pointer (i.e. a "callable" object which stores a reference to a function). I think delegates have some additional behavior, but I'm not sure exactly what (system 4 used to have a simple function pointer type which was later replaced by delegates, so presumably there is some difference between them beyond the just the name).

I'm guessing DG_CALLBEGIN reads a delegate object from the stack in preparation for the DG_CALL, which actually calls the delegate function.

If you run "aindump --delegates -o delegates.jaf xxx.ain" you can get the function prototypes for each delegate type.