I don't understand what you're trying to do. You've used some COBOL terms and some Sort terms, but it isn't clear how it all fits together.
You show a packed decimal field with a decimal point. Packed decimal fields only have an implied decimal point - the decimal point is not actually stored internally in the field. You say something about moving zero to some field, but I don't see how that fits in. You also talk about a COMP field, but PD is COMP-3, not COMP.
You need to explain what you're trying to do more clearly before I can help you.