Это они тебе процитировали кусок из Ареца, раздел 5.1 Structure of the object program.

The object program is transferred by the main scan to its destination (paper tape originally, store later) by means of the procedure fill result list (FRL). FRL has two parameters:
- the OPC–value, which is either the number of an operator from the complex (8 ≤ OPC ≤ 109), or has one of the values 0, 1, 2, or 3.
- a word w. For an operator from the complex the value of w is irrelevant, otherwise it is an X1 instruction (or in a few cases a constant or a code word), to be incorporated into the object program. The OPC–value then indicates whether in the loading phase following the main scan the instruction should be taken as it is (OPC = 0), the begin address of the object program should be added to it (OPC = 1), the address part of the instruction should be replaced by the corresponding entry in the future list (a list of future references produced by the main scan) (OPC = 2), or the begin address of the constant list should be added to the instruction (OPC = 3).

Всё это по сути перемещаемый код. Значения OPC = 1, 2, 3 задают тип перемещаемости. Но потом добавляет нужное смещение и "малое значение" OPC становится ненужным. На выход попадает только одно число:
- либо OPC в диапазоне 8...109
- либо слово w, то есть машинная инструкция

Что мы и видим.