O-type macros

There are a number of macros that cannot be classified as either type R or type S. They are simply referred to as “other macros” and are specified as O-type macros in the macro descriptions.

Examples of O-type macros are macros with an operand field allowing the specification of one register (frequently R1) that contains the start address of a parameter area.

The parameter area is defined in the data section of the program (DC statements) and contains the operand values.