These represent the program counter, plus or minus a numeric constant. Use them as targets for branch instructions, or to access small items of data embedded in code sections. You can define program-relative labels using a label on an instruction or on one of the data definition directives. See:

These represent a named register plus a numeric constant. They are most often used to access data in data sections. You can define them with a storage map. You can use the EQU directive to define additional register-relative labels, based on labels defined in storage maps. See:

These are numeric constants. They are integers in the range 0 to 2³²–1. They address the memory directly.