Form of Relocatable Code
Program code consists of instructions; each instruction may have an address field that contains the offset of a variable or label from its data area. In addition, the instruction will have a relocation bit or field that indicates whether the address should be relocated. If the relocation bit is set, the corresponding location counter is added to the address.
R is a relocation code; it could be:
Relocatable code may contain other kinds of code items, e.g., BSS codes to specify blocks to be filled with a specified value such as 0.