The 8086 family of processors recognizes four kinds of instruction operands: register, immediate, direct memory, and indirect memory. Each type of operand corresponds to a different addressing mode.
The four types of operands are summarized in the following list and described at length in the rest of this section.
| Operand Type | Addressing Mode |
| Register | An 8-bit or 16-bit register on the 8086–80486; can also be 32-bit on the 80386/486 |
| Immediate | A constant value contained in the instruction itself |
| Direct memory | A fixed location in memory |
| Indirect memory | A memory location determined at run time by using the address stored in one or two registers and a constant |