The architecture of 8086 can be divided into two parts
- Bus Interface Unit (BIU).
- Execution Unit (EU).
The bus interface unit is responsible for physical address calculations and predecoding instruction byte queue(6 byte long).
The bus interface unit makes the system bus signals available for external devices.
The 8086 addresses a segmented memory. The complete physical address which is 20-bit long is generated using segment and offset registers, each 16-bit long.