== Pipeline Design ==
Internally, the 8086 features a 16‑bit execution unit Execution Unit (EU) that performs arithmetic, logic, and control functions, while simultaneously a separate bus interface unit Bus Interface Unit (BIU) handles all data transfers and external communications.
The BIU includes a 6‑byte prefetch queue (4-byte for 8088). The EU fetches instructions from the prefetch queue (not directly from memory). It has no direct connection to the external system bus, relying entirely on the BIU for data and instruction access.