- The Enigma machine is a cipher device developed and used in the early- to mid-20th century to protect commercial, diplomatic, and military communication. It was employed extensively by Nazi Germany during World War II, in all branches of the German military. The Enigma machine was considered so secure that it was used to encipher the most top-secret messages.
- Latches inside: Reverse-engineering the Intel 8086’s instruction register (righto.com)
The Intel 8086 microprocessor is one of the most influential chips ever created; it led to the x86 architecture that dominates desktop and server computing today. But it is still simple enough that its circuitry can be studied under the microscope and understood. In this post, I explain the implementation of a dynamic latch, a circuit that holds a single bit. The 8086 has over 80 latches scattered throughout the chip, holding a variety of important processor state bits,1 but I’ll focus on the eight latches that implement the instruction register and hold the instruction that is being executed.