- The Intel 8086 processor contains many interesting components that can be understood through reverse engineering. In this article, I’ll discuss the adder that is used for address calculations. The photo below shows the tiny silicon die of the 8086 processor under a microscope. The left part of the chip has the 16-bit datapath including the registers and the Arithmetic-Logic Unit (ALU); you can see the pattern of circuitry repeated 16 times. The rectangle in the lower-right is the microcode ROM, defining the execution of each instruction.