- Reverse-engineering the 8086’s Arithmetic/Logic Unit from die photos (righto.com)
The Intel 8086 processor was introduced in 1978, setting the course of modern computing. While the x86 processor family has supported 64-bit processing for decades, the original 8086 was a 16-bit processor. As such, it has a 16-bit arithmetic logic unit (ALU).1 The arithmetic logic unit is the heart of a processor: it performs arithmetic operations such as addition and subtraction. It also carries out Boolean logic operations such as bitwise AND and OR as well as also bit shifts and rotates. Since a fast ALU is essential to the overall performance of a processor, ALUs often incorporate interesting design tricks.
- And, finally, as it is not enough, before commencing to rebuild the house in which we live, that it be pulled down, and materials and builders provided, or that we engage in the work ourselves, according to a plan which we have beforehand carefully drawn out, but as it is likewise necessary that we be furnished with some other house in which we may live commodiously during the operations, so that I might not remain irresolute in my actions, while my Reason compelled me to suspend my judgment, and that I might not be prevented from living thenceforward in the greatest possible felicity, I formed a provisory code of Morals, composed of three or four maxims, with which I am desirous to make you acquainted.