
In computer science, computer engineering and programming language implementations, a stack machine is a type of computer. In some cases, the term refers to a software scheme that simulates a stack machine. The main difference from other computers is that most of its instructions operate on a pushdown stack of numbers rather than numbers in registers. A stack computer is programmed with a reverse Polish notation instruction set. A stack machine must be a computer, and therefore must be Turing complete, unlike a pushdown automaton. Most computer systems implement a stack in some form to pass...