PLUS - A PL/I based ultracomputer simulator, I
Allan Gottlieb · 1980
This note describes a (presently implemented) ultracomputer emulator called PLUS which uses the multitasking and preprocessing features of PL/I to support a recursive ultracomputer programming style. Since the emulation to be described as written in PL/I, the powerful debugging features of the PL/I checkout compiler, as well as PL/I's separate compilation facility are available. This note also describes the emulation system and furnish a "User's Guide". In a subsequent part II we will discuss the system's implementation and prove both correctness and freedom from deadlock. 1. Introduction [UC] introduced the concept of an ultracomputer and reviewed various basic algorithms for such an ensemble of processors containing "shuffle" [Clos, Benes, and Stone] interconnections. [UCN3] described a style for programming ultracomputers and rewrote several of the basic algorithms in this style. This new style forbids recursion so the recursive algorithms of [UC] appeared in iterative form ...