Slac-127 Uc-32 W=c) Direct Emulation of Control Structures by a Parallel Micro-computer

This paper is a preliminary investigation of the organization of a parallel micro-computer designed to emulate a wide variety of sequential and parallel computers. This micro-computer allows tailoring of the control structure of an emulator so that it directly emulates (mirrors) the control structure of the computer to be emulated. An emulated control structure is implemented through a tree type data structure which is dynamically generated and manipulated by six primitive (built-in) operators D This data structure for control is used as a syntactic framework within which particular implementations of control concepts, such as iteration, recursion, co-routines, parallelism, interrupts, etc., can be easily expressed. The major features of the control data structure and the primitive operators are: 1) once the fixed control and data linkages among processes have been defined, they need not be rebuilt on subsequent executions of the control structure; 2) micro-programs may be written so that they execute independently of the number of physical processors present and still take advantage of available processors; 3) control structures for I/O processes, dataaccessing processes, and computational processes are expressed in a single uniform framework. This method of emulating control structures is in sharp contrast with the usual method of micro-programming control structures which handles control instructions in the same manner as other types of instructions, e.g., subroutines of micro-instructions, and provides a unifying method for the efficient emulation of a wide variety of sequential and parallel computers.