A Parallel RISC computer system is provided by a multi-mode dynamic multi-mode parallel processor array with one embodiment illustrating a tightly coupled VLSI embodiment with an architecture which can be extended to more widely placed processing elements through the interconnection network which couples multiple processors capable of MIMD mode processing to one another with broadcast of instructions to selected groups of units controlled by a controlling processor. The coupling of the processing elements logic enables dynamic mode assignment and dynamic mode switching, allowing processors operating in a SIMD mode to make maximum memory and cycle time usage. On and instruction by instruction level basis, modes can be switched from SIMD to MIMD, and even into SISD mode on the controlling processor for inherently sequential computation allowing a programmer or complier to build a program for the computer system which uses the optimal kind of parallelism (SISD, SIMD, MIMD). Furthermore, this execution, particularly in the SIMD mode, can be set up for running applications at the limit of memory cycle time. With the ALLNODE switch and alternatives paths a system can be dynamically achieved in a few cycles for many many processors. Each processing element and memory and has MIMD capability the processor's an instruction register, condition register and program counter provide common resources which are used in MIMD and SIMD. The program counter become a base register in SIMD mode.