Abstract: A data processing system which handles thirty-two bit logical addresses which can be derived from either sixteen bit logical addresses or thirty-two bit logical addresses, the latter being translated into physical addresses by unique translation means. The system includes means for decoding macro-instructions of both a basic and an extended instruction set, each macro-instruction containing in itself selected bit patterns which uniquely identify which type of instruction is to be decoded. The decoded macro-instructions provide the starting address of one or more micro-instructions, which address is supplied to a unique micro-instruction sequencing unit which appropriately decodes a selected field of each micro-instruction to obtain each successive micro-instruction. The system uses hierarchical memory storage using eight storage segments (rings), access to the rings being controlled in a privileged manner according to different levels of privilege.

Abstract: A data processing system having a host processor, a host memory, a host memory management unit and an input/output bus and further including a separate input/output (I/O) processor with its own local memory for handling the transfer of data between I/O devices on its own I/O processor I/O bus and the host main memory. The I/O processor has the capability of directly accessing main memory via the host standard data channel. The I/O processor has the capability of interrupting the host processor operation in a special way by a "micro-interrupt" process such that the host processor thereby re-allocates the contents of a selected memory allocation unit (MAP) of the host memory management unit faster than using standard interrupt routines.