Data General Corporation

Carl J Alsing

Charles J Holland

Steven Wallach

Michael L Ziegler

James Marriot Guyer

Ronald H Gruner

Michael B Druke

Kenneth D Holberger

Richard W Coyle

Edward J Rasala

Thomas West

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 instruction responsive apparatus thereof responds to unique microinstructions which, for example, provide for the selection of one of a plurality of interrupt routines each corresponding to an interrupt request from a different external device, provide for the sequential loading of a plurality of segment identification registers each pointing to selected memory management tables associated with a segment storage region of main memory, provide for a program counter relative jump operation, provide for zero-extending or sign-extending 16-bit words to 32-bit words having the same value, and provide for the multiplication of the lower 16 bits of two 32-bit accumulators and the sign-extension of the 16-bit result to form a 32-bit word.

Data processing system having instruction responsive apparatus for both

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. The memory system uses a bank of main memory modules which interface with the central processor system via a dual port cache memory, block data transfers between the main memory and the cache memory being controlled by a bank controller unit.

Data processing system

A microprogrammed processor in which control signals for data paths, the ALU function, the shifter and all other control signals are derived from the current microprogram control word which is normally periodically clocked into a ROM buffer. The processor provides for microbranching capability with and/or without a test, testing capabilities including direct addressing with simultaneous temporary address storage capability for future recall, and selective testing of computer instruction bits for decoding to address the next micro-instruction. Additional capabilities provide for flexible access to the micro-code instruction control store through a ROM address multiplexer which allows for selection of at least one of four possible micro-instruction addresses determined by micro-code control decode logic. The above functions are accomplished with a fifty-six bit micro-instruction format implemented with a sixteen bit word length, which allows for a flexible instruction set for a microprogrammed processor enabling a system to be designed to span the range from a minicomputer to a large processor.

Microprogram data processing technique and apparatus

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Hopkington, MA, United States of America

Carl J Alsing