Data General Corporation

James T Nealon

Thomas M Jones

John F Pilat

Richard G Bratt

Ronald H Gruner

Brett L Bachman

Gary Davidian

David H Bernstein

Craig J Mundie

Steven J Wallach

Stephen I Schleimer

Gerald F Clancy

Richard A Belgard

Edward S Gavrin

Paul Bowden

Charles J Young

Encachement apparatus consisting of first and second caches responsive to first and second keys, respectively, for outputting first and second data therefrom. In one embodiment, the second cache which includes a stack having a plurality of frames, outputs data contained in a current frame thereof in response to a second key which is obtained from the first cache. The data outputted from each cache is received substantially simultaneously at a combiner which combines such data to produce the desired third data from the dual cache system.

Encachement apparatus using two caches each responsive to a key for

The processor of the present invention can execute any of a plurality of dialects of 'S-Language' instructions. S-Languages are of a higher order than typical machine languages but of a lower order than the user's own high order language. They can be tailored for compatibility with user high order languages. Each instruction of a particular S-Language is interpreted by a sequence of microinstructions. In the processor of the present invention, dispatching to the microinstruction sequencer is controlled jointly by the instruction bit pattern and the current contents of a dialect register. Each procedure to be executed carries with it information from which the appropriate contents of the dialect register may be determined. Thus, the processor of the present invention can always operate as an effective optimum processor for executing the procedure regardless of the source language chosen for writing that procedure.

Digital data processing system capable of executing a plurality of

A digital computer uses a memory which is structured into objects, which are blocks of storage of arbitrary length, in which data items are accessed by descriptors which for a desired data item specify the object, the offset into that object, and the length of the data object. The computer system of the present invention further provides the ability to execute any of a plurality of dialects of internal instructions, the repertoire of such dialects being virtually infinite, since there is the ability to load a supporting microcode during operation as needed.

Digital computer system having descriptors for variable length

A data processing system having a flexible internal structure, protected from and effectively invisible to users, with multilevel control and stack mechanisms and capability of performing multiple, concurrent operations, and providing a flexible, simplified interface to users. Addressing mechanisms allow permanent, unique identification of information and an extremely large address space accessible and common to all such systems. Addresses are independent of system physical configuration and includes length field information specifying the number of data bits at the addressed location. In accordance with the invention as used in such system, the processor includes arithmetic logic (ALU) means for performing operations on operands. The number of bits in the results of such operations are compared with the number of bits specified by the length field of an address of the location to which the result can be transferred to indicate when such numbers of bits are not equal.

Digital data processing system using unique means for comparing

Encachement apparatus consisting of a first cache, a second cache connected to the first cache, registers for storing data, an adder receiving inputs from a first multiplexer connected to the first cache and a second multiplexer connected to the second cache and to the registers, and control apparatus connected to the first cache, the first multiplexer, and the second multiplexer. The first cache outputs a cache entry in response to a key. The cache entry contains a first displacement value, a base specifier specifying either one of the registers or the second cache, and in the case of entries specifying the second cache, a second displacement value. The first displacement value is output to the first multiplexer, the base specifier is output to the control apparatus, and the second displacement, if present, is output to the second cache. The control apparatus responds to the base specifier by causing the first multiplexer to select the displacement value output by the cache and causing the second multiplexer to select one of the values contained in the registers or the value output by the second cache in response to the second displacement. The adder then adds the value selected by the first multiplexer to the value selected by the second multiplexer and outputs the result.

Encachement apparatus

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Cary, NC, United States of America

James T Nealon