Data General Corporation

Other

John K Ahlstrom

David H Bernstein

Michael S Richmond

Walter A Wallach, Jr

Richard G Bratt

Craig J Mundie

Steven J Wallach

Stephen I Schleimer

Richard A Belgard

Gerald F Clancy

Ronald H Gruner

David A Farber

John F Pilat

Edward S Gavrin

Thomas M Jones

Brett L Bachman

Lawrence H Katz

Douglas M Wells

Douglas M Well

Apparatus in a digital computer system capable of performing a call operation and a return operation for obtaining addresses of data from names representing the data. Each name is permanently associated with a procedure containing instructions to which the digital computer system responds. Each name further corresponds to a name table entry which is permanently associated with the same procedure. The corresponding name table entry for a name specifies how a base address and a displacement are to be derived using a plurality of current base addresses. The values of these addresses change only when the computer system executes a call operation suspending a current execution of a procedure and commencing another current execution or a return operation terminating the current execution and resuming the execution which was suspended to commence the terminated execution. The operation of resolving a name, i.e., obtaining the address of the data represented by the name, is performed by name interpretation apparatus in processors of the data processing system. In response to a name, the name interpretation apparatus locates the name table entry corresponding to the name fetches the name table entry, calculates the base address and the displacement using the name table entry and the current architectural base addresses, and then adds the base address to the displacement to obtain the address of the data represented by the name.

Digital data processing system incorporating apparatus for resolving

A digital computer system having a memory system organized into objects for storing data and a processor for processing data in response to instructions. An object identifier and an access control list are associated with each object. The memory system responds to logical addresses for data which specify the object containing the data and the offset of the data in the object and to a current subject for which the processor is referencing the data. The memory system performs a memory operation for the processor only if the access control list for the object specified by the logical address allows the current subject to perform the desired memory operation. The objects include procedure objects and data objects. The procedure objects contain procedures including the instructions and name tables associated with the procedures. The instructions contain operations codes and names representing data. Each name corresponds to a name table entry in the name table associated with the procedure. The name table for a name contains information from which the processor may derive the logical address for the data represented by the name. The processor may then use the logical address to specify a memory operation on the data represented by the name.

Digital computer system incorporating object-based addressing and access

A digital computer system having a memory system organized into procedure and data objects, each having a unique identifier code and an access control list, for storing items of information and a processor for processing data in response to instructions. The instructions contain operation codes and names representing data. Each name corresponds to a name table entry in a name table which contains information from which the processor determines the location and the format for the data. The name table entry specifies a base address of one of a set thereof which change value only when a call or a return instruction is executed. A name interpretation system fetches a name table entry, calculates the base address and a displacement using the name table entry and the current architectural base address and adds the base address to the displacement to form the address of the data represented by the name.

Digital data processing system having a uniquely organized memory system

Apparatus in a digital computer system for obtaining descriptors of data from names representing the data. The digital computer system executes sequences of instructions. Names representing data processed during execution of an instruction sequence are associated with the instruction sequence. Each name associated with the instruction sequence corresponds to a name table entry associated with the instruction sequence. The operation of resolving a name, i.e., obtaining the descriptor for the data represented by the name, is performed by name processing apparatus in processors of the data processing system. In response to a name, the name processing apparatus locates the name table entry corresponding to the name obtains the descriptor for the item represented by the name using the information in the name table entry corresponding to the name. In a present embodiment, the descriptor specifies the address and length of a data item. The information in the name table entry specifies the address of the represented item by specifying a base address and a displacement and further specifies the length and type of the represented item.

A digital computer system in which data operands are represented by names. Each procedure includes a name table, and means are provided to employ the name table to resolve the names into storage addresses at run time. The system also has the ability to run any of a plurality of S-Languages (an S-Language being conceptually similar to a machine language but of higher order); each S-Language can be optimally tailored to a high-order user language. Each procedure includes a dialect code which indicates the dialect of S-Language to which the instructions in the current procedure belong, and the system has provision to execute each procedure accordingly.

Digital computer system having unique means of referring to operands and

A digital computer system including a memory and a processor. The memory operates in response to memory commands received from the processor. Items of data stored in the memory include instructions to which the processor responds. Each instruction contains an operation code which belongs to one of several sets of operation codes. The meaning of a given operation code is determined by the operation code set to which the instruction belongs. Some of the instructions also contain names representing items of data used in the operation specified by the operation code. The processor includes an operation code decoding system which decodes the operation code as required for the instruction set to which it belongs, a name resolution system for deriving the address of the data item represented by a name from the name using an architectural base address contained in the name resolution system, and a control system which controls the operation of the processor. The processor performs a call operation and a return operation. Only the call operation and the return operation may change the current architectural base address. The memory further contains name table entries associated with the names. Each name table entry contains information used by the name resolution system when it resolves a name.

Digital computer system including apparatus for resolving names

A digital computer system having a memory for storing and providing data including instructions and a processor for processing data in response to the instructions and providing memory operation specifiers to the memory which specify an address of a data item and the memory operation to be performed on it. The instructions in the digital computer system include operation codes belonging to more than one set of operation codes and names representing items to be processed in the operation specified by the operation code. The data in memory further includes name table entries. Each name table entry corresponds to a name and contains information specifying the address of the item represented by the name. The processor includes apparatus for decoding each operation code in response to the operation code and to a dialect value contained in the decoding apparatus which specifies which operation code set the operation code being decoded belongs to. The processor further includes apparatus for processing names by resolving them to produce the addresses specified by their corresponding name table entries and control apparatus responsive to the instruction decoding apparatus and the name processing apparatus for controlling the processor and providing memory operation specifiers containing the addresses produced by the name processing means to the memory.

Digital data processing system for executing instructions containing

A digital data processing system has a memory organized into objects containing at least operands and instructions. Each object is identified by a unique and permanent identifier code which identifies the data processing system and the object. The system utilizes unique addressing mechanisms the addresses of which have object fields, offset fields and length fields for specifying the location and the total number of bits of an addressed object. The system uses a protection technique to prevent unauthorized access to objects by users who are identified by a subject number which identifies the user, a process of the system for executing the user's procedure, and the type of operation of the system to be performed by the user's procedure. An access control list for each object includes an access control list entry for each subject having access rights to the object and means for confirming that a particular active subject has access rights to a particular object before permitting access to the object.

Data processing system having addressing mechanisms for processing

A digital data processing system has a memory organized into objects containing at least operands and instructions. Each object is identified by a unique and permanent identifier code which identifies the data processing system and the object. The system further uses multilevel microcode techniques for controlling sequences of microinstructions and for controlling the interval operations of the processor. The system uses a protection technique to prevent unauthorized access to objects by users who are identified by a subject number which identifies the user, a process of the system for executing a user's procedure, and the type of operation of the system to be performed by the user's procedure. An access control list for each object includes an access control list entry for each subject having access rights to the object and means for confirming that a particular active subject has access rights to a particular object before permitting access to the object. The system also includes stacks for containing information relating to the current state of execution of the system.

Data processing system using object-based information and a protection

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. The system is internally comprised of a plurality of separate, independent processors, each having a separate microinstruction control and at least one separate, independent port to a central communications and memory node. The communications and memory node is an independent processor having separate, independent microinstruction control and comprised of a plurality of independently operating, microinstruction controlled processors capable of performing multiple, concurrent memory and communications operations. 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. Information is identified to bit granular level and to information type and format. Protection mechanisms provide variable access rights associated with individual bodies of information. User language instructions are transformed into dialect coded, uniform, intermediate level instructions to provide equal facility of execution for all user languages. Operands are referred to by uniform format names which are transformed, by internal mechanisms transparent to users, into addresses.

Digital data processing system having unique addressing means and means

A method for executing call and return instructions in a digital computer system operating under control of microcode. The microcode may specify calls to and returns from sequences of microinstructions. A call microinstruction sequence corresponds to the call instruction. The call microcode in turn calls other microinstruction sequences for deriving pointers representing the location of the called procedure and of arguments from operands in the call instruction. As the call microcode obtains each argument pointer, it places the pointer on the stack. After it has obtained all of the argument pointers, it passes the pointer to the called procedure and a pointer to the argument pointers to a general call microinstruction sequence. That microinstruction sequence locates the called procedure, makes a new frame including the argument pointers, and saves the state necessary to resume execution of the call microinstruction sequence itself. It then obtains the state necessary to commence execution of the called procedure and causes execution of that procedure to commence. The microcode corresponding to the return instruction restores both the state necessary to resume execution of the calling procedure and the state necessary to resume execution of the call microinstruction sequence. When it resumes execution, the call microinstruction sequence completes the return operation.

Method of performing a call operation in a digital data processing

The processor of the present invention executes procedures, which comprise S-language instructions and names. S-languages are of higher order than typical machine languages and can be tailored to user high-order languages. Each procedure includes a dialect code which the processor interprets, enabling it to execute any of a plurality of dialects of S-languages. The processor includes means for resolving names into operand logical addresses. The processor possosses multiple levels of microcode control means, each with its own set of stacks.

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Mountain View, CA, United States of America

John K Ahlstrom