Abstract: A data processing system includes a number of subsystems all coupled in common to a system bus and communicate with each other by sending and receiving commands sent over the system bus. A central processing subsystem includes a response memory for storing indication of the responses sent by the receiving subsystem when receiving commands sent by the central processing subsystem. The responses include an acknowledge response, a not acknowledge response or no response--a timeout. Storing the acknowledge response and the timeout will enable the programmer to determine which of the three responses was received.

Abstract: An address boundary detector is disclosed that functions with an arithmetic logic unit (ALU) in a computer processor while the ALU generates addresses by adding an offset or displacement to a base address. The detector monitors bits of addresses to determine whether a data item can be completely stored within the same block or page of memory as that addressed by the base address from which it was derived.

Abstract: A multifunction arithmetic indicator that is associated with and controlled by an arithmetic logic unit (ALU) to store standard arithmetic indicator information such as overflow, carry, arithmetic sign and all bits equal zero that are generated by the ALU when processing binary information. A control unit sends control signals to multiplexers in the multifunction arithmetic indicator that cause the selection of appropriate arithmetic indicator information from the ALU, no matter what the bit length of binary words being processed by the ALU. The selected indicator information is stored in a register for later use.

Abstract: Memory failure detection apparatus is disclosed which is used with a large capacity memory that is organized in banks of memory, and with which error correction circuitry is used to correct correctable errors and provide an indication of same. The detection apparatus is responsive to the error indications and to a bank select addressing signal to provide and store error counts for a bank or banks of memory located on each memory board. A system processor periodically reads the error counts and responds to same to provide a maintenance message indicating that a specific memory board is to be replaced.

Abstract: What is disclosed is a time partitioned bus arrangement for use in a computer system wherein different circuits therein are interconnected by a plurality of busses and operation is such that information to be processed can be read out of one circuit, processed in some manner in another circuit, and the processed information be stored in the same or another circuit all within one cycle of a system clock in the computer system, and without the need for bus control circuits and bus interfaces in the circuitry connected to the busses. Some of the circuits have their input/output connected to only a single one of the busses, while other circuits have their input connected to one bus and their output connected to a different bus, and yet other circuits have either their input or output connected to one of the busses and their other input/output connected to circuitry external to the bus arrangement.

Abstract: A data processing system includes a central processor unit (CPU), a main memory and a memory management unit (MMU). Information is stored in main memory in segments, each segment being identified by a segment descriptor stored in a translation table in the MMU. Logical addresses from the CPU address segment descriptors in the MMU's translation table. These segment descriptors include the physical address of the location in main memory of the first word of the segment. If the segment descriptor is not in the translation table location, then the MMU operation is suspended while the segment descriptor is demand fetched from main memory.

Abstract: A priority resolver for providing unambiguous resolution of requests among competing processes vying for access to a common device and which is adapted to a non-distributed environment.

Abstract: A decoding logic system in a logic control system of a data processing system is disclosed, wherein the data processing system is comprized of a main memory unit communicating with the logic control system by way of a common communication bus, and wherein the logic control system and a CPU (central processing unit) communicate by way of a local communication bus. In response to a CPU request, CPU instructions stored in the main memory unit are received by the logic decoding system, and presented to the CPU in such a manner as to accommodate both memory bit and CPU computed bit modifications to the instructions during instruction execution, while avoiding interruptions in CPU activity caused by information transfer delays internal to the logic decoding system. Instruction modification also may be effected by incrementing or decrementing the instructions under firmware control.

Abstract: A logic control system is disclosed for accommodating the flow of both procedural information and CPU (central processing unit) instructions from a central memory system to a CPU without compromising memory bandwidths or CPU execution speeds because of transfer delays or timing variances. Instruction modifications and plural task assignments are accommodated during instruction execution.

Abstract: A logic control system is disclosed for accommodating the flow of both procedural information and CPU (central processing unit) instructions from a central memory system to a CPU without compromising memory bandwidths or CPU execution speeds because of transfer delays or timing variances. Instruction modifications and plural task assignments are accommodated during instruction execution.

Abstract: A logic control system comprised of a cache memory system and a transfer control logic unit is disclosed for accommodating the flow of both procedural information and CPU (central processing unit) instructions from a central memory system on a common communication bus to a CPU. The CPU and the transfer control logic unit communicate by way of the cache memory system with the common communication bus. In response to a CPU request to the central memory system, procedural information and instructions are requested by the transfer control logic unit from the cache memory system and presented to the CPU in such a manner as to avoid interruptions in CPU activity caused by information transfer delays.

Abstract: This disclosure relates to a control system for transferring binary words from a memory system. One thirty two bit double word may be loaded into a selected two of four sixteen bit registers. As a first of the two selected registers is read, another thirty two bit word may be loaded into the unselected registers. Alternatively, sixteen bit single words may be loaded into and read from the registers. When a word has procedural information, it is read from the registers onto a CPU control bus via a multiplexer. When a word is an encoded computer instruction to the CPU, it is read from the registers into a logic unit via a multiplexer. A decoded instruction from the logic unit is read onto a CPU control bus.

Abstract: A data processing system includes a memory subsystem for storing operands and instructions and a central processing unit (CPU) for manipulating the operands by executing the instructions. The CPU includes a control store for generating signals for controlling the CPU operation. Shifters made up of multiplexers shift operands between an outer bus and a write bus in response to control store signals. The multiplexers shift the operands left or right 1, 2 or 4-bit positions including open shifts and circular shifts and also perform byte position shifting and twinning.

Abstract: A cache memory for use in a data processing system wherein data words are identified by either an odd or an even address number and wherein system elements request the transfer of data words with the cache memory by supplying either an odd or an even memory request address number with a memory request, the cache memory including a first pllurality of addressable memory locations for storing data words associated with odd address numbers and a second plurality of memory locations for storing data words associated with even address numbers, and an adder for incrementing a memory request address number by one to generate the address number of the next successively stored data word to permit a set of memory address drivers to control the addressing and transferring of a data word stored in the first memory module and associated with an odd address number simultaneously with the addressing and transferring of a data word stored in the second memory module and addressed by an even address number.

Abstract: In a data processing system, a central processor unit requests procedural data words or non-procedural data words stored in the system memory. A control store device executes firmware instructions including a local bus field for controlling the transfer of the requested procedural data words and non-procedural data words to the central processor unit.

Abstract: The performance of a scientific ADD instruction is improved by storing the mantissas of both operands in each of two random access memories, selecting the mantissa with the smaller exponent, shifting that mantissa and performing the ADD operation of adding the mantissas in one machine cycle.

Abstract: Mantissa results of floating point operations are truncated to words of 24 bits each by storing the 64 bit mantissa result in a first address location of a random access memory, and storing binary ZEROs in the 48 least significant bit positions of a second address location of the random access memory. The mantissa result is truncated by addressing the high order 24 bits at the first address location and the 48 binary ZEROs at the second address location.

Abstract: A communications processor is coupled between a main memory and a plurality of communications channels and with a central processing unit and includes control mechanisms for processing the transfer of information between the processor and the main memory with minimum interruption of the central processing unit. The processor further includes control tables and a plurality of control routines enabling the processing of the transfer of the information between the processor and the channels. The routines are unique to the communications channel characteristics of the device coupled with the channel being serviced and is configurable to reflect any changes made in such characteristics.

Abstract: A hardware/firmware control system is disclosed for accommodating the concurrent bi-directional transfer of information between a communications channel such as a telephone line and a communications processor in a data processing system.