Abstract: A method for providing security for plaintext data being transferred between units in a computer system includes steps of dividing a memory into a series of addressable locations, each of the addressable locations having an address at which can be stored version information, a data authentication tag, and ciphertext corresponding to the plaintext. The system retrieves the ciphertext, the version information, and the data authentication tag, and generates encryption keys for decrypting the information stored at the address. If the data authentication tag indicates the plaintext data are valid, then the system provides the decrypted plaintext to the requestor, or encrypts new plaintext data and stores the corresponding ciphertext with new authentication and version information at the first address.

Abstract: A system for providing high security for data stored in memories in computer systems is disclosed. A different encryption key is used for every memory location, and a write counter hides rewriting of the same data to a given location. As a result, the data for every read or write transaction between the microprocessor and the memory is encrypted differently for each transaction for each address, thereby providing a high level of security for the data stored.

Abstract: A simulation of an electronics system which performs a set of operations of interest. A simulated supervisory circuit detects a state in which all the operations have been completed, and also determines the amount of time until the occurrence of the next relevant event. Simulation time is then advanced by that amount of time. This enables simulation time corresponding to an inactive system to be eliminated.

Abstract: An integrated circuit with a multiplexer system and a control circuit is described. The multiplexer system has an output terminal connected to an output pin of the integrated circuit and input terminals connected to internal nodes of the integrated circuit. In a normal mode the control circuit generates the control signals so that any one of the internal nodes is connected to the output pin so that the integrated circuit can function flexibly. In a test mode so that a different internal node is connected to the output pin in each cycle of a test clock signal.

Abstract: An integrated circuit with a multiplexer system and a control circuit is described. The multiplexer system has an output terminal connected to an output pin of the integrated circuit and input terminals connected to internal nodes of the integrated circuit. In a normal mode the control circuit generates the control signals so that any one of the internal nodes is connected to the output pin so that the integrated circuit can function flexibly. In a test mode so that a different internal node is connected to the output pin in each cycle of a test clock signal.

Abstract: A simulation of an electronics system which performs a set of operations of interest. A simulated supervisory circuit detects a state in which all the operations have been completed, and also determines the amount of time until the occurrence of the next relevant event. Simulation time is then advanced by that amount of time. This enables simulation time corresponding to an inactive system to be eliminated.

Abstract: A computer system simulator concurrently models both processor operation and signal logic behavior and provides a high degree of user interaction and flexibility in the observation and control of signal values and memory contents during the execution of a simulation. During simulation, source equations for signals can be requested for display either through direct input of a signal name or through graphical interface with the simulation display. Signal equations can in this manner be traced back through several levels, which conveniently provides important information during the observation and modification of signal values. Memory areas may be associated with a processor and loaded with data to be executed by that processor during the simulation. The data can be displayed in both numerical and assembly code mnemonic form, and may also be modified by entering numbers or assembly instructions. The simulated processor execution may thus be interactively modified during the simulation.

Abstract: The present invention provides for a computer system having a plurality of parallel processor units with each processor unit associated with at least one register for receiving data for the processor unit. The computer system has a bus unit, coupled to the output of each processor unit and the associated register of each processor unit, to transfer the output data of a first processor unit into an associated register of a second processor unit in a single computer operation. The second processor unit is prevented from reading the associated register until the bus unit transfers the output data from the first processor unit to the second processor unit.

Abstract: A technique for speeding CPU operations in handling branch instructions in which the target instructions is a short displacement away from its branch instruction is disclosed. When the target instruction is displaced within a predetermined number of instructions away, a logic block and counter issue an invalidating control signal which invalidates the execution of the branch instruction and instructions between the branch instruction and the target instruction. The invalidating control signal is removed when the target instruction is reached. Time is saved if the latency of the computer system is longer than the time required to cycle the instruction queue to the target instruction.

Abstract: The present invention provides for a computer system having a plurality of parallel processor units. The processor units are connected in common to a signal line with each processor capable of setting a first signal level on the line and monitoring the line in response to instructions to the processor. This allows each processor unit to be notified of the completion of a parallel operation by other participating processor units upon a second signal level on the signal line. More than one signal lines may be connected between the parallel processor units to provide synchronization of different parallel operations between different processor units.

Abstract: A parallel processing system is provided with a plurality of processors and a plurality of memories, and bus units with arbitration coupling the processors and memories. A bus unit provides a pathway between one processor and the bus unit's respective memory. Each bus unit arbitrates multiple simultaneous access requests for its respective memory and communicates its decisions to other bus units so that a memory access requiring multiple memories will only occur if all those memories are available. The coupling of processors to memories can change, dynamically, each bus cycle without the need for setup before the bus cycle either by pipelining or having unused bus cycles. In a specific embodiment, the memory access information is provided on high order address lines, where the processor logically accesses different memory address spaces to make different accesses, thereby sharing memory with other processors.

Abstract: A computer system having a plurality of parallel processor units with each processor unit having an output bus of n bits and an associated mask register is provided. The computer system comprises a bus unit, coupled to the output bus of each processor unit and each associated mask register, for masking the output bus bits with bits in the mask register of each processor unit and logically combining the resulting masked bits from each processor unit into an output bus of n bits in one computer operation.

Abstract: A computer system simulator concurrently models both processor operation and signal logic behavior and provides a high degree of user interaction and flexibility in the observation and control of signal values and memory contents during the execution of a simulation. During simulation, source equations for signals can be requested for display either through direct input of a signal name or through graphical interface with the simulation display. Signal equations can in this manner be traced back through several levels, which conveniently provides important information during the observation and modification of signal values. Memory areas may be associated with a processor and loaded with data to be executed by that processor during the simulation. The data can be displayed in both numerical and assembly code mnemonic form, and may also be modified by entering numbers or assembly instructions. The simulated processor execution may thus be interactively modified during the simulation.

Abstract: A computer system having a plurality of parallel processor units with each processor unit having an output bus of n bits and an associated mask register is provided. The computer system comprises a bus unit, coupled to the output bus of each processor unit and each associated mask register, for masking the output bus bits with bits in the mask register of each processor unit and logically combining the resulting masked bits from each processor unit into an output bus of n bits in one computer operation.