Abstract: The high-performance, RISC core based microprocessor architecture includes an instruction fetch unit for fetching instruction sets from an instruction store and an execution unit that implements the concurrent execution of a plurality of instructions through a parallel array of functional units. The fetch unit generally maintains a predetermined number of instructions in an instruction buffer. The execution unit includes an instruction selection unit, coupled to the instruction buffer, for selecting instructions for execution, and a plurality of functional units for performing instruction specified functional operations. A unified instruction scheduler, within the instruction selection unit, initiates the processing of instructions through the functional units when instructions are determined to be available for execution and for which at least one of the functional units implementing a necessary computational function is available.

Abstract: A high-performance, superscalar-based computer system with out-of-order instruction execution for enhanced resource utilization and performance throughput. The computer system fetches a plurality of fixed length instructions with a specified, sequential program order (in-order). The computer system includes an instruction execution unit including a register file, a plurality of functional units, and an instruction control unit for examining the instructions and scheduling the instructions for out-of-order execution by the functional units. The register file includes a set of temporary data registers that are utilized by the instruction execution control unit to receive data results generated by the functional units. The data results of each executed instruction are stored in the temporary data registers until all prior instructions have been executed, thereby retiring the executed instructions in-order.

Abstract: A high-performance, superscalar-based computer system with out-of-order instruction execution for enhanced resource utilization and performance throughput. The computer system fetches a plurality of fixed length instructions with a specified, sequential program order (in-order). The computer system includes an instruction execution unit including a register file, a plurality of functional units, and an instruction control unit for examining the instructions and scheduling the instructions for out-of-order execution by the functional units. The register file includes a set of temporary data registers that are utilized by the instruction execution control unit to receive data results generated by the functional units. The data results of each executed instruction are stored in the temporary data registers until all prior instructions have been executed, thereby retiring the executed instructions in-order.

Abstract: A computer system comprising a microprocessor architecture capable of supporting multiple processors comprising a memory array unit (MAU), an MAU system bus comprising data, address and control signal buses, an I/O bus comprising data, address and control signal buses, a plurality of I/O devices and a plurality of microprocessors. Data transfers between data and instruction caches and I/O devices and a memory and other I/O devices are handled using a switch network port data and instruction cache and I/O interface circuits. Access to the memory buses is controlled by arbitration circuits which utilize fixed and dynamic priority schemes.

Abstract: The high-performance, RISC core based microprocessor architecture includes an instruction fetch unit for fetching instruction sets from an instruction store and an execution unit that implements the concurrent execution of a plurality of instructions through a parallel array of functional units. The fetch unit generally maintains a predetermined number of instructions in an instruction buffer. The execution unit includes an instruction selection unit, coupled to the instruction buffer, for selecting instructions for execution, and a plurality of functional units for performing instruction specified functional operations. A unified instruction scheduler, within the instruction selection unit, initiates the processing of instructions through the functional units when instructions are determined to be available for execution and for which at least one of the functional units implementing a necessary computational function is available.

Abstract: A system and method for processing a sequence of requests for data by one or more central processing units (CPUs) after cache misses. Each CPU request includes a CPU-ID tag identifying the CPU issuing the request for data and an address identifying a location in lower-level memory where the data is stored. Cache-control ID tags are assigned to identify the locations in the request queue of the respective CPU-ID tags associated with each CPU request. Cache-control requests consisting of the cache-control ID tags and the respective address information are sent from the request queue to the lower-level memory or storage devices. Data is then returned along with the corresponding CCU-ID tags in the order in which it is returned by the storage devices. Finally, the sequence of CPU requests for data is fulfilled by returning the data and CPU-ID tag in the order in which the data was returned from lower-level memory.

Abstract: A computer system comprising a multiprocessor architecture capable of supporting multiple processors comprising a memory array unit (MAU), an MAU system bus comprising data, address and control signal buses, an I/O bus comprising data, address and control signal buses, a plurality of I/O devices and a plurality of microprocessors. Data transfers between data and instruction caches and I/O devices and a memory and other I/O devices are handled using a switch network and interface circuits. Access to the memory buses is controlled by arbitration circuits which utilize fixed and dynamic priority schemes. A row match comparison circuit is provided for reducing memory latency by giving an increased priority to successive requests for access to memory locations having the same row address.

Abstract: A high-performance, superscalar-based computer system with out-of-order instruction execution for enhanced resource utilization and performance throughput. The computer system fetches and stores program instruction sets. Each instruction set includes a plurality of fixed length instructions with a specified, sequential program order (in-order). The computer system includes an instruction execution unit including a register file, a plurality of functional units, and an instruction control unit for examining the instruction sets and scheduling the instructions for out-of-order execution by the functional units. The register file includes a set of temporary data registers which are utilized by the instruction execution control unit to receive data results generated by the functional units. The data results of each executed instruction are stored in the temporary data registers until all prior instructions have been executed, thereby retiring the executed instructions in-order.

Abstract: A computer system comprising a microprocessor architecture capable of supporting multiple processors. Data transfers between data and instruction caches, I/O devices, and a memory are handled using a switch network. Access to memory buses is controlled by arbitration circuits which utilize fixed and dynamic priority schemes. A test and set bypass circuit is provided for preventing a loss of memory bandwidth due to spin-locking. A row match comparison circuit is provided for reducing memory latency by giving an increased priority to successive requests for access to memory locations having the same row address. Dynamic switch/port arbitration is provided by changing device priority based on the intrinsic priority of the device, the number of times that a request has been serviced based on a row match, the number of times that a device has been denied service, and the number of times that a device has been serviced.

Abstract: A high-performance, superscalar-based computer system with out-of-order instruction execution and concurrent results distribution for enhanced resource utilization and performance throughput. The computer system architecture includes an instruction fetch unit for fetching program instruction sets. Each instruction set includes a plurality of fixed length instructions with a prescribed program order (in-order). The architecture also includes an instruction execution unit for dynamically examining the instruction sets and scheduling instructions for execution, including out-of-order execution, among a plurality of functional units. The data results of the executed instructions are concurrently distributed to a temporary buffer and a register file array and managed by associated control logic, including a register renaming unit, a dependency checker unit, done control unit, and retirement control unit.

Abstract: A high-performance, superscalar-based computer system with out-of-order instruction execution for enhanced resource utilization and performance throughput. The computer system fetches and stores program instruction sets. Each instruction set includes a plurality of fixed length instructions with a specified, sequential program order (in-order). The computer system includes an instruction execution unit including a register file, a plurality of functional units, and an instruction control unit for examining the instruction sets and scheduling the instructions for out-of-order execution by the functional units. The register file includes a set of temporary data registers which are utilized by the instruction execution control unit to receive data results generated by the functional units. The data results of each executed instruction are stored in the temporary data registers until all prior instructions have been executed, thereby retiring the executed instructions in-order.

Abstract: Fast trap mechanism for a microprocessor, wherein a vector trap table is maintained which contains space for a plurality of instructions in each table entry. When a fast trap occurs, control is transferred directly into the table entry corresponding to the trap number. The trap handler can be located completely inside the table entry, or it can transfer control to additional handler code.

Abstract: A method for use in a microprocessor to return execution to a main program after processing an interruption to the sequential processing of instructions from the main instruction stream is disclosed. The method comprises fetching instructions from a main instruction stream to a main buffer section of a prefetch buffer and executing said fetched instructions. The method also provides for handling interruptions to the processing of the main instruction stream and allowing return to the main instruction stream without requiring prefetching of instructions already fetched. Similarly, the method provides for handling interruptions of the processing of interruptions of the processing of the main instruction stream.

Abstract: A computer system comprising a microprocessor architecture capable of supporting multiple processors. Data transfers between data and instruction caches, I/O devices, and a memory am handled using a switch network. Access to memory buses is controlled by arbitration circuits which utilize fixed and dynamic priority schemes. A test and set bypass circuit is provided for preventing a loss of memory bandwidth due to spin-locking. A row match comparison circuit is provided for reducing memory latency by giving an increased priority to successive requests for access to memory locations having the same row address. Dynamic switch/port arbitration is provided by changing device priority based on the intrinsic priority of the device, the number of times that a request has been serviced based on a row match, the number of times that a device has been denied service, and the number of times that a device has been serviced.

Abstract: A data selection device having M+1 stages. Each stage has stored therein prioritized data. Selection of the highest prioritized data available at any instant in time is based on a comparison repeated M times of both the selectability and priority of data available from two different stages of the device. The highest prioritized data is provided at the output of the M+1 stage.