Abstract: A method and apparatus for overlaying hazard clearing with a jump instruction within a pipeline microprocessor is described. The apparatus includes hazard logic to detect when a jump instruction specifies that hazards are to be cleared as part of a jump operation. If hazards are to be cleared, the hazard logic disables branch prediction for the jump instruction, thereby causing the jump instruction to proceed down the pipeline until it is finally resolved, and flushing the pipeline behind the jump instruction. Disabling of branch prediction for the jump instruction effectively clears all execution and/or instruction hazards that preceded the jump instruction. Alternatively, hazard logic causes issue control logic to stall the jump instruction for n-cycles until all hazards are cleared. State tracking logic may be provided to determine whether any instructions are executing in the pipeline that create hazards. If so, hazard logic performs normally.

Abstract: Certain embodiments for reducing instruction storage space for a processor integrated in a network adapter chip may include generating MIPS instructions from corresponding new instructions. The new instructions may be in patch code instruction (PCI) format. The new instructions may be decoded and the MIPS instructions may be generated by a MIPS processor within a network adapter chip. Decoding the new instructions may also be referred to as interpreting the new instructions. The new instructions may comprise fewer bits than the generated MIPS instructions. The generated MIPS instructions may be executed by the MIPS processor within the network adapter chip.

Abstract: Multiple instruction set architectures are supported in a system that provides a power-efficient and flexible platform for virtual machine environments requiring multiple support for multiple instruction set architectures (ISAs). A processor includes multiple cores having disparate native ISAs and that may be selectively enabled for operation, so that power is conserved when support for a particular ISA is not required of the processor. A hypervisor controls operation of the cores, locates a core and enables it if necessary when a request to instantiate a virtual machine having a specified ISA is received. The ISA may be specified by a particular operating system and/or application program requirements.

Abstract: The present invention provides a system and method for managing load and store operations necessary for reading from and writing to memory or I/O in a superscalar RISC architecture environment. To perform this task, a load store unit is provided whose main purpose is to make load requests out of order whenever possible to get the load data back for use by an instruction execution unit as quickly as possible. A load operation can only be performed out of order if there are no address collisions and no write pendings. An address collision occurs when a read is requested at a memory location where an older instruction will be writing. Write pending refers to the case where an older instruction requests a store operation, but the store address has not yet been calculated. The data cache unit returns 8 bytes of unaligned data. The load/store unit aligns this data properly before it is returned to the instruction execution unit.

Abstract: A value representative of a processor's speculative branch prediction efficiency is determined and the speculative branch prediction depth is adjusted accordingly. The processor's speculative branch prediction efficiency may be represented by the average number of clocks per instruction (CPI), whereby an increase in the average CPI indicates that the processor is becoming less efficient due to incorrectly predicted speculative branch predictions and, conversely, a decrease indicates that the processor has a higher ratio of properly predicted speculative branch predictions.

Abstract: Disclosed are a method and system of tracking real time use of I/O control blocks on a processing unit basis, in a multiprocessing system, such that in the case of a processing unit failure, a list accurately and concisely identifies the control blocks that need to be recovered. This eliminates the need to scan all the I/O control blocks, greatly reducing the overall system recovery time and minimizing impact to the rest of the running system. The preferred embodiment of the invention uses a task control block structure to record which I/O control blocks are in use by each Processing Unit. Also, the lock word structure defined in the I/O control blocks is provided with an index back into the task control block to facilitate managing the task control block entries.

Abstract: A loop control system comprises at least one loop flag in an instruction word, at least one loop counter associated with the at least one loop flag operable to store and compute a number of times a program loop is to be executed, at least one start address register associated with the at least one loop flag operable to store a program loop starting address, and at least one end address register associated with the at least one loop flag operable to store a program loop ending address.

Abstract: A data processing system having a memory for storing instructions and several central processing units for executing instructions, each central processing unit includes an adaptive power supply which provides, among other data, temperature information. Circuitry is provided that receives the temperature information from the many central processing units, selects a central processing unit which has the lowest temperature and which is available to execute instructions and dispatches instructions to the selected central processing from the memory.

Abstract: A pre-decoder in a variable instruction length processor indicates properties of instructions in pre-decode bits stored in an instruction cache with the instructions. When all the encodings of pre-decode bits associate with one length instruction are defined, a property of an instruction of that length may be indicated by altering the instruction to emulate an instruction of a different length, and encoding the property in the pre-decode bits associated with instructions of the different length. One example of a property that may be so indicated is an undefined instruction.

Abstract: A Nyquist sampling frequency is determined for performance counter events to be measured. Based on the Nyquist sampling frequencies, a schedule for measuring the performance counter events is determined. The performance counter event measurements are then conducted in accordance with the schedule, whereby the measurements yield a set of sample data for each performance counter event. A signal reconstruction algorithm is applied to the set of sample data for each performance counter event to reconstruct an essentially complete signal for each performance counter event. The essentially complete signal for each performance counter event is then used to improve either a design or a utilization of either a microprocessor or an application to be executed on the microprocessor.

Abstract: Multiple hardware accelerators can be used to efficiently perform processes that would otherwise be performed by general purpose hardware running software. The software overhead and bus bandwidth associated with running multiple hardware acceleration processes can be reduced by chaining multiple independent hardware acceleration operations within a circuit card assembly. Multiple independent hardware accelerators can be configured on a single circuit card assembly that is coupled to a computing device. The computing device can generate a playlist of hardware acceleration operations identifying hardware accelerators and associated accelerator options. A task management unit on the circuit card assembly receives the playlist and schedules the hardware acceleration operations such that multiple acceleration operations may be successively chained together without intervening data exchanges with the computing device.

Abstract: A computer implemented method, apparatus, and computer program product for executing instructions. A determination is made as to whether a processor executing a plurality of instructions is in an instrumentation mode. The processor has a normal set of resources and an alternate set of resources in which the alternate set of resources is associated with the instrumentation mode. When a determination is made that the processor is in the instrumentation mode, the processor executes instrumentation instructions in the plurality of instructions using the alternate set of resources and executes all other instructions in the plurality of instructions using the normal set of resources.

Abstract: A processor and a method for executing VLIW instructions by first fetching a VLIW instruction and then identifying from option bits encoded in a first one of the instructions within the fetched VLIW instruction packet which, if any, of the remaining instructions within the VLIW instruction are to be executed in the same execution cycle as the first instruction. Finally, executing the first instruction and any remaining instructions identified from the encoded option bits.

Abstract: A system that facilitates improving performance of a processor during scout mode. During a normal-execution mode, the system executes instructions for using main thread. Upon encountering a stall condition during execution of the main thread, the system generates a checkpoint. The system then enters a scout mode, wherein instructions are speculatively executed by a speculative thread to prefetch future memory references, but results are not committed to the architectural state of the processor. Upon encountering a memory reference during scout mode, the system issues a prefetch for the memory reference. If the stall condition that caused the processor to enter scout mode is resolved, the system uses the checkpoint to resume execution of the main thread from the instruction that caused the stall condition, and simultaneously continues executing instructions in scout mode using the speculative thread from the point where the speculative thread left off.

Abstract: A method, system, and computer program product are provided for enhancing the execution of independent loads in a processing unit. The processing unit dispatches a first set of instructions in order from a first buffer for execution. The processing unit receives updated results from the execution of the first set of instructions. The processing unit updates, in a first register, at least one register entry associated with each instruction in the first set of instructions, with the updated results. The processing unit determines if the first set of instructions from the first buffer have completed execution. Responsive to the completed execution of the first set of instructions from the first buffer, the processing unit copies the set of entries from the first register to a second register.

Abstract: A computer implemented method, apparatus and computer program product for processing instructions. A determination is made as to whether an instruction is a start instrumentation instruction in response to identifying the instruction for execution while executing the instructions using a normal set of processor resources in a processor. Subsequent instructions are executed using an alternate set of processor resources until an end instrumentation instruction is encountered.

Abstract: Embodiments of the present invention provide a system that facilitates executing a memory barrier (membar) instruction in an execute-ahead processor, wherein the membar instruction forces buffered loads and stores to complete before allowing a following instruction to be issued.

Abstract: A pseudo pipeline including a plurality of pseudo pipeline stages and a control circuit. The control circuit may be configured to control the plurality of pseudo pipeline stages to provide pseudo pipelined operation.

Abstract: A method and apparatus enable supplementing a Branch Target Buffer (BTB) table with a recent entry queue that prevents unnecessary removal of valuable BTB table data of multiple entries for another entry. The recent entry queue detects when the startup latency of the BTB table prevents it from asynchronously aiding the microprocessor pipeline as designed for and thereby can delay the pipeline in the required situations such that the BTB table latency on startup can be overcome. The recent entry queue provides a quick access to BTB table entries that are accessed in a tight loop pattern where the throughput of the standalone BTB table cannot track the throughput of the microprocessor execution pipeline. By using the recent entry queue, the modified BTB table processes information at the rate of the execution pipeline which provides acceleration thereof.

Abstract: A method of checkpointing a microprocessor by providing, in parallel, a current read value from a queue and a next read value from the queue, and then selectively passing one of the current read value and next read value to a capture latch based on an instruction completion signal. The capture latch can directly drive the checkpoint register circuitry in the recovery unit of the microprocessor. If the queue is empty, a pair of multiplexers connected to the input of the register queue array are used to pass the input data value. The instruction completion signal may indicate whether all instructions in an instruction group have successfully completed.