A processor may include a baseline branch predictor and an empirical branch bias override circuit. The baseline branch predictor may receive a branch instruction associated with a given address identifier, and generate, based on a global branch history, an initial prediction of a branch direction for the instruction. The empirical branch bias override circuit may determine, dependent on a direction of an observed branch direction bias in executed branch instruction instances associated with the address identifier, whether the initial prediction should be overridden, may determine, in response to determining that the initial prediction should be overridden, a final prediction that matches the observed branch direction bias, or may determine, in response determining that the initial prediction should not be overridden, a final prediction that matches the initial prediction. The predictor may update an entry in the global branch history reflecting the resolved branch direction for the instruction following its execution.

A processor may include a gather-update-scatter accelerator, and circuitry to direct an instruction to the accelerator for execution. The instruction may include a search index, an operation to be performed, and a scalar data value. The accelerator may include a content-associative memory (CAM) storing multiple entries, each of which stores a respective index key and a data value associated with the index key. The accelerator may include a CAM controller, including circuitry to select, based on the information in the instruction, one of the plurality of entries in the CAM on which to operate, an arithmetic logic unit (ALU), including circuitry to perform an arithmetic or logical operation on the selected entry, the operation being dependent on the information in the instruction, and circuitry to store a result of the operation in the selected entry in the CAM.

A method for executing instructions using a plurality of virtual cores for a processor. The method includes receiving an incoming instruction sequence using a global front end scheduler, and partitioning the incoming instruction sequence into a plurality of code blocks of instructions. The method further includes generating a plurality of inheritance vectors describing interdependencies between instructions of the code blocks, and allocating the code blocks to a plurality of virtual cores of the processor, wherein each virtual core comprises a respective subset of resources of a plurality of partitionable engines. The code blocks are executed by using the partitionable engines in accordance with a virtual core mode and in accordance with the respective inheritance vectors.

A method for forwarding data from the store instructions to a corresponding load instruction in an out of order processor. The method includes accessing an incoming sequence of instructions, and of said sequence of instructions, splitting store instructions into a store address instruction and a store data instruction, wherein the store address performs address calculation and fetch, and wherein the store data performs a load of register contents to a memory address. The method further includes, of said sequence of instructions, splitting load instructions into a load address instruction and a load data instruction, wherein the load address performs address calculation and fetch, and wherein the load data performs a load of memory address contents into a register, and reordering the store address and load address instructions earlier and further away from LD/SD the instruction sequence to enable earlier dispatch and execution of the loads and the stores.

A graphics processing unit core 26 includes a plurality of processing pipelines 38, 40, 42, 44. A program instruction of a thread of program instructions being executed by a processing pipeline includes a next-instruction-type field 36 indicating an instruction type of a next program instruction following the current program instruction within the processing thread concerned. This next-instruction-type field is used to control selection of to which processing pipeline the next instruction is issued before that next instruction has been fetched and decoded. The next-instruction-type field may be passed along the processing pipeline as the least significant four bits within a program counter value associated with a current program instruction 32. The next-instruction-type field may also be used to control the forwarding of thread state variables between processing pipelines when a thread migrates between processing pipelines prior to the next program instruction being fetched or decoded.

Some implementations provide techniques and arrangements for causing an interrupt in a processor in response to an occurrence of a number of events. A first event counter counts the occurrences of a type of event within the processor and outputs a signal to activate a second event counter in response to reaching a first predefined count. The second event counter counts the occurrences of the type of event within the processor and causes an interrupt of the processor in response to reaching a second predefined count.

A method includes, in a processor (20) that processes instructions of program code, processing a first segment of the instructions. One or more destination registers are identified in the first segment using an approximate specification of register access by the instructions. Respective values of the destination registers are made available to a second segment of the instructions only upon verifying that the values are valid for readout by the second segment in accordance with the approximate specification. The second segment is processed at least partially in parallel with processing of the first segment, using the values made available from the first segment.

A unified architecture for dynamic generation, execution, synchronization and parallelization of complex instruction formats includes a virtual register file, register cache and register file hierarchy. A self-generating and synchronizing dynamic and static threading architecture provides efficient context switching.

A processing core of a plurality of processing cores is configured to execute a speculative region of code a single atomic memory transaction with respect one or more others of the plurality of processing cores. In response to determining an abort condition for issued one of the plurality of program instructions and in response to determining that the issued program instruction is not part of a mispredicted execution path, the processing core is configured to abort an attempt to execute the speculative region of code.

A processor core in an instruction block-based microarchitecture utilizes instruction blocks having headers that include an index to a size table that may be expressed using one of memory, register, logic, or code stream. A control unit in the processor core determines how many instructions to fetch for a current instruction block for mapping into an instruction window based on the block size that is indicated from the size table. As instruction block sizes are often unevenly distributed for a given program, utilization of the size table enables more flexibility in matching instruction blocks to the sizes of available slots in the instruction window as compared to arrangements in which instruction blocks have a fixed sized or are sized with less granularity. Such flexibility may enable denser instruction packing which increases overall processing efficiency by reducing the number of nops (no operations, such as null functions) in a given instruction block.