Abstract: Systems, apparatuses and methods for utilizing enhanced predicate registers which specify the element width and which elements are to be processed. The predicate size is dynamic, depending on the contents of the enhanced predicate register used for an instruction rather than being a static quality of a specific instruction. Specifying the element size in the enhanced predicate registers results in fewer instructions in an instruction set.

Abstract: Embodiments of a system and a method in which a processor may execute instructions that cause the processor to receive an input vector and a control vector are disclosed. The executed instructions may also cause the processor to perform a fixed-value addition operation dependent upon the input vector and the control vector.

Abstract: Embodiments of a system and a method in which a processor may execute instructions that cause the processor to receive an operand vector, a selection vector, and a control vector are disclosed. The executed instructions may also cause the processor to perform a wrapping rotate previous operation dependent upon the input vectors.

Abstract: Embodiments of a system and a method in which a processor may execute instructions that cause the processor to receive a basis vector, an operand vector, a selection vector, and a control vector are disclosed. The executed instructions may also cause the processor to perform a wrapping propagate operation dependent upon the input vectors.

Abstract: In an embodiment, a processor may implement a vector hazard check instruction to detect dependencies between vector memory operations based on the addresses of the vectors accessed by the vector memory operations. The addresses may be specified via a base address and a vector of indexes for each vector. In an embodiment, one of the base addresses may be an implied (or assumed) zero address, reducing the number of operands of the hazard check instruction.

Abstract: A processor may generate a result vector when executing a RunningShiftForDivide1P or RunningShiftForDivide2P instruction. For example, upon executing a RunningShiftForDivide1P/2P instruction, the processor may receive a first input vector and a second input vector. The processor then may record a base value from an element at a key element position in the first input vector. Next, when generating the result vector, for each active element in the result vector to the right of the key element position, the processor may generate a shifted base value using shift values from the second input vector. The processor then may correct the shifted base value when a predetermined condition is met. Next, the processor may set the element of the result vector equal to the shifted base value.

Abstract: The described embodiments provide a processor that executes a vector instruction. In the described embodiments, while executing instructions, the processor encounters a vector memory-accessing instruction that performs a memory operation for a set of elements in the memory-accessing instruction. In these embodiments, if an optional predicate vector is received, for each element in the memory-accessing instruction for which a corresponding element of the predicate vector is active, otherwise, for each element in the memory-accessing instruction, upon determining that addresses in the elements are likely to be arranged in a predetermined pattern, the processor predicts that the addresses in the elements are arranged in the predetermined pattern. The processor then performs a fast version of the memory operation corresponding to the predetermined pattern.

Abstract: In an embodiment, a processor may implement a vector instruction set including a conditional termination instruction (CTerm). The CTerm instruction may take two source operands and compare them according to a specified condition, updating flags as a result of the instruction. The flags may be used to affect predicate vector generation to control vectorized loop execution. In an embodiment, the vector instruction set may also include a conditional termination predicate instruction (CTPred). The CTPred instruction may take a pair of predicate vectors and a set of flags as operands, and may generate: a predicate vector to control parallel processing of vector elements, and a set of flags to control further loop processing. Either instruction may be used to efficiently manage vector loops in various embodiments, or the instructions may be used together.

Abstract: In an embodiment, a processor may implement a vector instruction set including one or more compare break instructions. The compare break instruction may take a pair of operands which may be compared to determine loop termination conditions, and may output a predicate vector indicating which vector elements correspond to loop iterations that are executed and which vector elements correspond to loop iterations that are not executed. The predicate vector may serve as a predicate to vector instructions forming the body of the loop, correctly executing the specified number of iterations. The compare break instruction may be coded to check for a variety of conditions (e.g. equal, not equal, greater than, less than, etc.). In an embodiment, the compare break instruction may take a predicate operand as well, which may be combined with the predicate vector produced by the comparison operations to produce the output vector.

Abstract: In an embodiment, a processor may implement a conditional stop instruction that includes a first predicate vector identifying the active elements of the instruction, a second predicate vector indicating true and false results for a conditional expression within a loop that is being vectorized, and a source operand specifying which combinations in the true and false results may indicate a dependency. The conditional stop instruction may generate a vector result indicating vector elements that have a dependency on a prior vector element, as well as an identification of which element position the dependency is on. More particularly, dependencies may be detected only on active elements as indicated by the first predicate vector. False dependencies that may occur due to inactive elements may be avoided, which may improve performance and/or provide for correct functional operation.

Abstract: A mechanism for executing speculative predicated instructions may include execution of initiating execution of a vector instruction when one or more operands upon which the vector instruction depends are available for use, even if a predicate vector that the vector instruction also depends is not available. If the predicate vector was not available, the results of the execution of the vector instruction may be temporarily held until the predicate vector becomes available, at which time, a destination vector may be updated with the results.

Abstract: A method for suppressing branch misprediction behavior is contemplated in which a conditional branch instruction that would cause the flow of control to branch around instructions in response to a determination that a predicate vector is null is predicted not taken. However, in response to detecting that the prediction is incorrect, misprediction behavior is inhibited.

Abstract: Systems, methods, and devices for dynamically mapping and remapping memory when a portion of memory is activated or deactivated are provided. In accordance with an embodiment, an electronic device may include several memory banks, one or more processors, and a memory controller. The memory banks may store data in hardware memory locations and may be independently deactivated. The processors may request the data using physical memory addresses, and the memory controller may translate the physical addresses to hardware memory locations. The memory controller may use a first memory mapping function when a first number of memory banks is active and a second memory mapping function when a second number is active. When one of the memory banks is to be deactivated, the memory controller may copy data from only the memory bank that is to be deactivated to the active remainder of memory banks.

Abstract: The described embodiments comprise a PredCount instruction and a SegCount instruction. When executed by a processor, the PredCount instruction causes the processor to analyze a predicate vector to determine a number of active elements in the predicate vector that exhibit a predetermined condition (e.g., that are set to a predetermined value) and to return a result indicating that number. When executed by a processor, the SegCount instruction causes the processor to determine a number of times that a GeneratePredicates instruction would be executed to generate a full set of predicates using active elements of an input vector.

Abstract: The described embodiments include a processor that executes a vector instruction. In the described embodiments, while dispatching instructions at runtime, the processor encounters a dependency-checking instruction. Upon determining that a result of the dependency-checking instruction is predictable, the processor dispatches a prediction micro-operation associated with the dependency-checking instruction, wherein the prediction micro-operation generates a predicted result vector for the dependency-checking instruction. The processor then executes the prediction micro-operation to generate the predicted result vector. In the described embodiments, when executing the prediction micro-operation to generate the predicted result vector, if a predicate vector is received, for each element of the predicted result vector for which the predicate vector is active, otherwise, for each element of the predicted result vector, the processor sets the element to zero.

Abstract: A method for suppressing prediction of a backward branch instruction used in a vector partitioning loop includes detecting the first backward branch instruction that occurs after a predicate generating instruction. The predicate generating instruction generates a predicate vector that is dependent upon a dependency vector where each element of the dependency vector indicates whether a data dependency exists between elements of a vector instruction. The method also includes receiving an indication of a prediction accuracy of a prediction of the backward branch instruction. If the prediction accuracy does not satisfy a threshold value, the prediction of the backward branch instruction is suppressed until the dependency vector on which the predicate-generating instruction depends is available.

Abstract: While fetching the instructions from a loop in program code, a processor calculates a number of times that a backward-branching instruction at the end of the loop will actually be taken when the fetched instructions are executed. Upon determining that the backward-branching instruction has been predicted taken more than the number of times that the branch instruction will actually be taken, the processor immediately commences a mispredict operation for the branch instruction, which comprises: (1) flushing fetched instructions from the loop that will not be executed from the processor, and (2) commencing fetching instructions from an instruction following the branch instruction.

Abstract: In an embodiment, a processor may include a completion time determination circuit. The completion time determination circuit may be configured to receive one or more source operands of a vector memory operation used to produce the addresses of the vector elements accessed by the vector memory operation. The completion time determination circuit may be configured to determine a completion time for the vector memory operation (e.g. based on a number of TLB accesses, a number of cache accesses, and/or other aspects of the vector memory operation). The completion time determination circuit may provide the completion time to an issue circuit, which may use the completion time to schedule operations dependent on the vector memory operation, if any.

Abstract: In an embodiment, a processor may include a completion time prediction circuit. The completion time prediction circuit may be configured to track one or more aspects of previous instances of a vector memory operation, and may be configured to predict a completion time for a current instance of the vector memory operation. The prediction may be used by the issue circuit to schedule operations dependent on the vector memory operation, if any.

Abstract: The described embodiments provide a processor that executes vector instructions. In the described embodiments, while dispatching instructions at runtime, the processor encounters an Actual instruction. Upon determining that a result of the Actual instruction is predictable, the processor dispatches a prediction micro-operation associated with the Actual instruction, wherein the prediction micro-operation generates a predicted result vector for the Actual instruction. The processor then executes the prediction micro-operation to generate the predicted result vector. In the described embodiments, when executing the prediction micro-operation to generate the predicted result vector, if the predicate vector is received, for each element of the predicted result vector for which the predicate vector is active, otherwise, for each element of the predicted result vector, generating the predicted result vector comprises setting the element of the predicted result vector to true.