Abstract:
An apparatus comprising: a set of registers; and mapping circuitry to perform a mapping operation to map each of a set of register specifiers to a respective register from among the set of registers in dependence on a mapping function. The mapping function is dependent on a key value. In addition, the mapping for at least two register specifiers from among the set of register specifiers is dependent on the same key value.
Abstract:
First processing circuitry processes at least part of a stream of program instructions. The first processing circuitry has registers for storing data and register renaming circuitry for mapping architectural register specifiers to physical register specifiers. A renaming data store stores renaming entries for identifying a register mapping between the architectural and physical register specifiers. At least some renaming entries have a count value indicating a number of speculation points occurring between generation of a previous count value and generation of the count value. The speculation points may for example be branch operation or load/store operations.
Abstract:
Data processing circuitry comprises a set of two or more computational units to perform respective computational operations; an instruction decoder to decode successive data processing instructions and, for a given data processing instruction, to control one or more of the computational units to perform those computational operations required to execute the given data processing instruction; and control circuitry responsive to the given data processing instruction, to control one or more others of the computational units to perform further computational operations, other than the computational operations required to execute the given data processing instruction, during execution of the given data processing instruction.
Abstract:
An apparatus has a number of data holding elements for holding data values which are reset to a reset value in response to a transition of a signal at a reset signal input of the data holding element from a first value to a second value. A reset tree is provided to distribute a reset signal received at root node of the reset tree to the reset signal inputs of the data holding elements. At least one reset attack detection element is provided, with its reset signal input coupled to a given node of the reset tree, to assert an error signal when its reset signal input transitions from the first value to a second value. Reset error clearing circuitry triggers clearing of the error signal, when the reset signal at the root node of the reset tree transitions from the second value to the first value.
Abstract:
Register renaming circuitry for a processing apparatus configured to process a stream of instructions from an instruction set specifying registers from an architectural set of registers. The apparatus including a physical set of registers configured to store data values being processed by the processing apparatus. Register renaming circuitry is configured to receive a stream of operations from an instruction decoder and to map registers that are to be written to by the stream of operations to physical registers within the physical set of registers that are currently available. The register renaming circuitry comprises register release circuitry configured to release the physical registers that have been mapped to the registers when a first set of conditions have been met, and to release the physical registers that have been mapped to the additional registers when a second set of conditions have been met.
Abstract:
An apparatus has processing circuitry to perform data processing in one of two or more operating states associated with different levels of privilege. At least one operating state holding element holds a state indication indicating a current operating state of the processing circuitry. In response to a transition of a reset signal from a first value to a second value for triggering a reset of the processing circuitry, the at least one operating state holding element resets the state indication to indicate a default operating state other than a most privileged operating state of the two or more operating states.
Abstract:
An apparatus and method includes execution circuitry including a wide operand execution unit configured to allow up to N bits of operand data to be processed during execution of a single instruction. Decoder circuitry decodes and generates, for each instruction, at least one control data block identifying an operation to be performed by the execution circuitry and at least two re-combineable control data blocks for the instruction. Issue queue control circuitry then allocates a slot in the issue queue for each of the at least two data blocks and up to M bits of associated operand data, and marks those allocated slots to identify that they contain re-combineable control data blocks. The issue queue control circuitry issues the combined block to said wide operand execution unit along with the operand data contained in each of the allocated slots for said at least two control data blocks.