Abstract: An integrated circuit 2 provided with multiple functional units 6, 8, 10, 12, 14, and 16 for performing data processing operations as part of advancing execution of a data processing task by the integrated circuit 2. Activity detection circuitry 26 determines which of these functional circuits is inactive at the given time. If a functional is inactive, then scan control circuitry 28 may perform a scan test operation thereon using an associated serial scan chain 34, 36, 38, 40, 42, 44.

Abstract: An integrated circuit 2 provided with multiple functional units 6, 8, 10, 12, 14, and 16 for performing data processing operations as part of advancing execution of a data processing task by the integrated circuit 2. Activity detection circuitry 26 determines which of these functional circuits is inactive at the given time. If a functional is inactive, then scan control circuitry 28 may perform a scan test operation thereon using an associated serial scan chain 34, 36, 38, 40, 42, 44.

Abstract: The application describes a data processor operable to process data, and comprising: a cache in which a storage location of a data item within said cache is identified by an address, said cache comprising a plurality of storage locations and said data processor comprising a cache directory operable to store a physical address indicator for each storage location comprising stored data; a hash value generator operable to generate a generated hash value from at least some of said bits of said address said generated hash value having fewer bits than said address; a buffer operable to store a plurality of hash values relating to said plurality of storage locations within said cache; wherein in response to a request to access said data item said data processor is operable to compare said generated hash value with at least some of said plurality of hash values stored within said buffer and in response to a match to indicate a indicated storage location of said data item; and said data processor is operable to access

Abstract: The application describes a data processor operable to process data, and comprising: a cache in which a storage location of a data item within said cache is identified by an address, said cache comprising a plurality of storage locations and said data processor comprising a cache directory operable to store a physical address indicator for each storage location comprising stored data; a hash value generator operable to generate a generated hash value from at least some of said bits of said address said generated hash value having fewer bits than said address; a buffer operable to store a plurality of hash values relating to said plurality of storage locations within said cache; wherein in response to a request to access said data item said data processor is operable to compare said generated hash value with at least some of said plurality of hash values stored within said buffer and in response to a match to indicate a indicated storage location of said data item; and said data processor is operable to access

Abstract: A multi-way set associative cache memory 6 is provided with lockdown control circuitry 26, 48 for controlling portions of that cache memory to store data which is locked within the cache memory 6 (i.e. not subject to eviction). Programmable lockdown data 38, 40, 42, 44, 46 specifies which ways contain any locked portions and also the size within each way of locked portion. Thus, individual cache ways can be partially locked.

Abstract: A self-test controller 10 is responsive to scanned in self-test instructions to carry out test operations including generating a sequence of memory addresses that is specified by the self-test instruction. Combining multiple such self-test instructions allows a custom test methodology to be built up by a user using a generic self-test controller 10.

Abstract: A data processor core 10 comprising a memory access interface portion 30 operable to perform data transfer operations between an external data source and at least one memory associated with said data processor core and a data processing portion 12 operable to perform further data processing operations in response to receipt of said processor clock signal CLK. The two portions of the core being operable to be independently enabled such that one portion may be active while the other is inactive.

Abstract: A data processor core 10 comprising: a memory access interface portion 30 operable to perform data transfer operations between an external data source and at least one memory 120 associated with said data processor core; a data processing portion 12 operable to perform data processing operations; a read/write port 40 operable to transfer data from said processor core to at least two buses 75A, 75B said at least two buses being operable to provide data communication between said processor core 10 and said at least one memory 120, said at least one memory 120 comprising at least two portions 120A, 120B, each of said at least two buses 75A, 75B being operable to provide data access to respective ones of said at least two portions 120A, 120B; arbitration logic 110 associated with said read/write port 40; wherein said arbitration logic is operable to route a data access request requesting access of data in one portion of said at least one memory received from said memory access interface to one of said at least tw

Abstract: A processor clock control device is disclosed that is operable to control switching between clock signals input to a processor in a glitch-free way.

Abstract: The present invention provides a data processing apparatus and method for testing power management instructions. The data processing apparatus comprises a processor for executing data processing instructions including power management instructions, at least one of the power management instructions being a command power management instruction. A power management controller is also provided for receiving command data from the processor when a command power management instruction is executed by the processor, and to control power management logic to perform an associated set of power management functions dependent on the command data. The data processing apparatus includes first power management logic controllable by the power management controller, with the power management controller also having an interface to enable communication with additional power management logic.

Abstract: A data processing system includes a processor core, a cache memory and a cache controller which operate to allow data accesses to a cache line for which a pending cache linefill operation exists to be serviced for those data words within the cache line that are valid at a particular point in time. One or more status bits are provided in association with each cache line indicating whether a line fill is pending for that cache line. The old data may be manipulated up to the point where the first new data is returned. New data items may be read once they have been written into a victim cache line even though the cache linefill is not completed. Stores to the victim cache line may be made via a fill buffer even though the linefill is still pending. The cache memory may include a content addressable memory (CAM) and the cache memory and controller may support a hit under miss operation.

Abstract: The present invention relates to a data processing apparatus and method for reducing leakage current during a power down mode of operation. The data processing apparatus comprises a dynamic node, precharge circuitry arranged during a precharge phase to precharge the dynamic node to a first voltage level, and evaluation circuitry arranged to receive a number of input signals and during an evaluate phase to selectively drive the dynamic node to a second voltage level dependent on the input signals. In accordance with the present invention, the apparatus also includes power down drive circuitry arranged when the data processing apparatus is to enter a power down mode to drive the dynamic node to the second voltage level. It has been found that by driving the dynamic node to the second voltage level during a power down mode of operation, a significant reduction in the leakage current is observed.

Abstract: A self-test controller 10 is responsive to scanned in self-test instructions to carry out test operations including generating a sequence of memory addresses that is specified by the self-test instruction. Combining multiple such self-test instructions allows a custom test methodology to be built up by a user using a generic self-test controller 10.

Abstract: The present invention provides a data processing apparatus and method for testing power management instructions. The data processing apparatus comprises a processor for executing data processing instructions including power management instructions, at least one of the power management instructions being a command power management instruction. A power management controller is also provided for receiving command data from the processor when a command power management instruction is executed by the processor, and to control power management logic to perform an associated set of power management functions dependent on the command data. The data processing apparatus includes first power management logic controllable by the power management controller, with the power management controller also having an interface to enable communication with additional power management logic.

Abstract: A data processing system 2 is described including a processor core 4 and a cache memory 6. A controller 16 operates to allow data accesses to a cache line for which a pending cache linefill operation exists to be serviced for those data words within the cache line that are valid at the particular point in time. The old data may be manipulated up to the point where the first new data is returned. New data items may be read once they have been written into a victim cache line 18 even though the cache linefill is not completed. Stores to the victim cache line 18 may be made via a fill buffer 12 even though the linefill is still pending.

Abstract: The present invention relates to a memory device and method for reducing leakage current during a power down mode of operation. The memory device comprises a column of memory cells, with each memory cell being arranged to store a data value, and a pair of bit lines coupled to the column of memory cells. Bit line precharge circuitry is provided for precharging the pair of bit lines to a predetermined voltage level during a precharge phase, the pair of bit lines being arranged such that, when a particular memory cell in the column is selected in an evaluate phase following the precharge phase, a relative change in voltage level between the pair of bit lines indicates the data value stored within the selected memory cell.