Abstract: A data processing apparatus and method of data processing are provided. The data processing apparatus comprises execution circuitry configured to execute a sequence of program instructions. Checkpoint circuitry is configured to identify an instance of a predetermined type of instruction in the sequence of program instructions and to store checkpoint information associated with that instance. The checkpoint information identifies a state of the data processing apparatus prior to execution of that instance of the predetermined type of instruction, wherein the predetermined type of instruction has an expected long completion latency.

Abstract: A data processing apparatus comprising at least one initiator operable to communicate with at least one recipient via a bus; said at least one initiator comprising an output port for sending data to said bus and an input port for receiving data from said bus; said data processing apparatus further comprising an initiator clock signal generator, an initiator output enable signal generator and an initiator input enable signal generator, said initiator being clocked by said initiator clock signal; said output port being clocked by said initiator output enable signal such that said output port is operable to assert data to a write channel on said bus in response to said initiator output enable signal having a first predetermined level and said input port is operable to latch data received on a read channel on said bus in response to said initiator input enable signal having a second predetermined level; wherein said initiator output enable signal generator and initiator input enable signal generator are configure

Abstract: A data processing apparatus comprises first and second processing circuitry. A conditional instruction executed by the second processing circuitry may have an outcome which is dependent on one of a plurality of sets of condition information maintained by the first processing circuitry. A first forwarding path can forward the sets of condition information from the first processing circuitry to a predetermined pipeline stage of a processing pipeline of the second processing circuitry. A request path can transmit a request signal from the second processing circuitry to the first processing circuitry, the request signal indicating a requested set of condition information which was not yet valid when a conditional instruction was at the predetermined pipeline stage. A second forwarding path may forward the requested set of condition information to a subsequent pipeline stage when the information becomes valid.

Abstract: A data processing apparatus comprises: at least one processor; having a private cache, a shared cache for storing data processed by the processor and by a further device, and coherency control circuitry. The coherency control circuitry is responsive to a write request from the further device to determine if data related to an address targeted by the write request is stored in the private cache, and if it is, forcing an eviction of the stored data from the private cache to the shared cache prior to perform the write to the shared cache. The data is stored in the private cache in conjunction with an indicator indicating if the stored data is consistent with data stored in a corresponding address in a further data store, and the stored data is evicted whether the stored data is indicated as being consistent or inconsistent.

Abstract: A data processing apparatus and method are provided. The data processing apparatus is configured to perform data processing operations in response to data processing instructions including a multiple operation instruction, in response to which multiple data processing operations are performed. The data processing apparatus comprises two or more data processing units configured to perform the data processing operations and an instruction arbitration unit configured to perform sub-division of a multiple operation instruction into a plurality of sub-instructions and to perform allocation of the plurality of sub-instructions amongst the two or more data processing units, wherein each sub-instruction is arranged to cause one of the two or more data processing units to perform at least one data processing operation of the multiple data processing operations.

Abstract: A data processing apparatus comprises first and second processing circuitry. A conditional instruction executed by the second processing circuitry may have an outcome which is dependent on one of a plurality of sets of condition information maintained by the first processing circuitry. A first forwarding path can forward the sets of condition information from the first processing circuitry to a predetermined pipeline stage of a processing pipeline of the second processing circuitry. A request path can transmit a request signal from the second processing circuitry to the first processing circuitry, the request signal indicating a requested set of condition information which was not yet valid when a conditional instruction was at the predetermined pipeline stage. A second forwarding path may forward the requested set of condition information to a subsequent pipeline stage when the information becomes valid.

Abstract: A data processing apparatus and method are provided for converting data values from a first endian format to a second endian format. Swizzle circuitry is provided for receiving a block of data containing at least one data value, and for converting each data value from the first endian format to the second endian format. The swizzle circuitry comprises first swizzle circuitry for performing a re-ordering operation on the block of data assuming the at least one data value contained therein is of a first size, in order to produce re-ordered data. Second swizzle circuitry is provided which is responsive to an indication that the at least one data value is of a size different to the first size to perform an additional re-ordering operation on the re-ordered data having regard to the size of the at least one data value in order to convert each data value to the second endian format.

Abstract: A data processing apparatus and method of data processing are provided. The data processing apparatus comprises execution circuitry configured to execute a sequence of program instructions. Checkpoint circuitry is configured to identify an instance of a predetermined type of instruction in the sequence of program instructions and to store checkpoint information associated with that instance. The checkpoint information identifies a state of the data processing apparatus prior to execution of that instance of the predetermined type of instruction, wherein the predetermined type of instruction has an expected long completion latency.

Abstract: A data processing apparatus and method of data processing are provided. The data processing apparatus comprises execution circuitry configured to execute a sequence of program instructions. Checkpoint circuitry is configured to identify an instance of a predetermined type of instruction in the sequence of program instructions and to store checkpoint information associated with that instance. The checkpoint information identifies a state of the data processing apparatus prior to execution of that instance of the predetermined type of instruction, wherein the predetermined type of instruction has an expected long completion latency.

Abstract: A data processing apparatus and method are provided. The data processing apparatus is configured to perform data processing operations in response to data processing instructions including a multiple operation instruction, in response to which multiple data processing operations are performed. The data processing apparatus comprises two or more data processing units configured to perform the data processing operations and an instruction arbitration unit configured to perform sub-division of a multiple operation instruction into a plurality of sub-instructions and to perform allocation of the plurality of sub-instructions amongst the two or more data processing units, wherein each sub-instruction is arranged to cause one of the two or more data processing units to perform at least one data processing operation of the multiple data processing operations.

Abstract: A data processing apparatus and method of data processing are provided. The data processing apparatus comprises execution circuitry configured to execute a sequence of program instructions. Checkpoint circuitry is configured to identify an instance of a predetermined type of instruction in the sequence of program instructions and to store checkpoint information associated with that instance. The checkpoint information identifies a state of the data processing apparatus prior to execution of that instance of the predetermined type of instruction, wherein the predetermined type of instruction has an expected long completion latency.

Abstract: An apparatus for processing data includes a processor operable in a plurality modes including at least one secure mode being a mode in a secure domain and at least one non-secure mode being a mode in a non-secure domain. When the processor is executing a program in a secure mode the program has access to secure data which is not accessible when the processor is operating in a non-secure mode. The processor is responsive to one or more exception conditions for triggering exception processing using an exception handler. The processor is operable to select the exception handler from among a plurality of possible exception handlers in dependence upon whether the processor is operating in the secure domain or the non-secure domain.

Abstract: A method and data processing apparatus comprise a cache having a plurality of data entries; an eviction buffer comprising an information portion and a data portion; and eviction logic to transfer information associated with a first of the plurality of data entries from the cache to the information portion and to determine, with reference to the information, whether the first of the plurality of data entries should be written to a memory by examining the information.

Abstract: An integrated circuit 2 is provided including multiple devices 4, 6, 8, 10, 12, 14 for communicating via an interconnect 16. A sending device 18 includes a sideband signal indicating the use of a representation of a repeating data word in place of that repeating data word itself. The receiving device can then form the repeating pattern of data words in response to receipt of the representation. This reduces the bandwidth consumed upon the interconnect 16.

Abstract: A data processing system including a processor operable in a plurality of modes and in either a secure domain or a non-secure domain. The system includes at least one secure mode being a mode in the secure domain, at least one non-secure mode being a mode in the non-secure domain, and a monitor mode. When the processor is executing a program in a secure mode the program has access to secure data which is not accessible when the processor is operating in a non-secure mode. Switching between the secure and non-secure modes takes place via the monitor mode and the processor is operable at least partially in the monitor mode to execute a monitor program managing switching between the secure and non-secure modes.

Abstract: A processor may utilise two operating systems (Non-Secure, Secure) between which calls may be made. In order that a second operating system can track task switches made by a first operating system, each time a call is made to the second operating system, this call includes an identifier to enable discrimination between the task which was executing on the first operating system when that call was made. The identifier can be a call identifier and/or a target thread identifier and may include further parameters.

Abstract: An apparatus for processing data includes a processor operable in a plurality modes including at least one secure mode being a mode in a secure domain and at least one non-secure mode being a mode in a non-secure domain. When the processor is executing a program in a secure mode the program has access to secure data which is not accessible when the processor is operating in a non-secure mode. The processor is responsive to one or more exception conditions for triggering exception processing using an exception handler. The processor is operable to select the exception handler from among a plurality of possible exception handlers in dependence upon whether the processor is operating in the secure domain or the non-secure domain.

Abstract: A processor may utilise two operating systems (Non-Secure, Secure) between which calls may be made. In order that a second operating system can track task switches made by a first operating system, each time a call is made to the second operating system, this call includes an identifier to enable discrimination between the task which was executing on the first operating system when that call was made. The identifier can be a call identifier and/or a target thread identifier and may include further parameters.

Abstract: An apparatus for processing data includes a processor operable in a plurality modes including at least one secure mode being a mode in a secure domain and at least one non-secure mode being a mode in a non-secure domain. When the processor is executing a program in a secure mode the program has access to secure data which is not accessible when the processor is operating in a non-secure mode. The processor is responsive to one or more exception conditions for triggering exception processing using an exception handler. The processor is operable to select the exception handler from among a plurality of possible exception handlers in dependence upon whether the processor is operating in the secure domain or the non-secure domain.

Abstract: Cache circuitry, a data processing apparatus including such cache circuitry, and a method of handling write requests within cache circuitry, are provided. The cache circuitry has a plurality of slots, with each slot arranged to store attributes associated with a pending access request. A record of identifiers that are available to associate with pending access requests is maintained, and control circuitry is responsive to an access request issued by a device to accept that access request as a pending access request by allocating one of the slots to that access request, obtaining one of said identifiers from the record to associate with that access request, and causing the attributes associated with that access request to be stored in the allocated slot along with the obtained identifier. A check procedure is performed to determine, for each pending access request, whether that access request is allowed to proceed.