Abstract:
An integrated circuit (IC) may include a cache memory, and a cache memory controller coupled to the cache memory. The cache memory controller may be configured to receive a cache miss associated with a memory location, issue pre-fetch requests, each pre-fetch request having a quality of service (QoS), and determine if a pre-fetch request has issued for the memory location associated with the cache miss.
Abstract:
Systems and methods are disclosed for pre-fetching data into a cache memory system. These systems and methods comprise retrieving a portion of data from a system memory and storing a copy of the retrieved portion of data in a cache memory. These systems and methods further comprise monitoring data that has been placed into pre-fetch memory.
Abstract:
A package includes a first die and a second die, at least one of said first and second dies being a memory. The dies are connected to each other through an interface. The interface is configured to transport a plurality of control signals. The number of control signals is greater than a width of the interface. At least one of the first and second dies performs a configurable grouping so as to provide a plurality of groups of control signals. The signals within a group are transmitted across the interface together.
Abstract:
A package includes a first die and a second die, at least one of said first and second dies being a memory. The dies are connected to each other through an interface. The interface is configured to transport both control signals and memory transactions. A sampling circuit samples the control signals before transport on the interface. The sampling circuit is controlled in dependence on at least one quality of service parameter associated with a respective control signal.
Abstract:
A package includes a die and at least one further die. The die has an interface configured to receive a transaction request from the further die via an interconnect and to transmit a response to the transaction request to said further die via the interconnect. The die also has mapping circuitry which is configured to receive the transaction request including at least first source identity information, wherein the first source identity information is associated with a source of the transaction request on the further die. The mapping circuitry is configured to modify the transaction request to replace the first source identity information with local source identity information, wherein that local source identity information is associated with the mapping circuitry. The mapping circuitry is configured to modify the received transaction request to provide said first source identity information in a further field.
Abstract:
An arrangement includes a first part and a second part. The first part includes a memory controller for accessing a memory, at least one first cache memory and a first directory. The second part includes at least one second cache memory configured to request access to said memory. The first directory is configured to use a first coherency protocol for the at least one first cache memory and a second different coherency protocol for the at least one second memory.
Abstract:
A circuit including an initiator of a transaction, an interconnect, and a controller. The controller is configured in response to a condition in a least one first part of the circuit to send a notification via the interconnect to at least one block in a second part of the circuit. The notification includes information about the condition in the first part of the circuit, the condition preventing a response to the transaction from being received by the initiator.
Abstract:
A system is provided in which a first circuit is protected by security features provided by a second circuit. The first circuit comprises a processor which retrieves content from a memory. Initially, the contents of the memory are authenticated using security features of the second circuit to check that the processor is accessing authenticated content. To maintain security during use, the second circuit checks that the processor is accessing content from valid regions of the memory, being those that have been authenticated, and re-checks the authenticity of the content of the valid regions of memory. The combination of checking that the processor is accessing from valid regions of the memory and authenticating the content stored in the valid regions maximizes the security of the system. If any of the checking or authentication steps fail then operation of the system is impaired. The first circuit is thus protected by security features provided by the second circuit.
Abstract:
The transmission of interrupts is described where the interrupt is represented at a peripheral device by the electrical level of a conductor but where it is conveyed to a receiving module by way of a message packet routed along a routing path. According to one aspect, the message packet includes the identification of the peripheral device which generated the interrupt and the receiving module acts on the message packet to implement an interrupt handling routine depending on the identification of the peripheral device. According to another aspect, the message packet includes a transaction identifier which uniquely identifies one of a series of interrupts, and the receiving module generates a response packet containing that transaction identifier thereby allowing the peripheral device to monitor whether or not its interrupts have been treated properly.
Abstract:
There is disclosed a computer,system including a microprocessor on an integrated circuit chip comprising an on-chip CPU and a communication bus. The communication bus provides a parallel communication path between the CPU and the first memory local to the CPU. An external port of the integrated circuit is connected to said bus and to an external computer device having a second memory. The external computer device is operable to transmit control signals through the port: a) to suspend execution by the CPU of instructions obtained from the first memory; b) to provide from the second memory boot code to be executed by the CPU; and c) to restart operation of the CPU using said boot code. There is also disclosed a method of operating such a computer system.