Abstract:
A method for maintaining cache coherency operates in a data processing system with a system memory and a plurality of processing units (PUs), each PU having a cache, and each PU coupled to at least another one of the plurality of PUs. A first PU receives a first data block for storage in a first cache of the first PU. The first PU stores the first data block in the first cache. The first PU assigns a first coherency state and a first tag to the first data block, wherein the first coherency state is one of a plurality of coherency states that indicate whether the first PU has accessed the first data block. The plurality of coherency states further indicate whether, in the event the first PU has not accessed the first data block, the first PU received the first data block from a neighboring PU.
Abstract:
A system and method for simulating a circuit design using both an unknown Boolean state and a negative unknown Boolean state is provided. When the circuit is simulated, one or more initial simulated logic elements are initialized to the unknown Boolean state. The initialized unknown Boolean states are then fed to one or more simulated logic elements and the simulator simulates the handling of the unknown Boolean state by the simulated logic elements. Examples of simulated logic elements include gates and latches, such as flip-flops, inverters, and basic logic gates. The processing results in at least one negative unknown Boolean state. An example of when a negative unknown Boolean state would result would be when the unknown Boolean state is inverted by an inverter. The resulting negative unknown Boolean state is then fed to other simulated logic elements that generate further simulation results based on processing the negative unknown Boolean state.
Abstract:
An access speculation predictor may predict whether to perform speculative retrieval of data for a data request from a main memory based on whether or not a domain indicator in the data request indicates that the cache line corresponding to the data has a special invalid state or not. In particular, a first address and a domain indicator are extracted from first data request. The first address is used to select a finite state machine (FSM) of a memory controller based on memory regions associated with the FSMs of the memory controller. Speculative retrieval of data for the first data request from main memory is controlled based on whether the domain indicator identifies the special invalid state or not and, if the domain indicator identifies that the cache line does not have the special invalid state, based on information stored in registers associated with the selected FSM.
Abstract:
In a method and apparatus associated with a bus controller, a set of mechanisms are selectively added to the bus controller, as well as to slave devices connected to the bus controller. A mechanism is also added to one or more master devices connected to the bus controller, in order to provide the master devices with a transaction ordering capability. The added mechanisms collectively achieve the objective of supporting connection of multiple slave devices to a common controller interface, and at the same time allowing pipelined operation of the slave devices. One embodiment of the invention is directed to a method for use with a bus and an associated bus controller, wherein the bus controller has respective master and slave interfaces for use in selectively interconnecting master devices and slave devices. The method comprises the steps of connecting one or more of the master devices to one of the master interfaces, and connecting each of a plurality of slave devices to the same one of the slave interfaces. The method further comprises operating a connected master device to send multiple commands to a selected one of the connected slave devices in accordance with a command pipelining procedure.
Abstract:
An improved method, device and data processing system are presented. In one embodiment, the method includes a source device sending a request for a bus grant to deliver data to a data bus connecting a source device and a destination device. The device receives the bus grant and logic within the device determines whether the bandwidth of the data bus allocated to the bus grant will be filled by the data. If the bandwidth of the data bus allocated to the bus grant will not be filled by the data, the device appends additional data to the first data and delivers the combined data to the data bus during the bus grant for the first data. When the bandwidth of the data bus allocated to the bus grant will be filled by the first data, the device delivers only the first data to the data bus during the bus grant.
Abstract:
An access speculation predictor may predict whether to perform speculative retrieval of data for a data request from a main memory based on whether or not a domain indicator in the data request indicates that the cache line corresponding to the data has a special invalid state or not. In particular, a first address and a domain indicator are extracted from first data request. The first address is used to select a finite state machine (FSM) of a memory controller based on memory regions associated with the FSMs of the memory controller. Speculative retrieval of data for the first data request from main memory is controlled based on whether the domain indicator identifies the special invalid state or not and, if the domain indicator identifies that the cache line does not have the special invalid state, based on information stored in registers associated with the selected FSM.
Abstract:
A circuit arrangement for bus arbitration alters the sequence in which device requests are arbitrated with respect to each other and to a previous arbitration sequence. To this end, an arbiter grants access to a first group of devices according to a predetermined sequence. The arbiter then automatically alters the sequence for a second group of devices, granting access to the bus for the second group according to the altered sequence. These features allow the order in which the arbiter sequences through the groups to be automatically varied with respect to each other, diminishing the likelihood of lockout.
Abstract:
The invention provides ARO1 polypeptides and DNA (RNA) encoding such ARO1 and a procedure for producing such polypeptides by recombinant techniques. Also provided are methods for utilizing such ARO1 for the treatment of infection, particularly fungal infections. Antagonists against such ARO1 and their use as a therapeutic to treat infections, particularly fungal infections are also provided. Further provided are diagnostic assays for detecting diseases related to the presence of ARO1 nucleic acid sequences and the polypeptides in a host. Also provided are diagnostic assays for detecting polynucleotides encoding arom and for detecting the polypeptide in a host.
Abstract:
Address error detection including a method that receives write data and a write address, the write address corresponding to a location in a memory. Error correction code (ECC) bits are generated based on the received write data. The write data is transformed at a computer based on the write address and the write data, to produce transformed write data. The transforming is configured to cause an ECC to detect an address error during a read operation to the write address in response to a mismatch between either the write address or the read address and data read from the location. The transformed write data and the ECC bits are written to the location in memory.
Abstract:
An access speculation predictor is provided that may be implemented using idle command processing resources, such as registers of idle finite state machines (FSMs) in a memory controller. The access speculation predictor may predict whether to perform speculative retrieval of data for a data request from a main memory of the data processing system based on history information stored for a memory region targeted by the data request. In particular, a first address may be extracted from the data request and compared to memory regions associated with second addresses stored in address registers of a plurality of FSMs of the memory controller. A FSM whose memory region includes the first address may be selected. History information for the memory region may be obtained from the selected FSM. The history information may be used to control whether to speculatively retrieve the data for the data request from a main memory.