A digital data processor includes an instruction memory storing instructions specifying a data processing operation and a data operand field, an instruction decoder coupled to the instruction memory for recalling instructions from the instruction memory and determining the operation and the data operand, and an operational unit coupled to a data register file and to an instruction decoder to perform a data processing operation upon an operand corresponding to an instruction decoded by the instruction decoder and storing results of the data processing operation. The operational unit is configured to perform a table write in response to a look up table initialization instruction by duplicating at least one data element from a source data register to create duplicated data elements, and writing the duplicated data elements to a specified location in a specified number of at least one table and a corresponding location in at least one other table.

A data transfer system including a first memory and a processor includes a second memory and a DMA controller. The processor performs RMW on data which has a size less than a cache line size and in which a portion of a cache line (a unit area of the first memory) is a write destination. Output target data is transferred from an I/O device to the second memory. Thereafter, the DMA controller transfers the output target data from the second memory to the first memory in one or a plurality of transfer unit sizes by which the number of occurrences of RMW is minimized.

A prefetch unit generates a prefetch address in response to an address associated with a memory read request received from the first or second cache. The prefetch unit includes a prefetch buffer that is arranged to store the prefetch address in an address buffer of a selected slot of the prefetch buffer, where each slot of the prefetch unit includes a buffer for storing a prefetch address, and two sub-slots. Each sub-slot includes a data buffer for storing data that is prefetched using the prefetch address stored in the slot, and one of the two sub-slots of the slot is selected in response to a portion of the generated prefetch address. Subsequent hits on the prefetcher result in returning prefetched data to the requestor in response to a subsequent memory read request received after the initial received memory read request.

In a cache memory used for communication between a host and a memory, the cache memory may include a plurality of cache sets, each comprising: a valid bit; N dirty bits; a tag; and N data sets respectively corresponding to the N dirty bits and each including data of a data chunk size substantially identical to a data chunk size of the host, wherein a data chunk size of the memory is N times as large as the data chunk size of the host, where N is an integer greater than or equal to 2.

Methods, systems, and devices for compressed logical-to-physical mapping for sequentially stored data are described. A memory device may use a hierarchical set of logical-to-physical mapping tables for mapping logical block address generated by a host device to physical addresses of the memory device. The memory device may determine whether all of the entries of a terminal logical-to-physical mapping table are consecutive physical addresses. In response to determining that all of the entries contain consecutive physical addresses, the memory device may store a starting physical address of the consecutive physical addresses as an entry in a higher-level table along with a flag indicating that the entry points directly to data in the memory device rather than pointing to a terminal logical-to-physical mapping table. The memory device may, for subsequent reads of data stored in one or more of the consecutive physical addresses, bypass the terminal table to read the data.

A method and apparatus including a cache controller coupled to a cache memory, wherein the cache controller receives a plurality of cache access requests, performs a pre-sorting of the plurality of cache access requests by a first stage of the cache controller to order the plurality of cache access requests, wherein the first stage functions by performing a presorting and pre-clustering process on the plurality of cache access requests in parallel to map the plurality of cache access requests from a first position to a second position corresponding to ports or banks of a cache memory, performs the combining and splitting of the plurality of cache access request by a second stage of the cache controller, and applies the plurality of cache access requests to the cache memory at line speed.

A method and apparatus including a cache controller coupled to a cache memory, wherein the cache controller receives a plurality of cache access requests, performs a pre-sorting of the plurality of cache access requests by a first stage of the cache controller to order the plurality of cache access requests, wherein the first stage functions by performing a presorting and pre-clustering process on the plurality of cache access requests in parallel to map the plurality of cache access requests from a first position to a second position corresponding to ports or banks of a cache memory, performs the combining and splitting of the plurality of cache access request by a second stage of the cache controller, and applies the plurality of cache access requests to the cache memory at line speed.

A prefetch unit generates a prefetch address in response to an address associated with a memory read request received from the first or second cache. The prefetch unit includes a prefetch buffer that is arranged to store the prefetch address in an address buffer of a selected slot of the prefetch buffer, where each slot of the prefetch unit includes a buffer for storing a prefetch address, and two sub-slots. Each sub-slot includes a data buffer for storing data that is prefetched using the prefetch address stored in the slot, and one of the two sub-slots of the slot is selected in response to a portion of the generated prefetch address. Subsequent hits on the prefetcher result in returning prefetched data to the requestor in response to a subsequent memory read request received after the initial received memory read request.

Systems and methods related to direct swap caching with zero line optimizations are described. A method for managing a system having a near memory and a far memory comprises receiving a request from a requestor to read a block of data that is either stored in the near memory or the far memory. The method includes analyzing a metadata portion associated with the block of data, the metadata portion comprising: both (1) information concerning whether the near memory contains the block of data or whether the far memory contains the block of data and (2) information concerning whether a data portion associated with the block of data is all zeros. The method further includes instead of retrieving the data portion from the far memory, synthesizing the data portion corresponding to the block of data to generate a synthesized data portion and transmitting the synthesized data portion to the requestor.

A digital data processor includes an instruction memory storing instructions each specifying a data processing operation and at least one data operand field, an instruction decoder coupled to the instruction memory for sequentially recalling instructions from the instruction memory and determining the data processing operation and the at least one data operand, and at least one operational unit coupled to a data register file and to an instruction decoder to perform a data processing operation upon at least one operand corresponding to an instruction decoded by the instruction decoder and storing results of the data processing operation. The operational unit is configured to increment histogram values in response to a histogram instruction by incrementing a bin entry at a specified location in a specified number of at least one histogram.