Abstract: The present invention relates Control circuitry that includes a circuit configured to receive a system level cache (SLC) dirty-set request comprising a dirty set flag, a memory address, and an address of a cache line (LA) in a SLC data array. The circuitry converts the memory address to a dynamic random-access memory (DRAM) page address (PA) which identifies a DRAM bank and a DRAM page and identifies either a hit, or no hit, is present according to whether the DRAM PA matches with PA address in any valid entry in a dirty line links cache (DLL$).

Abstract: A control circuit for controlling memory prefetch requests to system level cache (SLC). The control circuit includes a circuit identifying memory access requests received at the system level cache (SLC), where each of the memory access requests includes an address (ANEXT) of memory to be accessed. Another circuit associates a tracker with each of the memory access streams. A further circuit performs tracking for the memory access streams by: when the status is tracking and the address (ANEXT) points to an interval between the current address (ACURR) and the last prefetched address (ALAST), issuing a prefetch request to the SLC; and when the status is tracking, and distance (ADIST) between the current address (ACURR) and the last prefetched address (ALAST) is greater than a specified maximum prefetch for the associated tracker, waiting for further requests to control a prefetch process.

Abstract: An Advanced Microcontroller Bus Architecture (AMBA)/Advanced eXtensible Interface (AXI) compatible device and corresponding method capable of efficient reordering of responses from a last level cache (LLC) and/or dynamic random access memory (DRAM).

Abstract: An Advanced Microcontroller Bus Architecture (AMBA)/Advanced eXtensible Interface (AXI) compatible device and corresponding method capable of efficient reordering of responses from a last level cache (LLC) and/or dynamic random access memory (DRAM).

Abstract: A control circuit for controlling memory prefetch requests to system level cache (SLC). The control circuit includes a circuit identifying memory access requests received at the system level cache (SLC), where each of the memory access requests includes an address (ANEXT) of memory to be accessed. Another circuit associates a tracker with each of the memory access streams. A further circuit performs tracking for the memory access streams by: when the status is tracking and the address (ANEXT) points to an interval between the current address (ACURR) and the last prefetched address (ALAST), issuing a prefetch request to the SLC; and when the status is tracking, and distance (ADIST) between the current address (ACURR) and the last prefetched address (ALAST) is greater than a specified maximum prefetch for the associated tracker, waiting for further requests to control a prefetch process.

Abstract: The present invention relates Control circuitry that includes a circuit configured to receive a system level cache (SLC) dirty-set request comprising a dirty set flag, a memory address, and an address of a cache line (LA) in a SLC data array. The circuitry converts the memory address to a dynamic random-access memory (DRAM) page address (PA) which identifies a DRAM bank and a DRAM page and identifies either a hit, or no hit, is present according to whether the DRAM PA matches with PA address in any valid entry in a dirty line links cache (DLL$).

Abstract: Power conservation via DRAM access reduction is provided by a buffer/mini-cache selectively operable in a normal mode and a buffer mode. In the buffer mode, entered when CPUs begin operating in low-power states, non-cacheable accesses (such as generated by a DMA device) matching specified physical address ranges are processed by the buffer/mini-cache, instead of by a memory controller and DRAM. The buffer/mini-cache processing includes allocating lines when references miss, and returning cached data from the buffer/mini-cache when references hit. Lines are replaced in the buffer/mini-cache according to one of a plurality of replacement policies, including ceasing replacement when there are no available free lines. In the normal mode, entered when CPUs begin operating in high-power states, the buffer/mini-cache operates akin to a conventional cache and non-cacheable accesses are not processed therein.

Abstract: Small and power-efficient buffer/mini-cache sources and sinks selected DMA accesses directed to a memory space included in a coherency domain of a microprocessor when cached data in the microprocessor is inaccessible due to any or all of the microprocessor being in a low-power state not supporting snooping. Satisfying the selected DMA accesses via the buffer/mini-cache enables reduced power consumption by allowing the microprocessor (or portion thereof) to remain in the low-power state. The buffer/mini-cache may be operated (temporarily) incoherently with respect to the cached data in the microprocessor and flushed before deactivation to synchronize with the cached data when the microprocessor (or portion thereof) transitions to a high-power state that enables snooping. Alternatively the buffer/mini-cache may be operated in a manner (incrementally) coherent with the cached data.

Abstract: A small and power-efficient buffer/mini-cache sources and sinks selected DMA accesses directed to a memory space included in a coherency domain of a microprocessor when cached data in the microprocessor is inaccessible due to any or all of the microprocessor being in a low-power state not supporting snooping. Satisfying the selected DMA accesses via the buffer/mini-cache enables reduced power consumption by allowing the microprocessor (or portion thereof) to remain in the low-power state. The buffer/mini-cache may be operated (temporarily) incoherently with respect to the cached data in the microprocessor and flushed before deactivation to synchronize with the cached data when the microprocessor (or portion thereof) transitions to a high-power state that enables snooping. Alternatively the buffer/mini-cache may be operated in a manner (incrementally) coherent with the cached data.

Abstract: Power conservation via DRAM access reduction is provided by a buffer/mini-cache selectively operable in a normal mode and a buffer mode. In the buffer mode, entered when CPUs begin operating in low-power states, non-cacheable accesses (such as generated by a DMA device) matching specified physical address ranges are processed by the buffer/mini-cache, instead of by a memory controller and DRAM. The buffer/mini-cache processing includes allocating lines when references miss, and returning cached data from the buffer/mini-cache when references hit. Lines are replaced in the buffer/mini-cache according to one of a plurality of replacement policies, including ceasing replacement when there are no available free lines. In the normal mode, entered when CPUs begin operating in high-power states, the buffer/mini-cache operates akin to a conventional cache and non-cacheable accesses are not processed therein.

Abstract: There is described a system and method for use in a processing system of the type including a plurality of processor subsystems, each processor subsystem including a processor, and being coupled together and to a shared memory by a common bus, wherein the system and method permits exclusive execution of critical sections by each of the processors. A lock buffer associated with each of the processors caches the value of the interlock variable and a control section locally tests the stored interlock variable value responsive to an instruction from its processor. If the control section determines that the interlock variable has the available value, it causes the available value of the interlock variable to be conveyed to its associated processor and the busy value to be written to the local lock buffer and over the common bus to the shared memory under a write-through policy and for updating each lock buffer associated with the other processors under a write-update policy.