Described apparatuses and methods order memory address portions advantageously for cache-memory addressing. An address bus can have a smaller width than a memory address. The multiple bits of the memory address can be separated into most-significant bits (MSB) and least-significant bits (LSB) portions. The LSB portion is provided to a cache first. The cache can process the LSB portion before the MSB portion is received. The cache can use index bits of the LSB portion to index into an array of memory cells and identify multiple corresponding tags. The cache can also check the corresponding tags against lower tag bits of the LSB portion. A partial match may be labeled as a predicted hit, and a partial miss may be labeled as an actual miss, which can initiate a data fetch. With the remaining tag bits from the MSB portion, the cache can confirm or refute the predicted hit.

Described apparatuses and methods order memory address portions advantageously for cache-memory addressing. An address bus can have a smaller width than a memory address. The multiple bits of the memory address can be separated into most-significant bits (MSB) and least-significant bits (LSB) portions. The LSB portion is provided to a cache first. The cache can process the LSB portion before the MSB portion is received. The cache can use index bits of the LSB portion to index into an array of memory cells and identify multiple corresponding tags. The cache can also check the corresponding tags against lower tag bits of the LSB portion. A partial match may be labeled as a predicted hit, and a partial miss may be labeled as an actual miss, which can initiate a data fetch. With the remaining tag bits from the MSB portion, the cache can confirm or refute the predicted hit.

Systems, apparatuses, and methods related to tokens to indicate completion of data storage to memory are described. An example method may include storing a number of data values by a first page in a first row of an array of memory cells responsive to receipt of a first command from a host, where the first command is associated with an open transaction token, and receiving a second command from the host to store a number of data values by a second page in the first row. The method may further include sending a safety token to the host to indicate completion of storing the number of data values by the second page in the first row.

Systems, apparatuses, and methods related to tokens to indicate completion of data storage to memory are described. An example method may include storing a number of data values by a first page in a first row of an array of memory cells responsive to receipt of a first command from a host, where the first command is associated with an open transaction token, and receiving a second command from the host to store a number of data values by a second page in the first row. The method may further include sending a safety token to the host to indicate completion of storing the number of data values by the second page in the first row.

A cache control apparatus includes a data unit configured to store data on an index-specific basis, a tag unit configured to store, on the index-specific basis, a tag and a flag indicating whether the data has an uncorrectable error, and a control unit configured to refer to the flag, upon detecting a tag hit by performing a read access to the tag unit, to determine whether an uncorrectable error exists in the data corresponding to the tag hit, wherein the control unit performs process scheduling such that the read access to the tag unit and another access to the tag unit are performed simultaneously.

A cache memory is disclosed. The cache memory includes an instruction memory portion having a plurality of instruction memory locations configured to store instruction data encoding a plurality of CPU instructions. The cache memory also includes a tag memory portion having a plurality of tag memory locations configured to store tag data encoding a plurality of RAM memory address ranges the CPU instructions are stored in. The instruction memory portion includes a single memory circuit having an instruction memory array and a plurality of instruction peripheral circuits communicatively connected with the instruction memory array. The tag memory portion includes a plurality of tag memory circuits, where each of the tag memory circuits includes a tag memory array, and a plurality of tag peripheral circuits communicatively connected with the tag memory array.

A cache memory is disclosed. The cache memory includes an instruction memory portion having a plurality of instruction memory locations configured to store instruction data encoding a plurality of CPU instructions. The cache memory also includes a tag memory portion having a plurality of tag memory locations configured to store tag data encoding a plurality of RAM memory address ranges the CPU instructions are stored in. The instruction memory portion includes a single memory circuit having an instruction memory array and a plurality of instruction peripheral circuits communicatively connected with the instruction memory array. The tag memory portion includes a plurality of tag memory circuits, where each of the tag memory circuits includes a tag memory array, and a plurality of tag peripheral circuits communicatively connected with the tag memory array.

A tag check performed for a memory access operation comprises determining whether an address tag associated with a target address of the access corresponds to a guard tag stored in the memory system associated with a memory system location to be accessed. A given tag check architecturally required for a tag-checked load operation can be skipped when a number of tag-check-skip conditions are satisfied, including at least: that there is an older tag-checked store operation awaiting a pending tag check, for which a guard tag checked in the pending tag check is associated with a same block of one or more memory system locations as a guard tag to be checked in the given tag check; and that the address tag for the tag-checked load operation is the same as the address tag for the older tag-checked store operation.

Devices and methods for cache prefetching are provided. A device is provided which comprises memory and a processor. The memory comprises a DRAM cache, a cache dedicated to the processor and one or more intermediate caches between the dedicated cache and the DRAM cache. The processor is configured to issue prefetch requests to prefetch data, issue data access requests to fetch the data and when one or more previously issued prefetch requests are determined to be inaccurate, issue a prefetch request to prefetch a tag, corresponding to the memory address of requested data in the DRAM cache. A tag look-up is performed at the DRAM cache without performing tag look-ups at the dedicated cache or the intermediate caches. The tag is prefetched from the DRAM cache without prefetching the requested data.

Devices and methods for cache prefetching are provided. A device is provided which comprises memory and a processor. The memory comprises a DRAM cache, a cache dedicated to the processor and one or more intermediate caches between the dedicated cache and the DRAM cache. The processor is configured to issue prefetch requests to prefetch data, issue data access requests to fetch the data and when one or more previously issued prefetch requests are determined to be inaccurate, issue a prefetch request to prefetch a tag, corresponding to the memory address of requested data in the DRAM cache. A tag look-up is performed at the DRAM cache without performing tag look-ups at the dedicated cache or the intermediate caches. The tag is prefetched from the DRAM cache without prefetching the requested data.