# US 11,442,869 B2 · Cache memory, memory system including the same and operating method thereof

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- Number: US 11,442,869 B2
- Document ID: US11442869B2
- Status: Granted
- Kind: B2
- Application number: 16/721,391
- Filed: 2019-12-19
- Published: 2020-09-24
- Granted: 2022-09-13
- Earliest claimed: 2019-03-22
- Assignees: SK hynix Inc.
- Applicants: SK hynix Inc.
- Inventors: Seung-Gyu Jeong
- Web page: https://patentgrep.com/patent/US11442869B2

## CPC

- G06F 12/0893: Caches characterised by their organisation or structure
- G06F 12/0895: of parts of caches, e.g. directory or tag array
- G06F 12/0623: {for memory modules}
- G06F 12/0846: Cache with multiple tag or data arrays being simultaneously accessible
- G06F 12/0886: Variable-length word access
- G06F 12/12: Replacement control
- G06F 12/121: using replacement algorithms
- G06F 2212/1024: Latency reduction
- G06F 2212/608: Details relating to cache mapping
- G06F: ELECTRIC DIGITAL DATA PROCESSING (computer systems based on specific computational models G06N)

## Abstract

A cache memory includes a first cache area corresponding to even addresses, and a second cache area corresponding to odd addresses, wherein each of the first and second cache areas includes a plurality of cache sets, and each cache set includes a data set field suitable for storing data corresponding to an address among the even and odd addresses, and a pair field suitable for storing information on a location where data corresponding to an adjacent address which is adjacent to an address corresponding to the stored data is stored.

## Claims

### Claim 1

A cache memory comprising:
a first cache area corresponding to even addresses received from a host; and
a second cache area corresponding to odd addresses received from the host,
wherein each of the first and second cache areas includes a plurality of cache sets classified by a plurality of indexes which are low-order bits of the even addresses and the odd addresses so that N number of cache sets correspond to each index, where N is an integer greater than or equal to 4, and each cache set comprises:
a data set field configured to store data corresponding to an address among the even and odd addresses; and
a pair field configured to store location information for the N number of cache sets included in each index where data corresponding to an address which is adjacent to the address corresponding to the stored data, is stored in a corresponding data set field associated with the location information, and
wherein the stored data and the data corresponding to the adjacent address within each index are evicted together, based on the location information stored in the pair field.

### Claim 2 (depends on 1)

The cache memory of claim 1, wherein each index is configured to classify the cache sets in the first and second cache areas in response to lower bits than a least significant bit (LSB), among lower bits of an address.

### Claim 3 (depends on 1)

The cache memory of claim 1, wherein each cache set further includes a valid bit field indicating whether the data set field of a corresponding cache set has been updated from memory.

### Claim 4 (depends on 1)

The cache memory of claim 1, wherein each cache set further includes a tag field configured to store a plurality of bits of the even addresses and the odd addresses except for the low-order bits which are used for the plurality of indexes.

### Claim 5 (depends on 4)

The cache memory of claim 4, wherein each of the even addresses and each of the odd addresses is compared with the index and the tag field in a cache set to determine a hit or miss of data.

### Claim 6 (depends on 5)

The cache memory of claim 5, wherein when the host issues a write request, if a hit of data for an even address is determined then location information of a corresponding cache set is generated data and stored in a corresponding pair field.

### Claim 7 (depends on 5)

The cache memory of claim 5, wherein when the host issues a write request, if a hit of data for an odd address is determined then data associated with the odd address is stored in the data field of the corresponding cache set, if a miss of data in the odd address is determined then a new cache set is allocated for the odd address.