High speed CAM lookup using stored encoded key
US7761774B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Oct 28, 2005 |
| Grant date | Jul 20, 2010 |
| Priority date | — |
| Expiry date | Oct 1, 2028 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG06F2212/652
- WIPO fieldComputer technology
- WIPO sectorElectrical engineering
Abstract
The search key and key fields of a CAM in a cache are encoded with a Hamming distance of at least two to increase the speed of the CAM by ensuring each mismatching match line is discharged by at least two transistors in parallel. Where the cache is physically tagged, the search key is a physical address. The page address portion of the physical address is encoded prior to being stored in a TLB. The page offset bits are encoded in parallel with the TLB access, and concatenated with the encoded TLB entry. If a page address addresses a large memory page size, a plurality of corresponding sub-page addresses may be generated, each addressing a smaller page size. These sub-page addresses may be encoded and stored in a micro TLB. The encoded key and key field are tolerant of single-bit soft errors.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.