TLB with two physical pages per virtual tag
US5574877A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Sep 25, 1992 |
| Grant date | Nov 12, 1996 |
| Priority date | — |
| Expiry date | Sep 25, 2012 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG06F12/1027
- WIPO fieldComputer technology
- WIPO sectorElectrical engineering
Abstract
A TLB which has at least two page frame numbers (PFN) associated with each tag (Virtual Page Number) is provided. Thus, a match will produce two possible physical page frame numbers. The selection between these two is controlled by a bit provided directly from the virtual address, without translation. This bit is preferably the least significant bit of the virtual page number, or the first bit after the physical offset. This structure effectively doubles the capacity of the TLB without doubling the number of tags. Although the virtual space covered by each tag or VPN is necessarily restricted to two contiguous areas, the invention allows these two contiguous areas to be mapped to completely different regions of the physical address space. In addition to limiting the number of tags required, the number of comparators required is also similarly limited, with only the number of physical page frame numbers stored being required to double.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.