Method and system for managing a display image in compressed and uncompressed blocks
US6366289B1 · kind B1 · utility
Assignee
Inventor
Key dates
| Filing date | Jul 17, 1998 |
| Grant date | Apr 2, 2002 |
| Priority date | — |
| Expiry date | Jul 17, 2018 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG06F2212/401
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
A virtual frame buffer controller in a computer's display system manages accesses to a display image stored in discrete compressed and uncompressed blocks distributed in physical memory. The controller maps conventional linear pixel addresses of a virtual frame buffer to pixel locations within blocks stored at arbitrary places in physical memory. The virtual frame buffer controller maintains a data structure, called a pointer list, to keep track of the physical memory location and compression state of each block of pixels in the virtual frame buffer. The virtual frame buffer controller initiates a decompression process to decompress a block when a pixel request maps to a pixel in a compressed block. The block remains decompressed until physical memory needs to be reclaimed to free up memory. A software driver for the virtual frame buffer controller performs memory management functions, including adding to a free memory list when the virtual frame buffer requires more memory and reclaiming memory previously allocated to a block of pixels whose state has changed from a compressed to an uncompressed state, or from a decompressed back to a compressed state.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.