Imagination Technologies Limited

Videologic Limited

John Anthony Metcalfe

Martin Ashton

Hossein Yassaie

Graham Deacon

Aspects include a pixel source that produces data for a rendered surface divided into regions. A mapping identifies memory segments storing pixel data for each region of the surface. The mapping can identify memory segments storing pixel data from a prior rendered surface, for regions that were unchanged during rendering the rendering. Such changed/unchanged status is tracked on a region by region basis. A counter can be maintained for each memory segments to track how many surfaces use pixel data stored therein. A pool of free memory segments can be maintained. Reading a surface, such as to display a rendered surface by a display controller, includes identifying and reading the mapping to identify each memory segment storing pixel data for regions of the surface, reading such, and updating the counters for the memory segments that were read.

Systems and methods of partial frame buffer updating

A video/graphics memory system includes a memory device (30) having a memory core (14) and first and serial registers (16, 36). The memory device thus has a random-access port (24) for graphics data, a first serial access port (22) for image output to a display, and an auxiliary or second serial port (32) for input and output of video signal data. A single memory thus stores both video and graphics data, while the processor still has access to the random access port of the memory. Two video outputs can be provided simultaneously, or the data withdrawn through the auxiliary port can be subject to processing and then written back into the memory. In alternative arrangements, instead of using triple-ported RAM, the auxiliary port is provided by the use of external multiplexing circuitry.

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Dunstable, United Kingdom

John Anthony Metcalfe