Nvidia Corporation

Peter Tong

Colyn Scott Case

Shane J Keil

David Kirk McAllister

Dennis K Ma

Anders M Kugler

Sonny S Yeoh

Alexandre Joly

One embodiment of the present invention sets forth a technique for lossless compression of color data. Color data for a packet including multiple sub-pixel samples is compressed using a predictor map that is selected based on the sampling format specified for the graphics surface storing the color data. The predictor map defines one of the samples as an anchor that is represented exactly and a transform indicating which neighboring samples are used to compute difference samples for the other samples in the packet. The difference samples are truncated and tested to determine if the difference samples can fit into one or more compressed data formats, i.e., if the color data can be compressed without loss. When compression can be performed without loss, the transformed packet is output. Otherwise, the original packet is output.

Lossless frame buffer color compression

Devices and methods provide data from multiple storage locations to a processor. A data block containing data required by a processor is stored in two or more locations, e.g., in a local memory and a system memory, both of which are accessible to the processor's memory interface. The memory interface directs each read request for mirrored data to one or another of the mirror locations. Selection of a mirror location to be read is based on substantially real-time information about which mirror location is best able to handle the request. For instance, the selection of a mirror location to access can be based at least in part on information about the level of activity on various buses that connect the processor to the mirror locations.

Memory interface with dynamic selection among mirrored storage locations

Circuits, methods, and apparatus that allow the elimination of a frame buffer connected directly to a graphics processing unit. The graphics processing unit includes an on-chip memory. Following system power-up or reset, the GPU initially renders comparatively low-resolution images to the on-chip memory for display. Afterward, the GPU renders images, which are typically higher resolution, and stores them in a system memory, apart from the graphics processing unit. The on-chip memory, which is no longer needed for image storage, instead stores address information, referred to as page tables, identifying the location of data stored by the GPU in the separate system memory.

Zero frame buffer

A cache shared by multiple clients implements a client specific policy for replacing entries in the event of a cache miss. A request from any client can hit any entry in the cache. For purposes of replacing entries, at least of the clients is restricted, and when a cache miss results from a request by the restricted client, the entry to be replaced is selected from a fixed subset of the cache entries. When a cache misses results from a request by any client other than the restricted client, any cache entry, including a restricted entry, can be selected to be replaced.

Growing community of inventors

Cupertino, CA, United States of America

Peter Tong