International Business Machines Corporation

David Nolan Ault

Samuel I Ward

Bao G Truong

Patrick Richard Brown

William Bryan Tiernan

Emiliano Lozano

Mark Anthony Nadon

Performing a calculation using a coordinate rotation digital computer (CORDIC) algorithm. Execution of the CORDIC algorithm is begun. An error introduced by a truncated vector as a result of executing the CORDIC algorithm is pre-computed. The error is incorporated into a subsequent iteration of the CORDIC algorithm. Execution of the CORDIC algorithm is completed. The result of the CORDIC algorithm is stored.

Accuracy improvement in CORDIC through precomputation of the error bias

A texture image that comprises a set of texels wherein each texel is assigned a (u,v) coordinate pair of a texture coordinate space. Each texel is then stored in memory at a memory address determined by applying a transformation function to the texel's (u,v) coordinate pair. The transformation function is customized to associate two dimensional portions of the texture coordinate space to each page of memory. When the texture image (or a portion of the texture image) stored in memory is later mapped to an object during rendering the object, the allocation of two dimensional portions of the texture coordinate space to each memory page reduces the number of memory pages accessed during the rendering of the object. The reduction in the number of memory pages accessed during the texture mapping process translates into improved texture mapping performance. Preferably, the memory in which the texture image is stored comprises a dedicated texture memory of the graphics display system to eliminate contention with the frame buffer. In the presently preferred embodiment, the transformation function is accomplished by interleaving alternating u-bits and v-bits of the (u,v) coordinate pair to generate an offset value. The offset value is then added to a base address of the memory in which the texture image is stored to generate the memory address.

Method and apparatus for storing and accessing texture maps

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Austin, TX, United States of America

David Nolan Ault