| 摘要 |
<p>A high performance orthogonal rotator for a graphics processor orthogonally rotates pixel regions in a bit map by an angle of 90° or 270°. Optionally, the pixel regions can be vertically mirrored as well as orthogonally rotated. Source data bytes from a source bit map are loaded into columns of a matrix array constructed from parallel registers forming the rows. Orthogonal rotation and vertical mirroring is accomplished by the order in which bytes are loaded from the source bit map and by the order in which bytes are read into a destination bit map. To accomplish a 90° rotation without vertical mirroring, data bytes are first loaded into the matrix array columns beginning with the LSB column and ending with the MSB column. Then, data words are read beginning with the MSW located in the bottom register and ending with the LSW located in the top register. To achieve a 90° rotation with vertical mirroring, data bytes are first loaded into the matrix array columns beginning with the LSB column and ending with the MSB column. Then, data words are read beginning with the LSW in the top register and ending with the MSW in the bottom register. To accomplish a 270° rotation without vertical mirroring, data bytes are first loaded into the matrix array columns beginning with the MSB column and ending with the LSB column. Then, data words are read beginning with the LSW in the top register (108) and ending with the MSW in the bottom register. To effectuate a 270° rotation with vertical mirroring, data bytes are first loaded into the matrix array columns beginning with the MSB column and ending with the LSB column. Then, data words are read beginning with the MSW in the bottom register and ending with the LSW in the top register.</p> |
