Hardware assist for data block diagonal mirror image transformation

摘要

A data processing apparatus and method for quickly and efficiently producing a diagonally (170) mirrored image of a block of data (168). The apparatus comprises a first input operand (182) consisting of a first half of an N×N bit data block and a second input operand (184) consisting of a second half of an N×N bit data block. A first hardware bit transformation (188) forms an upper half of an N-way bit deal of the two operands (186), and a second hardware bit transformation (192) forms a lower half of the N-way bit deal (190). The upper and lower halves of the N-way bit deal represent a diagonally mirrored image (172) of the N×N bit data block. The method retrieves a data block from memory and packs it into two input operand registers. The two hardware bit transformations fill respective destination registers. The data is unpacked from the destination registers and stored to memory. Diagonally mirrored imaged of larger blocks of data can be formed using this technique on minor image blocks and swapping the mirrored minor image blocks.