| 摘要 |
<p>A pixel modification unit is provided for carrying out a variety of raster graphic manipulations in a RISC graphics processor. The pixel modification unit comprises a logic function unit, a masking unit, and a byte mirror unit. The logic function unit can perform any of 16 different logic operations between each bit of a source operand and a destination operand. The source operand may be a bit map fixed data, while the destination operand is pixel data in the bit map corresponding to the graphics image to be modified. The masking unit can mask any or all bits of a destination operand so that the logic function unit does not operate on the masked bits. When masking is implemented, the output of the pixel modification unit is derived from the masked bits from the destination operand and the unmasked bits which are operated on by the logic function unit. The byte mirror unit horizontally reflects a figure in the bit map via reversing the bit order of data bytes retrieved from the bit map.</p> |
