Window copy-swap using multi-buffer hardware support

1. Field of the Invention A 3D graphics controller configurable to simultaneously copy portions of a pixel region between a back buffer and a front buffer. The 3D graphics controller includes four memory controllers, each controlling a bank of frame buffer memory. A sequence of addresses defining a pixel region is generated. The addresses are distributed to the four memory controllers according to the memory banks (addresses) coupled thereto. Each memory controller is configured to read pixels according to the addresses and a first offset; and write the pixels according to the addresses and a second offset. The offsets are chosen so as not to shift pixels within the banks. Therefore, each memory controller simultaneously and independently copies a portion of the pixel region without accessing any other memory banks resulting in a copy of the entire pixel region.