CPUClear is a small hack, inspired by CPUBlit, that replaces the
BltClear()-Routine of the "graphics.library" with a  highly optimized 68020 (or
higher) version. This gains (in a simple test) approx. 60% speed and should be
even faster on an A3000, because the CPU works more efficiently with 32-Bit
ChipRAM. Source is included. Author: Peter Simons