To read BRAM to memory 00/1000. (from monitor)
	\4 0 0 0 10 0 A 3\U
    To write BRAM from memory 00/1000. (from monitor)
	\4 0 0 0 10 0 9 3\U
    To enable ROM CDAs at boot. (rom 3 only)
	Set bit 7 (high biit) of BRAM postion $59.
    To disable scanline interupts on pointer updates. (mouse arrow fix)
	Set bit 2 of BRAM postion $5F.