== Technical ==
Uses I/O portsPosition: [[I/O_Port_Summary|#FBEE]] Port FBEEh READ: Kempston Mouse 8 bit X position Port FBEFh READ: Kempston Mouse 8 bit Y position Note: The position values aren't reset after reading. To calculated the distance since last read: dist=new-old, old=new whereas, dist=00h : no move[[I dist=+01h..+7Fh moved right/O_Port_Summary|#FBEF]]up[[I dist=-01h..-80h moved left/O_Port_Summary|#FAEF]]down
Port FBEEh READButtons: 8 bit X movement Port FBFEh READ: 8 bit Y movement Port FAEFh READ:Kempston Mouse Buttons
bit 0: Left Button (active low)
bit 1: Right Button (active low)