21 ; save place in keytab
29 ; read port and flip bits if not kempston
36 jr z,$+3 ; skip next instruction
42 ; rotate E, moving required bit to bit 0
58 defw #F7FE,#FBFE,#FDFE,#FEFE
59 defw #EFFE,#DFFE,#BFFE,#7FFE
62 ; keys: 1/2 of row number + keypos from edge