UNDOCUMENTED OP CODES for the 6502 Below is a list of undocumented opcodes for the 6510 (the version of the 6502 used in Commodore 64 and 128). The 6510 is compatible with the 6502, but of course this needn't be true for these undodumented features! Things like this may differ between various manufacturers, too. NOTE: I haven't tested these opcodes myself - no responsibility is taken for any damage caused by using them!!! Below is 1) a description of the various instructions, in a mixture of 6502 assembler and C. 2) a table of the opcodes for each instruction and addressing mode. Have fun! AAX: M = A & X AMA: ORA #238; AND M; TAX ANA: AND M; CARRY=BIT 7 ANB: AND M; CARRY=BIT 7 AXM: X = A & X - M AXS: S = A & X; M = A & X & #17 DCP: DEC M; CMP M ISB: INC M; SBC M LAN: ROL M; AND M LAS: LDA M; TAX; TXS LAX: LDA M; TAX LOR: ASL M; ORA M RAD: ROR M; ADC M RAM: AND M; LSR A RBM: AND M; LSR A REO: LSR M; EOR M SBC: SBC M TEA: M = A & X & (M + 1) TEX: M = X & (M + 1) TEY: M = Y & #1 XMA: A = X & M & (A | #238)