The big ol'table of 6502 opcodes makes more sense in octal. note: b is a byte operand, w is a word operand, [] means accessing memory at the address inside. Opcodes with ? are unofficial. 0 1 2 3 4 5 6 7 00 BRK ORA[[b+X]] XX SLO[[b+X]]? NOP[b]? ORA[b] ASL[b] SLO[b]? 01 PHP ORA b ASL A ANC b? NOP[w]? ORA[w] ASL[w] SLO[w]? 02 BPL b ORA[[b]+Y] XX SLO[[b]+Y]? NOP[b+X]? ORA[b+X] ASL[b+X] SLO[b+X]? 03 CLC ORA[w+Y] NOP? SLO[w+Y]? NOP[w+X]? ORA[w+X] ASL[w+X] SLO[w+X]? 04 JSR w AND[[b+X]] XX RLA[[b+X]]? BIT[b] AND[b] ROL[b] RLA[b]? 05 PLP AND b ROL A ANC b? BIT[w] AND[w] ROL[w] RLA[w]? 06 BMI b AND[[b]+Y] XX RLA[[b]+Y]? NOP[b+X]? AND[b+X] ROL[b+X] RLA[b+X]? 07 SEC AND[w+Y] NOP? RLA[w+Y]? NOP[w+X]? AND[w+X] ROL[w+X] RLA[w+X]? 10 RTI EOR[[b+X]] XX SRE[[b+X]]? NOP[b]? EOR[b] LSR[b] SRE[b]? 11 PHA EOR b LSR A ALR b? JMP w EOR[w] LSR[w] SRE[w]? 12 BVC b EOR[[b]+Y] XX SRE[[b]+Y]? NOP[b+X]? EOR[b+X] LSR[b+X] SRE[b+X]? 13 CLI EOR[w+Y] NOP? SRE[w+Y]? NOP[w+X]? EOR[w+X] LSR[w+X] SRE[w+X]? 14 RTS ADC[[b+X]] XX RRA[[b+X]]? NOP[b]? ADC[b] ROR[b] RRA[b]? 15 PLA ADC b ROR A ARR b? JMP[w] ADC[w] ROR[w] RRA[w]? 16 BVS b ADC[[b]+Y] XX RRA[[b]+Y]? NOP[b+X]? ADC[b+X] ROR[b+X] RRA[b+X]? 17 SEI ADC[w+Y] NOP? RRA[w+Y]? NOP[w+X]? ADC[w+X] ROR[w+X] RRA[w+X]? 20 NOP b? STA[[b+X]] NOPb? SAX[[b+X]]? STY[b] STA[b] STX[b] SAX[b]? 21 DEY NOP b? TXA XX STY[w] STA[w] STX[w] SAX[w]? 22 BCC b STA[[b]+Y] XX XX STY[b+X] STA[b+X] STX[b+X] SAX[b+Y]? 23 TYA STA[w+Y] TXS XX XX STA[w+X] XX XX 24 LDY b LDA[[b+X]] LDX b LAX[[b+X]]? LDY[b] LDA[b] LDX[b] LAX[b]? 25 TAY LDA b TAX XX LDY[w] LDA[w] LDX[w] LAX[w]? 26 BCS b LDA[[b]+Y] XX LAX[[b]+Y]? LDY[b+X] LDA[b+X] LDX[b+X] LAX[b+Y]? 27 CLV LDA[w+Y] TSX XX LDY[w+X] LDA[w+X] LDX[w+Y] LAX[w+Y]? 30 CPY b CMP[[b+X]] NOPb? DCP[[b+X]]? CPY[b] CMP[b] DEC[b] DCP[b]? 31 INY CMP b DEX AXS b? CPY[w] CMP[w] DEC[w] DCP[w]? 32 BNE b CMP[[b]+Y] XX DCP[[b]+Y]? NOP[b+X]? CMP[b+X] DEC[b+X] DCP[b+X]? 33 CLD CMP[w+Y] NOP? DCP[w+Y]? NOP[w+X]? CMP[w+X] DEC[w+X] DCP[w+X]? 34 CPX b SBC[[b+X]] NOPb? ISC[[b+X]]? CPX[b] SBC[b] INC[b] ISC[b]? 35 INX SBC b NOP XX CPX[w] SBC[w] INC[w] ISC[w]? 36 BEQ b SBC[[b]+Y] XX ISC[[b]+Y]? NOP[b+X]? SBC[b+X] INC[b+X] ISC[b+X]? 37 SED SBC[w+Y] NOP? ISC[w+Y]? NOP[w+X]? SBC[w+X] INC[w+Y] ISC[w+X]?