Table Of Contents Dead Code Overview
Opcodes, short for “operation codes”, are the fundamental building blocks of machine language, which is the lowest level of programming language a computer or processor understands. Each opcode represents a specific instruction for the CPU to perform, like adding two numbers, moving data between memory locations, or comparing values.
In assembly language, a human-readable form of machine code, opcodes are usually written as abbreviated commands (like ADD, MOV, JMP) that correspond to specific binary or hexadecimal codes the CPU interprets directly.
These opcodes were used in dead code cheats, so they are assumed to be working:
| Opcode | Human-Readable Abbreviation | Description |
|---|---|---|
| 00 | BRK | Break |
| 02 | COP | Coprocessor Enable |
| 08 | PHP | Push Processor Status |
| 09 | ORA Immediate | OR Accumulator with Immediate Value |
| 15 | ORA Direct Page, X | OR Accumulator with Direct Page, X |
| 20 | JSR | Jump to Subroutine |
| 25 | AND Direct Page | AND Accumulator with Direct Page |
| 28 | PLP | Pull Processor Status |
| 29 | AND Immediate | AND Accumulator with Immediate Value |
| 48 | PHA | Push Accumulator |
| 5A | PHY | Push Y Register |
| 5C | JML | Jump Long |
| 64 | STZ Direct Page | Store Zero to Direct Page |
| 68 | PLA | Pull Accumulator |
| 6A | ROR Accumulator | Rotate Right Accumulator |
| 78 | SEI | Set Interrupt Disable |
| 7A | PLY | Pull Y Register |
| 87 | STA Direct Page | Store Accumulator to Direct Page |
| 89 | BIT Immediate | Test Bits Immediate |
| 8D | STA Absolute | Store Accumulator to Absolute Address |
| 8F | STA Absolute Long | Store Accumulator to Absolute Long Address |
| 9A | TXS | Transfer X Register to Stack Pointer |
| 9B | TXY | Transfer X to Y |
| 9C | STZ Absolute | Store Zero to Absolute Address |
| 9F | STA Absolute Long, X | Store Accumulator to Absolute Long Address, X |
| A2 | LDX Immediate | Load X Register with Immediate Value |
| A5 | LDA Direct Page | Load Accumulator from Direct Page |
| A9 | LDA Immediate | Load Accumulator with Immediate Value |
| AA | TAX | Transfer Accumulator to X Register |
| AD | LDA Absolute | Load Accumulator from Absolute Address |
| B4 | LDY Zero Page, X | Load Y Register from Zero Page, X |
| C0 | CPY Immediate | Compare Y Register with Immediate Value |
| C2 | REP | Reset Processor Status Bits |
| C9 | CMP Immediate | Compare Accumulator with Immediate Value |
| D0 | BNE | Branch if Not Equal |
| E0 | CPX Immediate | Compare X Register with Immediate Value |
| E2 | SEP | Set Processor Status Bits |
| EA | NOP | No Operation |
| FC | COP | Coprocessor Interrupt Vector |
| F0 | BEQ | Branch if Equal |
These opcodes were not used in dead code cheats and therefore were not verified as working:
| Opcode | Human-Readable Abbreviation | Description |
|---|---|---|
| 01 | ORA (Direct Page, X) | OR Accumulator with Direct Page, X |
| 03 | ORA (Stack Relative) | OR Accumulator with Stack Relative |
| 04 | TSB (Direct Page) | Test and Set Bits in Memory (Direct Page) |
| 05 | ORA (Direct Page) | OR Accumulator with Direct Page |
| 06 | ASL (Direct Page) | Arithmetic Shift Left (Direct Page) |
| 07 | ORA (Indirect Long) | OR Accumulator with Indirect Long |
| 0A | ASL (Accumulator) | Arithmetic Shift Left (Accumulator) |
| 0B | PHD | Push Direct Page Register |
| 0C | TSB (Absolute) | Test and Set Bits in Memory (Absolute) |
| 0D | ORA (Absolute) | OR Accumulator with Absolute |
| 0E | ASL (Absolute) | Arithmetic Shift Left (Absolute) |
| 0F | ORA (Absolute Long) | OR Accumulator with Absolute Long |
| 10 | BPL | Branch if Positive |
| 11 | ORA (Indirect, Y) | OR Accumulator with Indirect, Y |
| 12 | ORA (Indirect) | OR Accumulator with Indirect |
| 13 | ORA (Stack Relative, Y) | OR Accumulator with Stack Relative, Y |
| 14 | TRB (Direct Page) | Test and Reset Bits in Memory (Direct Page) |
| 16 | ASL (Direct Page, X) | Arithmetic Shift Left (Direct Page, X) |
| 17 | ORA (Indirect Long, Y) | OR Accumulator with Indirect Long, Y |
| 18 | CLC | Clear Carry Flag |
| 19 | ORA (Absolute, Y) | OR Accumulator with Absolute, Y |
| 1A | INC (Accumulator) | Increment Accumulator |
| 1B | TCS | Transfer Accumulator to Stack Pointer |
| 1C | TRB (Absolute) | Test and Reset Bits in Memory (Absolute) |
| 1D | ORA (Absolute, X) | OR Accumulator with Absolute, X |
| 1E | ASL (Absolute, X) | Arithmetic Shift Left (Absolute, X) |
| 1F | ORA (Absolute Long, X) | OR Accumulator with Absolute Long, X |
| 21 | AND (Direct Page, X) | AND Accumulator with Direct Page, X |
| 22 | JSL | Jump to Subroutine Long |
| 23 | AND (Stack Relative) | AND Accumulator with Stack Relative |
| 24 | BIT (Direct Page) | Test Bits in Accumulator (Direct Page) |
| 26 | ROL (Direct Page) | Rotate Left (Direct Page) |
| 27 | AND (Indirect Long) | AND Accumulator with Indirect Long |
| 2A | ROL (Accumulator) | Rotate Left (Accumulator) |
| 2B | PLD | Pull Direct Page Register |
| 2C | BIT (Absolute) | Test Bits in Accumulator (Absolute) |
| 2D | AND (Absolute) | AND Accumulator with Absolute |
| 2E | ROL (Absolute) | Rotate Left (Absolute) |
| 2F | AND (Absolute Long) | AND Accumulator with Absolute Long |
| 30 | BMI | Branch if Minus |
| 31 | AND (Indirect, Y) | AND Accumulator with Indirect, Y |
| 32 | AND (Indirect) | AND Accumulator with Indirect |
| 33 | AND (Stack Relative, Y) | AND Accumulator with Stack Relative, Y |
| 34 | BIT (Direct Page, X) | Test Bits in Accumulator (Direct Page, X) |
| 35 | AND (Direct Page, X) | AND Accumulator with Direct Page, X |
| 36 | ROL (Direct Page, X) | Rotate Left (Direct Page, X) |
| 37 | AND (Indirect Long, Y) | AND Accumulator with Indirect Long, Y |
| 38 | SEC | Set Carry Flag |
| 39 | AND (Absolute, Y) | AND Accumulator with Absolute, Y |
| 3A | DEC (Accumulator) | Decrement Accumulator |
| 3B | TSC | Transfer Stack Pointer to Accumulator |
| 3C | BIT (Absolute, X) | Test Bits in Accumulator (Absolute, X) |
| 3D | AND (Absolute, X) | AND Accumulator with Absolute, X |
| 3E | ROL (Absolute, X) | Rotate Left (Absolute, X) |
| 3F | AND (Absolute Long, X) | AND Accumulator with Absolute Long, X |
| 40 | RTI | Return from Interrupt |
| 41 | EOR (Direct Page, X) | Exclusive OR Accumulator with Direct Page, X |
| 42 | WDM | Reserved for Future Expansion |
| 43 | EOR (Stack Relative) | Exclusive OR Accumulator with Stack Relative |
| 44 | MVP | Block Move Positive |
| 45 | EOR (Direct Page) | Exclusive OR Accumulator with Direct Page |
| 46 | LSR (Direct Page) | Logical Shift Right (Direct Page) |
| 47 | EOR (Indirect Long) | Exclusive OR Accumulator with Indirect Long |
| 4A | LSR (Accumulator) | Logical Shift Right (Accumulator) |
| 4B | PHK | Push Program Bank Register |
| 4C | JMP | Jump to Address (Absolute) |
| 4D | EOR (Absolute) | Exclusive OR Accumulator with Absolute |
| 4E | LSR (Absolute) | Logical Shift Right (Absolute) |
| 4F | EOR (Absolute Long) | Exclusive OR Accumulator with Absolute Long |
| 50 | BVC | Branch if Overflow Clear |
| 51 | EOR (Indirect, Y) | Exclusive OR Accumulator with Indirect, Y |
| 52 | EOR (Indirect) | Exclusive OR Accumulator with Indirect |
| 53 | EOR (Stack Relative, Y) | Exclusive OR Accumulator with Stack Relative, Y |
| 54 | MVN | Block Move Negative |
| 56 | LSR (Direct Page, X) | Logical Shift Right (Direct Page, X) |
| 57 | EOR (Indirect Long, Y) | Exclusive OR Accumulator with Indirect Long, Y |
| 58 | CLI | Clear Interrupt Disable |
| 59 | EOR (Absolute, Y) | Exclusive OR Accumulator with Absolute, Y |
| 5B | TCD | Transfer Accumulator to Direct Page Register |
| 5D | EOR (Absolute, X) | Exclusive OR Accumulator with Absolute, X |
| 5E | LSR (Absolute, X) | Logical Shift Right (Absolute, X) |
| 5F | EOR (Absolute Long, X) | Exclusive OR Accumulator with Absolute Long, X |
| 60 | RTS | Return from Subroutine |
| 61 | ADC (Direct Page, X) | Add with Carry from Direct Page, X |
| 63 | ADC (Stack Relative) | Add with Carry from Stack Relative |
| 65 | ADC (Direct Page) | Add with Carry from Direct Page |
| 66 | ROR (Direct Page) | Rotate Right (Direct Page) |
| 67 | ADC (Indirect Long) | Add with Carry from Indirect Long |
| 69 | ADC (Immediate) | Add with Carry with Immediate |
| 6B | RTL | Return from Subroutine Long |
| 6C | JMP (Indirect) | Jump to Address (Indirect) |
| 6D | ADC (Absolute) | Add with Carry from Absolute |
| 6E | ROR (Absolute) | Rotate Right (Absolute) |
| 6F | ADC (Absolute Long) | Add with Carry from Absolute Long |
| 70 | BVS | Branch if Overflow Set |
| 71 | ADC (Indirect, Y) | Add with Carry from Indirect, Y |
| 72 | ADC (Indirect) | Add with Carry from Indirect |
| 73 | ADC (Stack Relative, Y) | Add with Carry from Stack Relative, Y |
| 74 | STZ (Direct Page, X) | Store Zero to Direct Page, X |
| 75 | ADC (Direct Page, X) | Add with Carry from Direct Page, X |
| 76 | ROR (Direct Page, X) | Rotate Right (Direct Page, X) |
| 77 | ADC (Indirect Long, Y) | Add with Carry from Indirect Long, Y |
| 79 | ADC (Absolute, Y) | Add with Carry from Absolute, Y |
| 7B | TDC | Transfer Direct Page Register to Accumulator |
| 7C | JMP (Absolute Indexed Indirect) | Jump to Address (Absolute Indexed Indirect) |
| 7D | ADC (Absolute, X) | Add with Carry from Absolute, X |
| 7E | ROR (Absolute, X) | Rotate Right (Absolute, X) |
| 7F | ADC (Absolute Long, X) | Add with Carry from Absolute Long, X |
| 81 | STA (Direct Page, X) | Store Accumulator to Direct Page, X |
| 83 | STA (Stack Relative) | Store Accumulator to Stack Relative |
| 84 | STY (Direct Page) | Store Y Register to Direct Page |
| 85 | STA (Direct Page) | Store Accumulator to Direct Page |
| 86 | STX (Direct Page) | Store X Register to Direct Page |
| 88 | DEY | Decrement Y Register |
| 8A | TXA | Transfer X Register to Accumulator |
| 8B | PHB | Push Data Bank Register |
| 8C | STY (Absolute) | Store Y Register to Absolute |
| 8E | STX (Absolute) | Store X Register to Absolute |
| 90 | BCC | Branch if Carry Clear |
| 91 | STA (Indirect, Y) | Store Accumulator to Indirect, Y |
| 92 | STA (Indirect) | Store Accumulator to Indirect |
| 93 | STA (Stack Relative, Y) | Store Accumulator to Stack Relative, Y |
| 94 | STY (Direct Page, X) | Store Y Register to Direct Page, X |
| 95 | STA (Direct Page, X) | Store Accumulator to Direct Page, X |
| 96 | STX (Direct Page, Y) | Store X Register to Direct Page, Y |
| 97 | STA (Indirect Long, Y) | Store Accumulator to Indirect Long, Y |
| 98 | TYA | Transfer Y Register to Accumulator |
| 99 | STA (Absolute, Y) | Store Accumulator to Absolute, Y |
| 9D | STA (Absolute, X) | Store Accumulator to Absolute, X |
| 9E | STZ (Absolute, X) | Store Zero to Absolute, X |
| A0 | LDY (Immediate) | Load Y Register with Immediate |
| A1 | LDA (Direct Page, X) | Load Accumulator from Direct Page, X |
| A3 | LDA (Stack Relative) | Load Accumulator from Stack Relative |
| A4 | LDY (Direct Page) | Load Y Register from Direct Page |
| A6 | LDX (Direct Page) | Load X Register from Direct Page |
| A7 | LDA (Indirect Long) | Load Accumulator from Indirect Long |
| A8 | TAY | Transfer Accumulator to Y Register |
| AB | PLB | Pull Data Bank Register |
| AC | LDY (Absolute) | Load Y Register from Absolute |
| AE | LDX (Absolute) | Load X Register from Absolute |
| AF | LDA (Absolute Long) | Load Accumulator from Absolute Long |
| B0 | BCS | Branch if Carry Set |
| B1 | LDA (Indirect, Y) | Load Accumulator from Indirect, Y |
| B2 | LDA (Indirect) | Load Accumulator from Indirect |
| B3 | LDA (Stack Relative, Y) | Load Accumulator from Stack Relative, Y |
| B5 | LDA (Direct Page, X) | Load Accumulator from Direct Page, X |
| B6 | LDX (Direct Page, Y) | Load X Register from Direct Page, Y |
| B7 | LDA (Indirect Long, Y) | Load Accumulator from Indirect Long, Y |
| B8 | CLV | Clear Overflow Flag |
| B9 | LDA (Absolute, Y) | Load Accumulator from Absolute, Y |
| BA | TSX | Transfer Stack Pointer to X Register |
| BB | TYX | Transfer Y Register to X Register |
| BC | LDY (Absolute, X) | Load Y Register from Absolute, X |
| BD | LDA (Absolute, X) | Load Accumulator from Absolute, X |
| BE | LDX (Absolute, Y) | Load X Register from Absolute, Y |
| BF | LDA (Absolute Long, X) | Load Accumulator from Absolute Long, X |
| C1 | CMP (Direct Page, X) | Compare Accumulator with Direct Page, X |
| C3 | CMP (Stack Relative) | Compare Accumulator with Stack Relative |
| C4 | CPY (Direct Page) | Compare Y Register with Direct Page |
| C5 | CMP (Direct Page) | Compare Accumulator with Direct Page |
| C6 | DEC (Direct Page) | Decrement Memory (Direct Page) |
| C7 | CMP (Indirect Long) | Compare Accumulator with Indirect Long |
| C8 | INY | Increment Y Register |
| CA | DEX | Decrement X Register |
| CB | WAI | Wait for Interrupt |
| CC | CPY (Absolute) | Compare Y Register with Absolute |
| CD | CMP (Absolute) | Compare Accumulator with Absolute |
| CE | DEC (Absolute) | Decrement Memory (Absolute) |
| CF | CMP (Absolute Long) | Compare Accumulator with Absolute Long |
| D1 | CMP (Indirect, Y) | Compare Accumulator with Indirect, Y |
| D2 | CMP (Indirect) | Compare Accumulator with Indirect |
| D3 | CMP (Stack Relative, Y) | Compare Accumulator with Stack Relative, Y |
| D4 | PEI | Push Effective Indirect Address |
| D5 | CMP (Direct Page, X) | Compare Accumulator with Direct Page, X |
| D6 | DEC (Direct Page, X) | Decrement Memory (Direct Page, X) |
| D7 | CMP (Indirect Long, Y) | Compare Accumulator with Indirect Long, Y |
| D8 | CLD | Clear Decimal Mode |
| D9 | CMP (Absolute, Y) | Compare Accumulator with Absolute, Y |
| DA | PHX | Push X Register |
| DB | STP | Stop the Clock |
| DC | JMP (Absolute Indirect Long) | Jump to Address (Absolute Indirect Long) |
| DD | CMP (Absolute, X) | Compare Accumulator with Absolute, X |
| DE | DEC (Absolute, X) | Decrement Memory (Absolute, X) |
| DF | CMP (Absolute Long, X) | Compare Accumulator with Absolute Long, X |
| E1 | SBC (Direct Page, X) | Subtract with Carry from Direct Page, X |
| E3 | SBC (Stack Relative) | Subtract with Carry from Stack Relative |
| E4 | CPX (Direct Page) | Compare X Register with Direct Page |
| E5 | SBC (Direct Page) | Subtract with Carry from Direct Page |
| E6 | INC (Direct Page) | Increment Memory (Direct Page) |
| E7 | SBC (Indirect Long) | Subtract with Carry from Indirect Long |
| E8 | INX | Increment X Register |
| E9 | SBC (Immediate) | Subtract with Carry with Immediate |
| EB | XBA | Exchange B and A Registers |
| EC | CPX (Absolute) | Compare X Register with Absolute |
| ED | SBC (Absolute) | Subtract with Carry from Absolute |
| EE | INC (Absolute) | Increment Memory (Absolute) |
| EF | SBC (Absolute Long) | Subtract with Carry from Absolute Long |
| F1 | SBC (Indirect, Y) | Subtract with Carry from Indirect, Y |
| F2 | SBC (Indirect) | Subtract with Carry from Indirect |
| F3 | SBC (Stack Relative, Y) | Subtract with Carry from Stack Relative, Y |
| F4 | PEA | Push Effective Absolute Address |
| F5 | SBC (Direct Page, X) | Subtract with Carry from Direct Page, X |
| F6 | INC (Direct Page, X) | Increment Memory (Direct Page, X) |
| F7 | SBC (Indirect Long, Y) | Subtract with Carry from Indirect Long, Y |
| F8 | SED | Set Decimal Mode |
| F9 | SBC (Absolute, Y) | Subtract with Carry from Absolute, Y |
| FB | PLX | Pull X Register |
| FD | SBC (Absolute, X) | Subtract with Carry from Absolute, X |
| FE | INC (Absolute, X) | Increment Memory (Absolute, X) |
| FF | SBC (Absolute Long, X) | Subtract with Carry from Absolute Long, X |