| Opcode | Mnemonic | Operands | Description |
|---|---|---|---|
| 0 | Halt | None | Stop program execution |
| 1 | Add | Op1,Op2 | Op1 = Op1 + Op2 |
| 2 | Subtract | Op1,Op2 | Op1 = Op1 – Op2 |
| 3 | Multiply | Op1,Op2 | Op1 = Op1 * Op2 |
| 4 | Divide | Op1,Op2 | Op1 = Op1 / Op2 (integer division) |
| 5 | Move | Op1,Op2 | Op1 = Op2 |
| 6 | Branch | Address | PC = Address |
| 7 | BrOnMinus | Op1,Address | if (Op1 < 0), PC = Address, else PC++ |
| 8 | BrOnPlus | Op1,Address | if (Op1 > 0), PC = Address else PC++ |
| 9 | BrOnZero | Op1,Address | if (Op1 = 0), PC = Address, else PC++ |
| 10 | Push | Op1 | SP++ then Memory[SP] = Op1 |
| 11 | Pop | Op1 | Op1 = Memory[SP], then SP-- |
| 12 | SystemCall | Op1 | Op1 is the System Call Identifier |