A virtual stack-based computer — push, pop, compute
| Op | Description |
|---|---|
| PUSH n | Push value n onto stack |
| POP | Remove top element |
| ADD | Pop two, push sum |
| SUB | Pop two, push (second - top) |
| MUL | Pop two, push product |
| DIV | Pop two, push (second / top) |
| DUP | Duplicate top element |
| SWAP | Swap top two elements |
| OVER | Copy second element to top |
| ROT | Rotate top three (a b c → b c a) |
| Output top without popping | |
| CLEAR | Clear entire stack |