| instruction | before | after | note |
|---|---|---|---|
| dup | val2 val1 | val2 val1 val1 | duplicate the top value |
| dup2 | val2 val1 | val2 val1 val2 val1 | |
| dup_x1 | val2 val1 | val1 val2 val1 | |
| dup_x2 | val3 val2 val1 | val1 val3 val2 val1 | |
| dup2_x1 | val3 val2 val1 | val2 val1 val3 val2 val1 | |
| dup2_x2 | val4 val3 val2 val1 | val2 val1 val4 val3 val2 val1 | |
| swap | val2 val1 | val1 val2 | |
| pop | val2 val1 | val2 | |
| pop2 | val3 val2 val1 | val3 |