# KOS_OP_JUMP_FALSE
- **Style**: LABEL. Arg = target pc (post-compile).
- **Stack**: Pops one value; if false, jump to `arg`; else advance PC.
- **Invariants**: Jump locality for target.
- **Compiler form:** Pre-compile arg = string label; post-compile arg = pc.

**Example:** Jump if TOS is false (e.g. "else" branch). Pool: 0 = False, 1 = 42, 2 = 0.

| index | opcode     | arg | arg view | comment |
|------:|------------|-----|----------|---------|
| 0     | CONST      | 0   | 0 (False)| stack: [..., False] |
| 1     | JUMP_FALSE | 4   | 4 (-> 4) | pop TOS; if false → pc=4 |
| 2     | CONST      | 1   | 1 (42)   | stack: [..., 42] |
| 3     | JUMP       | 5   | 5 (-> 5) | |
| 4     | LABEL      | --   | --        | else |
| 5     | CONST      | 2   | 2 (0)    | stack: [..., 0] |
| 6     | RETURN     | 1   | 1        | |