# Stack Relocators

<figure><img src="/files/aXh2x1q80A1g5onVYDDn" alt=""><figcaption></figcaption></figure>

Relocators **move items to new positions** without creating copies or removing data. They're essential for **rearranging values** to meet the **input requirements** of other opcodes.

#### OP\_SWAP

The **most basic relocator** exchanges the **top two items**:

| Word      | Input | Output | Description             |
| --------- | ----- | ------ | ----------------------- |
| `OP_SWAP` | x1 x2 | x2 x1  | Swaps the top two items |

**Example:** Arithmetic operations like subtraction are **order-sensitive**. If your stack has values in the **wrong order**, `OP_SWAP` fixes it:

// Want to compute: x1 - x2 // Stack has: x2 x1 x2 x1 OP\_SWAP OP\_SUB // Result: x1 - x2

#### OP\_ROT

`OP_ROT` (rotate) moves the **third item to the top**, shifting the **top two items down**:

| Word     | Input    | Output   | Description                  |
| -------- | -------- | -------- | ---------------------------- |
| `OP_ROT` | x1 x2 x3 | x2 x3 x1 | Rotates top three items left |

**Use case:** Bringing a buried value to the top when you need it for the next operation.

#### OP\_2SWAP and OP\_2ROT

These operate on pairs of values:

| Word       | Input             | Output            | Description                                |
| ---------- | ----------------- | ----------------- | ------------------------------------------ |
| `OP_2SWAP` | x1 x2 x3 x4       | x3 x4 x1 x2       | Swaps the top two pairs                    |
| `OP_2ROT`  | x1 x2 x3 x4 x5 x6 | x3 x4 x5 x6 x1 x2 | Moves the fifth and sixth items to the top |

#### OP\_ROLL

For **maximum control**, `OP_ROLL` moves an item from **any depth to the top** (removing it from its original position):

| Word      | Input                | Output          | Description                            |
| --------- | -------------------- | --------------- | -------------------------------------- |
| `OP_ROLL` | xn ... x2 x1 x0 \<n> | ... x2 x1 x0 xn | Moves item n positions back to the top |

**Key distinction:** Unlike `OP_PICK` which **copies**, `OP_ROLL` **moves**—the original position becomes empty as items shift.


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