> ## Documentation Index
> Fetch the complete documentation index at: https://voltaire.tevm.sh/llms.txt
> Use this file to discover all available pages before exploring further.

# isSwap()

> Check if opcode is SWAP1-SWAP16

<Card title="Try it Live" icon="play" href="https://playground.tevm.sh?example=primitives/opcode.ts">
  Run Opcode examples in the interactive playground
</Card>

## Opcode.isSwap()

Check if opcode is SWAP1-SWAP16.

<Tabs>
  <Tab title="Functional API">
    ```typescript theme={null}
    import { isSwap, SWAP1, SWAP16 } from 'tevm/Opcode'

    isSwap(SWAP1)   // true
    isSwap(SWAP16)  // true
    ```
  </Tab>
</Tabs>

## Parameters

* `opcode: BrandedOpcode` - Opcode to check

## Returns

`boolean` - True if SWAP1-SWAP16 (0x90-0x9F)

## SWAP Operations

Exchange top with item at depth 1-16:

* **SWAP1** (0x90): Swap top with 2nd
* **SWAP2** (0x91): Swap top with 3rd
* **SWAP16** (0x9F): Swap top with 17th

## Related

* [swapPosition()](/primitives/opcode/swap-position) - Get SWAP stack position