> ## 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.

# CODECOPY (0x39)

> Copy executing code to memory

<Warning>
  **This page is a placeholder.** All examples on this page are currently AI-generated and are not correct. This documentation will be completed in the future with accurate, tested examples.
</Warning>

## Overview

**Opcode:** `0x39`
**Introduced:** Frontier (EVM genesis)

CODECOPY copies a specified range of the currently executing code to memory.

## Specification

**Stack Input:**

```
destOffset (memory offset)
offset (code offset)
length (bytes to copy)
```

**Stack Output:**

```
[]
```

**Gas Cost:** 3 + memory expansion + (length / 32) \* 3 (rounded up)

## Behavior

Copies `length` bytes from executing code at `offset` to memory at `destOffset`. Zero-pads if code bounds exceeded.

## Examples

### Copy Runtime Code

```solidity theme={null}
function getRuntimeCode() public pure returns (bytes memory code) {
    assembly {
        let size := codesize()
        code := mload(0x40)
        mstore(code, size)
        codecopy(add(code, 0x20), 0, size)
        mstore(0x40, add(add(code, 0x20), size))
    }
}
```

### CREATE2 Factory

```solidity theme={null}
function deploy() public returns (address) {
    bytes memory code;
    assembly {
        let size := codesize()
        code := mload(0x40)
        codecopy(add(code, 0x20), 0, size)
    }
    // Use code for CREATE2
}
```

## Gas Cost

**Base:** 3 gas
**Memory expansion:** Variable
**Copy cost:** 3 gas per 32-byte word

## Implementation

<Tabs>
  <Tab title="TypeScript">
    ```typescript theme={null}
    export function codecopy(frame: FrameType): EvmError | null {
      // Pop destOffset, offset, length
      // Calculate gas (base + memory + copy cost)
      // Copy bytecode to memory
      // See full implementation in codebase

      frame.pc += 1;
      return null;
    }
    ```
  </Tab>
</Tabs>

## References

* [Yellow Paper](https://ethereum.github.io/yellowpaper/paper.pdf) - Section 9.1
* [EVM Codes - CODECOPY](https://www.evm.codes/#39)