CODESIZE (0x38)

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Overview

Opcode: 0x38 Introduced: Frontier (EVM genesis) CODESIZE pushes the byte length of the currently executing code onto the stack.

Specification

Stack Input:

[]

Stack Output:

size (uint256, in bytes)

Gas Cost: 2 (GasQuickStep) Operation:

stack.push(code.length)

Behavior

Returns the size of the currently executing bytecode, including deployed code and constructor code.

Examples

Basic Usage

function getCodeSize() public pure returns (uint256 size) {
    assembly {
        size := codesize()
    }
}

Code Copying

function copyOwnCode() public pure returns (bytes memory code) {
    assembly {
        let size := codesize()
        code := mload(0x40) // Free memory pointer
        mstore(code, size)
        codecopy(add(code, 0x20), 0, size)
        mstore(0x40, add(add(code, 0x20), size))
    }
}

Gas Cost

Cost: 2 gas (GasQuickStep)

Common Usage

Constructor Detection

During contract construction, CODESIZE includes constructor code. After deployment, only runtime code.

Implementation

TypeScript

export function codesize(frame: FrameType): EvmError | null {
  const gasErr = consumeGas(frame, 2n);
  if (gasErr) return gasErr;

  const pushErr = pushStack(frame, BigInt(frame.bytecode.length));
  if (pushErr) return pushErr;

  frame.pc += 1;
  return null;
}

References

Yellow Paper - Section 9.1
EVM Codes - CODESIZE

CALLDATACOPY (0x37)CODECOPY (0x39)

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Overview

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Examples

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Gas Cost

Common Usage

Constructor Detection

Implementation

References

​Overview

​Specification

​Behavior

​Examples

​Basic Usage

​Code Copying

​Gas Cost

​Common Usage

​Constructor Detection

​Implementation

​References

Overview

Specification

Behavior

Examples

Basic Usage

Code Copying

Gas Cost

Common Usage

Constructor Detection

Implementation

References