@Override
  public Operation.OperationResult executeFixedCostOperation(
      final MessageFrame frame, final EVM evm) {
    Code code = frame.getCode();
    if (code.getEofVersion() == 0) {
      return InvalidOperation.INVALID_RESULT;
    }
    int pc = frame.getPC();
    int index = code.readU8(pc + 1);

    final Bytes tmp = frame.getStackItem(0);
    frame.setStackItem(0, frame.getStackItem(index + 1));
    frame.setStackItem(index + 1, tmp);
    frame.setPC(pc + 1);

    return swapSuccess;
  }
Instantiates a new SwapN operation.

@param gasCalculator the gas calculator
evm/src/main/java/org/hyperledger/besu/evm/operation/SwapNOperation.java