function() external payable {
  // Do nothing if we haven't properly set up the delegator to delegate calls
  if (controllerLookupName == 0) {
    return;
  }

  // Get the delegation target contract
  address _target = controller.lookup(controllerLookupName);

  assembly {
    //0x40 is the address where the next free memory slot is stored in Solidity
    let _calldataMemoryOffset := mload(0x40)
    // new "memory end" including padding. The bitwise operations here ensure we get rounded up to the nearest 32 byte boundary
    let _size := and(add(calldatasize, 0x1f), not(0x1f))
    // Update the pointer at 0x40 to point at new free memory location so any theoretical allocation doesn't stomp our memory in this call
    mstore(0x40, add(_calldataMemoryOffset, _size))
    // Copy method signature and parameters of this call into memory
    calldatacopy(_calldataMemoryOffset, 0x0, calldatasize)
    // Call the actual method via delegation
    let _retval := delegatecall(
      gas,
      _target,
      _calldataMemoryOffset,
      calldatasize,
      0,
      0
    )
    switch _retval
    case 0 {
      // 0 == it threw, so we revert
      revert(0, 0)
    }
    default {
      // If the call succeeded return the return data from the delegate call
      let _returndataMemoryOffset := mload(0x40)
      // Update the pointer at 0x40 again to point at new free memory location so any theoretical allocation doesn't stomp our memory in this call
      mstore(0x40, add(_returndataMemoryOffset, returndatasize))
      returndatacopy(_returndataMemoryOffset, 0x0, returndatasize)
      return(_returndataMemoryOffset, returndatasize)
    }
  }
}