Load call data into memory.

def calldataload(computation: BaseComputation) -> None:
    """
    Load call data into memory.
    """
    start_position = computation.stack_pop(type_hint=constants.UINT256)

    value = computation.msg.data_as_bytes[start_position:start_position + 32]
    padded_value = value.ljust(32, b'\x00')
    normalized_value = padded_value.lstrip(b'\x00')

    computation.stack_push(normalized_value)