# ins => { "in1", "in2" }, # optional, creates n_op_in1, ... consts
# mode => "mode_Iu", # optional, predefines the mode
# emit => "emit code with templates", # optional for virtual nodes
-# attr => "attitional attribute arguments for constructor", # optional
+# attr => "additional attribute arguments for constructor", # optional
# init_attr => "emit attribute initialization template", # optional
# rd_constructor => "c source code which constructs an ir_node", # optional
# hash_func => "name of the hash function for this operation", # optional, get the default hash function else