On Jul 5, 1:09 pm, Pedram <pm567...@gmail.com> wrote: > Thanks for reply, > Sorry I can't explain too clear! I'm not English ;)
That's shocking. Everyone should be English. :-) > But I want to understand the implementation of long int object in > Python. How Python allocates memory and how it implements operations > for this object? I'd pick one operation (e.g., addition), and trace through the relevant functions in longobject.c. Look at the long_as_number table to see where to get started. In the case of addition, that table shows that the nb_add slot is given by long_add. long_add does any necessary type conversions (CONVERT_BINOP) and then calls either x_sub or x_add to do the real work. x_add calls _PyLong_New to allocate space for a new PyLongObject, then does the usual digit-by-digit-with-carry addition. Finally, it normalizes the result (removes any unnecessary zeros) and returns. As far as memory allocation goes: almost all operations call _PyLong_New at some point. (Except in py3k, where it's a bit more complicated because small integers are cached.) If you have more specific questions I'll have a go at answering them. Mark -- http://mail.python.org/mailman/listinfo/python-list
