On Jul 23, 12:08 pm, "Martin v. Löwis" <[EMAIL PROTECTED]> wrote: > >> Oh. How is the stack represented? > > > As usual, as successive locations in memory. > > I have the impression that CPython uses the same stack C does. > > Actually, it doesn't (at least not for the evaluation stack). > > In CPython, when a Python function starts, the maximum depth of the > evaluation stack is known, but it depends on the specific function > (of course). So Python needs to allocate an array for the evaluation > stack with known size, but can't do so on the C stack (at least not > portably), since you can't allocate dynamically-sized array as > a local variable in C. > > So instead, pymalloc is used to allocate the evaluation stack, and > it is part of the frame object (so the entire frame object is allocated > in one chunk, and then split up into local variables and evaluation > stack. > > > While conceptually, CPython may put objects on the stack, I am pretty > > sure it actually stacks references (C pointers) to objects in heap memory. > > Correct. > > >> Does it keep track of which stack > >> positions (TOS, TOS1, etc.) are in what registers? > > > I am sure they are not in registers, just normal memory. > > Correct. As discussed above, they are located on the heap (making > Python's frame stack a spaghetti stack). > > Regards, > Martin
Martin, I am curious and pursuing it as an independent project. I'd like to write a specialized function to allocate memory from an memory-mapped file instead of the heap. On Windows, to use CreateFileMapping and MapViewOfFile. The companion function, premalloc, would re-open an existing Python object from a handle. (It would need a name or index - > offset look-up.) svn.python.org is down, so I can't tell if Python already implements its own memory management, and if so how that would extrapolate to a byte-array allocated specifically. -- http://mail.python.org/mailman/listinfo/python-list
