Front page | perl.perl6.internals |
Postings from October 2002
At 3:27 PM +0100 10/29/02, Leopold Toetsch wrote:
>Jason Gloudon wrote:
>
>>On Tue, Oct 29, 2002 at 02:40:14PM +0100, Leopold Toetsch wrote:
>>
>>>>+ cur_var_ptr = (size_t)((ptrdiff_t)cur_var_ptr +
>>>>PARROT_PTR_ALIGNMENT)
>>>>
>>>When PARROT_PTR_ALIGNMENT is not 1, that much pointers -1 are
>>>skipped during stack scanning by incrementing cur_var_ptr by
>>>sizeof(size_t) * PARROT_PTR_ALIGNMENT bytes.
>>>
>>
>>ptrdiff_t is not a pointer type, so cur_var_ptr + PARROT_PTR_ALIGNMENT skips
>>exactly PARROT_PTR_ALIGNMENT bytes. You may not be matching ( )'s
>>quite right.
>
>
>Brr, yes. I checked with gdb. cur_var_ptr is incremented by
>PARROT_PTR_ALIGNMENT _bytes_ i.e. by 1 byte on i386. Can we really
>have e.g. odd aligned PMCs on stack? I don't think so. Or am I still
>missing something?
There was some indication back when this was first implemented that
the i386, at least when running windows, could have odd-aligned
pointers in stack-allocated data. Nobody was 100% sure, but better
safe than not, at least until someone can say definitively that we're
being too cautious.
--
Dan
--------------------------------------"it's like this"-------------------
Dan Sugalski even samurai
dan@sidhe.org have teddy bears and even
teddy bears get drunk
Thread Previous
|
Thread Next