Front page | perl.perl6.internals |
Postings from October 2002
Jason Gloudon wrote:
> ... By default both compilers align stack variables at their natural
> alignment, so PMC pointers would normally fall on 4 byte boundaries.
>
> However, it is also possible that someone might save a PMC pointer to an
> unaligned address on the stack (I can't imagine why). We could always say
> "don't do that!" for performance reasons.
So, this "someone" are we (parrot itself) + language extensions (PXS)
which have to be compiled with the same compiler options, parrot is
compiled with.
Using packed structures with PMCs/Buffers inside is a strict "don't do
that!".
Now, given above rules and _if_ each machine parrot is running on,
aligns a (PMC *)p at sizeof(PMC*) on the stack, we can safely define our
{lo,hi}_var_ptrs as PMC** and just iterate the $stack_p++.
If there are machines/compilers out there, that don't follow above rule,
we put some #ifdefs in trace_system_stack for these.
This part is too time critical to program for the LCD.
leo
Thread Previous
|
Thread Next