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Re: initializing wider-than-pointers
- From: DJ Delorie <dj at redhat dot com>
- To: wilson at specifixinc dot com
- Cc: gcc at gcc dot gnu dot org
- Date: Fri, 1 Jul 2005 21:27:48 -0400
- Subject: Re: initializing wider-than-pointers
- References: <200506300343.j5U3hmvU006826@greed.delorie.com> <42C5EBA3.4050808@specifixinc.com>
> Trying to fake two kinds of pointers when we only have one doesn't seem
> wise to me.
>
> A possible solution is to use function descriptors.
Both m32c (my local copy at least) and xstormy use 16 bit thunks to
reference the address of a function outside the first 64k of address
space.
In this case, it isn't good enough.
The particular case that *needs* a wider pointer is setting up
the reset vectors in ROM:
long rvec = (long)&start __attribute__((section(".resetvect")));
At the point where you need this address, you haven't had a chance to
copy the RAM into the lower 64k, so a thunk won't help. (yes,
assembler is one solution, but that doesn't stop the users from
complaining ;).
Note that my complaint about the lack of endian support in that code
still stands ;-)