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Re: two PPC gcc issues in 2.95.3 ->
On Mon, Jun 23, 2003 at 11:11:12AM -0500, Mark Douglas wrote:
> two questions:
>
> 1) I have heard from a 2.95.3 PPC gcc user that there exists some sort of
> relative addressing mode limitation. It's supposedly called "REL24". Have you
> heard of it? has this been resolved with later releases of the ppc gnu
> compiler?
REL24 means pc-relative calls and jumps must be within 2**24 bytes. This is
due to the instruction layout. You can direct the compiler to call functions
through a pointer with either the longcall attribute, or with the -mlongcall
switch which affects all function calls. You might check whether newer
releases of the linker will insert some code that is linked near the call, and
then loads up the long address and jumps to it.
> 2) are there any issues in C++ using "thunk" (sp?) with virtual functions?
> (PPC gcc of course) is anyone aware of this?
I recall fixing some problems with thunks many years ago. I don't recall the
details or the revision it was fixed in.
--
Michael Meissner
email: gnu@the-meissners.org
http://www.the-meissners.org