[Vm-dev] FFI plugin 64 bit updates (not yet)

David T. Lewis lewis at mail.msen.com
Fri Mar 21 18:54:53 UTC 2008

On Fri, Mar 21, 2008 at 09:56:10AM -0700, John M McIntosh wrote:
> On Mar 21, 2008, at 8:12 AM, David T. Lewis wrote:
> >
> >I have been working on updating FFI for 64 bit hosts (Linux).
> >
> Ah well maybe you can merge the two FFI assembler sets for os-x, the  
> one I created and the one from Ian's unix tree.
> I note the one from the unix tree is incorrect, it does not properly  
> do the boundary alignments so then quicktime FFI calls later fail in  
> vector processing code on
> a memory alignment exception.
> This of course is only triggered if you invoke quicktime via FFI on OS- 
> X.

Actually I am working with the cdecl implementation that Andreas wrote,
in platforms/unix/plugins/SqueakFFIPrims/any-libffi.c. My plan has been
to get this working on 64 bits, then move all the changes back to a 32 bit
Linux and get them working there with the apicall interface (x86-sysv-asm.S),
and then come back to the list to beg for help.

Why that approach? Because I don't know how to write the assembler routine
to set up a stack frame for 64 bit Linux. And that's only one of the reasons
that I warned you to expect some dumb questions ;)

So here comes the first of the dumb questions: Do you have an assembler
implementation that sets up a call stack for a 64 bit system, and that
would work on Linux as well as OS X? I had assumed that the conventions
would be completely different for 32 bit and 64 bit systems, but I did
not even bother to google the topic to find out.


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