[gobolinux-users] Re: AMD64 support?

[Dave Dodge]

On Thu, Jun 15, 2006 at 01:59:38AM -0300, teique wrote:
> Carlo Calica wrote:
> >But a supported binary package store would solve the problem of
> >needing 32bit userland too.
> I am thinking on recompiling absolutely everything in 64 bits to run 
> into my Athlon 64, every package..

One problem you can still run into is with commercial software that is
available for Linux as a native 32-bit executable.

> The point is, running 32bit applications at same time of 64bit will 
> cause any trouble?

It works fine if you have suitable libraries.

> or the problem is loading 32bit libs into 64bits apps (well that sounds 
> messy for sure ^^).

I don't think you can mix and match 32-bit and 64-bit components in
the same application at all.  For example a 32-bit library is going to
expect pointers and long integers to be 32 bits, which is going to
affect calling conventions, array sizes and offsets, structure layout
and padding, etc.  As a more fundamental problem, suppose your
application has a string it needs to pass to a 32-bit function, but
the string's address is high in the address space and cannot be
expressed with a 32-bit pointer.

> > The few real needs (maybe wine) could be handled as a chroot.

I've used Ubuntu's amd64 load, which is pretty much entirely native
64-bit.  They have an optional set of 32-bit compatibility libraries
which get dropped into (I think) /usr/lib32.  With a 32-bit libc and
libSDL, I've been able to run Quake4 on the machine without a chroot.

I think they're lacking a 32-bit toolchain on amd64, though.  If you
need to build your own 32-bit apps or libraries, you probably have to
set up a chroot and/or cross-compiler yourself.

I haven't tried using Wine on the system, so I don't know how they
deal with that.

                                                  -Dave Dodge