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Re: Multilib and Linux.


On Tue, 20 Apr 1999, David Miller wrote:

>    Date: Tue, 20 Apr 1999 22:57:59 +0100 (GMT)
>    From: Matthew Kirkwood <weejock@ferret.lmh.ox.ac.uk>
> 
>    On Tue, 20 Apr 1999, David Miller wrote:
> 
>    > I wonder how a Merced userland is going to work if we wish to
>    > allow people to still compile 32-bit x86 binaries, even though
>    > the instruction set is radically different between the two.
> 
>    Merced running i386 binaries is still stricly emulation, I believe,
>    so I'd see that as cross-compilation, rather than multiple ABIs.
> 
> I think it's still more of a gray area than this.  The x86
> instructions will execute natively on the processor, so in this
> light using your analysis we could say that executing 32-bit Sparc
> binaries on UltraSparc cpus is emulation and that compiling such
> 32-bit Sparc binaries would be cross-compilation. :-)

	(Apologies to those already aware of all this :)

	I believe NetBSD/sparc64 and NetBSD/mips64 (as and when it gets
	into gear) do pretty much this to handle 32 bit binaries with a
	compat_netbsd32 option.

	Since they handle other emulations (sunos, solaris, linux, etc)
	all of the relevant the machinery is already in place.

	Emulated binaries have a different syscall table, though they can
	end up using pretty much the same syscalls underneath.

	They also pick up files in '/emul/${emulation}/...' before '/...'.

	I only have 32bit NetBSD systems here, but in the case of
	compat_sunos you populate /emul/sunos/usr/lib with ld.so,
	libc.so.1.9, libdl.so.1.0 and anything else you need and
	everything "Just Works" :)

		David/absolute

 -=-  "I know its not the right thing, and I know its not the good thing"  -=-





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