On Thu, 25 Jan 2001, NetBSD Bob wrote:

> > > Offhand, can I compile a NetBSD-1.2 kernel on NetBSD-1.5
> > > by unrolling into a separate tree, and not break anything?
> >
> > i dont know if things would work quite right- config has certainly
> > changed betwen 1.3 and 1.4, and probably there some gcc idiosyncracies
> > that will make it barf on the 1.2 stuff..
>
> But, I would expect the config from 1.5 to be backwards compatible
> with 1.2, but, the reverse, touch and go.
>
	We went around a similar loop a month or so ago - there
	have been many changes to the format. You would want to
	compile a 1.2 config on 1.5.

> That was exactly my thought.  It does not have to be all that great a
> compile, but it just has to finish, and link into a completed kernel.
> If there was no great size change, then gcc was doing its job and
> a lot of misc gago has not crept in with gcc.  If it grew by
> say more than 10%, then gcc is throwing in things, because the
> code was the same.

	You might be better of compiling some large application
	such as ghostscript or pine, then compare the final binary
	and sizes of all the .o files generated. Link it statically
	on 1.5 also.

	I'd expect final binary to increase as libc has grown (locale
	support, extra features, etc), but the .o files should be
	pretty much the same. Smaller in -current with Matt's changes
	to gcc :)

		David/absolute		-- www.netbsd.org: No hype required --