[rescue] VAXstation questions

Peter Corlett abuse at cabal.org.uk
Thu May 15 05:11:17 CDT 2003

Dave McGuire  <mcguire at neurotica.com> wrote:
> On Wednesday, May 14, 2003, at 07:21 AM, Peter Corlett wrote:
>> Object size tells you nothing, really.
> Object size...the size of the resulting executable...tells you nothing
> about the instruction set compactness of the target architecture?

Sorry, I was sloppy in my usage. What I meant was that object size (which
does relate to instruction density) tells you nothing about the typical
memory usage of an OS running on that architecture.

I'd hazard a guess that VAX Linux (is there such a beast?) would use much
more memory than VAX VMS.

> So...Your examples were Linux binaries...I'm not a Linux person and don't
> know anything about its executable format, but there is the whole
> apple/orange comparison there.

The particular variety of Linux is ELF-based and uses glibc. It's relatively
heavy on resource compared to some simpler Unix-like systems, but hardly in
the Windows or even Red Hat league...

> But, within your two examples, while the M68K is a much more "compiler
> friendly" CISC architecture, I would fully expect GCC to produce better
> code (even though GCC generates fairly decent M68K code) on x86 than M68K
> because the GCC team has been wearing "x86 blinders" for the past several
> years now...targeting the bulk of their optimization efforts at that
> architecture while letting all the modern architectures rot.

I think this is probably correct, although I suspect that PPC is also an
important target these days. I note that gcc3.3 does seem to generate much
better m68k code than earlier versions.

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