RFC & patch: Rework MIPS command-line handling

[cgd@broadcom.com]

At Mon, 15 Jul 2002 18:22:39 +0000 (UTC), "Thiemo Seufer" wrote:
> > If the CPU aliases for the ISA aren't the minimal set for the ISA,
> > that sounds like a very good reason for somebody to go off and do
> > something better, i.e., create "actual ISA" definitions.
> > 
> > I believe that at least mipsisa32 and mipsisa64 -- ISAs which are
> > really ISAs in the code, rather than being CPUs -- are correct.  8-)
> 
> Are the CP0 and TLB instructions really covered by the ISA there?

I have never actually seen a complete and canonical MIPS ISA
definition pre-dating MIPS32/MIPS64.


> > And, in that view, -mabi=foo probably shouldn't change the ISA (and
> > definitely shouldn't downgrade it).
> 
> My idea is to get sane defaults from the ABI definition.
> 
> 	gcc -mabi=FOO
> 
> should create ABI conformant code, while
> 
> 	gcc -mabi=FOO -march=BAR
> 
> loosens the ABI restrictions in order to allow BAR opcodes.
> AFAICS this fulfils the "least surprise" priciple for hosted
> systems, and the embedded world can live with it, too.

Since I'm a bit behind on this discussion, I'll just have to risk
reiterating points already made in response to your msg by others:

That may be appropriate for "mips-linux" tools.

It's probably not appropriate for "mipsisa32-linux" tools, since
somebody configured the tools naming a specific architecture that they
wanted to build for by default.



cgd