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Re: PATCH: New approach to --with-cpu, take 4
On Thu, Aug 01, 2002 at 03:03:10PM -0700, cgd@broadcom.com wrote:
> At Thu, 1 Aug 2002 21:45:40 +0000 (UTC), "Daniel Jacobowitz" wrote:
> > See the earlier discussion with Richard about this. Right now, if you
> > have -mips3 -mips16 on the command line, you won't get -mips3 code :)
> > At least that's what I was told.
> >
> > The comment could use some thinking though.
>
> Ahh, but, to my understanding, there is a difference!
>
> if you say "-mips3 -mips16" you get "mips3"-flavored mips16.
>
> vs. "-mips1 -mips16" in which case you get "mips1"-flavored mips16.
>
> e.g. consider the dsubu vs. subu mips16 instructions (see
> mips16-opc.c).
>
>
> assume your default is -mips1.
>
> if you say -mips1, you want "mips1-flavored" mips16.
>
> if you say "-mips3 -mips16", then you do _not_ want the default of
> -mips1 to be applied.
>
>
> i think to get this right you need to check all of the -mipsN flags
> independently.
I agree that that would be logical. But check what the compiler actually
_does_.
The check (to match compiler behavior, again) should really be "the
last -mips option is -mips16". That's why the comment said it wasn't
quite right.
--
Daniel Jacobowitz Carnegie Mellon University
MontaVista Software Debian GNU/Linux Developer