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Re: Enable 32-bit Alignment
On Wed, Jul 04, 2007 at 04:20:29PM -0500, Menezes, Evandro wrote:
> HJ,
>
> > > Anyways, I wasn't able to find good information on older
> > processors (before Ppro), so I'd rather leave them as is.
> >
> > The old processors should take
> >
> > N x 66 90
> >
> > They may not be the best, but should run fine.
>
> On some of our 486 and 586-class embedded processors each prefix beyond 2 takes and extra cycle to decode.
>
> Everything else seems fine at first glance (I ask my colleagues to check it further), but I'd rather keep the oldies as is.
>
People who care about performance on those processors should pass
proper -mtune= to assembler. BTW, I don't think you will get
decent performace on those processors with default gcc optimization.
I don't want to penalize majority of current x86 processors by
default.
Maybe gcc should pass -mtune= to assembler if assembler supports it.
H.J.