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[patch] ARM vclt broken

Paul Brook paul@codesourcery.com
Thu Jan 4 04:39:00 GMT 2007 
On Thursday 04 January 2007 04:09, Daniel Jacobowitz wrote:
> On Thu, Jan 04, 2007 at 04:05:36AM +0000, Nick Clifton wrote:
> > Hi Paul,
> >
> > >The ARM NEON vclt and vcle instructions are aliases for vcgt and vcge
> > >respectively.
> >
> > Err, isn't that the other way around ?  Ie vclt is an alias for vcge and
> > vcle is an alias for vcgt ?
>
> Nope - in fact that's how everyone seems to get these particular
> instructions wrong.  "a < b" is "!(a >= b)", but there's an extra
> negation, so you can't use the same instruction for both.  However
> "a < b" is "b > a", so by swapping operands, you can use the same
> instruction.
>
> If I'm remembering Paul's explanation correctly, then binutils
> currently has this reversed and tries to encode "a > b" as "b <= a".

Correct.

Paul
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