[PATCH] S/390: DFP support 1/4: Add z9-ec option

Ulrich Weigand uweigand@de.ibm.com
Mon Mar 26 16:32:00 GMT 2007

Andreas Krebbel wrote:

> > I think there was a little misunderstanding here.  What you describe is 
> > exactly how things work for PowerPC as well.  I think what Janis was
> > trying to say, is that we should probably come up with a common set
> > of options between us.
> > 
> > So -mdfp or -mhard-dfp (whichever we choose) means we generate hw
> > DFP instructions and -mno-dfp or -msoft-dfp (again, whichever one
> > we choose) means no hw DFP instructions.
> > 
> > I'm torn between the options.  I slightly prefer our -mdfp over your
> > -mhard-dfp, but your -msoft-dfp seems to make more sense than -mno-dfp,
> > which might cause people to assume we're disabling DFP all together.

That's why I don't really like -mno-dfp.  And since the -mdfp/-mhard-dfp
would be on by default on the machines that support it anyway, the
-mno-dfp/-msoft-dfp is actually what users are more likely to have to
use ...

> I agree that it would be helpful to have the same dfp switches for all
> supporting platforms.
> As you probably expected I tend to stuck with the options I've introduced
> with the dfp S/390 patches :)  I simply think that -msoft-dfp/-mhard-dfp
> is a bit clearer.  Another - but not that important - point is that these 
> options are already implemented.
> But if there is a majority of people voting for -mdfp/-mno-dfp I wouldn't 
> stand in the way and post a patch changing the S/390 options as well.
> Regarding the S/390 back end of course Ulrich has the final say.

I'd *prefer* -msoft-dfp, but in the end it doesn't really matter 
all that much ...


  Dr. Ulrich Weigand
  GNU Toolchain for Linux on System z and Cell BE

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