> > Nope, the compiler doesn't use them.  But -mhard-float changes the calling
> > convention for floating point functions.  Code compiled -mhard-float
> > expects a floating point result to be returned in a floating point
> > register; code compiled -msoft-float expects it in r0(+r1 for doubles).
> > So the problem is that you cannot link the system libraries into your
> > program if you are expecting floating point results back.
> 
> Just out of academic interest how feasible would it be/what would be the
> major downside to having a gcc option that passed FP arguments on the
> stack/in integer registers for function calls, but used the FPA otherwise.
> Would this not permit interoperation between soft-float and hard-float
> code?
> 

Not particularly.

> Cheers,
> 
> David.
> 
> PS - Just for clarity: I'm not actually suggesting we do this, I'm just
> interested in understanding the issues.

I might even do it when working on the VFP stuff, since we will want a 
similar option there.

R.