In article <Pine.NEB.4.30.0102272206440.11503-100000@crowley.our-flat.net> you write:
>> 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.

Erm, I think that's what -mno-apcs-float is meant to do.  Whether it works
is another matter.

>Would this not permit interoperation between soft-float and hard-float
>code?

It wouldn't quite.  You'd still have to propogate exception flags and trap
enabling between the FPA and the softfloat code.

-- 
Ben Harris                                                   <bjh21@netbsd.org>
Portmaster, NetBSD/arm26               <URL:http://www.netbsd.org/Ports/arm26/>