On Thursday 30 November 2006 23:32, Andrew Morton wrote:
> On Thu, 30 Nov 2006 23:22:00 +0100
> Andi Kleen <[EMAIL PROTECTED]> wrote:
>
> > >
> > > static __inline__ int __test_and_set_bit(int nr, volatile void * addr)
> > > {
> > > int oldbit;
> > >
> > > __asm__(
> > > "btsl %2,%1\n\tsbbl %0,%0"
> > > :"=r" (oldbit),"+m" (ADDR)
> > > :"dIr" (nr));
> > > return oldbit;
> > > }
> > >
> > > explodes with gcc-3.4.4.
> >
> > Known issue. The new form is correct and needed, but the old gcc doesn't
> > accept
> > it. I haven't gotten a form that is both and correct and works on the old
> > compiler
> > out of the gcc hackers I asked.
>
> Oh, thanks.
>
> What does "d" do, btw? My gcc info page only covers "x86" and says only "`d'
> register"
Hmm, normally edx (aka Extended D register eXtended :) or rdx
But you're right it doesn't make sense here because 'd' is already included in
'r'.
Probably should be dropped.
>
> (And, more importantly, where is the best description of gcc asm constraints?)
Either info pages or gcc source. There was also a web page somewhere with a
tutorial,
but i don't think it was a full reference.
-Andi
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