[PATCH] Add BeOS support for libstdc++-v3

[Daniel Berlin]

On 22 Nov 2000, Gabriel Dos_Reis wrote:

> Richard Henderson <rth@redhat.com> writes:
> 
> | > | + {
> | > | +   unsigned long retval;
> | > | +   long int readval;
> | > | +   __asm__ ("lock");
> | > | +   retval = *p;
> | > | +
> | 
> | This is completely bogus.
> | 
> | One, you don't know for certain what instruction is going to
> | follow the lock.  Two, the lock prefix is only applicable to
> | specific instructions and movl isn't one of them.
> | 
> | > | +   __asm__ __volatile__ ("lock; xchgl %3, %1; sete %0"
> | > | +                         : "=q" (ret), "=m" (*p), "=a" (readval)
> | > | +                         : "r" (newval), "m" (*p));
> | 
> | Three, this does not even pretend to implement an atomic swap.
> | Since xchgl does not set flags, this puts garbage into your
> | return value.  In fact, since "ret" is not even defined, I can't
> | imagine that this even compiles.
> 
> Aha, I trusted Daniel when he said things went well for him.  Thanks
> for the spotting.

Yeah, it appears I screwed up the submit, and submitted a patch that was 
one revision two early. Which is why it works for me.
I ran multiple threads modifying strings and allocating things, with no 
problem.
 > 
> | Four, this is hardly BeOS specific.  If code like this is to
> | be included at all (instead of using atomicity.h), then it 
> | should be ifdef __i386__ and written like so:
> | 
> |   inline unsigned long _Atomic_swap(unsigned long *__p, unsigned long q)
> |   {
> |     __asm__ __volatile__ ("lock; xchgl %0,%1"
> | 			  : "=r"(q), "=m"(*__p)
> | 			  : "m"(*__p), "0"(q));
> |     return q;
> |   }
> 
> Daniel, could rework this part?


Already did, i'll be resubmitting in a moment.
> 
> -- Gaby
>