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

[Richard Henderson]

> | + {
> | +   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.

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;
  }



r~