Re: [Qemu-devel] [PATCH 01/15] atomic: introduce atomic operations

[Peter Maydell]

On 8 August 2012 07:25, Liu Ping Fan <address@hidden> wrote:
> +static inline void atomic_sub(int i, Atomic *v)
> +{
> +    asm volatile("lock; subl %1,%0"
> +             : "+m" (v->counter)
> +             : "ir" (i));
> +}

NAK. We don't want random inline assembly implementations of locking
primitives in QEMU, they are way too hard to keep working with all the
possible host architectures we support. I spent some time a while back
getting rid of the (variously busted) versions we had previously.

If you absolutely must use atomic ops, use the gcc builtins. For
preference, stick to higher level and less error-prone abstractions.

-- PMM