On Saturday, 20 September 2014 at 18:18:05 UTC, Walter Bright
wrote:
Please show me the inc/dec optimized x86 code.
There's no optimization of the inc/dec, you use regular inc/dec
within a larger xbegin/xend block.
You amortize the cost over all the lock-prefixed instructions you
would otherwise have executed in that block. There is no locking,
there is a transaction instead. Only if the transaction fails do
you execute the locking fallback code.
Suppose I pass a pointer to:
void foo(T* p);
How do I do dataflow?
You mean a separate compilation unit that the compiler don't have
access to? You don't, obviously.
The question was about mixing RC'd and non-RC'd objects.
Well, if you are talking about negative offset for ref counts,
then people do it. E.g. there are examples of systems that
provide C-compatible strings with length at offset -4 and ref
count at -8.
If you need to distinguish you can either use address-space info
or keep a negative int in the non-RC'd object.
