18 Jan
2008
18 Jan
'08
11:23 p.m.
On Jan 18, 2008 11:57 PM, Andrey Tcherepanov <moyt63c02@sneakemail.com> wrote:
Well, according to http://en.wikipedia.org/wiki/X86-64#Virtual_address_space_details it might be dangerous to rely on the fact that top 16 bits are not currently used.
You need only to rely on it on older machines that do not have DCAS. Microsoft has a lock free list that chooses at runtime whether to use plain CAS with 48 ptr + 16 bit ABA counter (actually it is probably something like 44/20 by relying on minimum alignment), or DCAS on more recent machines. -- gpd