Rewritten the following global utility constants:
`umax` returns max number, restricted to unsigned.
`smax` returns max signed number, restricted to integrals.
`smin` returns min signed number, restricted to signed.
`amin` returns smin or zero, less restricted.
`amax` returns smax or umax, less restricted.
Fix operators == and <=> for synthesized rel-ops.
Please, stop pretending...
You need these templates for generic code.
In other words, in another templates.
Stop increasing compilation time for no reason.
Add atomic_t<>::observe() (relaxed load)
Add atomic_fence_XXX() (barrier functions)
Get rid of MFENCE instruction, replace with no-op LOCK OR on stack.
Remove <atomic> dependence from stdafx.h and relevant headers.
Notification with "phantom value" could be useful in theory.
As an alternative way of sending signal from the notifier.
But current implementation is just useless.
Also fixed slow_mutex (not used anywhere).
Instead of plain waiting while equal to some value,
it can be something like less, or greater, or even bitcount.
But it's a draft and untested. Hopefully doesn't break anything.
Hashtable increased and flatten, tree-alike extensions removed.
Some things simplified, so it can actually decrease perf a bit.
But most platforms shouldn't be affected.
Removed limit of 56 waiters per pointer.
Real limit now is about 65535.
Arbitrary maximum set to 8, but really we need 2, maybe 3.
Added atomic_wait::list object for multi-waiting.
Added atomic_wait::get_unique_tsc just in case.
Only compare masks for overlap for second overload (with mask provided).
Explicit "new value" can be provided in new 3-arg overloads.
Also rename atomic_storage_futex -> atomic_wait_engine.
Reduced static memory amount for waitable atomics.
Allow notifier to skip notifications if wait/notify masks don't overlap.
Improve raw_notify to wake up the thread by its id, add thread_id arg.
Add optional mask argument to notify_one() and notify_all().
Remove vm::reservation_lock from it.
Use lock bits to prevent memory clobbering in GETLLAR.
Improve u128 for MSVC since it's used for bitlocking.
Improve 128 bit atomics for the same reason.
Improve vm::reservation_op and friends.
