sync
Instruction Type M
Format
(qp) sync.i
Description
sync.i ensures that when previously initiated Flush Cache (fc) operations issued by the local processor become visible to local data memory references, prior Flush Cache operations are also observed by the local processor instruction fetch stream. sync.i also ensures that at the time previously initiated Flush Cache (fc) operations are observed on a remote processor by data memory references they are also observed by instruction memory references on the remote processor. sync.i is ordered with respect to all cache flush operations as observed by another processor. A sync.i and a previous fc must be in separate instruction groups. If semantically required, the programmer must explicitly insert ordered data references (acquire, release, or fence type) to appropriately constrain sync.i (and hence fc) visibility to the data stream on other processors.
sync.i is used to maintain an ordering relationship between instruction and data caches on local and remote processors. An instruction serialize operation can be used to ensure synchronization initiated by sync.i on the local processor has been observed by a given point in program execution.
An example of self-modifying code (local processor):
st [L1] = data //store into local instruction stream
fc L1 //flush stale datum from instruction/data cache
;; //require instruction boundary between fc and sync.i
sync.i //ensure local/remote data/inst caches are synchronized
;;
srlz.i //ensure sync has been observed by the local processor,
;; //ensure subsequent instructions observe modified
//memory
L1: target //instruction modified
For details, see Volume 3: Instruction Set Reference of the Intel(R) Itanium(R) Architecture Software Developer's Manual . For the latest updates on the instruction set information, go to the web site.