Advanced Configuration and Power Interface Specification

Processor Configuration and Control
Reg = SelectedLocalState(CurrentProcessor).EntryMethod
WCWL = SelectedLocalState(CurrentProcessor).WCWL
MR = SelectedLocalState(CurrentProcessor).MR
for level = Parent(CurrentProcessor) to system
LocalState = SelectedLocalState(level)
If LocalState == Run
break
EM = LocalState.EntryMethod
WCWL = WCWL+ LocalState.WCWL
MR = LocalState.MR
If IsInteger(EM)
Reg.Addr = Reg.Addr+ZeroExtend(EM)
Else
// Entry method here overrides any previous method
Reg = EM
CompositeState.EntryMethod = Reg
CompositeState.WCWL=WCWL
CompositeState.MR=MR
In OS Initiated mode it is also necessary for the OSPM to tell the platform on which hierarchy level the
calling processor is the last to go idle and request a power state. To do this, the algorithm above is modified
as follows:
Reg = SelectedLocalState(CurrentProcessor).EntryMethod
WCWL = SelectedLocalState(CurrentProcessor).WCWL
MR = SelectedLocalState(CurrentProcessor).MR
RegDecided = False
// Retrieve Level Index from Processor’s _LPI object
LastLevel = GetLevelIDOfLevel(CurrentProcessor)
for level = Parent(CurrentProcessor) to system
LocalState = SelectedLocalState(level)
If LocalState == Run
break
EM = LocalState.EntryMethod
WCWL = WCWL+ LocalState.WCWL
EM = LocalState.EntryMethod
If IsInteger(EM)
Reg.Addr = Reg.Addr+ZeroExtend(EM)
Else
// Entry method is register
Reg = EM
If IsProcessorLastInLevel(CurrentProcessor,level)
// If calling processor is last one to go idle in
// current level, retrieve Level Index from
// the container’s _LPI object
LastLevel = GetLevelIDOfLevel(level)
Reg.Addr = Reg.Addr+LastLevel
CompositeState.EntryMethod = Reg
CompositeState.WCWL=WCWL
CompositeState.MR=MR
In a platform coordinated system, it is possible for an LPI belonging to a hierarchy node above the
processor level to use an integer value of zero as its entry method. This results in the entry command
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