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title "Hal Processor Idle"
;++
;
;Copyright (c) 1991 Microsoft Corporation
;
;Module Name:
;
; ixidle.asm
;
;Abstract:
;
;
;Author:
;
;
;Revision History:
;
;--
.386p
.xlist
include hal386.inc
include callconv.inc ; calling convention macros
include i386\kimacro.inc
include mac386.inc
.list
_TEXT$01 SEGMENT DWORD PUBLIC 'CODE'
ASSUME DS:FLAT, ES:FLAT, SS:NOTHING, FS:NOTHING, GS:NOTHING
page ,132
subttl "HalProcessorIdle"
;++
;
; VOID
; HalProcessorIdle(
; VOID
; )
;
; Routine Description:
;
; This function is called when the current processor is idle.
;
; This function is called with interrupts disabled, and the processor
; is idle until it receives an interrupt. The does not need to return
; until an interrupt is received by the current processor.
;
; This is the lowest level of processor idle. It occurs frequently,
; and this function (alone) should not put the processor into a
; power savings mode which requeres large amount of time to enter & exit.
;
; Return Value:
;
;--
cPublicProc _HalProcessorIdle, 0
;
; the following code sequence "sti-halt" puts the processor
; into a Halted state, with interrupts enabled, without processing
; an interrupt before halting. The STI instruction has a delay
; slot such that it does not take effect until after the instruction
; following it - this has the effect of HALTing without allowing
; a possible interrupt and then enabling interrupts while HALTed.
;
;
; On an MP hal we don't stop the processor, since that causes
; the SNOOP to slow down as well
;
sti
ifdef NT_UP
hlt
endif
;
; Now return to the system. If there's still no work, then it
; will call us back to halt again.
;
stdRET _HalProcessorIdle
stdENDP _HalProcessorIdle
_TEXT$01 ends
end
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