WindowsXP/Source/XPSP1/NT/base/ntos/ex/i386/tickcnt.asm
2024-08-03 16:30:48 +02:00

72 lines
1.2 KiB
NASM

title "NtGetTickCount"
;++
;
; Copyright (c) 1989 Microsoft Corporation
;
; Module Name:
;
; tickcnt.asm
;
; Abstract:
;
;
; This module contains the implementation for the fast NtGetTickCount service
;
;
; Author:
;
; Mark Lucovsky (markl) 19-Oct-1996
;
; Environment:
;
; Kernel mode.
;
; Revision History:
;
;
;--
.386p
; .xlist
include ks386.inc
include callconv.inc ; calling convention macros
; .list
extrn _KeTickCount:DWORD
extrn _ExpTickCountMultiplier:DWORD
_TEXT SEGMENT DWORD PUBLIC 'CODE'
ASSUME DS:FLAT, ES:FLAT, SS:NOTHING, FS:NOTHING, GS:NOTHING
page ,132
;++
;
; Routine Description:
;
; This function returns number of milliseconds since the system
; booted. This function is designed to support the Win32 GetTicKCount
; API.
;
; Arguments:
;
; NONE
;
; Return Value:
;
; Returns the number of milliseconds that have transpired since boot
;
;--
cPublicProc _NtGetTickCount, 0
cPublicFpo 0, 0
mov eax,dword ptr [_KeTickCount]
mul dword ptr [_ExpTickCountMultiplier]
shrd eax,edx,24 ; compute resultant tick count
stdRET _NtGetTickCount
stdENDP _NtGetTickCount
_TEXT ends
end