mirror of https://github.com/acidanthera/audk.git
267 lines
7.4 KiB
C
267 lines
7.4 KiB
C
/** @file
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Timer Library functions built upon local APIC on IA32/x64.
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This library uses the local APIC library so that it supports x2APIC mode.
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Copyright (c) 2010 - 2015, Intel Corporation. All rights reserved.<BR>
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This program and the accompanying materials
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are licensed and made available under the terms and conditions of the BSD License
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which accompanies this distribution. The full text of the license may be found at
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http://opensource.org/licenses/bsd-license.php.
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THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,
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WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
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**/
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#include <Base.h>
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#include <Library/TimerLib.h>
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#include <Library/BaseLib.h>
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#include <Library/PcdLib.h>
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#include <Library/DebugLib.h>
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#include <Library/LocalApicLib.h>
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/**
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Internal function to return the frequency of the local APIC timer.
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@return The frequency of the timer in Hz.
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**/
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UINT32
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EFIAPI
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InternalX86GetTimerFrequency (
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VOID
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)
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{
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UINTN Divisor;
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GetApicTimerState (&Divisor, NULL, NULL);
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return PcdGet32(PcdFSBClock) / (UINT32)Divisor;
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}
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/**
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Stalls the CPU for at least the given number of ticks.
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Stalls the CPU for at least the given number of ticks. It's invoked by
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MicroSecondDelay() and NanoSecondDelay().
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This function will ASSERT if the APIC timer intial count returned from
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GetApicTimerInitCount() is zero.
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@param Delay A period of time to delay in ticks.
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**/
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VOID
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EFIAPI
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InternalX86Delay (
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IN UINT32 Delay
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)
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{
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INT32 Ticks;
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UINT32 Times;
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UINT32 InitCount;
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UINT32 StartTick;
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//
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// In case Delay is too larger, separate it into several small delay slot.
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// Devided Delay by half value of Init Count is to avoid Delay close to
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// the Init Count, timeout maybe missing if the time consuming between 2
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// GetApicTimerCurrentCount() invoking is larger than the time gap between
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// Delay and the Init Count.
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//
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InitCount = GetApicTimerInitCount ();
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ASSERT (InitCount != 0);
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Times = Delay / (InitCount / 2);
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Delay = Delay % (InitCount / 2);
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//
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// Get Start Tick and do delay
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//
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StartTick = GetApicTimerCurrentCount ();
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do {
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//
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// Wait until time out by Delay value
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//
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do {
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CpuPause ();
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//
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// Get Ticks from Start to Current.
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//
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Ticks = StartTick - GetApicTimerCurrentCount ();
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//
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// Ticks < 0 means Timer wrap-arounds happens.
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//
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if (Ticks < 0) {
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Ticks += InitCount;
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}
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} while ((UINT32)Ticks < Delay);
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//
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// Update StartTick and Delay for next delay slot
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//
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StartTick -= (StartTick > Delay) ? Delay : (Delay - InitCount);
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Delay = InitCount / 2;
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} while (Times-- > 0);
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}
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/**
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Stalls the CPU for at least the given number of microseconds.
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Stalls the CPU for the number of microseconds specified by MicroSeconds.
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@param MicroSeconds The minimum number of microseconds to delay.
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@return The value of MicroSeconds inputted.
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**/
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UINTN
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EFIAPI
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MicroSecondDelay (
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IN UINTN MicroSeconds
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)
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{
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InternalX86Delay (
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(UINT32)DivU64x32 (
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MultU64x64 (
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InternalX86GetTimerFrequency (),
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MicroSeconds
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),
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1000000u
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)
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);
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return MicroSeconds;
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}
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/**
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Stalls the CPU for at least the given number of nanoseconds.
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Stalls the CPU for the number of nanoseconds specified by NanoSeconds.
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@param NanoSeconds The minimum number of nanoseconds to delay.
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@return The value of NanoSeconds inputted.
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**/
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UINTN
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EFIAPI
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NanoSecondDelay (
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IN UINTN NanoSeconds
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)
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{
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InternalX86Delay (
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(UINT32)DivU64x32 (
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MultU64x64 (
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InternalX86GetTimerFrequency (),
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NanoSeconds
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),
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1000000000u
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)
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);
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return NanoSeconds;
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}
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/**
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Retrieves the current value of a 64-bit free running performance counter.
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The counter can either count up by 1 or count down by 1. If the physical
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performance counter counts by a larger increment, then the counter values
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must be translated. The properties of the counter can be retrieved from
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GetPerformanceCounterProperties().
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@return The current value of the free running performance counter.
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**/
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UINT64
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EFIAPI
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GetPerformanceCounter (
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VOID
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)
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{
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return (UINT64)GetApicTimerCurrentCount ();
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}
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/**
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Retrieves the 64-bit frequency in Hz and the range of performance counter
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values.
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If StartValue is not NULL, then the value that the performance counter starts
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with immediately after is it rolls over is returned in StartValue. If
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EndValue is not NULL, then the value that the performance counter end with
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immediately before it rolls over is returned in EndValue. The 64-bit
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frequency of the performance counter in Hz is always returned. If StartValue
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is less than EndValue, then the performance counter counts up. If StartValue
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is greater than EndValue, then the performance counter counts down. For
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example, a 64-bit free running counter that counts up would have a StartValue
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of 0 and an EndValue of 0xFFFFFFFFFFFFFFFF. A 24-bit free running counter
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that counts down would have a StartValue of 0xFFFFFF and an EndValue of 0.
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@param StartValue The value the performance counter starts with when it
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rolls over.
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@param EndValue The value that the performance counter ends with before
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it rolls over.
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@return The frequency in Hz.
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**/
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UINT64
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EFIAPI
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GetPerformanceCounterProperties (
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OUT UINT64 *StartValue, OPTIONAL
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OUT UINT64 *EndValue OPTIONAL
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)
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{
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if (StartValue != NULL) {
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*StartValue = (UINT64)GetApicTimerInitCount ();
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}
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if (EndValue != NULL) {
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*EndValue = 0;
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}
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return (UINT64) InternalX86GetTimerFrequency ();
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}
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/**
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Converts elapsed ticks of performance counter to time in nanoseconds.
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This function converts the elapsed ticks of running performance counter to
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time value in unit of nanoseconds.
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@param Ticks The number of elapsed ticks of running performance counter.
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@return The elapsed time in nanoseconds.
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**/
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UINT64
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EFIAPI
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GetTimeInNanoSecond (
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IN UINT64 Ticks
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)
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{
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UINT64 Frequency;
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UINT64 NanoSeconds;
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UINT64 Remainder;
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INTN Shift;
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Frequency = GetPerformanceCounterProperties (NULL, NULL);
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//
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// Ticks
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// Time = --------- x 1,000,000,000
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// Frequency
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//
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NanoSeconds = MultU64x32 (DivU64x64Remainder (Ticks, Frequency, &Remainder), 1000000000u);
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//
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// Ensure (Remainder * 1,000,000,000) will not overflow 64-bit.
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// Since 2^29 < 1,000,000,000 = 0x3B9ACA00 < 2^30, Remainder should < 2^(64-30) = 2^34,
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// i.e. highest bit set in Remainder should <= 33.
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//
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Shift = MAX (0, HighBitSet64 (Remainder) - 33);
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Remainder = RShiftU64 (Remainder, (UINTN) Shift);
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Frequency = RShiftU64 (Frequency, (UINTN) Shift);
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NanoSeconds += DivU64x64Remainder (MultU64x32 (Remainder, 1000000000u), Frequency, NULL);
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return NanoSeconds;
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}
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