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X86TimerLib.c File Reference
#include <Base.h>
#include <Library/TimerLib.h>
#include <Library/BaseLib.h>
#include <Library/PcdLib.h>
#include <Library/DebugLib.h>
#include <Library/LocalApicLib.h>

Go to the source code of this file.

Functions

UINT32 EFIAPI InternalX86GetTimerFrequency (VOID)
 
VOID EFIAPI InternalX86Delay (IN UINT32 Delay)
 
UINTN EFIAPI MicroSecondDelay (IN UINTN MicroSeconds)
 
UINTN EFIAPI NanoSecondDelay (IN UINTN NanoSeconds)
 
UINT64 EFIAPI GetPerformanceCounter (VOID)
 
UINT64 EFIAPI GetPerformanceCounterProperties (OUT UINT64 *StartValue OPTIONAL, OUT UINT64 *EndValue OPTIONAL)
 
UINT64 EFIAPI GetTimeInNanoSecond (IN UINT64 Ticks)
 

Detailed Description

Timer Library functions built upon local APIC on IA32/x64.

This library uses the local APIC library so that it supports x2APIC mode.

Copyright (c) 2010 - 2018, Intel Corporation. All rights reserved.
SPDX-License-Identifier: BSD-2-Clause-Patent

Definition in file X86TimerLib.c.

Function Documentation

◆ GetPerformanceCounter()

UINT64 EFIAPI GetPerformanceCounter ( VOID  )

Retrieves the current value of a 64-bit free running performance counter.

The counter can either count up by 1 or count down by 1. If the physical performance counter counts by a larger increment, then the counter values must be translated. The properties of the counter can be retrieved from GetPerformanceCounterProperties().

Returns
The current value of the free running performance counter.

Definition at line 170 of file X86TimerLib.c.

◆ GetPerformanceCounterProperties()

UINT64 EFIAPI GetPerformanceCounterProperties ( OUT UINT64 *StartValue  OPTIONAL,
OUT UINT64 *EndValue  OPTIONAL 
)

Retrieves the 64-bit frequency in Hz and the range of performance counter values.

If StartValue is not NULL, then the value that the performance counter starts with immediately after is it rolls over is returned in StartValue. If EndValue is not NULL, then the value that the performance counter end with immediately before it rolls over is returned in EndValue. The 64-bit frequency of the performance counter in Hz is always returned. If StartValue is less than EndValue, then the performance counter counts up. If StartValue is greater than EndValue, then the performance counter counts down. For example, a 64-bit free running counter that counts up would have a StartValue of 0 and an EndValue of 0xFFFFFFFFFFFFFFFF. A 24-bit free running counter that counts down would have a StartValue of 0xFFFFFF and an EndValue of 0.

Parameters
StartValueThe value the performance counter starts with when it rolls over.
EndValueThe value that the performance counter ends with before it rolls over.
Returns
The frequency in Hz.

Definition at line 202 of file X86TimerLib.c.

◆ GetTimeInNanoSecond()

UINT64 EFIAPI GetTimeInNanoSecond ( IN UINT64  Ticks)

Converts elapsed ticks of performance counter to time in nanoseconds.

This function converts the elapsed ticks of running performance counter to time value in unit of nanoseconds.

Parameters
TicksThe number of elapsed ticks of running performance counter.
Returns
The elapsed time in nanoseconds.

Definition at line 231 of file X86TimerLib.c.

◆ InternalX86Delay()

VOID EFIAPI InternalX86Delay ( IN UINT32  Delay)

Stalls the CPU for at least the given number of ticks.

Stalls the CPU for at least the given number of ticks. It's invoked by MicroSecondDelay() and NanoSecondDelay().

This function will ASSERT if the APIC timer intial count returned from GetApicTimerInitCount() is zero.

Parameters
DelayA period of time to delay in ticks.

Definition at line 50 of file X86TimerLib.c.

◆ InternalX86GetTimerFrequency()

UINT32 EFIAPI InternalX86GetTimerFrequency ( VOID  )

Internal function to return the frequency of the local APIC timer.

Returns
The frequency of the timer in Hz.

Definition at line 26 of file X86TimerLib.c.

◆ MicroSecondDelay()

UINTN EFIAPI MicroSecondDelay ( IN UINTN  MicroSeconds)

Stalls the CPU for at least the given number of microseconds.

Stalls the CPU for the number of microseconds specified by MicroSeconds.

Parameters
MicroSecondsThe minimum number of microseconds to delay.
Returns
The value of MicroSeconds inputted.

Definition at line 113 of file X86TimerLib.c.

◆ NanoSecondDelay()

UINTN EFIAPI NanoSecondDelay ( IN UINTN  NanoSeconds)

Stalls the CPU for at least the given number of nanoseconds.

Stalls the CPU for the number of nanoseconds specified by NanoSeconds.

Parameters
NanoSecondsThe minimum number of nanoseconds to delay.
Returns
The value of NanoSeconds inputted.

Definition at line 141 of file X86TimerLib.c.