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Functions
TimerLib.h File Reference

Functions

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

Detailed Description

Provides calibrated delay and performance counter services.

Copyright (c) 2006 - 2011, Intel Corporation. All rights reserved.
SPDX-License-Identifier: BSD-2-Clause-Patent

Function Documentation

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

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.
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.
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.
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.