mirror of https://github.com/acidanthera/audk.git
98 lines
3.1 KiB
C
98 lines
3.1 KiB
C
/** @file
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Provides calibrated delay and performance counter services.
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Copyright (c) 2006 - 2008, Intel Corporation
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All rights reserved. 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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#ifndef __TIMER_LIB__
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#define __TIMER_LIB__
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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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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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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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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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#endif
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