sravan/system76-edk2
1
0
Fork 0
Code Issues Pull Requests Packages Projects Releases Wiki Activity

Add new API GetTimeInNanoSecond() to TimerLib to convert elapsed ticks to time in unit of nanoseconds.

Browse Source 
Signed-off-by: xdu2
Reviewed-by: mdkinney

git-svn-id: https://edk2.svn.sourceforge.net/svnroot/edk2/trunk/edk2@12206 6f19259b-4bc3-4df7-8a09-765794883524
This commit is contained in:
xdu2
2011-08-25 05:59:17 +00:00
parent 6e5ed099af
commit b9610b9cb5
10 changed files with 382 additions and 8 deletions
Download Patch File Download Diff File Expand all files Collapse all files

46
MdePkg/Library/SecPeiDxeTimerLibCpu/X86TimerLib.c
View File

@@ -1,7 +1,7 @@
/** @file
Timer Library functions built upon local APIC on IA32/x64.
Copyright (c) 2006 - 2008, Intel Corporation. All rights reserved.<BR>
Copyright (c) 2006 - 2011, Intel Corporation. All rights reserved.<BR>
This program and the accompanying materials
are licensed and made available under the terms and conditions of the BSD License
which accompanies this distribution. The full text of the license may be found at
@@ -255,3 +255,47 @@ GetPerformanceCounterProperties (
return (UINT64) InternalX86GetTimerFrequency (ApicBase);
}
/**
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.
@param Ticks The number of elapsed ticks of running performance counter.
@return The elapsed time in nanoseconds.
**/
UINT64
EFIAPI
GetTimeInNanoSecond (
IN UINT64 Ticks
)
{
UINT64 Frequency;
UINT64 NanoSeconds;
UINT64 Remainder;
INTN Shift;
Frequency = GetPerformanceCounterProperties (NULL, NULL);
//
// Ticks
// Time = --------- x 1,000,000,000
// Frequency
//
NanoSeconds = MultU64x32 (DivU64x64Remainder (Ticks, Frequency, &Remainder), 1000000000u);
//
// Ensure (Remainder * 1,000,000,000) will not overflow 64-bit.
// Since 2^29 < 1,000,000,000 = 0x3B9ACA00 < 2^30, Remainder should < 2^(64-30) = 2^34,
// i.e. highest bit set in Remainder should <= 33.
//
Shift = MAX (0, HighBitSet64 (Remainder) - 33);
Remainder = RShiftU64 (Remainder, (UINTN) Shift);
Frequency = RShiftU64 (Frequency, (UINTN) Shift);
NanoSeconds += DivU64x64Remainder (MultU64x32 (Remainder, 1000000000u), Frequency, NULL);
return NanoSeconds;
}