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

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

View File

@@ -274,3 +274,47 @@ GetPerformanceCounterProperties (
return mTscFrequency;
}
/**
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;
}

View File

@@ -263,3 +263,47 @@ GetPerformanceCounterProperties (
return InternalGetTscFrequency ();
}
/**
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;
}