diff options
| -rw-r--r-- | ArmPkg/Library/ArmArchTimerLib/ArmArchTimerLib.c | 51 |
1 files changed, 50 insertions, 1 deletions
diff --git a/ArmPkg/Library/ArmArchTimerLib/ArmArchTimerLib.c b/ArmPkg/Library/ArmArchTimerLib/ArmArchTimerLib.c index 4361905e14..1be90c515c 100644 --- a/ArmPkg/Library/ArmArchTimerLib/ArmArchTimerLib.c +++ b/ArmPkg/Library/ArmArchTimerLib/ArmArchTimerLib.c @@ -1,7 +1,7 @@ /** @file
Generic ARM implementation of TimerLib.h
- Copyright (c) 2011-2014, ARM Limited. All rights reserved.
+ Copyright (c) 2011-2016, ARM Limited. All rights reserved.
This program and the accompanying materials
are licensed and made available under the terms and conditions of the BSD License
@@ -242,3 +242,52 @@ GetPerformanceCounterProperties ( return (UINT64)ArmGenericTimerGetTimerFreq ();
}
+
+/**
+ 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 NanoSeconds;
+ UINT32 Remainder;
+ UINT32 TimerFreq;
+
+ TimerFreq = GetPlatformTimerFreq ();
+ //
+ // Ticks
+ // Time = --------- x 1,000,000,000
+ // Frequency
+ //
+ NanoSeconds = MultU64xN (
+ DivU64x32Remainder (
+ Ticks,
+ TimerFreq,
+ &Remainder),
+ 1000000000U
+ );
+
+ //
+ // Frequency < 0x100000000, so Remainder < 0x100000000, then (Remainder * 1,000,000,000)
+ // will not overflow 64-bit.
+ //
+ NanoSeconds += DivU64x32 (
+ MultU64xN (
+ (UINT64) Remainder,
+ 1000000000U),
+ TimerFreq
+ );
+
+ return NanoSeconds;
+}
|