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

[mirror_edk2.git] / MdePkg / Library / SecPeiDxeTimerLibCpu / IpfTimerLib.c

diff --git a/MdePkg/Library/SecPeiDxeTimerLibCpu/IpfTimerLib.c b/MdePkg/Library/SecPeiDxeTimerLibCpu/IpfTimerLib.c
index 06d5a3cebcba7d170c1becf3affe9910647a855f..714b99eec41431a6fca7fedfd29098df2d9d9346 100644 (file)
--- a/MdePkg/Library/SecPeiDxeTimerLibCpu/IpfTimerLib.c
+++ b/MdePkg/Library/SecPeiDxeTimerLibCpu/IpfTimerLib.c
@@ -1,7 +1,7 @@
 /** @file\r
   Timer Library functions built upon ITC on IPF.\r
 \r
-  Copyright (c) 2006 - 2008, Intel Corporation. All rights reserved.<BR>\r
+  Copyright (c) 2006 - 2011, Intel Corporation. All rights reserved.<BR>\r
   This program and the accompanying materials\r
   are licensed and made available under the terms and conditions of the BSD License\r
   which accompanies this distribution.  The full text of the license may be found at\r
@@ -170,3 +170,47 @@ GetPerformanceCounterProperties (
 \r
   return BaseFrequence * (PalRet.r11 >> 32) / (UINT32)PalRet.r11;\r
 }\r
+\r
+/**\r
+  Converts elapsed ticks of performance counter to time in nanoseconds.\r
+\r
+  This function converts the elapsed ticks of running performance counter to\r
+  time value in unit of nanoseconds.\r
+\r
+  @param  Ticks     The number of elapsed ticks of running performance counter.\r
+\r
+  @return The elapsed time in nanoseconds.\r
+\r
+**/\r
+UINT64\r
+EFIAPI\r
+GetTimeInNanoSecond (\r
+  IN      UINT64                     Ticks\r
+  )\r
+{\r
+  UINT64  Frequency;\r
+  UINT64  NanoSeconds;\r
+  UINT64  Remainder;\r
+  INTN    Shift;\r
+\r
+  Frequency = GetPerformanceCounterProperties (NULL, NULL);\r
+\r
+  //\r
+  //          Ticks\r
+  // Time = --------- x 1,000,000,000\r
+  //        Frequency\r
+  //\r
+  NanoSeconds = MultU64x32 (DivU64x64Remainder (Ticks, Frequency, &Remainder), 1000000000u);\r
+\r
+  //\r
+  // Ensure (Remainder * 1,000,000,000) will not overflow 64-bit.\r
+  // Since 2^29 < 1,000,000,000 = 0x3B9ACA00 < 2^30, Remainder should < 2^(64-30) = 2^34,\r
+  // i.e. highest bit set in Remainder should <= 33.\r
+  //\r
+  Shift = MAX (0, HighBitSet64 (Remainder) - 33);\r
+  Remainder = RShiftU64 (Remainder, (UINTN) Shift);\r
+  Frequency = RShiftU64 (Frequency, (UINTN) Shift);\r
+  NanoSeconds += DivU64x64Remainder (MultU64x32 (Remainder, 1000000000u), Frequency, NULL);\r
+\r
+  return NanoSeconds;\r
+}\r