MdePkg/DxeRuntimeDebugLibSerialPort: Add new APIs

[mirror_edk2.git] / MdePkg / Library / BaseLib / GetPowerOfTwo64.c

diff --git a/MdePkg/Library/BaseLib/GetPowerOfTwo64.c b/MdePkg/Library/BaseLib/GetPowerOfTwo64.c
index 8372a7f1361594ff413134c574edb82d4c83d26e..3574bc4d3c8e5a4bb4416631bbbe11339047076b 100644 (file)
--- a/MdePkg/Library/BaseLib/GetPowerOfTwo64.c
+++ b/MdePkg/Library/BaseLib/GetPowerOfTwo64.c
@@ -1,22 +1,25 @@
 /** @file\r
   Math worker functions.\r
 \r
-  Copyright (c) 2006, Intel Corporation<BR>\r
-  All rights reserved. This program and the accompanying materials\r
+  Copyright (c) 2006 - 2010, 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
-  http://opensource.org/licenses/bsd-license.php\r
+  http://opensource.org/licenses/bsd-license.php.\r
 \r
   THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,\r
   WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.\r
 \r
 **/\r
 \r
+\r
+\r
+\r
 #include "BaseLibInternals.h"\r
 \r
 /**\r
   Returns the value of the highest bit set in a 64-bit value. Equivalent to\r
-  1 << HighBitSet64(x).\r
+  1 << log2(x).\r
 \r
   This function computes the value of the highest bit set in the 64-bit value\r
   specified by Operand. If Operand is zero, then zero is returned.\r
@@ -33,8 +36,9 @@ GetPowerOfTwo64 (
   IN      UINT64                    Operand\r
   )\r
 {\r
-  INTN                              BitPos;\r
+  if (Operand == 0) {\r
+    return 0;\r
+  }\r
 \r
-  BitPos = HighBitSet64 (Operand);\r
-  return BitPos >= 0 ? LShiftU64 (1, BitPos) : 0;\r
+  return LShiftU64 (1, (UINTN) HighBitSet64 (Operand));\r
 }\r