Moved the MdePkg to OldMdePkg so that new code in MdePkg does not break existing...

[mirror_edk2.git] / OldMdePkg / Library / BaseLib / HighBitSet64.c

diff --git a/OldMdePkg/Library/BaseLib/HighBitSet64.c b/OldMdePkg/Library/BaseLib/HighBitSet64.c
new file mode 100644 (file)
index 0000000..6b3c585
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+++ b/OldMdePkg/Library/BaseLib/HighBitSet64.c
@@ -0,0 +1,52 @@
+/** @file\r
+  Math worker functions.\r
+\r
+  Copyright (c) 2006, Intel Corporation<BR>\r
+  All rights reserved. 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
+\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
+#include "BaseLibInternals.h"\r
+\r
+/**\r
+  Returns the bit position of the highest bit set in a 64-bit value. Equivalent\r
+  to log2(x).\r
+\r
+  This function computes the bit position of the highest bit set in the 64-bit\r
+  value specified by Operand. If Operand is zero, then -1 is returned.\r
+  Otherwise, a value between 0 and 63 is returned.\r
+\r
+  @param  Operand The 64-bit operand to evaluate.\r
+\r
+  @return Position of the highest bit set in Operand if found.\r
+  @retval -1  Operand is zero.\r
+\r
+**/\r
+INTN\r
+EFIAPI\r
+HighBitSet64 (\r
+  IN      UINT64                    Operand\r
+  )\r
+{\r
+  if (Operand == (UINT32)Operand) {\r
+    //\r
+    // Operand is just a 32-bit integer\r
+    //\r
+    return HighBitSet32 ((UINT32)Operand);\r
+  }\r
+\r
+  //\r
+  // Operand is really a 64-bit integer\r
+  //\r
+  if (sizeof (UINTN) == sizeof (UINT32)) {\r
+    return HighBitSet32 (((UINT32*)&Operand)[1]) + 32;\r
+  } else {\r
+    return HighBitSet32 ((UINT32)RShiftU64 (Operand, 32)) + 32;\r
+  }\r
+}\r