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

[mirror_edk2.git] / OldMdePkg / Library / BaseLib / LowBitSet64.c

diff --git a/OldMdePkg/Library/BaseLib/LowBitSet64.c b/OldMdePkg/Library/BaseLib/LowBitSet64.c
new file mode 100644 (file)
index 0000000..a3e5ba0
--- /dev/null
+++ b/OldMdePkg/Library/BaseLib/LowBitSet64.c
@@ -0,0 +1,46 @@
+/** @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 lowest bit set in a 64-bit value.\r
+\r
+  This function computes the bit position of the lowest 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 lowest bit set in Operand if found.\r
+  @retval -1  Operand is zero.\r
+\r
+**/\r
+INTN\r
+EFIAPI\r
+LowBitSet64 (\r
+  IN      UINT64                    Operand\r
+  )\r
+{\r
+  INTN                              BitIndex;\r
+\r
+  if (Operand == 0) {\r
+    return -1;\r
+  }\r
+\r
+  for (BitIndex = 0;\r
+       (Operand & 1) == 0;\r
+       BitIndex++, Operand = RShiftU64 (Operand, 1));\r
+  return BitIndex;\r
+}\r