X-Git-Url: https://git.proxmox.com/?p=mirror_edk2.git;a=blobdiff_plain;f=OldMdePkg%2FLibrary%2FBaseLib%2FLowBitSet64.c;fp=OldMdePkg%2FLibrary%2FBaseLib%2FLowBitSet64.c;h=a3e5ba08422a01d90a8fb18177db3413523df8a7;hp=0000000000000000000000000000000000000000;hb=586cd1f1f4129ab7ec24543d4968801e17cc870b;hpb=144d783d40c8a02113350feabd1b9a55b692313f

diff --git a/OldMdePkg/Library/BaseLib/LowBitSet64.c b/OldMdePkg/Library/BaseLib/LowBitSet64.c
new file mode 100644
index 0000000000..a3e5ba0842
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+++ b/OldMdePkg/Library/BaseLib/LowBitSet64.c
@@ -0,0 +1,46 @@
+/** @file
+  Math worker functions.
+
+  Copyright (c) 2006, Intel Corporation<BR>
+  All rights reserved. This program and the accompanying materials
+  are licensed and made available under the terms and conditions of the BSD License
+  which accompanies this distribution.  The full text of the license may be found at
+  http://opensource.org/licenses/bsd-license.php
+
+  THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,
+  WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
+
+**/
+
+#include "BaseLibInternals.h"
+
+/**
+  Returns the bit position of the lowest bit set in a 64-bit value.
+
+  This function computes the bit position of the lowest bit set in the 64-bit
+  value specified by Operand. If Operand is zero, then -1 is returned.
+  Otherwise, a value between 0 and 63 is returned.
+
+  @param  Operand The 64-bit operand to evaluate.
+
+  @return Position of the lowest bit set in Operand if found.
+  @retval -1  Operand is zero.
+
+**/
+INTN
+EFIAPI
+LowBitSet64 (
+  IN      UINT64                    Operand
+  )
+{
+  INTN                              BitIndex;
+
+  if (Operand == 0) {
+    return -1;
+  }
+
+  for (BitIndex = 0;
+       (Operand & 1) == 0;
+       BitIndex++, Operand = RShiftU64 (Operand, 1));
+  return BitIndex;
+}