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| author | vanjeff <vanjeff@6f19259b-4bc3-4df7-8a09-765794883524> | 2007-06-22 03:21:45 +0000 |
|---|---|---|
| committer | vanjeff <vanjeff@6f19259b-4bc3-4df7-8a09-765794883524> | 2007-06-22 03:21:45 +0000 |
| commit | e1f414b6a7d8a0424e0e01f655b09a4612b4d0e8 (patch) | |
| tree | 32d74f9463f0b5c6a28ff6aff73709219d437604 /MdePkg/Library/BaseLib/HighBitSet64.c | |
| parent | e053747a04ad7b8d71c7593b93e1575ba0057a91 (diff) | |
| download | edk2-platforms-e1f414b6a7d8a0424e0e01f655b09a4612b4d0e8.tar.xz | |
Import some basic libraries instances for Mde Packages.
git-svn-id: https://edk2.svn.sourceforge.net/svnroot/edk2/trunk/edk2@2704 6f19259b-4bc3-4df7-8a09-765794883524
Diffstat (limited to 'MdePkg/Library/BaseLib/HighBitSet64.c')
| -rw-r--r-- | MdePkg/Library/BaseLib/HighBitSet64.c | 57 |
1 files changed, 57 insertions, 0 deletions
diff --git a/MdePkg/Library/BaseLib/HighBitSet64.c b/MdePkg/Library/BaseLib/HighBitSet64.c new file mode 100644 index 0000000000..e9319877cb --- /dev/null +++ b/MdePkg/Library/BaseLib/HighBitSet64.c @@ -0,0 +1,57 @@ +/** @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 common header file for this module.
+//
+#include "CommonHeader.h"
+
+#include "BaseLibInternals.h"
+
+/**
+ Returns the bit position of the highest bit set in a 64-bit value. Equivalent
+ to log2(x).
+
+ This function computes the bit position of the highest 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 highest bit set in Operand if found.
+ @retval -1 Operand is zero.
+
+**/
+INTN
+EFIAPI
+HighBitSet64 (
+ IN UINT64 Operand
+ )
+{
+ if (Operand == (UINT32)Operand) {
+ //
+ // Operand is just a 32-bit integer
+ //
+ return HighBitSet32 ((UINT32)Operand);
+ }
+
+ //
+ // Operand is really a 64-bit integer
+ //
+ if (sizeof (UINTN) == sizeof (UINT32)) {
+ return HighBitSet32 (((UINT32*)&Operand)[1]) + 32;
+ } else {
+ return HighBitSet32 ((UINT32)RShiftU64 (Operand, 32)) + 32;
+ }
+}
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