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author | andrewfish <andrewfish@6f19259b-4bc3-4df7-8a09-765794883524> | 2010-07-22 19:22:34 +0000 |
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committer | andrewfish <andrewfish@6f19259b-4bc3-4df7-8a09-765794883524> | 2010-07-22 19:22:34 +0000 |
commit | 5fc3b5d6c8f3f23823069f060e8ffc8f80bccdf7 (patch) | |
tree | eea72342052d6a03beb207bc579884b008f531eb /UnixPkg/Library/UnixBaseLib/HighBitSet32.c | |
parent | 7119d96a6fdd28b2e215b20f97996193ca871a57 (diff) | |
download | edk2-5fc3b5d6c8f3f23823069f060e8ffc8f80bccdf7.zip edk2-5fc3b5d6c8f3f23823069f060e8ffc8f80bccdf7.tar.gz edk2-5fc3b5d6c8f3f23823069f060e8ffc8f80bccdf7.tar.bz2 |
Added to support X64 port (with SV5 ABI). May be able to remove after we port everything, but Sec, to EFI X64 ABI.
git-svn-id: https://edk2.svn.sourceforge.net/svnroot/edk2/trunk/edk2@10683 6f19259b-4bc3-4df7-8a09-765794883524
Diffstat (limited to 'UnixPkg/Library/UnixBaseLib/HighBitSet32.c')
-rw-r--r-- | UnixPkg/Library/UnixBaseLib/HighBitSet32.c | 47 |
1 files changed, 47 insertions, 0 deletions
diff --git a/UnixPkg/Library/UnixBaseLib/HighBitSet32.c b/UnixPkg/Library/UnixBaseLib/HighBitSet32.c new file mode 100644 index 0000000..8d055fe --- /dev/null +++ b/UnixPkg/Library/UnixBaseLib/HighBitSet32.c @@ -0,0 +1,47 @@ +/** @file
+ Math worker functions.
+
+ Copyright (c) 2006 - 2008, Intel Corporation. All rights reserved.<BR>
+ 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 highest bit set in a 32-bit value. Equivalent
+ to log2(x).
+
+ This function computes the bit position of the highest bit set in the 32-bit
+ value specified by Operand. If Operand is zero, then -1 is returned.
+ Otherwise, a value between 0 and 31 is returned.
+
+ @param Operand The 32-bit operand to evaluate.
+
+ @retval 0..31 Position of the highest bit set in Operand if found.
+ @retval -1 Operand is zero.
+
+**/
+INTN
+EFIAPI
+HighBitSet32 (
+ IN UINT32 Operand
+ )
+{
+ INTN BitIndex;
+
+ if (Operand == 0) {
+ return - 1;
+ }
+ for (BitIndex = 31; (INT32)Operand > 0; BitIndex--, Operand <<= 1);
+ return BitIndex;
+}
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