5fc3b5d6c8
git-svn-id: https://edk2.svn.sourceforge.net/svnroot/edk2/trunk/edk2@10683 6f19259b-4bc3-4df7-8a09-765794883524
51 lines
1.3 KiB
C
51 lines
1.3 KiB
C
/** @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 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.
|
|
|
|
@retval 0..63 The lowest bit set in Operand was 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;
|
|
}
|