blob: c1bc16c596999f0e0b23bf6c565e98461f79e29e (
plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
|
/** @file
Math worker functions.
Copyright (c) 2006 - 2008, Intel Corporation. All rights reserved.<BR>
SPDX-License-Identifier: BSD-2-Clause-Patent
**/
#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;
}
|
