blob: 520511b7fe82b5a6fc3c895455e97cabdf2a01c6 (
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
|
/** @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 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;
}
|
