blob: 4f06dfc8835cee1274c4dec1c133b56eb070dc6c (
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
45
46
47
48
49
|
/** @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 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.
@retval 0..63 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;
}
}
|
