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git.proxmox.com Git - mirror_edk2.git/blob - MdePkg/Library/BaseLib/HighBitSet64.c
4 Copyright (c) 2006, Intel Corporation<BR>
5 All rights reserved. This program and the accompanying materials
6 are licensed and made available under the terms and conditions of the BSD License
7 which accompanies this distribution. The full text of the license may be found at
8 http://opensource.org/licenses/bsd-license.php
10 THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,
11 WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
16 // Include common header file for this module.
20 #include "BaseLibInternals.h"
23 Returns the bit position of the highest bit set in a 64-bit value. Equivalent
26 This function computes the bit position of the highest bit set in the 64-bit
27 value specified by Operand. If Operand is zero, then -1 is returned.
28 Otherwise, a value between 0 and 63 is returned.
30 @param Operand The 64-bit operand to evaluate.
32 @return Position of the highest bit set in Operand if found.
33 @retval -1 Operand is zero.
42 if (Operand
== (UINT32
)Operand
) {
44 // Operand is just a 32-bit integer
46 return HighBitSet32 ((UINT32
)Operand
);
50 // Operand is really a 64-bit integer
52 if (sizeof (UINTN
) == sizeof (UINT32
)) {
53 return HighBitSet32 (((UINT32
*)&Operand
)[1]) + 32;
55 return HighBitSet32 ((UINT32
)RShiftU64 (Operand
, 32)) + 32;