1 /** @file
2 64-bit left shift function for IA-32.
3
4 Copyright (c) 2006 - 2015, Intel Corporation. All rights reserved.<BR>
5 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.
9
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.
12
13 **/
14
15
16
17
18 /**
19 Shifts a 64-bit integer left between 0 and 63 bits. The low bits
20 are filled with zeros. The shifted value is returned.
21
22 This function shifts the 64-bit value Operand to the left by Count bits. The
23 low Count bits are set to zero. The shifted value is returned.
24
25 @param Operand The 64-bit operand to shift left.
26 @param Count The number of bits to shift left.
27
28 @return Operand << Count
29
30 **/
31 UINT64
32 EFIAPI
InternalMathLShiftU64(IN UINT64 Operand,IN UINTN Count)33 InternalMathLShiftU64 (
34 IN UINT64 Operand,
35 IN UINTN Count
36 )
37 {
38 _asm {
39 mov cl, byte ptr [Count]
40 xor eax, eax
41 mov edx, dword ptr [Operand + 0]
42 test cl, 32 // Count >= 32?
43 jnz L0
44 mov eax, edx
45 mov edx, dword ptr [Operand + 4]
46 L0:
47 shld edx, eax, cl
48 shl eax, cl
49 }
50 }
51
52