/** @file | |
64-bit left shift function for IA-32. | |
Copyright (c) 2006 - 2015, Intel Corporation. All rights reserved.<BR> | |
SPDX-License-Identifier: BSD-2-Clause-Patent | |
**/ | |
/** | |
Shifts a 64-bit integer left between 0 and 63 bits. The low bits | |
are filled with zeros. The shifted value is returned. | |
This function shifts the 64-bit value Operand to the left by Count bits. The | |
low Count bits are set to zero. The shifted value is returned. | |
@param Operand The 64-bit operand to shift left. | |
@param Count The number of bits to shift left. | |
@return Operand << Count | |
**/ | |
UINT64 | |
EFIAPI | |
InternalMathLShiftU64 ( | |
IN UINT64 Operand, | |
IN UINTN Count | |
) | |
{ | |
_asm { | |
mov cl, byte ptr [Count] | |
xor eax, eax | |
mov edx, dword ptr [Operand + 0] | |
test cl, 32 // Count >= 32? | |
jnz L0 | |
mov eax, edx | |
mov edx, dword ptr [Operand + 4] | |
L0: | |
shld edx, eax, cl | |
shl eax, cl | |
} | |
} |