CloverBootloader/MdePkg/Library/BaseLib/Ia32/LRotU64.c
2019-09-03 12:58:42 +03:00

50 lines
1.1 KiB
C

/** @file
64-bit left rotation for Ia32
Copyright (c) 2006 - 2015, Intel Corporation. All rights reserved.<BR>
SPDX-License-Identifier: BSD-2-Clause-Patent
**/
/**
Rotates a 64-bit integer left between 0 and 63 bits, filling
the low bits with the high bits that were rotated.
This function rotates the 64-bit value Operand to the left by Count bits. The
low Count bits are fill with the high Count bits of Operand. The rotated
value is returned.
@param Operand The 64-bit operand to rotate left.
@param Count The number of bits to rotate left.
@return Operand <<< Count
**/
UINT64
EFIAPI
InternalMathLRotU64 (
IN UINT64 Operand,
IN UINTN Count
)
{
_asm {
mov cl, byte ptr [Count]
mov edx, dword ptr [Operand + 4]
mov eax, dword ptr [Operand + 0]
shld ebx, edx, cl
shld edx, eax, cl
ror ebx, cl
shld eax, ebx, cl
test cl, 32 ; Count >= 32?
jz L0
mov ecx, eax
mov eax, edx
mov edx, ecx
L0:
}
}