audk/MdePkg/Library/BaseLib/Ia32/LRotU64.c

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/** @file
64-bit left rotation for Ia32
Copyright (c) 2006 - 2007, Intel Corporation<BR>
All rights reserved. This program and the accompanying materials
are licensed and made available under the terms and conditions of the BSD License
which accompanies this distribution. The full text of the license may be found at
http://opensource.org/licenses/bsd-license.php
THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,
WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
**/
/**
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?
cmovnz ecx, eax
cmovnz eax, edx
cmovnz edx, ecx
}
}