audk/OldMdePkg/Library/BaseLib/Ia32/LShiftU64.c

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/** @file
64-bit left shift function for IA-32.
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.
**/
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?
cmovz eax, edx
cmovz edx, dword ptr [Operand + 4]
shld edx, eax, cl
shl eax, cl
}
}