audk/MdePkg/Library/BaseLib/Ia32/ReadCr4.c

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/** @file
AsmReadCr4 function
Copyright (c) 2006 - 2008, 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.
**/
/**
Reads the current value of the Control Register 4 (CR4).
Reads and returns the current value of CR4. This function is only available
on IA-32 and x64. This returns a 32-bit value on IA-32 and a 64-bit value on
x64.
@return The value of the Control Register 4 (CR4).
**/
UINTN
EFIAPI
AsmReadCr4 (
VOID
)
{
__asm {
_emit 0x0f // mov eax, cr4
_emit 0x20
_emit 0xE0
}
}