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

45 lines
1.3 KiB
C

/** @file
AsmMwait 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.
**/
/**
Executes an MWAIT instruction.
Executes an MWAIT instruction with the register state specified by Eax and
Ecx. Returns Eax. This function is only available on IA-32 and x64.
@param RegisterEax The value to load into EAX or RAX before executing the MONITOR
instruction.
@param RegisterEcx The value to load into ECX or RCX before executing the MONITOR
instruction.
@return RegisterEax
**/
UINTN
EFIAPI
AsmMwait (
IN UINTN RegisterEax,
IN UINTN RegisterEcx
)
{
_asm {
mov eax, RegisterEax
mov ecx, RegisterEcx
_emit 0x0f // mwait
_emit 0x01
_emit 0xC9
}
}