1 /** @file
2 AsmMwait function
3
4 Copyright (c) 2006 - 2008, Intel Corporation. All rights reserved.<BR>
5 This program and the accompanying materials
6 are licensed and made available under the terms and conditions of the BSD License
7 which accompanies this distribution. The full text of the license may be found at
8 http://opensource.org/licenses/bsd-license.php.
9
10 THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,
11 WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
12
13 **/
14
15 /**
16 Executes an MWAIT instruction.
17
18 Executes an MWAIT instruction with the register state specified by Eax and
19 Ecx. Returns Eax. This function is only available on IA-32 and x64.
20
21 @param RegisterEax The value to load into EAX or RAX before executing the MONITOR
22 instruction.
23 @param RegisterEcx The value to load into ECX or RCX before executing the MONITOR
24 instruction.
25
26 @return RegisterEax
27
28 **/
29 UINTN
30 EFIAPI
AsmMwait(IN UINTN RegisterEax,IN UINTN RegisterEcx)31 AsmMwait (
32 IN UINTN RegisterEax,
33 IN UINTN RegisterEcx
34 )
35 {
36 _asm {
37 mov eax, RegisterEax
38 mov ecx, RegisterEcx
39 _emit 0x0f // mwait
40 _emit 0x01
41 _emit 0xC9
42 }
43 }
44
45