MdePkg/BaseLib: Support IA32 processors without CLFLUSH

[mirror_edk2.git] / MdePkg / Library / BaseLib / Ia32 / Monitor.c

/** @file\r
  AsmMonitor function\r
\r
  Copyright (c) 2006 - 2008, Intel Corporation. All rights reserved.<BR>\r
  This program and the accompanying materials\r
  are licensed and made available under the terms and conditions of the BSD License\r
  which accompanies this distribution.  The full text of the license may be found at\r
  http://opensource.org/licenses/bsd-license.php.\r
\r
  THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,\r
  WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.\r
\r
**/\r
\r
/**\r
  Sets up a monitor buffer that is used by AsmMwait().\r
\r
  Executes a MONITOR instruction with the register state specified by Eax, Ecx\r
  and Edx. Returns Eax. This function is only available on IA-32 and x64.\r
\r
  @param  RegisterEax The value to load into EAX or RAX before executing the MONITOR\r
                      instruction.\r
  @param  RegisterEcx The value to load into ECX or RCX before executing the MONITOR\r
                      instruction.\r
  @param  RegisterEdx The value to load into EDX or RDX before executing the MONITOR\r
                      instruction.\r
\r
  @return RegisterEax\r
\r
**/\r
UINTN\r
EFIAPI\r
AsmMonitor (\r
  IN      UINTN                     RegisterEax,\r
  IN      UINTN                     RegisterEcx,\r
  IN      UINTN                     RegisterEdx\r
  )\r
{\r
  _asm {\r
    mov     eax, RegisterEax\r
    mov     ecx, RegisterEcx\r
    mov     edx, RegisterEdx\r
    _emit   0x0f             // monitor\r
    _emit   0x01\r
    _emit   0xc8\r
  }\r
}\r
\r