MdePkg/Library/BaseLib/Ia32/CpuId.c

   1 /** @file
   2   AsmCpuid function.
   3
   4   Copyright (c) 2006, Intel Corporation<BR>
   5   All rights reserved. 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 #if _MSC_EXTENSIONS
  16
  17 UINT32
  18 EFIAPI
  19 AsmCpuid (
  20   IN      UINT32                    Index,
  21   OUT     UINT32                    *RegisterEax,  OPTIONAL
  22   OUT     UINT32                    *RegisterEbx,  OPTIONAL
  23   OUT     UINT32                    *RegisterEcx,  OPTIONAL
  24   OUT     UINT32                    *RegisterEdx   OPTIONAL
  25   )
  26 {
  27   _asm {
  28     mov     eax, Index
  29     cpuid
  30     push    ecx
  31     mov     ecx, RegisterEax
  32     jecxz   SkipEax
  33     mov     [ecx], eax
  34 SkipEax:
  35     mov     ecx, RegisterEbx
  36     jecxz   SkipEbx
  37     mov     [ecx], ebx
  38 SkipEbx:
  39     pop     eax
  40     mov     ecx, RegisterEcx
  41     jecxz   SkipEcx
  42     mov     [ecx], eax
  43 SkipEcx:
  44     mov     ecx, RegisterEdx
  45     jecxz   SkipEdx
  46     mov     [ecx], edx
  47 SkipEdx:
  48     mov     eax, Index
  49   }
  50 }
  51
  52 #endif