UefiCpuPkg: Move AsmRelocateApLoopStart from Mpfuncs.nasm to AmdSev.nasm

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

/** @file\r
  AsmCpuidEx function.\r
\r
  Copyright (c) 2006 - 2010, Intel Corporation. All rights reserved.<BR>\r
  SPDX-License-Identifier: BSD-2-Clause-Patent\r
\r
**/\r
\r
/**\r
  Retrieves CPUID information using an extended leaf identifier.\r
\r
  Executes the CPUID instruction with EAX set to the value specified by Index\r
  and ECX set to the value specified by SubIndex. This function always returns\r
  Index. This function is only available on IA-32 and x64.\r
\r
  If Eax is not NULL, then the value of EAX after CPUID is returned in Eax.\r
  If Ebx is not NULL, then the value of EBX after CPUID is returned in Ebx.\r
  If Ecx is not NULL, then the value of ECX after CPUID is returned in Ecx.\r
  If Edx is not NULL, then the value of EDX after CPUID is returned in Edx.\r
\r
  @param  Index         The 32-bit value to load into EAX prior to invoking the\r
                        CPUID instruction.\r
  @param  SubIndex      The 32-bit value to load into ECX prior to invoking the\r
                        CPUID instruction.\r
  @param  RegisterEax   A pointer to the 32-bit EAX value returned by the CPUID\r
                        instruction. This is an optional parameter that may be\r
                        NULL.\r
  @param  RegisterEbx   A pointer to the 32-bit EBX value returned by the CPUID\r
                        instruction. This is an optional parameter that may be\r
                        NULL.\r
  @param  RegisterEcx   A pointer to the 32-bit ECX value returned by the CPUID\r
                        instruction. This is an optional parameter that may be\r
                        NULL.\r
  @param  RegisterEdx   A pointer to the 32-bit EDX value returned by the CPUID\r
                        instruction. This is an optional parameter that may be\r
                        NULL.\r
\r
  @return Index.\r
\r
**/\r
UINT32\r
EFIAPI\r
AsmCpuidEx (\r
  IN      UINT32  Index,\r
  IN      UINT32  SubIndex,\r
  OUT     UINT32  *RegisterEax   OPTIONAL,\r
  OUT     UINT32  *RegisterEbx   OPTIONAL,\r
  OUT     UINT32  *RegisterEcx   OPTIONAL,\r
  OUT     UINT32  *RegisterEdx   OPTIONAL\r
  )\r
{\r
  _asm {\r
    mov     eax, Index\r
    mov     ecx, SubIndex\r
    cpuid\r
    push    ecx\r
    mov     ecx, RegisterEax\r
    jecxz   SkipEax\r
    mov     [ecx], eax\r
SkipEax:\r
    mov     ecx, RegisterEbx\r
    jecxz   SkipEbx\r
    mov     [ecx], ebx\r
SkipEbx:\r
    pop     eax\r
    mov     ecx, RegisterEcx\r
    jecxz   SkipEcx\r
    mov     [ecx], eax\r
SkipEcx:\r
    mov     ecx, RegisterEdx\r
    jecxz   SkipEdx\r
    mov     [ecx], edx\r
SkipEdx:\r
    mov     eax, Index\r
  }\r
}\r