1 /** @file 2 AsmCpuidEx function. 3 4 Copyright (c) 2006 - 2010, 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 Retrieves CPUID information using an extended leaf identifier. 17 18 Executes the CPUID instruction with EAX set to the value specified by Index 19 and ECX set to the value specified by SubIndex. This function always returns 20 Index. This function is only available on IA-32 and x64. 21 22 If Eax is not NULL, then the value of EAX after CPUID is returned in Eax. 23 If Ebx is not NULL, then the value of EBX after CPUID is returned in Ebx. 24 If Ecx is not NULL, then the value of ECX after CPUID is returned in Ecx. 25 If Edx is not NULL, then the value of EDX after CPUID is returned in Edx. 26 27 @param Index The 32-bit value to load into EAX prior to invoking the 28 CPUID instruction. 29 @param SubIndex The 32-bit value to load into ECX prior to invoking the 30 CPUID instruction. 31 @param RegisterEax A pointer to the 32-bit EAX value returned by the CPUID 32 instruction. This is an optional parameter that may be 33 NULL. 34 @param RegisterEbx A pointer to the 32-bit EBX value returned by the CPUID 35 instruction. This is an optional parameter that may be 36 NULL. 37 @param RegisterEcx A pointer to the 32-bit ECX value returned by the CPUID 38 instruction. This is an optional parameter that may be 39 NULL. 40 @param RegisterEdx A pointer to the 32-bit EDX value returned by the CPUID 41 instruction. This is an optional parameter that may be 42 NULL. 43 44 @return Index. 45 46 **/ 47 UINT32 48 EFIAPI 49 AsmCpuidEx ( 50 IN UINT32 Index, 51 IN UINT32 SubIndex, 52 OUT UINT32 *RegisterEax, OPTIONAL 53 OUT UINT32 *RegisterEbx, OPTIONAL 54 OUT UINT32 *RegisterEcx, OPTIONAL 55 OUT UINT32 *RegisterEdx OPTIONAL 56 ) 57 { 58 _asm { 59 mov eax, Index 60 mov ecx, SubIndex 61 cpuid 62 push ecx 63 mov ecx, RegisterEax 64 jecxz SkipEax 65 mov [ecx], eax 66 SkipEax: 67 mov ecx, RegisterEbx 68 jecxz SkipEbx 69 mov [ecx], ebx 70 SkipEbx: 71 pop eax 72 mov ecx, RegisterEcx 73 jecxz SkipEcx 74 mov [ecx], eax 75 SkipEcx: 76 mov ecx, RegisterEdx 77 jecxz SkipEdx 78 mov [ecx], edx 79 SkipEdx: 80 mov eax, Index 81 } 82 } 83
