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
AsmCpuidEx(IN UINT32 Index,IN UINT32 SubIndex,OUT UINT32 * RegisterEax,OPTIONAL OUT UINT32 * RegisterEbx,OPTIONAL OUT UINT32 * RegisterEcx,OPTIONAL OUT UINT32 * RegisterEdx OPTIONAL)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