使用 XState 內容
本檔包含範例，示範如何使用 XState 內容函式來擷取和設定線程上的擴充功能。 下列範例會操作 FeatureId 2 （Feature Mask 4） 所定義的 Intel 進階向量延伸模組 （AVX） 狀態。 Intel AVX 定義於 可從 https://go.microsoft.com/fwlink/p/?linkid=212716取得的「Intel 進階向量延伸程式設計參考」中。
Windows 7 SP1：AVX API 會先在 Windows 7 上實作 SP1。 由於沒有適用於 Windows 7 SP1 的 SDK，這表示沒有可用的標頭和連結庫檔案可供使用。 在此情況下，呼叫端必須從本檔宣告所需的函式，並使用 「Kernel32.dll」 上的 GetModuleHandle 取得這些函式的指標，然後呼叫 GetProcAddress。
#include <stdlib.h>
#include <stdio.h>
#include <tchar.h>
#include <windows.h>
#include <winerror.h>
// Windows 7 SP1 is the first version of Windows to support the AVX API.
// The value for CONTEXT_XSTATE has changed between Windows 7 and
// Windows 7 SP1 and greater.
// While the value will be correct for future SDK headers, we need to set
// this value manually when building with a Windows 7 SDK for running on
// Windows 7 SPI OS bits.
#undef CONTEXT_XSTATE
#if defined(_M_X64)
#define CONTEXT_XSTATE (0x00100040)
#else
#define CONTEXT_XSTATE (0x00010040)
#endif
// Since the AVX API is not declared in the Windows 7 SDK headers and
// since we don't have the proper libs to work with, we will declare
// the API as function pointers and get them with GetProcAddress calls
// from kernel32.dll. We also need to set some #defines.
#define XSTATE_AVX (XSTATE_GSSE)
#define XSTATE_MASK_AVX (XSTATE_MASK_GSSE)
typedef DWORD64 (WINAPI *PGETENABLEDXSTATEFEATURES)();
PGETENABLEDXSTATEFEATURES pfnGetEnabledXStateFeatures = NULL;
typedef BOOL (WINAPI *PINITIALIZECONTEXT)(PVOID Buffer, DWORD ContextFlags, PCONTEXT* Context, PDWORD ContextLength);
PINITIALIZECONTEXT pfnInitializeContext = NULL;
typedef BOOL (WINAPI *PGETXSTATEFEATURESMASK)(PCONTEXT Context, PDWORD64 FeatureMask);
PGETXSTATEFEATURESMASK pfnGetXStateFeaturesMask = NULL;
typedef PVOID (WINAPI *LOCATEXSTATEFEATURE)(PCONTEXT Context, DWORD FeatureId, PDWORD Length);
LOCATEXSTATEFEATURE pfnLocateXStateFeature = NULL;
typedef BOOL (WINAPI *SETXSTATEFEATURESMASK)(PCONTEXT Context, DWORD64 FeatureMask);
SETXSTATEFEATURESMASK pfnSetXStateFeaturesMask = NULL;
VOID
PrintThreadAvxState (
__in HANDLE hThread
)
{
PVOID Buffer;
PCONTEXT Context;
DWORD ContextSize;
DWORD64 FeatureMask;
DWORD FeatureLength;
ULONG Index;
BOOL Success;
PM128A Xmm;
PM128A Ymm;
// If this function was called before and we were not running on
// at least Windows 7 SP1, then bail.
if (pfnGetEnabledXStateFeatures == (PGETENABLEDXSTATEFEATURES)-1)
{
_tprintf(_T("This needs to run on Windows 7 SP1 or greater.\n"));
return;
}
// Get the addresses of the AVX XState functions.
if (pfnGetEnabledXStateFeatures == NULL)
{
HMODULE hm = GetModuleHandle(_T("kernel32.dll"));
if (hm == NULL)
{
pfnGetEnabledXStateFeatures = (PGETENABLEDXSTATEFEATURES)-1;
_tprintf(_T("GetModuleHandle failed (error == %d).\n"), GetLastError());
return;
}
pfnGetEnabledXStateFeatures = (PGETENABLEDXSTATEFEATURES)GetProcAddress(hm, "GetEnabledXStateFeatures");
pfnInitializeContext = (PINITIALIZECONTEXT)GetProcAddress(hm, "InitializeContext");
pfnGetXStateFeaturesMask = (PGETXSTATEFEATURESMASK)GetProcAddress(hm, "GetXStateFeaturesMask");
pfnLocateXStateFeature = (LOCATEXSTATEFEATURE)GetProcAddress(hm, "LocateXStateFeature");
pfnSetXStateFeaturesMask = (SETXSTATEFEATURESMASK)GetProcAddress(hm, "SetXStateFeaturesMask");
if (pfnGetEnabledXStateFeatures == NULL
|| pfnInitializeContext == NULL
|| pfnGetXStateFeaturesMask == NULL
|| pfnLocateXStateFeature == NULL
|| pfnSetXStateFeaturesMask == NULL)
{
pfnGetEnabledXStateFeatures = (PGETENABLEDXSTATEFEATURES)-1;
_tprintf(_T("This needs to run on Windows 7 SP1 or greater.\n"));
return;
}
}
FeatureMask = pfnGetEnabledXStateFeatures();
if ((FeatureMask & XSTATE_MASK_AVX) == 0)
{
_tprintf(_T("The AVX feature is not enabled.\n"));
return;
}
ContextSize = 0;
Success = pfnInitializeContext(NULL,
CONTEXT_ALL | CONTEXT_XSTATE,
NULL,
&ContextSize);
if ((Success == TRUE) || (GetLastError() != ERROR_INSUFFICIENT_BUFFER))
{
_tprintf(_T("Unexpected result from InitializeContext (success == %d, error == %d).\n"),
Success,
GetLastError());
}
Buffer = malloc(ContextSize);
if (Buffer == NULL)
{
_tprintf(_T("Out of memory.\n"));
return;
}
Success = pfnInitializeContext(Buffer,
CONTEXT_ALL | CONTEXT_XSTATE,
&Context,
&ContextSize);
if (Success == FALSE)
{
_tprintf(_T("InitializeContext failed (error == %d).\n"), GetLastError());
goto Cleanup;
}
Success = pfnSetXStateFeaturesMask(Context, XSTATE_MASK_AVX);
if (Success == FALSE)
{
_tprintf(_T("SetXStateFeaturesMask failed (error == %d).\n"), GetLastError());
goto Cleanup;
}
Success = GetThreadContext(hThread, Context);
// Note: Thread state may not be accurate. For best results, suspend
// the thread and use the CONTEXT_EXCEPTION_REQUEST flags prior to
// calling GetThreadContext.
if (Success == FALSE)
{
_tprintf(_T("GetThreadContext failed (error == %d).\n"), GetLastError());
goto Cleanup;
}
Success = pfnGetXStateFeaturesMask(Context, &FeatureMask);
if (Success == FALSE)
{
_tprintf(_T("GetXStateFeatureMask failed (error == %d).\n"), GetLastError());
goto Cleanup;
}
//
// The AVX feature consists of 8 (x86) or 16 (x64) 256-bit Ymm registers.
// The lower 128 bits share storage with the corresponding Xmm (SSE)
// registers and the high 128 bits are denoted by Ymm_H0 - Ymm_Hn.
//
if ((FeatureMask & XSTATE_MASK_AVX) == 0)
{
_tprintf(_T("AVX is in the INIT state (YMM_H registers are all zero).\n"));
goto Cleanup;
}
Xmm = (PM128A)pfnLocateXStateFeature(Context, XSTATE_LEGACY_SSE, &FeatureLength);
Ymm = (PM128A)pfnLocateXStateFeature(Context, XSTATE_AVX, NULL);
//
// Print values in the YMM registers.
//
for (Index = 0; Index < FeatureLength / sizeof(Xmm[0]); Index += 1)
{
_tprintf(_T("Ymm%d: %I64d %I64d %I64d %I64d\n"),
Index,
Xmm[Index].Low,
Xmm[Index].High,
Ymm[Index].Low,
Ymm[Index].High);
}
Cleanup:
free(Buffer);
return;
}
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