VC6下编译进Ring0代码的疑惑

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VC6下编译进Ring0代码的疑惑,操作系统XPSP2,CPU:AMD3000+。现象，VC6总会优化代码，编译出来的代码不是想要的。

代码如下：

// tt.cpp : Defines the entry point for the application.
//

#include "stdafx.h"

#define _X86_

#include windows.h
#include stdio.h
#include aclapi.h
#include conio.h
#include windef.h
#include shellapi.h

typedef long NTSTATUS;
typedef unsigned short USHORT;
#define NT_SUCCESS(Status) ((NTSTATUS)(Status) = 0)
#define OBJ_INHERIT 0x00000002L
#define OBJ_PERMANENT 0x00000010L
#define OBJ_EXCLUSIVE 0x00000020L
#define OBJ_CASE_INSENSITIVE 0x00000040L
#define OBJ_OPENIF 0x00000080L
#define OBJ_OPENLINK 0x00000100L
#define OBJ_KERNEL_HANDLE 0x00000200L
#define OBJ_VALID_ATTRIBUTES 0x000003F2L

typedef struct _UNICODE_STRING {
 USHORT Length;
 USHORT MaximumLength;
 
#ifdef MIDL_PASS
 [size_is(MaximumLength / 2), length_is((Length) / 2) ] USHORT * Buffer;
#else // MIDL_PASS
 PWSTR Buffer;
#endif // MIDL_PASS
} UNICODE_STRING;

typedef UNICODE_STRING *PUNICODE_STRING;
typedef const UNICODE_STRING *PCUNICODE_STRING;
#define UNICODE_NULL ((WCHAR)0) // winnt

typedef struct _OBJECT_ATTRIBUTES {
 ULONG Length;
 HANDLE RootDirectory;
 PUNICODE_STRING ObjectName;
 ULONG Attributes;
 PVOID SecurityDescriptor; // Points to type SECURITY_DESCRIPTOR
 PVOID SecurityQualityOfService; // Points to type SECURITY_QUALITY_OF_SERVICE
} OBJECT_ATTRIBUTES;

typedef OBJECT_ATTRIBUTES *POBJECT_ATTRIBUTES;

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#define InitializeObjectAttributes( p, n, a, r, s ) {
 (p)-Length = sizeof( OBJECT_ATTRIBUTES );
 (p)-RootDirectory = r;
 (p)-Attributes = a;
 (p)-ObjectName = n;
 (p)-SecurityDescriptor = s;
 (p)-SecurityQualityOfService = NULL;
}

extern "C"
typedef VOID (*pRtlInitUnicodeString)( PUNICODE_STRING DestinationString,PCWSTR SourceString);

extern "C"
typedef NTSTATUS (*pZwOpenSection)(OUT PHANDLE SectionHandle,IN ACCESS_MASK DesiredAccess,IN POBJECT_ATTRIBUTES ObjectAttributes);

extern "C"
typedef NTSTATUS (*pZwClose)(IN HANDLE Handle);

static const HINSTANCE NTDLLHANDLE=(HINSTANCE)0x7c920000; //ntdll.dll加载的位置可以用GetModuleHandle获取

#define STATUS_SUCCESS ((NTSTATUS)0x00000000L) // ntsubauth
#define STATUS_ACCESS_DENIED ((NTSTATUS)0xC0000022L)
//#pragma comment(lib,"C:NTDDKlibfrei386tdll.lib")

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#define ENTERRING0 _asm pushad
 _asm pushf
_asm cli

#define LEAVERING0 _asm popf
 _asm popad
_asm retf

typedef struct gdtr {
 unsigned short Limit;
 unsigned short BaseLow;
 unsigned short BaseHigh;
} Gdtr_t, *PGdtr_t;

typedef struct {
 unsigned short offset_0_15;
 unsigned short selector;
 
 unsigned char param_count : 4;
 unsigned char some_bits : 4;
 
 unsigned char type : 4;
 unsigned char app_system : 1;
 unsigned char dpl : 2;
 unsigned char present : 1;
 
 unsigned short offset_16_31;
} CALLGATE_DESCRIPTOR;

void PrintWin32Error( DWORD ErrorCode )
{
 LPVOID lpMsgBuf;
 
 FormatMessage(FORMAT_MESSAGE_ALLOCATE_BUFFER | FORMAT_MESSAGE_FROM_SYSTEM, NULL, ErrorCode, MAKELANGID(LANG_NEUTRAL, SUBLANG_DEFAULT), (LPTSTR) &lpMsgBuf, 0, NULL);
 printf("%s", lpMsgBuf );
 LocalFree( lpMsgBuf );
}

ULONG MiniMmGetPhysicalAddress(ULONG virtualaddress)
{
 if(virtualaddress0x80000000||virtualaddress=0xA0000000)
  return 0;
 return virtualaddress&0x1FFFF000;
}

VOID SetPhyscialMemorySectionCanBeWrited(HANDLE hSection)
{
 PACL pDacl=NULL;
 PACL pNewDacl=NULL;
 PSECURITY_DESCRIPTOR pSD=NULL;
 DWORD dwRes;
 EXPLICIT_ACCESS ea;

 if(dwRes=GetSecurityInfo(hSection,SE_KERNEL_OBJECT,DACL_SECURITY_INFORMATION, NULL,NULL,&pDacl,NULL,&pSD) != ERROR_SUCCESS)
 {
  printf( "GetSecurityInfo Error %u", dwRes );
  goto CleanUp;
 }
 
 ZeroMemory(&ea, sizeof(EXPLICIT_ACCESS));
 ea.grfAccessPermissions = SECTION_MAP_WRITE;
 ea.grfAccessMode = GRANT_ACCESS;
 ea.grfInheritance= NO_INHERITANCE;
 ea.Trustee.TrusteeForm = TRUSTEE_IS_NAME;
 ea.Trustee.TrusteeType = TRUSTEE_IS_USER;
 ea.Trustee.ptstrName = "CURRENT_USER";
 
 if(dwRes=SetEntriesInAcl(1,&ea,pDacl,&pNewDacl)!=ERROR_SUCCESS)
 {
  printf( "SetEntriesInAcl %u", dwRes );
  goto CleanUp;
 }
 
 if(dwRes=SetSecurityInfo(hSection,SE_KERNEL_OBJECT,DACL_SECURITY_INFORMATION,NULL,NULL,pNewDacl,NULL)!=ERROR_SUCCESS)
 {
  printf("SetSecurityInfo %u",dwRes);
  goto CleanUp;
 }
 
CleanUp:
 
 if(pSD)
  LocalFree(pSD);
 if(pNewDacl)
  LocalFree(pSD);
}
#define RING0PROC void __declspec (naked)

BOOL ExecRing0Proc(ULONG Entry,ULONG seglen)
{
 Gdtr_t gdt;
 __asm sgdt gdt;
 
 ULONG mapAddr=MiniMmGetPhysicalAddress(gdt.BaseHigh16U|gdt.BaseLow);
 if(!mapAddr) return 0;
 
 HANDLE hSection=NULL;
 NTSTATUS status;
 OBJECT_ATTRIBUTES objectAttributes;
 UNICODE_STRING objName;
 CALLGATE_DESCRIPTOR *cg;
 
 status = STATUS_SUCCESS;
 
 pRtlInitUnicodeString RtlInitUnicodeString;
 pZwOpenSection ZwOpenSection;
 pZwClose ZwClose;
 
 RtlInitUnicodeString=(pRtlInitUnicodeString)GetProcAddress(NTDLLHANDLE,"RtlInitUnicodeString");
 ZwOpenSection=(pZwOpenSection)GetProcAddress(NTDLLHANDLE,"ZwOpenSection");
 ZwClose=(pZwClose)GetProcAddress(NTDLLHANDLE,"ZwClose");

 RtlInitUnicodeString(&objName,L"DevicePhysicalMemory");
 InitializeObjectAttributes(&objectAttributes, &objName, OBJ_CASE_INSENSITIVE | OBJ_KERNEL_HANDLE, NULL, (PSECURITY_DESCRIPTOR) NULL);
 status = ZwOpenSection(&hSection,SECTION_MAP_READ|SECTION_MAP_WRITE,&objectAttributes);
 
 //if(status == STATUS_ACCESS_DENIED) //这个地方就一直加强改写才行！
 {
  status = ZwOpenSection(&hSection,READ_CONTROL|WRITE_DAC,&objectAttributes);
  SetPhyscialMemorySectionCanBeWrited(hSection);
  ZwClose(hSection);
  status = ZwOpenSection(&hSection,SECTION_MAP_READ|SECTION_MAP_WRITE,&objectAttributes);
 }
 
 if(status != STATUS_SUCCESS)
 {
  printf("Error Open PhysicalMemory Section Object,Status:%08X",status);
  return 0;
 }
 
 PVOID BaseAddress;
 BaseAddress=MapViewOfFile(hSection,
  FILE_MAP_READ|FILE_MAP_WRITE,
  0,
  mapAddr, //low part
  (gdt.Limit+1));
 if(!BaseAddress)
 {
  printf("Error MapViewOfFile:");
  PrintWin32Error(GetLastError());
  return 0;
 }
 
 BOOL setcg=FALSE;
 
 for(cg=(CALLGATE_DESCRIPTOR *)((ULONG)BaseAddress+(gdt.Limit&0xFFF8));(ULONG)cg(ULONG)BaseAddress;cg--)
  if(cg-type == 0){
   cg-offset_0_15 = LOWORD(Entry);
   cg-selector = 8;
   cg-param_count = 0;
   cg-some_bits = 0;
   cg-type = 0xC; // 386 call gate
   cg-app_system = 0; // A system descriptor
   cg-dpl = 3; // Ring 3 code can call
   cg-present = 1;
   cg-offset_16_31 = HIWORD(Entry);
  
   setcg=TRUE;
   break;
  }
 
  if(!setcg){
   ZwClose(hSection);
   return 0;
  }
  char *msg=new char[1000];
  sprintf(msg,"BaseAddress=%xhSection=%xmapAddr=%x",BaseAddress,hSection,mapAddr);
  MessageBox(NULL,msg,NULL,NULL);
  delete [] msg;
  short farcall[3];
 
  farcall[2]=((short)((ULONG)cg-(ULONG)BaseAddress))|3; //Ring 3 callgate;
  if(!VirtualLock((PVOID)Entry,seglen))
  {
   printf("Error VirtualLock:");
   PrintWin32Error(GetLastError());
   return 0;
  }  SetThreadPriority(GetCurrentThread(),THREAD_PRIORITY_TIME_CRITICAL);
  Sleep(0);
 
  _asm call fword ptr [farcall];
 
  MessageBox(NULL,"com",NULL,NULL);
  SetThreadPriority(GetCurrentThread(),THREAD_PRIORITY_NORMAL);
 
  VirtualUnlock((PVOID)Entry,seglen);
 
  //Clear callgate
  *(ULONG *)cg=0;
  *((ULONG *)cg+1)=0;
  ZwClose(hSection);
  MessageBox(NULL,"com2",NULL,NULL);
  return TRUE;
}

struct _RING0DATA
{
 DWORD mcr0,mcr2,mcr3;
 unsigned short BaseMemory;
 unsigned short ExtendedMemory;
}r0Data;

RING0PROC Ring0Proc1()
{
 ENTERRING0;
 _asm {
  mov eax, cr0
   mov r0Data.mcr0, eax;
  mov eax, cr2
   mov r0Data.mcr2, eax;
  mov eax, cr3
   mov r0Data.mcr3, eax;
 }
 LEAVERING0;
}

RING0PROC Ring0Proc2()
{
 ENTERRING0;
 _outp( 0x70, 0x15 );
 
 _asm
 {
  mov ax,0
   in al,71h
   mov r0Data.BaseMemory,ax
 }
 
 _outp( 0x70, 0x16 );
 r0Data.BaseMemory += _inp(0x71) 8;
 _outp( 0x70, 0x17 );
 r0Data.ExtendedMemory = _inp( 0x71 );
 _outp( 0x70, 0x18 );
 r0Data.ExtendedMemory += _inp(0x71) 8;
 LEAVERING0;
}