Windows 32位和64位之间的代码差异

// Retrieve NT header from base address.
IMAGE_NT_HEADERS *GetNtHeaderFromBase( void *pBaseAddr )
{
 IMAGE_DOS_HEADER       *pDosHeader;
 IMAGE_NT_HEADERS       *pNtHeaders;

 pDosHeader = ((IMAGE_DOS_HEADER *)pBaseAddr);
 if(pDosHeader->e_magic != 0x5A4D)
  return NULL;

 pNtHeaders = ((IMAGE_NT_HEADERS *)((DWORD)pBaseAddr + pDosHeader->e_lfanew));
 if(pNtHeaders->Signature != 0x4550)
  return NULL;

 return ((pNtHeaders == NULL) ? NULL : pNtHeaders);
}


// This emulates GetProcAddress.
void *GetFuncAddr( DWORD pBaseAddr,char *lpszFuncName ) 
{
 IMAGE_NT_HEADERS       *pNtHeaders;
 IMAGE_DATA_DIRECTORY   *pDataDir;
 IMAGE_EXPORT_DIRECTORY *pExportDir;
 const char      **lpszNames;
 DWORD       *lpdwFuncs,dwIndex;

 pNtHeaders = GetNtHeaderFromBase((void *)pBaseAddr);
 if(pNtHeaders == NULL)
  return NULL;

 pDataDir = ((IMAGE_DATA_DIRECTORY *)(pNtHeaders->OptionalHeader.DataDirectory + IMAGE_DIRECTORY_ENTRY_EXPORT));
 if(pDataDir == NULL)
  return NULL;

 pExportDir = ((IMAGE_EXPORT_DIRECTORY *)(pBaseAddr + pDataDir->VirtualAddress));
 if(pExportDir == NULL)
  return NULL;

 lpdwFuncs  = ((DWORD *)(pBaseAddr + pExportDir->AddressOfFunctions));
 lpszNames  = ((const char **)(pBaseAddr + pExportDir->AddressOfNames));
 if(lpdwFuncs == NULL || lpszNames == NULL)
  return NULL;

 for(dwIndex = 0; dwIndex < pExportDir->NumberOfFunctions; dwIndex++)
 { 
  // decrypt funcname and get the address
  if(!cmpstr(((char *)(pBaseAddr + lpszNames[dwIndex])),lpszFuncName))
   return (void*)(pBaseAddr + lpdwFuncs[dwIndex]);
 }

 return NULL;
}

但是当我在Windows Vista x64上运行程序时,我遇到了访问冲突.我认为这是GetNtHeaderFromBase上的数字(在IMAGE_DOS_HEADER和IMAGE_NET_HEADER上传递的数字),但我无法找到任何关于它在x64位二进制文??件上可能是什么的引用.

任何人都知道我需要对此代码进行哪些更改才能使其在64位Windows下运行？
或者,一种更好的方法来实现类似于getprocaddress的函数,该函数适用于x32和x64？

感谢您的帮助和代码.

杰西.