精确计算代码段执行时间

#include <cstdio>
#include <Windows.h>
#include <atlbase.h>
#include <Tlhelp32.h>
#include <time.h>
//...........
int WINAPI findString(int lpmem,int memsize,int lpString,int StringSize,int AddrList)//;  //
{
	int nRet=-1;
	__asm
	{
		pushad;
		mov edx,lpmem;
		add edx,memsize;
		sub edx,StringSize;
		mov edi,lpmem;
		mov esi,lpString;
		mov eax,[esi];
		mov ecx,[esi+4];
		mov ebx,AddrList;
LableBegin:
		cmp eax,[edi];
		jnz LableNext;
		cmp ecx,[edi+4];
		jnz LableNext;
		mov ecx,StringSize;
		push edi;
		repz cmpsb;
		pop edi;
		mov esi,lpString;
		mov ecx,[esi+4];
		jnz LableNext;
LableSave:
		mov ebx,edi;
		add ebx,4;
LableNext:
		inc edi;
		cmp edi,edx;
		jnz LableBegin;
LableRet:
		mov nRet,ebx;
		popad;
	}
	return nRet;
}
//>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
int SearchByteShuZu(byte * bForSearch,int ifLen, byte* bWaitSearch, int iwLen,int iFirstSearchPos)
{//int SearchByteShuZu(byte * bForSearch,int ifLen, byte* bWaitSearch, int iwLen,int iFirstSearchPos);//寻找字节集数组(待寻找的,待寻找的最大长度,要寻找的,要寻找的长度,起始寻找位置)  返回-1 为未找到 位置从0开始
	int iCurrentPos=0;//待搜索位置
	if (iFirstSearchPos>ifLen)//超过待搜索的长度
	{
		return -1;
	}
	if (iwLen>ifLen)//要搜索的长度比 待搜索的长度大 返回
	{
		return -1;
	}
	if (iwLen==0||ifLen==0)
	{
		return -1;//0 返回
	}
	//    bForSearch+=iFirstSearchPos;//设置起始搜索位置
	iCurrentPos+=iFirstSearchPos;//设置起始搜索位置
	bForSearch+=iCurrentPos;//设置指针 对应
	while(1)
	{
		while(*bForSearch!=*bWaitSearch)//找到第一个相同的
		{
			iCurrentPos+=1;//当前搜索位置前进1
			bForSearch+=1;//当前指针前进1
			if (iCurrentPos>ifLen)    //长度超过待搜索的整体长度返回
			{
				return -1;
			}
		}
		for (int i=0;i<iwLen;++i)//开始对比
		{
			if (*(bForSearch+i)!=*(bWaitSearch+i))
			{
				iCurrentPos+=1;//当前搜索位置前进1
				bForSearch+=1;//当前指针前进1
				//设置下指针前进1
				break;//找到一个不同的 跳出
			}
			if (i+1==iwLen)
			{
				return iCurrentPos;//找到列
			}
		}
	}
}
__int64 FileTimeToQuadWord(PFILETIME pft)
{
	return Int64ShllMod32(pft->dwHighDateTime,32)|pft->dwLowDateTime;
}
__int64 GetThreadRunTime()	//取线程当前占用cpu时间  单位:100ns(纳秒)
{
	FILETIME ftKernelTime,ftUserTime,ftDummy;
	GetThreadTimes(GetCurrentThread(),&ftDummy,&ftDummy,&ftKernelTime,&ftUserTime);
	return FileTimeToQuadWord(&ftKernelTime)+FileTimeToQuadWord(&ftUserTime);
}
char szFind[0x20000000];
int main()
{
	LPSTR szsea="45644564";
	
	__int64 qwStartTime=0,qwTime=0;
	qwStartTime=GetThreadRunTime();//setvalue
	srand(time(NULL));
	for (int i=0;i<sizeof(szFind)/sizeof(DWORD);i++)
	{
		((DWORD*)szFind)[i]=rand();
	}
	qwTime=GetThreadRunTime()-qwStartTime;
	printf("/r/nSetValue:%I64d*100ns  %dms/r/n",qwTime,qwTime/1000/10);
	qwStartTime=GetThreadRunTime();
	findString((int)szFind,sizeof(szFind),(int)szsea,8,0);
	qwTime=GetThreadRunTime()-qwStartTime;
	printf("/r/nfindString:%I64d*100ns  %dms/r/n",qwTime,qwTime/1000/10);
	qwStartTime=GetThreadRunTime();
	SearchByteShuZu((byte*)szFind,sizeof(szFind),(byte*)szsea,8,0);
	qwTime=GetThreadRunTime()-qwStartTime;
	printf("/r/nSearchByteShuZu:%I64d*100ns  %dms/r/n",qwTime,qwTime/1000/10);
	return 0;
}

int memfind(const char *mem, const char *str, int sizem, int sizes)   
{   
int   da,i,j;   
if (sizes == 0) da = strlen(str);   
else da = sizes;   
for (i = 0; i < sizem; i++)   
{   
for (j = 0; j < da; j ++)   
if (mem[i+j] != str[j]) break;   
if (j == da) return i;   
}   
return -1;   
}