基本算术的计算代价

来源：互联网发布：中国在非洲知乎编辑：程序博客网时间：2024/04/29 16:54

手头一时没找到相关指令周期的资料及相关算法，随便写了个程序测了一下，

实验结果为运行N次的代价：

1: int + int , time=12
1: int - int , time=11
1: int * int , time=13
1: int / int , time=48

1: int64 + int 64, time=24
1: int64 * int 64, time=109
1: int64 / int 64, time=162

1: double + double, time=87
1: double * double, time=99
1: double / double, time=173

----------------- 源代码 ---------------------------------------------

void main_test()
{
CTime tFrom, tTo;

#define TOTAL_TIME_CAL 614748

#define AA(a) X(a) X(a) X(a) X(a) X(a) X(a)X(a) X(a) X(a) X(a) X(a) X(a) X(a) X(a) X(a) X(a)
#define X(a)\a;a;a;a;a;a;a;a;a;a;a;a;a;a;a;a;a;a;a;a;a;a;a;a;a;a;a;a;a;a;a;a;a;a;a;a;a;a;a;a;a;a;a;a;a;a;a;a;\ a;a;a;a;a;a;a;a;a;a;a;a;a;a;a;a;a;a;a;a;a;a;a;a;a;a;a;a;a;a;a;a;a;a;a;a;a;a;a;a;a;a;a;a;a;a;a;a;\
a;a;a;a;a;a;a;a;a;a;a;a;a;a;a;a;a;a;a;a;a;a;a;a;a;a;a;a;a;a;a;a;a;a;a;a;a;a;a;a;a;a;a;a;a;a;a;a;\ a;a;a;a;a;a;a;a;a;a;a;a;a;a;a;a;a;a;a;a;a;a;a;a;a;a;a;a;a;a;a;a;a;a;a;a;a;a;a;a;a;a;a;a;a;a;a;a;\
a;a;a;a;a;a;a;a;a;a;a;a;a;a;a;a;a;a;a;a;a;a;a;a;a;a;a;a;a;a;a;a;a;a;a;a;a;a;a;a;a;a;a;a;a;a;a;a;\
a;a;a;a;a;a;a;a;a;a;a;a;a;a;a;a;a;a;a;a;a;a;a;a;a;a;a;a;a;a;a;a;a;a;a;a;a;a;a;a;a;a;a;a;a;a;a;a;\
a;a;a;a;a;a;a;a;a;a;a;a;a;a;a;a;a;a;a;a;a;a;a;a;a;a;a;a;a;a;a;a;a;a;a;a;a;a;a;a;a;a;a;a;a;a;a;a;\
a;a;a;a;a;a;a;a;a;a;a;a;a;a;a;a;a;a;a;a;a;a;a;a;a;a;a;a;a;a;a;a;a;a;a;a;a;a;a;a;a;a;a;a;a;a;a;a;\
a;a;a;a;a;a;a;a;a;a;a;a;a;a;a;a;a;a;a;a;a;a;a;a;a;a;a;a;a;a;a;a;a;a;a;a;a;a;a;a;a;a;a;a;a;a;a;a;\
a;a;a;a;a;a;a;a;a;a;a;a;a;a;a;a;a;a;a;a;a;a;a;a;a;a;a;a;a;a;a;a;a;a;a;a;a;a;a;a;a;a;a;a;a;a;a;a;\
a;a;a;a;a;a;a;a;a;a;a;a;a;a;a;a;a;a;a;a;a;a;a;a;a;a;a;a;a;a;a;a;a;a;a;a;a;a;a;a;a;a;a;a;a;a;a;a;\

int __i;
int i1,i2,i3;
__int64 ii1,ii2,ii3;
i1=9876543;i2=1234567;
ii1=98765432123;ii2=1234567;
int time_diff,time_diff1;

// ---- time to deduction------------------------------------------------------------------

tFrom = CTime::GetCurrentTime();
for(__i = 0; __i < TOTAL_TIME_CAL;__i++)
{
//do nothing here, maybe thecompiler can totally remove this loop-code for optimization.
}
tTo = CTime::GetCurrentTime();
time_diff1 = (int)((tTo -tFrom).GetTotalSeconds());
TRACE(" 1:time_wasted=%d \r\n", time_diff1);

// after using macro AA(), the consumption canbe thought as 0

//------------------------------------------------------------------------------------------

//time_diff1 = 0;

tFrom = CTime::GetCurrentTime();
for(__i = 0; __i < TOTAL_TIME_CAL;__i++)
{
AA(i3 = i1 + i2);
}
tTo = CTime::GetCurrentTime();
time_diff = (int)((tTo -tFrom).GetTotalSeconds());
TRACE(" 1: int + int , time=%d \r\n",time_diff-time_diff1);

tFrom = CTime::GetCurrentTime();
for(__i = 0; __i < TOTAL_TIME_CAL;__i++)
{
AA(i3 = i1 - i2);
}
tTo = CTime::GetCurrentTime();
time_diff = (int)((tTo -tFrom).GetTotalSeconds());
TRACE(" 1: int - int , time=%d \r\n",time_diff-time_diff1);

tFrom = CTime::GetCurrentTime();
for(__i = 0; __i < TOTAL_TIME_CAL;__i++)
{
AA(i3 = i1 * i2);
}
tTo = CTime::GetCurrentTime();
time_diff = (int)((tTo -tFrom).GetTotalSeconds());
TRACE(" 1: int * int , time=%d \r\n",time_diff-time_diff1);

tFrom = CTime::GetCurrentTime();
for(__i = 0; __i < TOTAL_TIME_CAL;__i++)
{
AA(i3 = i1 / i2);
}
tTo = CTime::GetCurrentTime();
time_diff = (int)((tTo -tFrom).GetTotalSeconds());
TRACE(" 1: int / int , time=%d \r\n",time_diff-time_diff1);

//----------------------------------------------------------------------------------------------
tFrom = CTime::GetCurrentTime();
for(__i = 0; __i < TOTAL_TIME_CAL;__i++)
{
AA(ii3 = ii1 + ii2);
}
tTo = CTime::GetCurrentTime();
time_diff = (int)((tTo -tFrom).GetTotalSeconds());
TRACE(" 1: int64 + int 64, time=%d \r\n",time_diff-time_diff1);

tFrom = CTime::GetCurrentTime();
for(__i = 0; __i < TOTAL_TIME_CAL;__i++)
{
AA(ii3 = ii1 * ii2);
}
tTo = CTime::GetCurrentTime();
time_diff = (int)((tTo -tFrom).GetTotalSeconds());
TRACE(" 1: int64 * int 64, time=%d \r\n",time_diff-time_diff1);

tFrom = CTime::GetCurrentTime();
for(__i = 0; __i < TOTAL_TIME_CAL;__i++)
{
AA(ii3 = ii1 / ii2);
}
tTo = CTime::GetCurrentTime();
time_diff = (int)((tTo -tFrom).GetTotalSeconds());
TRACE(" 1: int64 / int 64, time=%d \r\n",time_diff-time_diff1);

//---------------------------------------------------
double f1= 1234567.89123;
double f2= 3.789543434;
double f3;

tFrom = CTime::GetCurrentTime();
for(__i = 0; __i < TOTAL_TIME_CAL;__i++)
{
AA(f3 = f1 + f2);
}
tTo = CTime::GetCurrentTime();
time_diff = (int)((tTo -tFrom).GetTotalSeconds());
TRACE(" 1: double + double, time=%d \r\n",time_diff-time_diff1);

tFrom = CTime::GetCurrentTime();
for(__i = 0; __i < TOTAL_TIME_CAL;__i++)
{
AA(f3 = f1 * f2);
}
tTo = CTime::GetCurrentTime();
time_diff = (int)((tTo -tFrom).GetTotalSeconds());
TRACE(" 1: double * double, time=%d \r\n",time_diff-time_diff1);

tFrom = CTime::GetCurrentTime();
for(__i = 0; __i < TOTAL_TIME_CAL;__i++)
{
AA(f3 = f1 / f2);
}
tTo = CTime::GetCurrentTime();
time_diff = (int)((tTo -tFrom).GetTotalSeconds());
TRACE(" 1: double / double, time=%d \r\n",time_diff-time_diff1);
}

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