"for loop" code in assembly language

Now I am doing benchmark testing on window 7. I think it is  32-bit target, right ?

I am using masm32

not necessarily. Win 7 can run on both 32 and 64 bit processors. You need to check your processor specs and then look at its instruction set and write the code accordingly

and gcc+ on window is also targeted for 32-bit, Right ?

How cl.exe from visual studio 2013, when I compile C++ program, it will target to 32 or 64 bit ?

So now , if I use g++ and masm32 for C and Aseembly code that will be fair to do th benchmark testing

Please advise

both program code are running for 32-bit with the same processor and same computer , why you concern the processor type ?

My systeminfo:

window7 64-bit
Intel(R) Pentium(R) CPU P6300 @ 2.27GHz 2.27GHz (dual core)

So, what is  assembly code on window 7 64-bit with Intel(R) Pentium(R) CPU P6300 @ 2.27GHz 2.27GHz (dual core)  for simulating the following C++ code ?
Actually I can get ASM code if  convert C++ code to ASM code with g++ option but it is not target  or it is same for the running time.

int main(){
int max = 2e8;
int a,b,c;
for (int i = 0; i < max; i++) {
    a = 1234 + 5678 + i;
    b = 1234 * 5678 + i;
	c=1234/2+i;
   }
return 0;
}

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In other words, any effiicient  ASM code is better than from C++ code converting to ASM code ?

Other question or thought:
If you can write the window 7 from ASM code instead of C++ , the window 7 will run 10x faster as Apple OS  but the man power resource required  for doing that is 10X expensive  more than C++ window 7 & or 8.1 since ASM coding line is in term of 10,000 unit

Phoffirce, thansk for your good rely. I review your post again, I am still not clear

Before talking about ASM code, my timing test for C++ code might be wrong and result is misleading. From your post, my timing  test for C++ code is  no meaning since C++ compiler think it is nothing to do within the for loop, so it run faster and it's misleading, right ?

When I compile it by gc++
g++ speed.cpp -o speed

Which is compiled in Release Mode, Right  ?

Could you describe more  about terminology of Debug or Release mode in C++ compiler respectively that I get a little bit confusing ? Any good aticles is about that topic ?

I tried to do change it from return 0 to return a/2 + b/3 + c*4 as you said but the result is same, it still output timing is 11ms from getmilliCOunt() function in C++

Please review my cpp code as follows,  I ran it at linux shell wiht "./speed"
Please advise

#ifndef STDIO_H
#include <stdio.h>
#define STDIO_H 
#endif
#include <iostream>
#include <sys/timeb.h>
using namespace std;
int getMilliCount(){
	timeb tb;
	ftime(&tb);
	int nCount = tb.millitm + (tb.time & 0xfffff) * 1000;
	return nCount;
}int getMilliSpan(int nTimeStart){
	int nSpan = getMilliCount() - nTimeStart;
	if(nSpan < 0)
		nSpan += 0x100000 * 1000;
	return nSpan;
}
int main(){
int max = 2e6;
int a,b,c;
	// CODE YOU WANT TO TIME
	int start = getMilliCount();
	for (int i = 0; i < max; i++) {
    a = 1234 + 5678 + i;
    b = 1234 * 5678 + i;
	c=1234/2+i;
   }
int milliSecondsElapsed = getMilliSpan(start);
printf("\n\nElapsed time = %u milliseconds %d\n", milliSecondsElapsed,max);
 return a/2 + b/3 + c*4;
}

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ozo, from your post, Now I get better understanding, compiler  C++ will do optimization  automatically so its code can run faster( than classic C Language that I need to prove it).  In Compile C++ optimization, compiler might treat the "for loop" is  nothing to be executed since it's nothing to do besides just variable adding and main() is nothing return beside "0", so the output code is just making  single simple code to call single memory copy for final  a,b,c variable  change with last i=2e6  since the "for loop" function is no other meaning code such as printf("a=%d",a) in "for loop" so that after C++ optimization, The following code is just optimized from taking out "for loop" which may NOT be same as the OP code(not opcode) from C++, but just idea if we have single printf() before return 0;

int main(){
int max = 2e8;
int a,b,c,i; i=max;
a = 1234 + 5678 + 2e8;b = 1234 * 5678 + 2e8;c=1234/2+2e8;
printf("%d=%d=%d\n",a,b,c);
return 0;
}

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it will run faster but it is not fair to compare the timing test  with ASM code.

This link describe gcc/g++ for  disable and enable optimization option and level
http://www.network-theory.co.uk/docs/gccintro/gccintro_49.html

Since I've  used the g++ not including -Ox flag so the compiled code result on the topic post is non-optimization, in other words, the for loop operation  is executed. For optimization option enabled, the "for loop" is NOT included.

The time result I get for the optimization and non-optimization on the  c++ program is recorded as follows on linux apache VPS server  and showed that optimization code run faster than normal one.

Variable(Max)  NON-Optimization  Optimization
===================================
2e6                             10ms                   4ms
2e8                             1105ms               560ms

Since the timing result on c++ program is changed largely from max=2e6 to 2e8 on the non-optimzation version, so it proved the for loop is running  and also check its  asm code  that looping code  is also included. how to get asm code from  g++ , the link  describes it at https://www3.ntu.edu.sg/home/ehchua/programming/cpp/gcc_make.html



Rwniceing

For timing analysis on different program language , it prefer to compare code without smart optimization from compiler . Efficient  code writing will improve the code speed but not too much to be improved. For the topic answer, I suggest to using g++ with non-optimization option and -S option to generate non-optimization ASM code, and based the ASM code and re-write the code and see there is any code improvement or not, and then do the timing comparison between new improving ASM code and C++ code that will be a fair timing test  since both different language has NO any smart optimization and NO skip-code or No skip-function optimization included.

Thanks for all of your reply. This will continue in new thread for asm language code improvement in code efficient writing.

Rwniceing

note that the compiler generated assembly code isn't the only way to code the logic. I can write out several variations of a set of assembly instructions which have the same final objective.

So just setting g++ to use the non-optimization option isn't going to work always.

What about using a different compiler with a different setting?

So in effect it comes down to the implementation of the compiler and in other words how the coder decides to write the assembly

Classical C is running faster than C++ on my topic post code that might not be interesting since I thought the root cause similar to as your first post in this thread. Small task use Small-size register or memory  to achieve output  faster than Small task use Big tools, big register or big memory.

My study example might be too small for timing benchmark of different language
which include, script, c, c++,c#,javascript, nodejs, php, asp, asm....etc

So I might need to choose other good example code

Your test code above is far too simple for useful measurements.  This page http://en.wikipedia.org/wiki/Benchmark_%28computing%29#Open_source_benchmarks list common benchmark programs that are actually used to measure CPU and computer performance.

>> Could you describe more  about terminology of Debug or Release mode in C++
   For Release mode, use -O2; Debug mode, use -g.

Here are results that shows that there are no loops executed when using -O2 when the function returns 0 and does not use the calculations in the loops. I am using nested loops.

Notice that I am now using the += operation. You can revert back to the = operation and may see surprising timing results (depending on your platform and compiler version).

#ifndef STDIO_H
#include <stdio.h>
#define STDIO_H 
#endif
#include <iostream>
#include <sys/timeb.h>
using namespace std;
int getMilliCount(){
   timeb tb;
   ftime(&tb);
   int nCount = tb.millitm + (tb.time & 0xfffff) * 1000;
   return nCount;
}int getMilliSpan(int nTimeStart){
   int nSpan = getMilliCount() - nTimeStart;
   if(nSpan < 0)
      nSpan += 0x100000 * 1000;
   return nSpan;
}

int foo(unsigned long long loopCnt) {
   unsigned int a=0,b=0,c=0;

   // CODE YOU WANT TO TIME
   int start = getMilliCount();
   for (unsigned long long i = 0; i < loopCnt; i++) {
      for(unsigned long long j = 0; j < loopCnt/4; j++) {
         a += 1234 + 5678 + i + j;
         b += 1234 * 5678 + i + j;
         c += 1234/2+i+j;
      }
   }
   int msElapsed = getMilliSpan(start);
   printf("Elapsed time = %4u ms    Loop Count = %.1e\n", msElapsed, (float)loopCnt);
   return 0;
//   return a + b + c;
}

int main(){
   unsigned int x, y, z=5;
   
   x = foo(2e3L);
   y = foo(2e4L);
   z = foo(2e5L);
   printf("%u %u %u\n", x, y, z);
}

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Following output is for return a+b+c case:
paulh@ubuntu:~/EE/Test$ rm a.out; g++ -O2 speed.cpp && ./a.out 
Elapsed time =    1 ms    Loop Count = 2.0e+03
Elapsed time =  145 ms    Loop Count = 2.0e+04
Elapsed time = 14404 ms    Loop Count = 2.0e+05
4246405632 2889473536 2998446080
paulh@ubuntu:~/EE/Test$ rm a.out; g++ -O speed.cpp && ./a.out 
Elapsed time =    2 ms    Loop Count = 2.0e+03
Elapsed time =  145 ms    Loop Count = 2.0e+04
Elapsed time = 14292 ms    Loop Count = 2.0e+05
4246405632 2889473536 2998446080

Following output is for "return 0" case:
paulh@ubuntu:~/EE/Test$ rm a.out; g++ -O2 speed.cpp && ./a.out 
Elapsed time =    0 ms    Loop Count = 2.0e+03
Elapsed time =    0 ms    Loop Count = 2.0e+04
Elapsed time =    0 ms    Loop Count = 2.0e+05
0 0 0
paulh@ubuntu:~/EE/Test$ rm a.out; g++ -O speed.cpp && ./a.out 
Elapsed time =    1 ms    Loop Count = 2.0e+03
Elapsed time =   98 ms    Loop Count = 2.0e+04
Elapsed time = 9532 ms    Loop Count = 2.0e+05
0 0 0

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phoffric, now I understood clearly what you said in your previous posts, thank for your reply.

For my memo :

This link describes  a tools for  performance benchmarking  for different  Game programs from using different languages on x86(1 or 4cores)  and  x64(one and 4 cores) processor at
http://benchmarksgame.alioth.debian.org/u32/which-programs-are-fastest.php