Programming Forums > Application Development > C++

Klarre · Nov 14th, 2005, 2:32 PM

I want to do a call to the win32 api function GetTickCount(). Sadly it crashes. So I got two questions to ask you:
1. Why does it crashes?
2. In which register do the function put its return value? eax?

(Toggle Plain Text)

#include <iostream>
#include <windows.h>

int main()
{
	_asm
	{
		call GetTickCount
	}

	system("pause");
	return 0;
}

Polyphemus_ · Nov 14th, 2005, 2:43 PM

1. Sorry, I don't know.

2. It stores its return value in eax.

Ooble · Nov 14th, 2005, 3:20 PM

Can I ask why you don't just call this in the C++ code?

(Toggle Plain Text)

int current_time = GetTickCount();

Is this for an assignment or something? If it is, please make a decent attempt at it yourself first. Oh, and a "please" or a "thanks for your time" always helps.

Klarre · Nov 14th, 2005, 3:45 PM

Quote:

Originally Posted by Ooble

Can I ask why you don't just call this in the C++ code?

(Toggle Plain Text)

int current_time = GetTickCount();

Is this for an assignment or something? If it is, please make a decent attempt at it yourself first. Oh, and a "please" or a "thanks for your time" always helps.

I shall ask your questions. If you have read in the assembly forum the last week you might have seen that I have been doing a lot of posts. This because I am working on an OpenGL application totally written in assembly code (to minimize file size, and for learning/fun). I do have bad debugging opportunities in my GL app, so I have been testing all my code in inline first. The next step in my project is to make a timer that calculates the delta time between each frame, and therefor I need a call to the GetTickCount function.

This is not an assignment. And I have been testing to solve the problem for a while now. But a strange thing is (that probably are not strange) that it worked great to call the function from my assembly app! To bad I can't see if it works...yet.

And oh! Thank you guys for taking time answearing my questions!

/Klarre

The Dark · Nov 14th, 2005, 5:25 PM

I had a look at the code generated by the C compiler when calling

(Toggle Plain Text)

GetTickCount();

and it seems you need to use

(Toggle Plain Text)

  _asm
  {
    call dword ptr GetTickCount
  }

and yes, the result is in EAX

Klarre · Nov 15th, 2005, 2:48 AM

Quote:

Originally Posted by The Dark

I had a look at the code generated by the C compiler when calling

(Toggle Plain Text)

GetTickCount();

and it seems you need to use

(Toggle Plain Text)

  _asm
  {
    call dword ptr GetTickCount
  }

and yes, the result is in EAX

Problem solved!
Thank you The Dark! It works great now!

Ooble · Nov 15th, 2005, 10:51 AM

Damn... gotta pay more attention to post count, I guess. Sorry 'bout that...

Nov 14th, 2005, 2:32 PM	#1
Klarre Game engine designer Join Date: May 2005 Location: Sweden Posts: 296 Rep Power: 4	[x86 inline]Register needs to be prepared? I want to do a call to the win32 api function GetTickCount(). Sadly it crashes. So I got two questions to ask you: 1. Why does it crashes? 2. In which register do the function put its return value? eax? (Toggle Plain Text) #include <iostream> #include <windows.h> int main() { _asm { call GetTickCount } system("pause"); return 0; } #include <iostream> #include <windows.h> int main() { _asm { call GetTickCount } system("pause"); return 0; }

Nov 14th, 2005, 3:20 PM	#3
Ooble I eat cake for breakfast. Join Date: Jul 2004 Location: In my box. Posts: 4,434 Rep Power: 9	Can I ask why you don't just call this in the C++ code? (Toggle Plain Text) int current_time = GetTickCount(); int current_time = GetTickCount(); Is this for an assignment or something? If it is, please make a decent attempt at it yourself first. Oh, and a "please" or a "thanks for your time" always helps. __________________ Me :: You :: Them

Nov 14th, 2005, 5:25 PM	#5
The Dark Expert Programmer Join Date: Jun 2005 Posts: 824 Rep Power: 4	I had a look at the code generated by the C compiler when calling (Toggle Plain Text) GetTickCount(); GetTickCount(); and it seems you need to use (Toggle Plain Text) _asm { call dword ptr GetTickCount } _asm { call dword ptr GetTickCount } and yes, the result is in EAX

Nov 15th, 2005, 10:51 AM	#7
Ooble I eat cake for breakfast. Join Date: Jul 2004 Location: In my box. Posts: 4,434 Rep Power: 9	Damn... gotta pay more attention to post count, I guess. Sorry 'bout that... __________________ Me :: You :: Them

Thread Tools
Show Printable Version Email this Page
Display Modes
Linear Mode Switch to Hybrid Mode Switch to Threaded Mode

Nov 14th, 2005, 2:43 PM	#2
Polyphemus_ Expert Programmer Join Date: Aug 2005 Location: Rotterdam, the Netherlands Posts: 942 Rep Power: 4	1. Sorry, I don't know. 2. It stores its return value in eax.

Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)

Programming Forums > Application Development > C++

[x86 inline]Register needs to be prepared?