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WereMole



Joined: 28 May 2016
Posts: 5
WereMole
What causes the WM_PAINT message to be repeated called in the OPELGL.ASM example?
Post 09 Oct 2016, 01:15
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revolution
When all else fails, read the source


Joined: 24 Aug 2004
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revolution
Because the update region is never validated Windows will continue to send WM_PAINT messages.
Post 09 Oct 2016, 03:01
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WereMole



Joined: 28 May 2016
Posts: 5
WereMole
Thank you. I did not understand the importance of the validation.

https://msdn.microsoft.com/en-us/library/windows/desktop/dd145213(v=vs.85).aspx

To verify this I modified the WIN64 > OPENGL example.

I added three lines. The code was:

proc WindowProc uses rbx rsi rdi, hwnd,wmsg,wparam,lparam
mov [hwnd],rcx
frame

now:

proc WindowProc uses rbx rsi rdi, hwnd,wmsg,wparam,lparam
mov [hwnd],rcx
mov [wmsg],rdx
mov [wparam],r8
mov [lparam],r9
frame

Then I changed the end of .wmpaint from:

jmp .finish

To:

mov rcx,[hwnd]
mov rdx,[wmsg]
mov r8,[lparam]
mov r9,[wparam]

jmp .defwndproc

The animation stopped.

Thanks again
Post 09 Oct 2016, 11:49
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ml64



Joined: 17 Jul 2020
Posts: 8
ml64
This trick doesn't work with MDI Child windows.
Are there any ways to force the WM_PAINT for MDI without using a timer?
Post 29 Apr 2021, 11:26
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bitRAKE



Joined: 21 Jul 2003
Posts: 3205
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bitRAKE
If not timer then separate thread, or main message loop. Could also forward message from parent?

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Post 29 Apr 2021, 21:31
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ml64



Joined: 17 Jul 2020
Posts: 8
ml64
bitRAKE wrote:
If not timer then separate thread, or main message loop. Could also forward message from parent?

Message from the Frame Window would be slower than the Main loop.
The Main Loop is the best way, thanks!
BTW, why not using RDTSC instead of GetTickCount()
Post 04 May 2021, 14:52
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revolution
When all else fails, read the source


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revolution
RDTSC is a variable speed timer of unknown frequency. It can slow down and speed up relative to real time.

Because of that RDTSC is unreliable for anything that needs regular timing intervals.
Post 04 May 2021, 15:16
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bitRAKE



Joined: 21 Jul 2003
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bitRAKE
Code:
mov rax,[dword 0x7FFE0008] ; use KUSER_SHARED_DATA.InterruptTime    
...is kind of universal across windows versions, used by MS software for timing, etc. It's a 100ns timer - give it a try.

(May the 4th be with you. Laughing )

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Post 04 May 2021, 15:43
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revolution
When all else fails, read the source


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revolution
bitRAKE wrote:
Code:
mov rax,[dword 0x7FFE0008] ; use KUSER_SHARED_DATA.InterruptTime    
...is kind of universal across windows versions, used by MS software for timing, etc. It's a 100ns timer - give it a try.)
Yeah, it is the same value used for all applications. But it isn't really a 100ns timer. It only has 100ns resolution. The update intervals are much longer, more like 10ms, or there abouts. But the update interval also depends upon the OS version. Some have a higher rate and other are lower. Generally the server versions like to use a longer update interval.

Test it in your own systems to see what their settings are.
Post 04 May 2021, 23:25
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bitRAKE



Joined: 21 Jul 2003
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bitRAKE
I thought someone wrote a nice app to display all the timers and their resolutions. Did a bit of a search and couldn't find it. Some days the internet feels like swiss cheese.

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Post 05 May 2021, 00:34
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DimonSoft



Joined: 03 Mar 2010
Posts: 937
Location: Belarus
DimonSoft
bitRAKE wrote:
Code:
mov rax,[dword 0x7FFE0008] ; use KUSER_SHARED_DATA.InterruptTime    
...is kind of universal across windows versions, used by MS software for timing, etc. It's a 100ns timer - give it a try.

For the sake of completeness. Is it documented anywhere? I mean, it’s well-known but it might be subject to change in the future if undocumented.
Post 05 May 2021, 07:24
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revolution
When all else fails, read the source


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Location: In your JS exploiting you and your system
revolution
No, these "tricks" are never documented.

Just use the normal APIs GetSystemTimeAsFileTime etc. They return the same value anyway.

I think some people assume the extra call-ret overhead will break the whole system, and decide to make their code fragile instead by reading from fixed "magic number" addresses.

Or maybe some people just like the idea of making code "clever". In a way it does look "cool", right? You have some obscure code that magically works, nothing could be cooler, right? If you want hacker cred then it might work out well. Razz
Post 05 May 2021, 12:08
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bitRAKE



Joined: 21 Jul 2003
Posts: 3205
Location: vpcmipstrm
bitRAKE
DimonSoft wrote:
bitRAKE wrote:
Code:
mov rax,[dword 0x7FFE0008] ; use KUSER_SHARED_DATA.InterruptTime    
...is kind of universal across windows versions, used by MS software for timing, etc. It's a 100ns timer - give it a try.

For the sake of completeness. Is it documented anywhere? I mean, it’s well-known but it might be subject to change in the future if undocumented.
Google: KUSER_SHARED_DATA site:microsoft.com
Or check the DDK.

For a verbose explanation of how it's changed over time:
https://www.geoffchappell.com/studies/windows/km/ntoskrnl/inc/api/ntexapi_x/kuser_shared_data/index.htm

Microsoft has documented structures through NDAs in the past in order to avoid litigation (unfair business practice of using KUSER_SHARED_DATA in their software). Some of these "protected trade secrets" have become more public over time.

As for the glorification of ignorance, I have very little to say about that:
Code:
if Elite_Hacker or Clever or Cool_Kid or Just_Sensible
  mov rax,[dword 0x7FFE0008]
else
  call [GetSystemTimeAsFileTime]
end if    
...some programmers never learn to branch.

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Post 06 May 2021, 01:12
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Tomasz Grysztar



Joined: 16 Jun 2003
Posts: 7889
Location: Kraków, Poland
Tomasz Grysztar
bitRAKE wrote:
As for the glorification of ignorance, I have very little to say about that: (...)
I use such API in fasm/fasmg* and I can run their PE versions even in non-Windows environments that provide the compatible functions, for example under DOS with HX extender. Following the universally known and supported API is very sensible when you expect to run the program in diverse environments.

I would say the difference is whether you code for Win32, or for NT 3.50+ kernel.
___
* Even worse, I use GetSystemTime and SystemTimeToFileTime, to get it to work on pre-Win2000 systems, even Win32s.
Post 06 May 2021, 06:43
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bitRAKE



Joined: 21 Jul 2003
Posts: 3205
Location: vpcmipstrm
bitRAKE
Even ReactOS has support for it:
https://github.com/mirror/reactos/blob/c6d2b35ffc91e09f50dfb214ea58237509329d6b/reactos/include/ndk/ketypes.h#L416

...and Wine has it, too.

Some replies should just be cut short, the later part of my previous reply added nothing to the discussion. It was not meant to imply that using the API is bad in any way.

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Post 06 May 2021, 10:08
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Furs



Joined: 04 Mar 2016
Posts: 1607
Furs
revolution wrote:
I think some people assume the extra call-ret overhead will break the whole system, and decide to make their code fragile instead by reading from fixed "magic number" addresses.
You also avoid importing the function...

Anyway, since this thing is used by MS code, it's probably safe/stable to use. If they changed it, then it would break those (already compiled) apps. And obviously Wine has to do it to support them.
Post 06 May 2021, 12:34
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Tomasz Grysztar



Joined: 16 Jun 2003
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Location: Kraków, Poland
Tomasz Grysztar
Apparently there also were some 32-bit applications using the int 2Ah to get the time, and Windows developers went the extra mile to keep supporting it in 32-bit kernel.
Post 06 May 2021, 12:59
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revolution
When all else fails, read the source


Joined: 24 Aug 2004
Posts: 18071
Location: In your JS exploiting you and your system
revolution
Furs wrote:
... it's probably safe/stable to use.
And using the published API is definitely safe to use.

Why all the hate for the API?
Post 06 May 2021, 13:37
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DimonSoft



Joined: 03 Mar 2010
Posts: 937
Location: Belarus
DimonSoft
revolution wrote:
Why all the hate for the API?

It usually stops when one encounters the case where they have to dig through their 5-years-old code that SUDDENLY!!!111 stopped working with next OS version. What could go wrong? Smile
Post 07 May 2021, 10:54
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