Memory Management

[Luis Carlos Busquets Pérez]

Concerning the e-mail
http://www.winehq.org/pipermail/wine-devel/2010-April/082900.html

it seems that it is broken because in wine there is no way to ensure 
that the string will be in the lower 2GB. Actually, according to the 
Windows Memory Management model:

http://www.intellectualheaven.com/Articles/WinMM.pdf

only the 2 lower Gb are able to be used in user mode in Windows. So 
actually in Windows OS you have a way to ensure that all user things 
will be in the lower 2Gb. Is there something similar in WINE, If not, 
would it not be logical to replicate also that behaviour, so that then 
d3dxhandle can rely in the MSB? What is more, if there is not that way 
to ensure that, and I guess that the  d3dxx_xx.dll might rely on that to 
distinguish between strings and d3dxhandle, there might be cases even 
using the original d3dx, programmes would crash in wine when the wine 
implementation allocates strings in  memory positions where then MSB = 1.

[Dmitry Timoshkov]

Luis Carlos Busquets Pérez  wrote:
> Concerning the e-mail
> http://www.winehq.org/pipermail/wine-devel/2010-April/082900.html
>
> it seems that it is broken because in wine there is no way to ensure 
> that the string will be in the lower 2GB.

Wine behaviour depends on what application requests. You can't make
Wine implementation rely on something that could change from app to app.

[Stefan Dösinger]

Am 25.09.2010 um 05:32 schrieb Luis Carlos Busquets Pérez:
> Concerning the e-mail
> http://www.winehq.org/pipermail/wine-devel/2010-April/082900.html

If I remember correctly d3dx is broken by design in that regard. See D3DXCONSTTABLE_LARGEADDRESSAWARE in 
D3DXGetShaderConstantTableEx: http://msdn.microsoft.com/en-us/library/bb943959(v=VS.85).aspx

It seems that by default native makes the assumtion that there are no pointers with the highest bit set. If the app requests large address spaces via the flag in the .exe file it is supposed to pass D3DXCONSTTABLE_LARGEADDRESSAWARE to d3dx. Obviously there are apps that don't do that, like Eve Online.

Of course it'd be perfect if you can find a way that provides all the features native d3dx9 provides and doesn't rely on the address space layout. I think that the constant table functions are called often and are performance critical, so maybe this is all a nasty performance hack.