Horde3D

i tried to compile horde3d via cmake with gcc on windows, but the getTime() function of the Timer class



causes a crash in every application (for example the demos)

I have no idea what that assembler thing is doing, by commenting it out it works, but thats a dirty "solution" for that problem...

thanks, hs0

That asm instruction is used as a "serialization instruction". It guarantees that all instructions before which are still queued are finished before CPUID is executed. This should make sure that the timer query is at the right position in the program instruction stream and not somehow reordered. However, I am not sure if this serialization is really required.

On Windows/MSVC I would suggest using the intrinsic function _ReadWriteBarrier instead of an asm hack

These kinds of reordering instructions are generally only required for multi-core stuff. Seing Horde is a single-threaded library (at the moment?) we shouldn't need it (or the ThreadAffinity stuff either?)

***ignore me - I was thinking about another issue***

_________________
Tristam MacDonald - [swiftcoding]

The thread affinity is not directly related to threading in horde. Unfortunately, the whole windows performance timer is a bit messy. According to Microsoft (and many forum/blog posts), there was (is?) a bug in some systems where QueryPerformanceCounter returns different results when the application runs on different cores.

That serialization instruction was required for RDTSC to avoid out-of-order execution. Probably it is not required for QueryPerformanceCounter but some people still suggest using it. The reported crash could be related to some registers not being restored properly.

Honestly, I would like to get rid of these hacks. We could just try to do that and see on how many systems we get problems.

okay, since neither the bullet (physics library) timing code nor the glfw timer on windows include the affinity/cpuid stuff, i think it's relativly safe to drop it

kind regards,
hs0

nice, the problem is completly gone with gcc 4.4.1!
(I previously used gcc 3.4.5)