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- Subject: AW: LUA_NUMBER -> Integer conversion bug
- From: Sebastian Rohde <rohde@...>
- Date: Mon, 13 Mar 2006 10:38:03 +0100
> Maybe. Maybe not. Do you use Direct3D/DirectX? If yes, then you
> are just shadowing the problem here and it will come back to
> haunt you elsewhere. Read:
> It should be noted that turning on D3DCREATE_FPU_PRESERVE
> reportedly has no detectable performance impact on modern CPUs.
I can see your point but I don't think that lua handles this problem
correctly. As soon as lua does "conversion tricks" that assume the
coprocessor to be in a specific state lua has to take care about being in
that state AND recovering the old state afterwards. This is what you expect
from DirectX and what DirectX is does using D3DCREATE_FPU_PRESERVE.
Everything that does an implicit assumption concerning the FPU state (which
I did not find noted in any doc yet?) has to be considered as a bug, imho.