Messages in this thread |  | | Subject | Re: Using %cr2 to reference "current" | Date | Tue, 6 Nov 2001 18:19:46 +0000 (GMT) | From | Alan Cox <> |
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> That said, how expensive is loading %cr2 anyway? We can do all the same > tricks with a 16kB stack and just playing games with using the higher bits > as the "offset", ie things like
So thats another 600K on my box vanished. I suspect the page faults will outweigh it
> the stack larger (we steal 2kB for the coloring, but we'd use an order-2 > allocation that at least SGI wants to do regardless).
16K stack is serious "people who cant program" country.
> I would not be surprised if "mov %cr2,%reg" will break a netburst trace > cache entity, or even cause microcode to be executed. While I _guarantee_ > that all future Intel CPU's will continue to be fast at mixtures of simple > arithmetic operations like "add" and "and".
True enough, but then we can go to
andl %%esp, %0 movl (%%eax), %%eax
which doesnt really change the cost much, lets us colour the task structs nicely, and lets us colour the stack somewhat by offseting esp from the base - and all in standard instructions
Alan
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