[ros-dev] RE: [ion]
19742: - ImplementRtlPrefectMemoryNonTemporal.Patch
by Patrick Baggett<email@example.com> and myself.
w3seek at reactos.com
Wed Nov 30 11:44:00 CET 2005
Alex Ionescu wrote:
> If you have a "nop" by default, then your job is as follows:
> - Detect support for the instruction
> - If it's NOT supported, overwrite with ret.
> Additionnally, the default state of the function is to WORK, which
> fundamentally speaking is wrong because you're assuming that the
> advanced functionality exists, and then you're disabling it. Since
> you're trying to be safe, then the whole point is to protect from the
> potential BSOD.
> However, with a "ret" by default, you only overwrite with nop if the
> instruction IS supported. Apart from the design issue itself, I think
> the premise here is that more CPUs don't have the support for the
> function, then the ones that do.
That depends on whether the machine supports it or not, it's not a
general optimization. But you made it sound like one ;)
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