On Tue, 23 May 2000, Jamie Lokier wrote:
>
> That's what the GCC manual used to say. But then one day, they noticed
> that modern code sometimes has non-empty loops that can be optimised
> into empty loops.
Note that it is slightly different when you have sources that you can
test and fix after compiling, and when you have legacy binaries from 1981
that are supposed to run unchanged and that you really can't "fix" - if
they have an empty loop, they have an empty loop.
There's a ton of funky stuff we _could_ do if we wanted to implement the
x86 "right". Sadly, we have to be quite careful ;)
[ You _really_ don't want to know about taking page faults in the middle
of a task switch that is the result of a task gate being used to handle
another page fault, which in turn happened while we were loading the
second part of a page-crossing 32-bit word. Question: do you mark the
page table entry for the incomplete part that you already checked as
accessed or not? ]
Linus
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